From e7db610849e73190dbfce8eea6eb60929174894f Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Wed, 13 May 2026 21:40:57 -0600
Subject: [PATCH 001/130] Add README family section template helpers

---
 packages/ast-template/src/index.ts            | 88 ++++++++++++++++++-
 .../test/session.integration.test.ts          | 50 +++++++++++
 2 files changed, 137 insertions(+), 1 deletion(-)

diff --git a/packages/ast-template/src/index.ts b/packages/ast-template/src/index.ts
index ff06f4f..75c32b1 100644
--- a/packages/ast-template/src/index.ts
+++ b/packages/ast-template/src/index.ts
@@ -11,7 +11,8 @@ import {
   DEFAULT_TEMPLATE_TOKEN_CONFIG,
   applyTemplateTreeExecutionToDirectory,
   planTemplateTreeExecutionFromDirectories,
-  reportTemplateDirectoryRunner
+  reportTemplateDirectoryRunner,
+  resolveTemplateTokens
 } from '@structuredmerge/ast-merge';
 import { mergeMarkdown } from '../../markdown-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
@@ -19,6 +20,91 @@ import { mergeToml } from '../../toml-merge/src/index';
 
 export const packageName = '@structuredmerge/ast-template';
 
+export const README_FAMILY_LANGUAGE_ORDER = ['go', 'ruby', 'rust', 'typescript'] as const;
+
+const README_FAMILY_LANGUAGE_LABELS: Readonly<Record<string, string>> = {
+  go: 'Go',
+  ruby: 'Ruby',
+  rust: 'Rust',
+  typescript: 'TypeScript'
+};
+
+function readmeFamilyLabel(language: string): string {
+  return README_FAMILY_LANGUAGE_LABELS[language] ?? language;
+}
+
+function stringField(value: unknown): string {
+  return typeof value === 'string' ? value : '';
+}
+
+function recordField(value: unknown): Readonly<Record<string, unknown>> {
+  return value && typeof value === 'object' && !Array.isArray(value)
+    ? (value as Readonly<Record<string, unknown>>)
+    : {};
+}
+
+export function readmeFamilyLanguageAliases(
+  selfLanguage: string,
+  languageOrder: readonly string[] = README_FAMILY_LANGUAGE_ORDER
+): Readonly<Record<string, string>> {
+  const aliases: Record<string, string> = {
+    SELF_LANG: readmeFamilyLabel(selfLanguage),
+    SELF_LANG_ID: selfLanguage
+  };
+  languageOrder
+    .filter((language) => language !== selfLanguage)
+    .forEach((language, index) => {
+      const prefix = `IMP_LANG${index + 1}`;
+      aliases[prefix] = readmeFamilyLabel(language);
+      aliases[`${prefix}_ID`] = language;
+    });
+
+  return aliases;
+}
+
+export function readmeFamilyTokenValues(
+  family: Readonly<Record<string, unknown>>
+): Readonly<Record<string, string>> {
+  const self = recordField(family.self);
+  const selfId = stringField(self.id);
+  const implementations = new Map<string, Readonly<Record<string, unknown>>>();
+  const rawImplementations = Array.isArray(family.implementations) ? family.implementations : [];
+  for (const rawImplementation of rawImplementations) {
+    const implementation = recordField(rawImplementation);
+    implementations.set(stringField(implementation.id), implementation);
+  }
+
+  const tokens: Record<string, string> = {
+    ...readmeFamilyLanguageAliases(selfId),
+    FAMILY_SECTION_HEADING: stringField(family.section_heading),
+    FAMILY_DESCRIPTION: stringField(family.description),
+    SELF_PACKAGE_ROOT: stringField(self.package_root),
+    SELF_PACKAGE_MANAGER: stringField(self.package_manager)
+  };
+
+  README_FAMILY_LANGUAGE_ORDER.filter((language) => language !== selfId).forEach((language, index) => {
+    const implementation = implementations.get(language) ?? {};
+    const prefix = `IMP_LANG${index + 1}`;
+    tokens[`${prefix}_PACKAGE_ROOT`] = stringField(implementation.package_root);
+    tokens[`${prefix}_PACKAGE_MANAGER`] = stringField(implementation.package_manager);
+  });
+
+  return tokens;
+}
+
+export function renderReadmeFamilySection(
+  templatePartial: string,
+  family: Readonly<Record<string, unknown>>,
+  config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
+): string {
+  const replacements: Record<string, string> = {};
+  for (const [key, value] of Object.entries(readmeFamilyTokenValues(family))) {
+    replacements[`SM|${key}`] = value;
+  }
+
+  return resolveTemplateTokens(templatePartial, replacements, config);
+}
+
 export type DirectorySessionMode = 'plan' | 'apply' | 'reapply';
 
 export interface TemplateDirectorySessionReport {
diff --git a/packages/ast-template/test/session.integration.test.ts b/packages/ast-template/test/session.integration.test.ts
index a6ac630..39dc7c2 100644
--- a/packages/ast-template/test/session.integration.test.ts
+++ b/packages/ast-template/test/session.integration.test.ts
@@ -74,6 +74,9 @@ import {
   reportDefaultAdapterCapabilitiesFromDirectories,
   importSessionInvocationEnvelope,
   reportTemplateDirectorySessionStatus,
+  readmeFamilyLanguageAliases,
+  readmeFamilyTokenValues,
+  renderReadmeFamilySection,
   reapplyTemplateDirectorySessionToDirectory,
   sessionCommandEnvelope,
   sessionCommandPayloadEnvelope,
@@ -96,6 +99,53 @@ interface SessionFixtureSection {
   expected: unknown;
 }
 
+interface ReadmeFamilySectionTemplateContractFixture {
+  canonical_language_order: string[];
+  alias_derivation_cases: Array<{
+    self: string;
+    expected_aliases: Record<string, string>;
+    expected_alternative_ids: string[];
+  }>;
+  metadata_case: {
+    family: Record<string, unknown>;
+    expected_token_values: Record<string, string>;
+  };
+  template_partial: string;
+  expected_rendered_partial: string;
+}
+
+describe('README family section template contract fixture', () => {
+  it('conforms to the shared fixture', () => {
+    const fixturePath = path.resolve(
+      process.cwd(),
+      '..',
+      'fixtures',
+      'diagnostics',
+      'slice-738-readme-family-section-template-contract',
+      'readme-family-section-template-contract.json'
+    );
+    const fixture = JSON.parse(readFileSync(fixturePath, 'utf8')) as ReadmeFamilySectionTemplateContractFixture;
+
+    for (const testCase of fixture.alias_derivation_cases) {
+      const aliases = readmeFamilyLanguageAliases(testCase.self, fixture.canonical_language_order);
+      for (const [key, expected] of Object.entries(testCase.expected_aliases)) {
+        expect(aliases[key]).toBe(expected);
+      }
+      expect([aliases.IMP_LANG1_ID, aliases.IMP_LANG2_ID, aliases.IMP_LANG3_ID]).toEqual(
+        testCase.expected_alternative_ids
+      );
+    }
+
+    const tokenValues = readmeFamilyTokenValues(fixture.metadata_case.family);
+    for (const [key, expected] of Object.entries(fixture.metadata_case.expected_token_values)) {
+      expect(tokenValues[key]).toBe(expected);
+    }
+    expect(renderReadmeFamilySection(fixture.template_partial, fixture.metadata_case.family)).toBe(
+      fixture.expected_rendered_partial
+    );
+  });
+});
+
 describe('template directory session report fixture', () => {
   it('conforms to the shared fixture', () => {
     const fixturePath = path.resolve(

From 12b0db91eb568c1b4b333c0ee79a4056be2d033c Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 00:00:14 -0600
Subject: [PATCH 002/130] Apply README family sections from ast-template

---
 packages/ast-template/src/index.ts            | 90 +++++++++++++++++++
 .../test/session.integration.test.ts          | 19 ++++
 2 files changed, 109 insertions(+)

diff --git a/packages/ast-template/src/index.ts b/packages/ast-template/src/index.ts
index 75c32b1..d1459ef 100644
--- a/packages/ast-template/src/index.ts
+++ b/packages/ast-template/src/index.ts
@@ -105,6 +105,96 @@ export function renderReadmeFamilySection(
   return resolveTemplateTokens(templatePartial, replacements, config);
 }
 
+export function applyReadmeFamilySection(
+  templatePartial: string,
+  packageMetadata: Readonly<Record<string, unknown>>,
+  family: Readonly<Record<string, unknown>>,
+  destinationContent: string | null,
+  config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
+): { content: string; changed: boolean } {
+  const renderedSection = renderReadmeFamilySection(templatePartial, family, config).replace(/\n+$/u, '');
+  const baseContent =
+    destinationContent ??
+    `# ${stringField(packageMetadata.name)}\n\n${stringField(packageMetadata.summary)}\n`;
+  const content = replaceOrInsertMarkdownHeadingSection(
+    baseContent,
+    stringField(family.section_heading),
+    2,
+    renderedSection
+  );
+
+  return { content, changed: content !== baseContent };
+}
+
+function replaceOrInsertMarkdownHeadingSection(
+  content: string,
+  headingText: string,
+  headingLevel: number,
+  replacement: string
+): string {
+  const normalized = content.replace(/\n+$/u, '');
+  if (normalized === '') {
+    return `${replacement}\n`;
+  }
+
+  const lines = normalized.split('\n');
+  const headingPrefix = `${'#'.repeat(headingLevel)} `;
+  const headingIndex = lines.findIndex((line) => line.trim() === `${headingPrefix}${headingText}`);
+  if (headingIndex >= 0) {
+    let end = lines.length;
+    for (let index = headingIndex + 1; index < lines.length; index += 1) {
+      const level = markdownHeadingLevel(lines[index]);
+      if (level > 0 && level <= headingLevel) {
+        end = index;
+        break;
+      }
+    }
+    const outputLines = [
+      ...lines.slice(0, headingIndex),
+      ...replacement.split('\n'),
+      ...(end < lines.length && lines[end] !== '' ? [''] : []),
+      ...lines.slice(end)
+    ];
+    return `${outputLines.join('\n')}\n`;
+  }
+
+  const insertAt = readmeFamilySectionInsertIndex(lines);
+  const outputLines = [
+    ...lines.slice(0, insertAt),
+    ...(insertAt > 0 && lines[insertAt - 1] !== '' ? [''] : []),
+    ...replacement.split('\n'),
+    ...(insertAt < lines.length && lines[insertAt] !== '' ? [''] : []),
+    ...lines.slice(insertAt)
+  ];
+  return `${outputLines.join('\n')}\n`;
+}
+
+function markdownHeadingLevel(line: string): number {
+  const trimmed = line.trim();
+  const match = /^(#{1,6})\s/u.exec(trimmed);
+  return match ? match[1].length : 0;
+}
+
+function readmeFamilySectionInsertIndex(lines: readonly string[]): number {
+  let index = 0;
+  if (markdownHeadingLevel(lines[0] ?? '') === 1) {
+    index = 1;
+    while (index < lines.length && lines[index] === '') {
+      index += 1;
+    }
+  }
+  while (index < lines.length) {
+    if (lines[index] === '') {
+      while (index < lines.length && lines[index] === '') {
+        index += 1;
+      }
+      return index;
+    }
+    index += 1;
+  }
+  return lines.length;
+}
+
 export type DirectorySessionMode = 'plan' | 'apply' | 'reapply';
 
 export interface TemplateDirectorySessionReport {
diff --git a/packages/ast-template/test/session.integration.test.ts b/packages/ast-template/test/session.integration.test.ts
index 39dc7c2..0cf2e23 100644
--- a/packages/ast-template/test/session.integration.test.ts
+++ b/packages/ast-template/test/session.integration.test.ts
@@ -74,6 +74,7 @@ import {
   reportDefaultAdapterCapabilitiesFromDirectories,
   importSessionInvocationEnvelope,
   reportTemplateDirectorySessionStatus,
+  applyReadmeFamilySection,
   readmeFamilyLanguageAliases,
   readmeFamilyTokenValues,
   renderReadmeFamilySection,
@@ -107,11 +108,18 @@ interface ReadmeFamilySectionTemplateContractFixture {
     expected_alternative_ids: string[];
   }>;
   metadata_case: {
+    package: Record<string, unknown>;
     family: Record<string, unknown>;
     expected_token_values: Record<string, string>;
   };
   template_partial: string;
   expected_rendered_partial: string;
+  readme_application_cases: Array<{
+    label: string;
+    destination_content: string | null;
+    expected_content: string;
+    changed: boolean;
+  }>;
 }
 
 describe('README family section template contract fixture', () => {
@@ -143,6 +151,17 @@ describe('README family section template contract fixture', () => {
     expect(renderReadmeFamilySection(fixture.template_partial, fixture.metadata_case.family)).toBe(
       fixture.expected_rendered_partial
     );
+
+    for (const testCase of fixture.readme_application_cases) {
+      const actual = applyReadmeFamilySection(
+        fixture.template_partial,
+        fixture.metadata_case.package,
+        fixture.metadata_case.family,
+        testCase.destination_content
+      );
+      expect(actual.content).toBe(testCase.expected_content);
+      expect(actual.changed).toBe(testCase.changed);
+    }
   });
 });
 

From 2f20eb0daff1f0412201ad23b8ad797d7a939282 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 00:39:43 -0600
Subject: [PATCH 003/130] Sync README family sections across packages

---
 packages/ast-template/src/index.ts            | 76 +++++++++++++++++++
 .../test/session.integration.test.ts          | 41 +++++++++-
 2 files changed, 116 insertions(+), 1 deletion(-)

diff --git a/packages/ast-template/src/index.ts b/packages/ast-template/src/index.ts
index d1459ef..da40e9c 100644
--- a/packages/ast-template/src/index.ts
+++ b/packages/ast-template/src/index.ts
@@ -7,6 +7,8 @@ import type {
   TemplateTokenConfig,
   TemplateTreeRunResult
 } from '@structuredmerge/ast-merge';
+import { mkdirSync, readFileSync, writeFileSync } from 'node:fs';
+import path from 'node:path';
 import {
   DEFAULT_TEMPLATE_TOKEN_CONFIG,
   applyTemplateTreeExecutionToDirectory,
@@ -126,6 +128,80 @@ export function applyReadmeFamilySection(
   return { content, changed: content !== baseContent };
 }
 
+export interface ReadmeFamilyPackage {
+  id: string;
+  readme_path: string;
+  package: Readonly<Record<string, unknown>>;
+  family: Readonly<Record<string, unknown>>;
+}
+
+export interface ReadmeFamilyPackageReportEntry {
+  id: string;
+  readme_path: string;
+  changed: boolean;
+  created: boolean;
+}
+
+export interface ReadmeFamilyPackageReport {
+  package_count: number;
+  changed_count: number;
+  created_count: number;
+  entries: ReadmeFamilyPackageReportEntry[];
+}
+
+export function applyReadmeFamilySectionsToPackageDirectories(
+  root: string,
+  templatePartial: string,
+  packages: readonly ReadmeFamilyPackage[],
+  config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
+): ReadmeFamilyPackageReport {
+  const report: ReadmeFamilyPackageReport = {
+    package_count: packages.length,
+    changed_count: 0,
+    created_count: 0,
+    entries: []
+  };
+
+  for (const packageEntry of packages) {
+    const readmePath = path.join(root, ...packageEntry.readme_path.split('/'));
+    let destinationContent: string | null = null;
+    let created = false;
+    try {
+      destinationContent = readFileSync(readmePath, 'utf8');
+    } catch (error) {
+      if ((error as NodeJS.ErrnoException).code === 'ENOENT') {
+        created = true;
+      } else {
+        throw error;
+      }
+    }
+
+    const application = applyReadmeFamilySection(
+      templatePartial,
+      packageEntry.package,
+      packageEntry.family,
+      destinationContent,
+      config
+    );
+    if (application.changed) {
+      mkdirSync(path.dirname(readmePath), { recursive: true });
+      writeFileSync(readmePath, application.content);
+      report.changed_count += 1;
+      if (created) {
+        report.created_count += 1;
+      }
+    }
+    report.entries.push({
+      id: packageEntry.id,
+      readme_path: packageEntry.readme_path,
+      changed: application.changed,
+      created: created && application.changed
+    });
+  }
+
+  return report;
+}
+
 function replaceOrInsertMarkdownHeadingSection(
   content: string,
   headingText: string,
diff --git a/packages/ast-template/test/session.integration.test.ts b/packages/ast-template/test/session.integration.test.ts
index 0cf2e23..cce8725 100644
--- a/packages/ast-template/test/session.integration.test.ts
+++ b/packages/ast-template/test/session.integration.test.ts
@@ -1,6 +1,6 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
 
-import { mkdirSync, readFileSync, rmSync } from 'node:fs';
+import { mkdirSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import path from 'node:path';
 import { describe, expect, it } from 'vitest';
 import type {
@@ -75,6 +75,7 @@ import {
   importSessionInvocationEnvelope,
   reportTemplateDirectorySessionStatus,
   applyReadmeFamilySection,
+  applyReadmeFamilySectionsToPackageDirectories,
   readmeFamilyLanguageAliases,
   readmeFamilyTokenValues,
   renderReadmeFamilySection,
@@ -120,6 +121,17 @@ interface ReadmeFamilySectionTemplateContractFixture {
     expected_content: string;
     changed: boolean;
   }>;
+  package_directory_case: {
+    packages: Array<{
+      id: string;
+      readme_path: string;
+      package: Record<string, unknown>;
+      family: Record<string, unknown>;
+      initial_content: string | null;
+      expected_content: string;
+    }>;
+    expected_report: unknown;
+  };
 }
 
 describe('README family section template contract fixture', () => {
@@ -162,6 +174,33 @@ describe('README family section template contract fixture', () => {
       expect(actual.content).toBe(testCase.expected_content);
       expect(actual.changed).toBe(testCase.changed);
     }
+
+    const tempRoot = path.resolve(
+      process.cwd(),
+      'packages',
+      'ast-template',
+      'tmp',
+      'readme-family-packages'
+    );
+    rmSync(tempRoot, { recursive: true, force: true });
+    for (const packageCase of fixture.package_directory_case.packages) {
+      if (packageCase.initial_content !== null) {
+        const readmePath = path.join(tempRoot, ...packageCase.readme_path.split('/'));
+        mkdirSync(path.dirname(readmePath), { recursive: true });
+        writeFileSync(readmePath, packageCase.initial_content);
+      }
+    }
+    const report = applyReadmeFamilySectionsToPackageDirectories(
+      tempRoot,
+      fixture.template_partial,
+      fixture.package_directory_case.packages
+    );
+    expect(report).toEqual(fixture.package_directory_case.expected_report);
+    for (const packageCase of fixture.package_directory_case.packages) {
+      const readmePath = path.join(tempRoot, ...packageCase.readme_path.split('/'));
+      expect(readFileSync(readmePath, 'utf8')).toBe(packageCase.expected_content);
+    }
+    rmSync(tempRoot, { recursive: true, force: true });
   });
 });
 

From 52abe27ba7aace5618343830a24bd63a2b5d63c9 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 02:52:09 -0600
Subject: [PATCH 004/130] Add TypeScript README style generation

---
 packages/kettle-nodule/src/index.ts           | 359 ++++++++++++++++++
 .../kettle-nodule/test/thin-slice.test.ts     | 141 ++++++-
 2 files changed, 499 insertions(+), 1 deletion(-)

diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index c57e5c4..e44fc24 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -83,6 +83,53 @@ export interface ProjectReport {
   readonly diagnostics: readonly Diagnostic[];
 }
 
+export interface ReadmeStyleReport {
+  readonly readmePath: string;
+  readonly changed: boolean;
+  readonly style: string;
+  readonly preservedSections: readonly string[];
+  readonly renderedSections: readonly string[];
+  readonly omittedSections: readonly string[];
+  readonly missingIntegrations: readonly string[];
+  readonly disabledIntegrations: readonly string[];
+  readonly unresolvedLogoSlugs: readonly string[];
+  readonly licenseFilesChanged: boolean;
+  readonly copyrightAuthors: readonly string[];
+  readonly finalContent: string;
+}
+
+interface KettleConfig {
+  readonly readme?: ReadmeConfig;
+}
+
+interface ReadmeConfig {
+  readonly style?: string;
+  readonly project_emoji?: string;
+  readonly logo_row?: {
+    readonly enabled?: boolean;
+    readonly max_count?: number;
+    readonly logos?: readonly ReadmeLogo[];
+  };
+  readonly badges?: {
+    readonly disabled?: readonly string[];
+  };
+  readonly preserve_sections?: readonly string[];
+  readonly section_aliases?: Record<string, string>;
+  readonly conditional_sections?: {
+    readonly floss_funding?: string;
+  };
+  readonly license?: {
+    readonly spdx?: readonly string[];
+  };
+}
+
+interface ReadmeLogo {
+  readonly type?: string;
+  readonly slug?: string;
+  readonly alt?: string;
+  readonly href?: string;
+}
+
 interface PackageJson {
   readonly name?: string;
   readonly description?: string;
@@ -228,6 +275,23 @@ export function applyProject(projectRoot: string): ProjectReport {
   return report;
 }
 
+export function planReadmeStyle(projectRoot: string): ReadmeStyleReport {
+  const facts = discoverFacts(projectRoot);
+  const config = readKettleConfig(projectRoot).readme ?? {};
+  const readmePath = path.join(projectRoot, 'README.md');
+  const original = existsSync(readmePath) ? readFileSync(readmePath, 'utf8') : '';
+  const hasSecurity = existsSync(path.join(projectRoot, 'SECURITY.md'));
+  return renderReadmeStyle(original, facts, config, hasSecurity);
+}
+
+export function applyReadmeStyle(projectRoot: string): ReadmeStyleReport {
+  const report = planReadmeStyle(projectRoot);
+  if (!report.changed) return report;
+
+  writeFileSync(path.join(projectRoot, report.readmePath), report.finalContent);
+  return report;
+}
+
 function executeRecipe(input: {
   readonly projectRoot: string;
   readonly recipe: PackagingRecipe;
@@ -553,6 +617,301 @@ function repositoryUrl(repository: PackageJson['repository']): string | undefine
   return repository?.url;
 }
 
+function readKettleConfig(projectRoot: string): KettleConfig {
+  const configPath = path.join(projectRoot, 'kettle.yml');
+  if (!existsSync(configPath)) return {};
+  return parseKettleConfig(readFileSync(configPath, 'utf8'));
+}
+
+function parseKettleConfig(source: string): KettleConfig {
+  const readme: {
+    style?: string;
+    project_emoji?: string;
+    logo_row?: { enabled?: boolean; max_count?: number; logos: ReadmeLogo[] };
+    badges?: { disabled: string[] };
+    preserve_sections?: string[];
+    section_aliases?: Record<string, string>;
+    conditional_sections?: { floss_funding?: string };
+    license?: { spdx: string[] };
+  } = {};
+  let section = '';
+  let list = '';
+  let currentLogo: Record<string, string> | undefined;
+  for (const rawLine of source.split('\n')) {
+    const line = rawLine.trimEnd();
+    const trimmed = line.trim();
+    if (trimmed.length === 0 || trimmed === 'readme:') continue;
+    if (trimmed.endsWith(':') && !trimmed.startsWith('- ')) {
+      const key = trimmed.slice(0, -1);
+      if (['logo_row', 'badges', 'section_aliases', 'conditional_sections', 'license'].includes(key)) {
+        section = key;
+        list = '';
+      } else if (section === 'logo_row' && key === 'logos') {
+        list = 'logos';
+        readme.logo_row ??= { logos: [] };
+      } else if (section === 'badges' && key === 'disabled') {
+        list = 'disabled';
+        readme.badges ??= { disabled: [] };
+      } else if (section === 'license' && key === 'spdx') {
+        list = 'spdx';
+        readme.license ??= { spdx: [] };
+      } else {
+        section = key;
+      }
+      continue;
+    }
+    if (trimmed.startsWith('- ')) {
+      const value = unquote(trimmed.slice(2));
+      if (section === 'logo_row' && list === 'logos') {
+        currentLogo = {};
+        readme.logo_row ??= { logos: [] };
+        readme.logo_row.logos.push(currentLogo);
+        const [key, rest] = splitYamlPair(value);
+        if (key) currentLogo[key] = rest;
+      } else if (section === 'badges' && list === 'disabled') {
+        readme.badges ??= { disabled: [] };
+        readme.badges.disabled.push(value);
+      } else if (section === 'license' && list === 'spdx') {
+        readme.license ??= { spdx: [] };
+        readme.license.spdx.push(value);
+      } else if (section === 'preserve_sections') {
+        readme.preserve_sections ??= [];
+        readme.preserve_sections.push(value);
+      }
+      continue;
+    }
+    const [key, value] = splitYamlPair(trimmed);
+    if (!key) continue;
+    if (section === '') {
+      if (key === 'style') readme.style = value;
+      if (key === 'project_emoji') readme.project_emoji = value;
+      if (key === 'preserve_sections') section = 'preserve_sections';
+    } else if (section === 'logo_row') {
+      readme.logo_row ??= { logos: [] };
+      if (currentLogo && list === 'logos') {
+        currentLogo[key] = value;
+      } else if (key === 'enabled') {
+        readme.logo_row.enabled = value === 'true';
+      } else if (key === 'max_count') {
+        readme.logo_row.max_count = Number.parseInt(value, 10);
+      }
+    } else if (section === 'section_aliases') {
+      readme.section_aliases ??= {};
+      readme.section_aliases[key] = value;
+    } else if (section === 'conditional_sections') {
+      readme.conditional_sections ??= {};
+      if (key === 'floss_funding') readme.conditional_sections.floss_funding = value;
+    }
+  }
+  return { readme };
+}
+
+function splitYamlPair(value: string): readonly [string, string] {
+  const index = value.indexOf(':');
+  if (index < 0) return ['', ''];
+  return [value.slice(0, index).trim(), unquote(value.slice(index + 1).trim())];
+}
+
+function unquote(value: string): string {
+  return value.replace(/^["']|["']$/g, '');
+}
+
+function renderReadmeStyle(
+  destination: string,
+  facts: PackageFacts,
+  rawConfig: ReadmeConfig,
+  hasSecurity: boolean
+): ReadmeStyleReport {
+  const config = defaultReadmeConfig(rawConfig);
+  const preserved = preservedReadmeSections(destination, config);
+  const license = readmeLicense(config, facts);
+  const [logoRow, unresolvedLogoSlugs] = readmeLogoRow(config);
+  const [badgeCloud, missingIntegrations, disabledIntegrations] = readmeBadgeCloud(
+    config,
+    facts,
+    license,
+    hasSecurity
+  );
+  const renderedSections = [
+    ...(logoRow ? ['Logos'] : []),
+    'Project Name',
+    'Badges',
+    'Synopsis',
+    'Info you can shake a stick at',
+    'Installation',
+    'Configuration',
+    'Basic Usage',
+    'Versioning',
+    'License',
+    'A request for help'
+  ];
+  const omittedSections = ['Hostile RubyGems Takeover', 'Secure Installation'];
+  const includeFunding = shouldIncludeFunding(config, license);
+  if (includeFunding) renderedSections.push('FLOSS Funding');
+  else omittedSections.push('FLOSS Funding');
+  if (hasSecurity) renderedSections.push('Security');
+  else omittedSections.push('Security');
+  renderedSections.push('Contributing');
+
+  const sections = [
+    ...(logoRow ? [logoRow] : []),
+    `# ${config.project_emoji} ${facts.package.name}`,
+    ...(badgeCloud ? [badgeCloud] : []),
+    `## 🌻 Synopsis\n\n${preserved.synopsis ?? ''}`,
+    `## 💡 Info you can shake a stick at\n\nCompatible with ${facts.npm.packageManager ?? 'the configured npm runtime'}.\n\n<details markdown="1">\n<summary>Compatibility, federated DVCS, and enterprise support</summary>\n\nAdditional compatibility and support details are generated from package metadata and shared fixtures.\n\n</details>`,
+    `## ✨ Installation\n\n\`\`\`console\n${packageManagerCommand(facts.npm.packageManager)} add ${facts.package.name}\n\`\`\``,
+    `## ⚙️ Configuration\n\n${preserved.configuration ?? ''}`,
+    `## 🔧 Basic Usage\n\n${preserved['basic usage'] ?? ''}`,
+    ...(includeFunding
+      ? [
+          '## 🦷 FLOSS Funding\n\nThis free software project accepts funding support when configured by the package maintainer.'
+        ]
+      : []),
+    ...(hasSecurity ? ['## 🔐 Security\n\nSee [SECURITY.md](SECURITY.md).'] : []),
+    '## 🤝 Contributing\n\nContributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.',
+    '## 📌 Versioning\n\nThis project follows semantic versioning for its public API where practical.',
+    `## 📄 License\n\n${licenseParagraph(license)}`,
+    '## 🤑 A request for help\n\nPlease support the project by using it, reporting issues, and contributing improvements.'
+  ];
+  const finalContent = ensureTrailingNewline(sections.join('\n\n'));
+  return {
+    readmePath: 'README.md',
+    changed: finalContent !== destination,
+    style: config.style,
+    preservedSections: ['Synopsis', 'Configuration', 'Basic Usage'],
+    renderedSections,
+    omittedSections,
+    missingIntegrations,
+    disabledIntegrations,
+    unresolvedLogoSlugs,
+    licenseFilesChanged: false,
+    copyrightAuthors: [],
+    finalContent
+  };
+}
+
+function defaultReadmeConfig(config: ReadmeConfig): Required<Pick<ReadmeConfig, 'style' | 'project_emoji' | 'preserve_sections' | 'section_aliases'>> & ReadmeConfig {
+  return {
+    ...config,
+    style: config.style ?? 'thin',
+    project_emoji: config.project_emoji ?? '💎',
+    preserve_sections: config.preserve_sections ?? ['Synopsis', 'Configuration', 'Basic Usage'],
+    section_aliases: {
+      summary: 'synopsis',
+      usage: 'basic usage',
+      'configuration options': 'configuration',
+      setup: 'basic usage',
+      ...Object.fromEntries(
+        Object.entries(config.section_aliases ?? {}).map(([from, to]) => [
+          normalizeReadmeHeading(from),
+          normalizeReadmeHeading(to)
+        ])
+      )
+    }
+  };
+}
+
+function preservedReadmeSections(
+  content: string,
+  config: Required<Pick<ReadmeConfig, 'preserve_sections' | 'section_aliases'>> & ReadmeConfig
+): Record<string, string> {
+  const sections = markdownSectionBodies(content);
+  return Object.fromEntries(
+    config.preserve_sections.map((section) => {
+      const key = normalizeReadmeHeading(section);
+      const alias = Object.entries(config.section_aliases).find(([, to]) => to === key)?.[0];
+      return [key, sections[key] ?? (alias ? sections[alias] : undefined) ?? ''];
+    })
+  );
+}
+
+function markdownSectionBodies(content: string): Record<string, string> {
+  const lines = content.split('\n');
+  const headings = lines.flatMap((line, index) => {
+    const match = line.match(/^(#{1,6})\s+(.+?)\s*#*\s*$/);
+    return match ? [{ index, level: match[1]!.length, key: normalizeReadmeHeading(match[2]!) }] : [];
+  });
+  return Object.fromEntries(
+    headings.map((heading, index) => {
+      const next = headings.slice(index + 1).find((candidate) => candidate.level <= heading.level);
+      return [
+        heading.key,
+        lines
+          .slice(heading.index + 1, next?.index ?? lines.length)
+          .join('\n')
+          .trim()
+      ];
+    })
+  );
+}
+
+function normalizeReadmeHeading(value: string): string {
+  const fields = value.trim().split(/\s+/);
+  return fields.length > 1 && !/^[A-Za-z0-9]/.test(fields[0]!)
+    ? fields.slice(1).join(' ').toLowerCase()
+    : value.trim().toLowerCase();
+}
+
+function readmeLicense(config: ReadmeConfig, facts: PackageFacts): string {
+  return config.license?.spdx?.join(' OR ') || facts.package.licenseExpression || 'MIT';
+}
+
+function readmeLogoRow(config: ReadmeConfig): readonly [string, readonly string[]] {
+  if (config.logo_row?.enabled === false) return ['', []];
+  const maxCount = Math.min(Math.max(config.logo_row?.max_count ?? 3, 1), 3);
+  const unresolved: string[] = [];
+  const parts = (config.logo_row?.logos ?? []).slice(0, maxCount).flatMap((logo) => {
+    const type = logo.type?.trim().toLowerCase().replaceAll('-', '_') ?? '';
+    const slug = logo.slug?.trim() ?? '';
+    if (!['language', 'org', 'project', 'affiliated_project'].includes(type) || slug.length === 0) {
+      unresolved.push(slug);
+      return [];
+    }
+    const ref = slug.replaceAll('/', '-');
+    const alt = logo.alt?.trim() || slug;
+    const href = logo.href?.trim() || `https://logos.galtzo.com/assets/images/${slug}/`;
+    return [
+      `[![${alt}][🖼️${ref}-i]][🖼️${ref}]\n[🖼️${ref}-i]: https://logos.galtzo.com/assets/images/${slug}/avatar-192px.svg\n[🖼️${ref}]: ${href}`
+    ];
+  });
+  return [parts.join('\n'), unresolved];
+}
+
+function readmeBadgeCloud(
+  config: ReadmeConfig,
+  facts: PackageFacts,
+  license: string,
+  hasSecurity: boolean
+): readonly [string, readonly string[], readonly string[]] {
+  const disabled = [...(config.badges?.disabled ?? [])];
+  const missing = ['codecov', 'coveralls', 'qlty', 'codeql'].filter(
+    (integration) => !disabled.includes(integration)
+  );
+  const badges = [
+    ...(facts.package.sourceUrl
+      ? [`[![Source](https://img.shields.io/badge/source-github-238636.svg)](${facts.package.sourceUrl})`]
+      : []),
+    `![License](https://img.shields.io/badge/license-${license.replaceAll(' ', '%20')}-259D6C.svg)`,
+    ...(hasSecurity
+      ? ['[![Security](https://img.shields.io/badge/security-policy-259D6C.svg)](SECURITY.md)']
+      : [])
+  ];
+  return [badges.join(' '), missing, disabled];
+}
+
+function shouldIncludeFunding(config: ReadmeConfig, license: string): boolean {
+  const policy = config.conditional_sections?.floss_funding?.trim().toLowerCase();
+  if (['disabled', 'false', 'never'].includes(policy ?? '')) return false;
+  if (['enabled', 'true', 'always'].includes(policy ?? '')) return true;
+  return license === 'MIT';
+}
+
+function licenseParagraph(license: string): string {
+  return license === 'MIT'
+    ? 'This project is made available under the terms of the MIT License.'
+    : `This project is made available under the following license expression: ${license}.`;
+}
+
 function normalizeFundingUrls(funding: PackageJson['funding']): readonly string[] {
   if (!funding) return [];
   const entries = Array.isArray(funding) ? funding : [funding];
diff --git a/packages/kettle-nodule/test/thin-slice.test.ts b/packages/kettle-nodule/test/thin-slice.test.ts
index 2e73bad..8683b21 100644
--- a/packages/kettle-nodule/test/thin-slice.test.ts
+++ b/packages/kettle-nodule/test/thin-slice.test.ts
@@ -4,8 +4,10 @@ import { describe, expect, it } from 'vitest';
 import {
   applyPackagedTemplateInventory,
   applyProject,
+  applyReadmeStyle,
   planPackagedTemplateInventory,
-  planProject
+  planProject,
+  planReadmeStyle
 } from '../src/index';
 
 interface ThinSliceFixture {
@@ -136,4 +138,141 @@ describe('kettle-nodule thin vertical slice', () => {
     expect(readFileSync(path.join(projectRoot, '.github/workflows/ci.yml'), 'utf8')).toBe(ci);
     rmSync(projectRoot, { force: true, recursive: true });
   });
+
+  it('conforms to the README style profile', () => {
+    const fixturePath = path.resolve(
+      import.meta.dirname,
+      '..',
+      '..',
+      '..',
+      '..',
+      'fixtures',
+      'diagnostics',
+      'slice-740-kettle-readme-style-profile',
+      'kettle-readme-style-profile.json'
+    );
+    const styleFixture = JSON.parse(readFileSync(fixturePath, 'utf8')) as {
+      readonly profile: { readonly name: string };
+    };
+    expect(styleFixture.profile.name).toBe('kettle-readme-style-profile');
+    const projectRoot = path.resolve(import.meta.dirname, '..', 'tmp', 'readme-style-profile');
+    rmSync(projectRoot, { force: true, recursive: true });
+    writeTree(projectRoot, {
+      'package.json': JSON.stringify(
+        {
+          name: '@acme/widget',
+          version: '0.1.0',
+          description: 'Example npm package',
+          repository: { url: 'https://github.com/acme/widget' },
+          license: 'MIT',
+          type: 'module',
+          packageManager: 'pnpm@9.1.0'
+        },
+        null,
+        2
+      ),
+      'kettle.yml': [
+        'readme:',
+        '  style: thin',
+        '  project_emoji: "📦"',
+        '  logo_row:',
+        '    enabled: true',
+        '    max_count: 3',
+        '    logos:',
+        '      - type: language',
+        '        slug: typescript-lang',
+        '        alt: TypeScript language logo',
+        '      - type: org',
+        '        slug: acme',
+        '        alt: Acme org logo',
+        '      - type: affiliated_project',
+        '        slug: tree-sitter/tree-sitter',
+        '        alt: Tree-sitter project logo',
+        '      - type: project',
+        '        slug: acme/ignored',
+        '        alt: Ignored fourth logo',
+        '  preserve_sections:',
+        '    - Synopsis',
+        '    - Configuration',
+        '    - Basic Usage',
+        '  section_aliases:',
+        '    Usage: Basic Usage',
+        '  conditional_sections:',
+        '    floss_funding: default_for_mit_opt_in_otherwise',
+        '  badges:',
+        '    disabled:',
+        '      - coveralls',
+        '  license:',
+        '    spdx:',
+        '      - MIT',
+        ''
+      ].join('\n'),
+      'SECURITY.md': '# Security\n',
+      'README.md': [
+        '# Old Package',
+        '',
+        '## Summary',
+        '',
+        'Destination synopsis.',
+        '',
+        '## Configuration',
+        '',
+        'Destination configuration.',
+        '',
+        '## Usage',
+        '',
+        'Destination usage.',
+        ''
+      ].join('\n')
+    });
+
+    const plan = planReadmeStyle(projectRoot);
+    expect(plan.changed).toBe(true);
+    expect(plan.style).toBe('thin');
+    expect(plan.preservedSections).toEqual(
+      expect.arrayContaining(['Synopsis', 'Configuration', 'Basic Usage'])
+    );
+    expect(plan.renderedSections).toEqual(
+      expect.arrayContaining([
+        'Logos',
+        'Project Name',
+        'Badges',
+        'Synopsis',
+        'Installation',
+        'Configuration',
+        'Basic Usage',
+        'FLOSS Funding',
+        'Security',
+        'Contributing',
+        'Versioning',
+        'License',
+        'A request for help'
+      ])
+    );
+    expect(plan.omittedSections).toEqual(
+      expect.arrayContaining(['Hostile RubyGems Takeover', 'Secure Installation'])
+    );
+    expect(plan.missingIntegrations).toEqual(expect.arrayContaining(['codecov', 'qlty']));
+    expect(plan.missingIntegrations).not.toContain('coveralls');
+    expect(plan.disabledIntegrations).toContain('coveralls');
+    expect(plan.finalContent).not.toContain('Ignored fourth logo');
+    for (const snippet of [
+      '# 📦 @acme/widget',
+      '## 🌻 Synopsis\n\nDestination synopsis.',
+      '## ⚙️ Configuration\n\nDestination configuration.',
+      '## 🔧 Basic Usage\n\nDestination usage.',
+      '## 🔐 Security\n\nSee [SECURITY.md](SECURITY.md).',
+      '## 🦷 FLOSS Funding',
+      'pnpm add @acme/widget',
+      'https://logos.galtzo.com/assets/images/tree-sitter/tree-sitter/avatar-192px.svg'
+    ]) {
+      expect(plan.finalContent).toContain(snippet);
+    }
+
+    const apply = applyReadmeStyle(projectRoot);
+    expect(apply.changed).toBe(true);
+    const second = applyReadmeStyle(projectRoot);
+    expect(second.changed).toBe(false);
+    rmSync(projectRoot, { force: true, recursive: true });
+  });
 });

From b280562ee8ef2888df5301b8a737526781937a82 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 03:05:32 -0600
Subject: [PATCH 005/130] Add README to TypeScript template inventory

---
 packages/kettle-nodule/src/index.ts            |  5 ++++-
 packages/kettle-nodule/test/thin-slice.test.ts | 11 ++++++++++-
 2 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index e44fc24..9742b51 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -207,7 +207,8 @@ export function packagedTemplateInventoryPack(): RecipePack {
       templateRecipe('.github/workflows/ci.yml'),
       templateRecipe('.gitignore'),
       templateRecipe('.npmrc'),
-      templateRecipe('.prettierrc.json')
+      templateRecipe('.prettierrc.json'),
+      templateRecipe('README.md')
     ]
   };
 }
@@ -548,6 +549,8 @@ function packagedTemplateContent(targetPath: string): string {
       return 'engine-strict=true\nfund=true\n';
     case '.prettierrc.json':
       return '{\n  "singleQuote": true,\n  "trailingComma": "none"\n}\n';
+    case 'README.md':
+      return '# {{PACKAGE_NAME}}\n\n## Synopsis\n\n## Installation\n\n```sh\n{{PACKAGE_MANAGER_COMMAND}} add {{PACKAGE_NAME}}\n```\n\n## Configuration\n\n## Basic Usage\n';
     default:
       return '';
   }
diff --git a/packages/kettle-nodule/test/thin-slice.test.ts b/packages/kettle-nodule/test/thin-slice.test.ts
index 8683b21..dc292b5 100644
--- a/packages/kettle-nodule/test/thin-slice.test.ts
+++ b/packages/kettle-nodule/test/thin-slice.test.ts
@@ -121,7 +121,8 @@ describe('kettle-nodule thin vertical slice', () => {
       '.github/workflows/ci.yml',
       '.gitignore',
       '.npmrc',
-      '.prettierrc.json'
+      '.prettierrc.json',
+      'README.md'
     ];
     const plan = planPackagedTemplateInventory(projectRoot);
     expect(plan.recipePack.name).toBe('kettle-nodule-packaged-template-inventory');
@@ -132,10 +133,18 @@ describe('kettle-nodule thin vertical slice', () => {
     const ci = readFileSync(path.join(projectRoot, '.github/workflows/ci.yml'), 'utf8');
     expect(ci).toContain('node-version: "20"');
     expect(ci).toContain('- run: pnpm test');
+    const readme = readFileSync(path.join(projectRoot, 'README.md'), 'utf8');
+    expect(readme).toContain('# @acme/widget');
+    expect(readme).toContain('## Synopsis');
+    expect(readme).toContain('## Installation');
+    expect(readme).toContain('pnpm add @acme/widget');
+    expect(readme).toContain('## Configuration');
+    expect(readme).toContain('## Basic Usage');
 
     const second = applyPackagedTemplateInventory(projectRoot);
     expect(second.changedFiles).toEqual([]);
     expect(readFileSync(path.join(projectRoot, '.github/workflows/ci.yml'), 'utf8')).toBe(ci);
+    expect(readFileSync(path.join(projectRoot, 'README.md'), 'utf8')).toBe(readme);
     rmSync(projectRoot, { force: true, recursive: true });
   });
 

From 18657e821bc8ebcc7b6a4be6036ffc3126ed0c41 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 03:21:58 -0600
Subject: [PATCH 006/130] Add README family command profile

---
 packages/ast-template/src/index.ts            | 57 ++++++++++++++++++-
 .../test/session.integration.test.ts          | 11 ++++
 2 files changed, 66 insertions(+), 2 deletions(-)

diff --git a/packages/ast-template/src/index.ts b/packages/ast-template/src/index.ts
index da40e9c..b27c44b 100644
--- a/packages/ast-template/src/index.ts
+++ b/packages/ast-template/src/index.ts
@@ -149,11 +149,62 @@ export interface ReadmeFamilyPackageReport {
   entries: ReadmeFamilyPackageReportEntry[];
 }
 
+export interface ReadmeFamilySectionCommand {
+  profile_name: string;
+  mode?: DirectorySessionMode;
+  root: string;
+  template_partial: string;
+  packages: readonly ReadmeFamilyPackage[];
+}
+
+export interface ReadmeFamilySectionCommandReport {
+  profile_name: string;
+  mode: DirectorySessionMode;
+  runner: ReadmeFamilyPackageReport;
+}
+
 export function applyReadmeFamilySectionsToPackageDirectories(
   root: string,
   templatePartial: string,
   packages: readonly ReadmeFamilyPackage[],
   config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
+): ReadmeFamilyPackageReport {
+  return runReadmeFamilySectionsForPackageDirectories(root, templatePartial, packages, true, config);
+}
+
+export function planReadmeFamilySectionsForPackageDirectories(
+  root: string,
+  templatePartial: string,
+  packages: readonly ReadmeFamilyPackage[],
+  config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
+): ReadmeFamilyPackageReport {
+  return runReadmeFamilySectionsForPackageDirectories(root, templatePartial, packages, false, config);
+}
+
+export function runReadmeFamilySectionCommand(
+  command: ReadmeFamilySectionCommand,
+  config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
+): ReadmeFamilySectionCommandReport {
+  const mode = command.mode ?? 'plan';
+  return {
+    profile_name: command.profile_name,
+    mode,
+    runner: runReadmeFamilySectionsForPackageDirectories(
+      command.root,
+      command.template_partial,
+      command.packages,
+      mode === 'apply' || mode === 'reapply',
+      config
+    )
+  };
+}
+
+function runReadmeFamilySectionsForPackageDirectories(
+  root: string,
+  templatePartial: string,
+  packages: readonly ReadmeFamilyPackage[],
+  writeChanges: boolean,
+  config: TemplateTokenConfig = DEFAULT_TEMPLATE_TOKEN_CONFIG
 ): ReadmeFamilyPackageReport {
   const report: ReadmeFamilyPackageReport = {
     package_count: packages.length,
@@ -184,8 +235,10 @@ export function applyReadmeFamilySectionsToPackageDirectories(
       config
     );
     if (application.changed) {
-      mkdirSync(path.dirname(readmePath), { recursive: true });
-      writeFileSync(readmePath, application.content);
+      if (writeChanges) {
+        mkdirSync(path.dirname(readmePath), { recursive: true });
+        writeFileSync(readmePath, application.content);
+      }
       report.changed_count += 1;
       if (created) {
         report.created_count += 1;
diff --git a/packages/ast-template/test/session.integration.test.ts b/packages/ast-template/test/session.integration.test.ts
index cce8725..25b2cf8 100644
--- a/packages/ast-template/test/session.integration.test.ts
+++ b/packages/ast-template/test/session.integration.test.ts
@@ -79,6 +79,7 @@ import {
   readmeFamilyLanguageAliases,
   readmeFamilyTokenValues,
   renderReadmeFamilySection,
+  runReadmeFamilySectionCommand,
   reapplyTemplateDirectorySessionToDirectory,
   sessionCommandEnvelope,
   sessionCommandPayloadEnvelope,
@@ -196,6 +197,16 @@ describe('README family section template contract fixture', () => {
       fixture.package_directory_case.packages
     );
     expect(report).toEqual(fixture.package_directory_case.expected_report);
+    const commandReport = runReadmeFamilySectionCommand({
+      profile_name: 'update-readme-family-section',
+      mode: 'plan',
+      root: tempRoot,
+      template_partial: fixture.template_partial,
+      packages: fixture.package_directory_case.packages
+    });
+    expect(commandReport.profile_name).toBe('update-readme-family-section');
+    expect(commandReport.mode).toBe('plan');
+    expect(commandReport.runner.changed_count).toBe(0);
     for (const packageCase of fixture.package_directory_case.packages) {
       const readmePath = path.join(tempRoot, ...packageCase.readme_path.split('/'));
       expect(readFileSync(readmePath, 'utf8')).toBe(packageCase.expected_content);

From c444a0a0c1eb705d2cf15d2dd3bc95664b0937f5 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 03:26:22 -0600
Subject: [PATCH 007/130] Render README family backend matrix

---
 packages/kettle-nodule/src/index.ts           | 32 ++++++++++++++++++-
 .../kettle-nodule/test/thin-slice.test.ts     |  4 ++-
 2 files changed, 34 insertions(+), 2 deletions(-)

diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index 9742b51..58eeecf 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -761,7 +761,7 @@ function renderReadmeStyle(
     `# ${config.project_emoji} ${facts.package.name}`,
     ...(badgeCloud ? [badgeCloud] : []),
     `## 🌻 Synopsis\n\n${preserved.synopsis ?? ''}`,
-    `## 💡 Info you can shake a stick at\n\nCompatible with ${facts.npm.packageManager ?? 'the configured npm runtime'}.\n\n<details markdown="1">\n<summary>Compatibility, federated DVCS, and enterprise support</summary>\n\nAdditional compatibility and support details are generated from package metadata and shared fixtures.\n\n</details>`,
+    `## 💡 Info you can shake a stick at\n\nCompatible with ${facts.npm.packageManager ?? 'the configured npm runtime'}.\n\n${readmeFamilyIntroAndBackendMatrix()}`,
     `## ✨ Installation\n\n\`\`\`console\n${packageManagerCommand(facts.npm.packageManager)} add ${facts.package.name}\n\`\`\``,
     `## ⚙️ Configuration\n\n${preserved.configuration ?? ''}`,
     `## 🔧 Basic Usage\n\n${preserved['basic usage'] ?? ''}`,
@@ -793,6 +793,36 @@ function renderReadmeStyle(
   };
 }
 
+function readmeFamilyIntroAndBackendMatrix(): string {
+  return [
+    '<details markdown="1">',
+    '<summary>StructuredMerge package family and backend compatibility</summary>',
+    '',
+    'StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.',
+    '',
+    '| Package | Layer | Families | Status | README role |',
+    '|---|---|---|---|---|',
+    '| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |',
+    '| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |',
+    '| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |',
+    '| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |',
+    '| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |',
+    '| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |',
+    '| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |',
+    '| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |',
+    '| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |',
+    '| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |',
+    '',
+    '| Backend | Languages | Families | Note |',
+    '|---|---|---|---|',
+    '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |',
+    '| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |',
+    '| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |',
+    '',
+    '</details>'
+  ].join('\n');
+}
+
 function defaultReadmeConfig(config: ReadmeConfig): Required<Pick<ReadmeConfig, 'style' | 'project_emoji' | 'preserve_sections' | 'section_aliases'>> & ReadmeConfig {
   return {
     ...config,
diff --git a/packages/kettle-nodule/test/thin-slice.test.ts b/packages/kettle-nodule/test/thin-slice.test.ts
index dc292b5..f4b517f 100644
--- a/packages/kettle-nodule/test/thin-slice.test.ts
+++ b/packages/kettle-nodule/test/thin-slice.test.ts
@@ -273,7 +273,9 @@ describe('kettle-nodule thin vertical slice', () => {
       '## 🔐 Security\n\nSee [SECURITY.md](SECURITY.md).',
       '## 🦷 FLOSS Funding',
       'pnpm add @acme/widget',
-      'https://logos.galtzo.com/assets/images/tree-sitter/tree-sitter/avatar-192px.svg'
+      'https://logos.galtzo.com/assets/images/tree-sitter/tree-sitter/avatar-192px.svg',
+      'StructuredMerge packages provide fixture-backed merge behavior',
+      '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source |'
     ]) {
       expect(plan.finalContent).toContain(snippet);
     }

From 1a4b7df47e1e4fd3bd27c1e4dbc9fcce7eebbad1 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 03:33:47 -0600
Subject: [PATCH 008/130] Generate package READMEs

---
 packages/ast-merge/README.md                 | 71 ++++++++++++++++++++
 packages/ast-template/README.md              | 71 ++++++++++++++++++++
 packages/binary-merge/README.md              | 71 ++++++++++++++++++++
 packages/go-merge/README.md                  | 71 ++++++++++++++++++++
 packages/js-yaml-merge/README.md             | 71 ++++++++++++++++++++
 packages/json-merge/README.md                | 71 ++++++++++++++++++++
 packages/kettle-nodule/README.md             | 71 ++++++++++++++++++++
 packages/markdown-it-merge/README.md         | 71 ++++++++++++++++++++
 packages/markdown-merge/README.md            | 71 ++++++++++++++++++++
 packages/peggy-toml-merge/README.md          | 71 ++++++++++++++++++++
 packages/plain-merge/README.md               | 71 ++++++++++++++++++++
 packages/ruby-merge/README.md                | 71 ++++++++++++++++++++
 packages/rust-merge/README.md                | 71 ++++++++++++++++++++
 packages/toml-merge/README.md                | 71 ++++++++++++++++++++
 packages/tree-haver/README.md                | 71 ++++++++++++++++++++
 packages/typescript-compiler-merge/README.md | 71 ++++++++++++++++++++
 packages/typescript-merge/README.md          | 71 ++++++++++++++++++++
 packages/yaml-merge/README.md                | 71 ++++++++++++++++++++
 packages/zip-merge/README.md                 | 71 ++++++++++++++++++++
 19 files changed, 1349 insertions(+)
 create mode 100644 packages/ast-merge/README.md
 create mode 100644 packages/ast-template/README.md
 create mode 100644 packages/binary-merge/README.md
 create mode 100644 packages/go-merge/README.md
 create mode 100644 packages/js-yaml-merge/README.md
 create mode 100644 packages/json-merge/README.md
 create mode 100644 packages/kettle-nodule/README.md
 create mode 100644 packages/markdown-it-merge/README.md
 create mode 100644 packages/markdown-merge/README.md
 create mode 100644 packages/peggy-toml-merge/README.md
 create mode 100644 packages/plain-merge/README.md
 create mode 100644 packages/ruby-merge/README.md
 create mode 100644 packages/rust-merge/README.md
 create mode 100644 packages/toml-merge/README.md
 create mode 100644 packages/tree-haver/README.md
 create mode 100644 packages/typescript-compiler-merge/README.md
 create mode 100644 packages/typescript-merge/README.md
 create mode 100644 packages/yaml-merge/README.md
 create mode 100644 packages/zip-merge/README.md

diff --git a/packages/ast-merge/README.md b/packages/ast-merge/README.md
new file mode 100644
index 0000000..980957b
--- /dev/null
+++ b/packages/ast-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/ast-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/ast-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/ast-template/README.md b/packages/ast-template/README.md
new file mode 100644
index 0000000..53225ac
--- /dev/null
+++ b/packages/ast-template/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/ast-template
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/ast-template
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/binary-merge/README.md b/packages/binary-merge/README.md
new file mode 100644
index 0000000..3584d14
--- /dev/null
+++ b/packages/binary-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/binary-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/binary-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/go-merge/README.md b/packages/go-merge/README.md
new file mode 100644
index 0000000..c031ace
--- /dev/null
+++ b/packages/go-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/go-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/go-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/js-yaml-merge/README.md b/packages/js-yaml-merge/README.md
new file mode 100644
index 0000000..63a9bfc
--- /dev/null
+++ b/packages/js-yaml-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/js-yaml-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/js-yaml-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/json-merge/README.md b/packages/json-merge/README.md
new file mode 100644
index 0000000..05cbe15
--- /dev/null
+++ b/packages/json-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/json-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/json-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/kettle-nodule/README.md b/packages/kettle-nodule/README.md
new file mode 100644
index 0000000..57177a8
--- /dev/null
+++ b/packages/kettle-nodule/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/kettle-nodule
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/kettle-nodule
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/markdown-it-merge/README.md b/packages/markdown-it-merge/README.md
new file mode 100644
index 0000000..6aa7ebc
--- /dev/null
+++ b/packages/markdown-it-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/markdown-it-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/markdown-it-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/markdown-merge/README.md b/packages/markdown-merge/README.md
new file mode 100644
index 0000000..b2a3781
--- /dev/null
+++ b/packages/markdown-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/markdown-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/markdown-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/peggy-toml-merge/README.md b/packages/peggy-toml-merge/README.md
new file mode 100644
index 0000000..ceb4eb9
--- /dev/null
+++ b/packages/peggy-toml-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/peggy-toml-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/peggy-toml-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/plain-merge/README.md b/packages/plain-merge/README.md
new file mode 100644
index 0000000..2530aa9
--- /dev/null
+++ b/packages/plain-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/plain-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/plain-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/ruby-merge/README.md b/packages/ruby-merge/README.md
new file mode 100644
index 0000000..05a2eae
--- /dev/null
+++ b/packages/ruby-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/ruby-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/ruby-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/rust-merge/README.md b/packages/rust-merge/README.md
new file mode 100644
index 0000000..482b6a9
--- /dev/null
+++ b/packages/rust-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/rust-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/rust-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/toml-merge/README.md b/packages/toml-merge/README.md
new file mode 100644
index 0000000..24c2f03
--- /dev/null
+++ b/packages/toml-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/toml-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/toml-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/tree-haver/README.md b/packages/tree-haver/README.md
new file mode 100644
index 0000000..f4f5597
--- /dev/null
+++ b/packages/tree-haver/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/tree-haver
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/tree-haver
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/typescript-compiler-merge/README.md b/packages/typescript-compiler-merge/README.md
new file mode 100644
index 0000000..5be9d21
--- /dev/null
+++ b/packages/typescript-compiler-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/typescript-compiler-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/typescript-compiler-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/typescript-merge/README.md b/packages/typescript-merge/README.md
new file mode 100644
index 0000000..e1c5f6e
--- /dev/null
+++ b/packages/typescript-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/typescript-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/typescript-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/yaml-merge/README.md b/packages/yaml-merge/README.md
new file mode 100644
index 0000000..afc5c5b
--- /dev/null
+++ b/packages/yaml-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/yaml-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/yaml-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.
diff --git a/packages/zip-merge/README.md b/packages/zip-merge/README.md
new file mode 100644
index 0000000..5b60541
--- /dev/null
+++ b/packages/zip-merge/README.md
@@ -0,0 +1,71 @@
+# 💎 @structuredmerge/zip-merge
+
+[![Source](https://img.shields.io/badge/source-github-238636.svg)](git+https://github.com/structuredmerge/structuredmerge-typescript.git) ![License](https://img.shields.io/badge/license-MIT-259D6C.svg)
+
+## 🌻 Synopsis
+
+
+
+## 💡 Info you can shake a stick at
+
+Compatible with the configured npm runtime.
+
+<details markdown="1">
+<summary>StructuredMerge package family and backend compatibility</summary>
+
+StructuredMerge packages provide fixture-backed merge behavior for document, configuration, source, archive, and binary formats. Shared contracts live in fixtures, while Go, Ruby, Rust, and TypeScript packages expose language-native APIs over the same behavior.
+
+| Package | Layer | Families | Status | README role |
+|---|---|---|---|---|
+| ast-template | workflow | template, readme | active | applies shared templates, package README sections, and package-directory sync workflows |
+| ast-merge | core | template, review, structured-edit | active | documents provider-neutral contracts, token resolution, review state, and execution reports |
+| tree-haver | backend substrate | parser, backend | active | documents backend selection, language-pack integration, position data, and capability reporting |
+| markdown-merge | family | markdown | active | documents Markdown heading, fenced-code, nested-family, and provider behavior |
+| json-merge | family | json, jsonc | active | documents JSON and JSONC merge behavior; old jsonc-merge is superseded |
+| toml-merge | family | toml | active | documents TOML table, value, parser, and backend behavior |
+| yaml-merge | family | yaml | active | documents YAML mapping, sequence, scalar, and backend behavior |
+| ruby-merge | family | ruby-source | active | documents Ruby source merge behavior; old prism-merge is backend/provider prior art |
+| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
+| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
+
+| Backend | Languages | Families | Note |
+|---|---|---|---|
+| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
+| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
+| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
+
+</details>
+
+## ✨ Installation
+
+```console
+npm add @structuredmerge/zip-merge
+```
+
+## ⚙️ Configuration
+
+
+
+## 🔧 Basic Usage
+
+
+
+## 🦷 FLOSS Funding
+
+This free software project accepts funding support when configured by the package maintainer.
+
+## 🤝 Contributing
+
+Contributions are welcome. Missing optional service integrations are reported by the generator instead of rendered as broken badges.
+
+## 📌 Versioning
+
+This project follows semantic versioning for its public API where practical.
+
+## 📄 License
+
+This project is made available under the terms of the MIT License.
+
+## 🤑 A request for help
+
+Please support the project by using it, reporting issues, and contributing improvements.

From 01b2e07f2ed4080481c8f955b664702bda2fc2ba Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 03:39:51 -0600
Subject: [PATCH 009/130] Render backend compatibility reconciliation

---
 packages/ast-merge/README.md                   | 7 +++++++
 packages/ast-template/README.md                | 7 +++++++
 packages/binary-merge/README.md                | 7 +++++++
 packages/go-merge/README.md                    | 7 +++++++
 packages/js-yaml-merge/README.md               | 7 +++++++
 packages/json-merge/README.md                  | 7 +++++++
 packages/kettle-nodule/README.md               | 7 +++++++
 packages/kettle-nodule/src/index.ts            | 7 +++++++
 packages/kettle-nodule/test/thin-slice.test.ts | 3 ++-
 packages/markdown-it-merge/README.md           | 7 +++++++
 packages/markdown-merge/README.md              | 7 +++++++
 packages/peggy-toml-merge/README.md            | 7 +++++++
 packages/plain-merge/README.md                 | 7 +++++++
 packages/ruby-merge/README.md                  | 7 +++++++
 packages/rust-merge/README.md                  | 7 +++++++
 packages/toml-merge/README.md                  | 7 +++++++
 packages/tree-haver/README.md                  | 7 +++++++
 packages/typescript-compiler-merge/README.md   | 7 +++++++
 packages/typescript-merge/README.md            | 7 +++++++
 packages/yaml-merge/README.md                  | 7 +++++++
 packages/zip-merge/README.md                   | 7 +++++++
 21 files changed, 142 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge/README.md b/packages/ast-merge/README.md
index 980957b..39b4ae6 100644
--- a/packages/ast-merge/README.md
+++ b/packages/ast-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/ast-template/README.md b/packages/ast-template/README.md
index 53225ac..7af119c 100644
--- a/packages/ast-template/README.md
+++ b/packages/ast-template/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/binary-merge/README.md b/packages/binary-merge/README.md
index 3584d14..5a686f8 100644
--- a/packages/binary-merge/README.md
+++ b/packages/binary-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/go-merge/README.md b/packages/go-merge/README.md
index c031ace..c6a6509 100644
--- a/packages/go-merge/README.md
+++ b/packages/go-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/js-yaml-merge/README.md b/packages/js-yaml-merge/README.md
index 63a9bfc..f77ad5b 100644
--- a/packages/js-yaml-merge/README.md
+++ b/packages/js-yaml-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/json-merge/README.md b/packages/json-merge/README.md
index 05cbe15..97d84d2 100644
--- a/packages/json-merge/README.md
+++ b/packages/json-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/kettle-nodule/README.md b/packages/kettle-nodule/README.md
index 57177a8..9a58194 100644
--- a/packages/kettle-nodule/README.md
+++ b/packages/kettle-nodule/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index 58eeecf..189a9ab 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -819,6 +819,13 @@ function readmeFamilyIntroAndBackendMatrix(): string {
     '| native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |',
     '| plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |',
     '',
+    '| Compatibility claim | Current disposition | Fixture source |',
+    '|---|---|---|',
+    '| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |',
+    '| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |',
+    '| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |',
+    '| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |',
+    '',
     '</details>'
   ].join('\n');
 }
diff --git a/packages/kettle-nodule/test/thin-slice.test.ts b/packages/kettle-nodule/test/thin-slice.test.ts
index f4b517f..f590f1f 100644
--- a/packages/kettle-nodule/test/thin-slice.test.ts
+++ b/packages/kettle-nodule/test/thin-slice.test.ts
@@ -275,7 +275,8 @@ describe('kettle-nodule thin vertical slice', () => {
       'pnpm add @acme/widget',
       'https://logos.galtzo.com/assets/images/tree-sitter/tree-sitter/avatar-192px.svg',
       'StructuredMerge packages provide fixture-backed merge behavior',
-      '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source |'
+      '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source |',
+      '| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist |'
     ]) {
       expect(plan.finalContent).toContain(snippet);
     }
diff --git a/packages/markdown-it-merge/README.md b/packages/markdown-it-merge/README.md
index 6aa7ebc..18054d5 100644
--- a/packages/markdown-it-merge/README.md
+++ b/packages/markdown-it-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/markdown-merge/README.md b/packages/markdown-merge/README.md
index b2a3781..d3fdbc9 100644
--- a/packages/markdown-merge/README.md
+++ b/packages/markdown-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/peggy-toml-merge/README.md b/packages/peggy-toml-merge/README.md
index ceb4eb9..f37618d 100644
--- a/packages/peggy-toml-merge/README.md
+++ b/packages/peggy-toml-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/plain-merge/README.md b/packages/plain-merge/README.md
index 2530aa9..05ba658 100644
--- a/packages/plain-merge/README.md
+++ b/packages/plain-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/ruby-merge/README.md b/packages/ruby-merge/README.md
index 05a2eae..cf8fe8c 100644
--- a/packages/ruby-merge/README.md
+++ b/packages/ruby-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/rust-merge/README.md b/packages/rust-merge/README.md
index 482b6a9..090d43a 100644
--- a/packages/rust-merge/README.md
+++ b/packages/rust-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/toml-merge/README.md b/packages/toml-merge/README.md
index 24c2f03..386e9d0 100644
--- a/packages/toml-merge/README.md
+++ b/packages/toml-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/tree-haver/README.md b/packages/tree-haver/README.md
index f4f5597..a70b454 100644
--- a/packages/tree-haver/README.md
+++ b/packages/tree-haver/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/typescript-compiler-merge/README.md b/packages/typescript-compiler-merge/README.md
index 5be9d21..a465363 100644
--- a/packages/typescript-compiler-merge/README.md
+++ b/packages/typescript-compiler-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/typescript-merge/README.md b/packages/typescript-merge/README.md
index e1c5f6e..61944d6 100644
--- a/packages/typescript-merge/README.md
+++ b/packages/typescript-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/yaml-merge/README.md b/packages/yaml-merge/README.md
index afc5c5b..e1b9a40 100644
--- a/packages/yaml-merge/README.md
+++ b/packages/yaml-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/zip-merge/README.md b/packages/zip-merge/README.md
index 5b60541..1bbb0e1 100644
--- a/packages/zip-merge/README.md
+++ b/packages/zip-merge/README.md
@@ -34,6 +34,13 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | native ecosystem parser | Ruby | ruby, yaml, markdown, toml | Backend-specific Ruby packages are provider prior art or adapters, not the source schema. |
 | plain structured text | Go, Ruby, Rust, TypeScript | plain, binary, zip | Families without parser requirements document preservation, byte ranges, archive members, and diagnostics. |
 
+| Compatibility claim | Current disposition | Fixture source |
+|---|---|---|
+| Old Ruby runtime backend tables | Prior art only; not a cross-language support promise | slice-741 backend/platform reconciliation |
+| tree-sitter-language-pack | Current portable parser substrate for Go, Ruby, Rust, and TypeScript | slices 122, 135, 171, 195, 215 |
+| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
+| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
+
 </details>
 
 ## ✨ Installation

From 98fdd4869e5d5fb930c40b6417d3a2ec98063d44 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 03:43:56 -0600
Subject: [PATCH 010/130] Render reusable README examples

---
 packages/ast-merge/README.md                   | 9 +++++++++
 packages/ast-template/README.md                | 9 +++++++++
 packages/binary-merge/README.md                | 9 +++++++++
 packages/go-merge/README.md                    | 9 +++++++++
 packages/js-yaml-merge/README.md               | 9 +++++++++
 packages/json-merge/README.md                  | 9 +++++++++
 packages/kettle-nodule/README.md               | 9 +++++++++
 packages/kettle-nodule/src/index.ts            | 9 +++++++++
 packages/kettle-nodule/test/thin-slice.test.ts | 3 ++-
 packages/markdown-it-merge/README.md           | 9 +++++++++
 packages/markdown-merge/README.md              | 9 +++++++++
 packages/peggy-toml-merge/README.md            | 9 +++++++++
 packages/plain-merge/README.md                 | 9 +++++++++
 packages/ruby-merge/README.md                  | 9 +++++++++
 packages/rust-merge/README.md                  | 9 +++++++++
 packages/toml-merge/README.md                  | 9 +++++++++
 packages/tree-haver/README.md                  | 9 +++++++++
 packages/typescript-compiler-merge/README.md   | 9 +++++++++
 packages/typescript-merge/README.md            | 9 +++++++++
 packages/yaml-merge/README.md                  | 9 +++++++++
 packages/zip-merge/README.md                   | 9 +++++++++
 21 files changed, 182 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge/README.md b/packages/ast-merge/README.md
index 39b4ae6..63b616f 100644
--- a/packages/ast-merge/README.md
+++ b/packages/ast-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/ast-template/README.md b/packages/ast-template/README.md
index 7af119c..9cc28d3 100644
--- a/packages/ast-template/README.md
+++ b/packages/ast-template/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/binary-merge/README.md b/packages/binary-merge/README.md
index 5a686f8..969312d 100644
--- a/packages/binary-merge/README.md
+++ b/packages/binary-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/go-merge/README.md b/packages/go-merge/README.md
index c6a6509..6b77d59 100644
--- a/packages/go-merge/README.md
+++ b/packages/go-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/js-yaml-merge/README.md b/packages/js-yaml-merge/README.md
index f77ad5b..09507b8 100644
--- a/packages/js-yaml-merge/README.md
+++ b/packages/js-yaml-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/json-merge/README.md b/packages/json-merge/README.md
index 97d84d2..38df3e5 100644
--- a/packages/json-merge/README.md
+++ b/packages/json-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/kettle-nodule/README.md b/packages/kettle-nodule/README.md
index 9a58194..d209ee8 100644
--- a/packages/kettle-nodule/README.md
+++ b/packages/kettle-nodule/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index 189a9ab..baa7b7b 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -826,6 +826,15 @@ function readmeFamilyIntroAndBackendMatrix(): string {
     '| Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |',
     '| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |',
     '',
+    '| Reusable example | README role | Source fixture |',
+    '|---|---|---|',
+    '| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |',
+    '| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |',
+    '| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |',
+    '| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |',
+    '| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |',
+    '| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |',
+    '',
     '</details>'
   ].join('\n');
 }
diff --git a/packages/kettle-nodule/test/thin-slice.test.ts b/packages/kettle-nodule/test/thin-slice.test.ts
index f590f1f..b9f9ac6 100644
--- a/packages/kettle-nodule/test/thin-slice.test.ts
+++ b/packages/kettle-nodule/test/thin-slice.test.ts
@@ -276,7 +276,8 @@ describe('kettle-nodule thin vertical slice', () => {
       'https://logos.galtzo.com/assets/images/tree-sitter/tree-sitter/avatar-192px.svg',
       'StructuredMerge packages provide fixture-backed merge behavior',
       '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source |',
-      '| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist |'
+      '| bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist |',
+      '| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections |'
     ]) {
       expect(plan.finalContent).toContain(snippet);
     }
diff --git a/packages/markdown-it-merge/README.md b/packages/markdown-it-merge/README.md
index 18054d5..0631a51 100644
--- a/packages/markdown-it-merge/README.md
+++ b/packages/markdown-it-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/markdown-merge/README.md b/packages/markdown-merge/README.md
index d3fdbc9..d730361 100644
--- a/packages/markdown-merge/README.md
+++ b/packages/markdown-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/peggy-toml-merge/README.md b/packages/peggy-toml-merge/README.md
index f37618d..810f323 100644
--- a/packages/peggy-toml-merge/README.md
+++ b/packages/peggy-toml-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/plain-merge/README.md b/packages/plain-merge/README.md
index 05ba658..9e4c03e 100644
--- a/packages/plain-merge/README.md
+++ b/packages/plain-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/ruby-merge/README.md b/packages/ruby-merge/README.md
index cf8fe8c..df76f1e 100644
--- a/packages/ruby-merge/README.md
+++ b/packages/ruby-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/rust-merge/README.md b/packages/rust-merge/README.md
index 090d43a..8d627c1 100644
--- a/packages/rust-merge/README.md
+++ b/packages/rust-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/toml-merge/README.md b/packages/toml-merge/README.md
index 386e9d0..3e43c26 100644
--- a/packages/toml-merge/README.md
+++ b/packages/toml-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/tree-haver/README.md b/packages/tree-haver/README.md
index a70b454..e4e6ed7 100644
--- a/packages/tree-haver/README.md
+++ b/packages/tree-haver/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/typescript-compiler-merge/README.md b/packages/typescript-compiler-merge/README.md
index a465363..06c0d04 100644
--- a/packages/typescript-compiler-merge/README.md
+++ b/packages/typescript-compiler-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/typescript-merge/README.md b/packages/typescript-merge/README.md
index 61944d6..b169d95 100644
--- a/packages/typescript-merge/README.md
+++ b/packages/typescript-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/yaml-merge/README.md b/packages/yaml-merge/README.md
index e1b9a40..58cb800 100644
--- a/packages/yaml-merge/README.md
+++ b/packages/yaml-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation
diff --git a/packages/zip-merge/README.md b/packages/zip-merge/README.md
index 1bbb0e1..55c6e3f 100644
--- a/packages/zip-merge/README.md
+++ b/packages/zip-merge/README.md
@@ -41,6 +41,15 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | Native parser/adaptor backends | Implementation-specific providers documented through family fixtures | slices 122 and 183 |
 | bash-merge, dotenv-merge, rbs-merge | Excluded from generated support tables until explicit scope decisions exist | slice-741 unresolved package list |
 
+| Reusable example | README role | Source fixture |
+|---|---|---|
+| Freeze tokens | Show how destination-owned regions are preserved without filling project-specific usage sections | slice-743 reusable README configuration examples |
+| Match preference | Summarize template-wins and destination-wins conflict choices through current policy vocabulary | slice-743 reusable README configuration examples |
+| Template-only behavior | Explain accept/skip handling for unmatched template entries | slice-743 reusable README configuration examples |
+| Debug report inspection | Point users to structured reports and diagnostics instead of ad hoc debug prose | slice-743 reusable README configuration examples |
+| Backend selection | Describe portable backend selection without old Ruby runtime support tables | slice-743 reusable README configuration examples |
+| Package-directory README command | Document plan/apply/convergence workflow for shared README updates | slice-743 reusable README configuration examples |
+
 </details>
 
 ## ✨ Installation

From 72cdc2286f7244c42c4a15b4af5809775ecf53dc Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 04:00:14 -0600
Subject: [PATCH 011/130] Render JSONC migration note

---
 packages/ast-merge/README.md                 | 2 ++
 packages/ast-template/README.md              | 2 ++
 packages/binary-merge/README.md              | 2 ++
 packages/go-merge/README.md                  | 2 ++
 packages/js-yaml-merge/README.md             | 2 ++
 packages/json-merge/README.md                | 2 ++
 packages/kettle-nodule/README.md             | 2 ++
 packages/kettle-nodule/src/index.ts          | 2 ++
 packages/markdown-it-merge/README.md         | 2 ++
 packages/markdown-merge/README.md            | 2 ++
 packages/peggy-toml-merge/README.md          | 2 ++
 packages/plain-merge/README.md               | 2 ++
 packages/ruby-merge/README.md                | 2 ++
 packages/rust-merge/README.md                | 2 ++
 packages/toml-merge/README.md                | 2 ++
 packages/tree-haver/README.md                | 2 ++
 packages/typescript-compiler-merge/README.md | 2 ++
 packages/typescript-merge/README.md          | 2 ++
 packages/yaml-merge/README.md                | 2 ++
 packages/zip-merge/README.md                 | 2 ++
 20 files changed, 40 insertions(+)

diff --git a/packages/ast-merge/README.md b/packages/ast-merge/README.md
index 63b616f..d396f92 100644
--- a/packages/ast-merge/README.md
+++ b/packages/ast-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/ast-template/README.md b/packages/ast-template/README.md
index 9cc28d3..b31fab6 100644
--- a/packages/ast-template/README.md
+++ b/packages/ast-template/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/binary-merge/README.md b/packages/binary-merge/README.md
index 969312d..67df47f 100644
--- a/packages/binary-merge/README.md
+++ b/packages/binary-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/go-merge/README.md b/packages/go-merge/README.md
index 6b77d59..db0c91e 100644
--- a/packages/go-merge/README.md
+++ b/packages/go-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/js-yaml-merge/README.md b/packages/js-yaml-merge/README.md
index 09507b8..9e50e27 100644
--- a/packages/js-yaml-merge/README.md
+++ b/packages/js-yaml-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/json-merge/README.md b/packages/json-merge/README.md
index 38df3e5..40ca56f 100644
--- a/packages/json-merge/README.md
+++ b/packages/json-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/kettle-nodule/README.md b/packages/kettle-nodule/README.md
index d209ee8..f7c3a04 100644
--- a/packages/kettle-nodule/README.md
+++ b/packages/kettle-nodule/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index baa7b7b..e00e3a6 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -813,6 +813,8 @@ function readmeFamilyIntroAndBackendMatrix(): string {
     '| zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |',
     '| binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |',
     '',
+    'JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.',
+    '',
     '| Backend | Languages | Families | Note |',
     '|---|---|---|---|',
     '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |',
diff --git a/packages/markdown-it-merge/README.md b/packages/markdown-it-merge/README.md
index 0631a51..911f51c 100644
--- a/packages/markdown-it-merge/README.md
+++ b/packages/markdown-it-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/markdown-merge/README.md b/packages/markdown-merge/README.md
index d730361..1e5c328 100644
--- a/packages/markdown-merge/README.md
+++ b/packages/markdown-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/peggy-toml-merge/README.md b/packages/peggy-toml-merge/README.md
index 810f323..4491a65 100644
--- a/packages/peggy-toml-merge/README.md
+++ b/packages/peggy-toml-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/plain-merge/README.md b/packages/plain-merge/README.md
index 9e4c03e..8d15407 100644
--- a/packages/plain-merge/README.md
+++ b/packages/plain-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/ruby-merge/README.md b/packages/ruby-merge/README.md
index df76f1e..cf8c545 100644
--- a/packages/ruby-merge/README.md
+++ b/packages/ruby-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/rust-merge/README.md b/packages/rust-merge/README.md
index 8d627c1..edeaa07 100644
--- a/packages/rust-merge/README.md
+++ b/packages/rust-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/toml-merge/README.md b/packages/toml-merge/README.md
index 3e43c26..0786f20 100644
--- a/packages/toml-merge/README.md
+++ b/packages/toml-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/tree-haver/README.md b/packages/tree-haver/README.md
index e4e6ed7..3b17445 100644
--- a/packages/tree-haver/README.md
+++ b/packages/tree-haver/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/typescript-compiler-merge/README.md b/packages/typescript-compiler-merge/README.md
index 06c0d04..b0feda1 100644
--- a/packages/typescript-compiler-merge/README.md
+++ b/packages/typescript-compiler-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/typescript-merge/README.md b/packages/typescript-merge/README.md
index b169d95..9bf9554 100644
--- a/packages/typescript-merge/README.md
+++ b/packages/typescript-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/yaml-merge/README.md b/packages/yaml-merge/README.md
index 58cb800..2f6d248 100644
--- a/packages/yaml-merge/README.md
+++ b/packages/yaml-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/zip-merge/README.md b/packages/zip-merge/README.md
index 55c6e3f..ae4c6d2 100644
--- a/packages/zip-merge/README.md
+++ b/packages/zip-merge/README.md
@@ -28,6 +28,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 | zip-merge | family | zip, archive | active | documents ZIP member planning and raw-preservation behavior |
 | binary-merge | family | binary | active | documents binary preservation and diagnostics behavior |
 
+JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |

From ba8c85623f6defee1948430f554c644cb4e9f402 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 04:07:53 -0600
Subject: [PATCH 012/130] Render YAML provider note

---
 packages/ast-merge/README.md                 | 2 ++
 packages/ast-template/README.md              | 2 ++
 packages/binary-merge/README.md              | 2 ++
 packages/go-merge/README.md                  | 2 ++
 packages/js-yaml-merge/README.md             | 2 ++
 packages/json-merge/README.md                | 2 ++
 packages/kettle-nodule/README.md             | 2 ++
 packages/kettle-nodule/src/index.ts          | 2 ++
 packages/markdown-it-merge/README.md         | 2 ++
 packages/markdown-merge/README.md            | 2 ++
 packages/peggy-toml-merge/README.md          | 2 ++
 packages/plain-merge/README.md               | 2 ++
 packages/ruby-merge/README.md                | 2 ++
 packages/rust-merge/README.md                | 2 ++
 packages/toml-merge/README.md                | 2 ++
 packages/tree-haver/README.md                | 2 ++
 packages/typescript-compiler-merge/README.md | 2 ++
 packages/typescript-merge/README.md          | 2 ++
 packages/yaml-merge/README.md                | 2 ++
 packages/zip-merge/README.md                 | 2 ++
 20 files changed, 40 insertions(+)

diff --git a/packages/ast-merge/README.md b/packages/ast-merge/README.md
index d396f92..057e5b7 100644
--- a/packages/ast-merge/README.md
+++ b/packages/ast-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/ast-template/README.md b/packages/ast-template/README.md
index b31fab6..70e7fd8 100644
--- a/packages/ast-template/README.md
+++ b/packages/ast-template/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/binary-merge/README.md b/packages/binary-merge/README.md
index 67df47f..0b7c9bc 100644
--- a/packages/binary-merge/README.md
+++ b/packages/binary-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/go-merge/README.md b/packages/go-merge/README.md
index db0c91e..e7cbc3c 100644
--- a/packages/go-merge/README.md
+++ b/packages/go-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/js-yaml-merge/README.md b/packages/js-yaml-merge/README.md
index 9e50e27..9b94316 100644
--- a/packages/js-yaml-merge/README.md
+++ b/packages/js-yaml-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/json-merge/README.md b/packages/json-merge/README.md
index 40ca56f..5c1863c 100644
--- a/packages/json-merge/README.md
+++ b/packages/json-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/kettle-nodule/README.md b/packages/kettle-nodule/README.md
index f7c3a04..8ce37cf 100644
--- a/packages/kettle-nodule/README.md
+++ b/packages/kettle-nodule/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index e00e3a6..d750f4c 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -815,6 +815,8 @@ function readmeFamilyIntroAndBackendMatrix(): string {
     '',
     'JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.',
     '',
+    'YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby\'s `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.',
+    '',
     '| Backend | Languages | Families | Note |',
     '|---|---|---|---|',
     '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |',
diff --git a/packages/markdown-it-merge/README.md b/packages/markdown-it-merge/README.md
index 911f51c..8c82488 100644
--- a/packages/markdown-it-merge/README.md
+++ b/packages/markdown-it-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/markdown-merge/README.md b/packages/markdown-merge/README.md
index 1e5c328..66c4d72 100644
--- a/packages/markdown-merge/README.md
+++ b/packages/markdown-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/peggy-toml-merge/README.md b/packages/peggy-toml-merge/README.md
index 4491a65..23343f1 100644
--- a/packages/peggy-toml-merge/README.md
+++ b/packages/peggy-toml-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/plain-merge/README.md b/packages/plain-merge/README.md
index 8d15407..1564877 100644
--- a/packages/plain-merge/README.md
+++ b/packages/plain-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/ruby-merge/README.md b/packages/ruby-merge/README.md
index cf8c545..edcd9be 100644
--- a/packages/ruby-merge/README.md
+++ b/packages/ruby-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/rust-merge/README.md b/packages/rust-merge/README.md
index edeaa07..8152e76 100644
--- a/packages/rust-merge/README.md
+++ b/packages/rust-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/toml-merge/README.md b/packages/toml-merge/README.md
index 0786f20..a595f76 100644
--- a/packages/toml-merge/README.md
+++ b/packages/toml-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/tree-haver/README.md b/packages/tree-haver/README.md
index 3b17445..dc5e127 100644
--- a/packages/tree-haver/README.md
+++ b/packages/tree-haver/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/typescript-compiler-merge/README.md b/packages/typescript-compiler-merge/README.md
index b0feda1..a1ea418 100644
--- a/packages/typescript-compiler-merge/README.md
+++ b/packages/typescript-compiler-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/typescript-merge/README.md b/packages/typescript-merge/README.md
index 9bf9554..225f0ca 100644
--- a/packages/typescript-merge/README.md
+++ b/packages/typescript-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/yaml-merge/README.md b/packages/yaml-merge/README.md
index 2f6d248..e83c1ec 100644
--- a/packages/yaml-merge/README.md
+++ b/packages/yaml-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/zip-merge/README.md b/packages/zip-merge/README.md
index ae4c6d2..1b93e77 100644
--- a/packages/zip-merge/README.md
+++ b/packages/zip-merge/README.md
@@ -30,6 +30,8 @@ StructuredMerge packages provide fixture-backed merge behavior for document, con
 
 JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. The old `jsonc-merge` package name is superseded in the cross-language toolset; only Ruby may grow a legacy `require "jsonc/merge"` wrapper if packaging compatibility requires it. Current fixture-backed JSONC claims are parse support and comment-neutral owner structure; comment-preserving merge output, freeze blocks, and JSONC emitter behavior need dedicated fixtures before they appear in package examples.
 
+YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |

From 3987da2954d41825339cb45f6dcd743ade37f542 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 04:17:22 -0600
Subject: [PATCH 013/130] Render Markdown provider note

---
 packages/ast-merge/README.md                 | 2 ++
 packages/ast-template/README.md              | 2 ++
 packages/binary-merge/README.md              | 2 ++
 packages/go-merge/README.md                  | 2 ++
 packages/js-yaml-merge/README.md             | 2 ++
 packages/json-merge/README.md                | 2 ++
 packages/kettle-nodule/README.md             | 2 ++
 packages/kettle-nodule/src/index.ts          | 2 ++
 packages/markdown-it-merge/README.md         | 2 ++
 packages/markdown-merge/README.md            | 2 ++
 packages/peggy-toml-merge/README.md          | 2 ++
 packages/plain-merge/README.md               | 2 ++
 packages/ruby-merge/README.md                | 2 ++
 packages/rust-merge/README.md                | 2 ++
 packages/toml-merge/README.md                | 2 ++
 packages/tree-haver/README.md                | 2 ++
 packages/typescript-compiler-merge/README.md | 2 ++
 packages/typescript-merge/README.md          | 2 ++
 packages/yaml-merge/README.md                | 2 ++
 packages/zip-merge/README.md                 | 2 ++
 20 files changed, 40 insertions(+)

diff --git a/packages/ast-merge/README.md b/packages/ast-merge/README.md
index 057e5b7..d4f4327 100644
--- a/packages/ast-merge/README.md
+++ b/packages/ast-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/ast-template/README.md b/packages/ast-template/README.md
index 70e7fd8..a2e8368 100644
--- a/packages/ast-template/README.md
+++ b/packages/ast-template/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/binary-merge/README.md b/packages/binary-merge/README.md
index 0b7c9bc..882106c 100644
--- a/packages/binary-merge/README.md
+++ b/packages/binary-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/go-merge/README.md b/packages/go-merge/README.md
index e7cbc3c..842f374 100644
--- a/packages/go-merge/README.md
+++ b/packages/go-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/js-yaml-merge/README.md b/packages/js-yaml-merge/README.md
index 9b94316..8c536d2 100644
--- a/packages/js-yaml-merge/README.md
+++ b/packages/js-yaml-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/json-merge/README.md b/packages/json-merge/README.md
index 5c1863c..0a48d31 100644
--- a/packages/json-merge/README.md
+++ b/packages/json-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/kettle-nodule/README.md b/packages/kettle-nodule/README.md
index 8ce37cf..9f480c6 100644
--- a/packages/kettle-nodule/README.md
+++ b/packages/kettle-nodule/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/kettle-nodule/src/index.ts b/packages/kettle-nodule/src/index.ts
index d750f4c..2757496 100644
--- a/packages/kettle-nodule/src/index.ts
+++ b/packages/kettle-nodule/src/index.ts
@@ -817,6 +817,8 @@ function readmeFamilyIntroAndBackendMatrix(): string {
     '',
     'YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby\'s `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.',
     '',
+    'Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.',
+    '',
     '| Backend | Languages | Families | Note |',
     '|---|---|---|---|',
     '| tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |',
diff --git a/packages/markdown-it-merge/README.md b/packages/markdown-it-merge/README.md
index 8c82488..9b9b38f 100644
--- a/packages/markdown-it-merge/README.md
+++ b/packages/markdown-it-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/markdown-merge/README.md b/packages/markdown-merge/README.md
index 66c4d72..fa67ee9 100644
--- a/packages/markdown-merge/README.md
+++ b/packages/markdown-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/peggy-toml-merge/README.md b/packages/peggy-toml-merge/README.md
index 23343f1..2873bf7 100644
--- a/packages/peggy-toml-merge/README.md
+++ b/packages/peggy-toml-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/plain-merge/README.md b/packages/plain-merge/README.md
index 1564877..8b1d2aa 100644
--- a/packages/plain-merge/README.md
+++ b/packages/plain-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/ruby-merge/README.md b/packages/ruby-merge/README.md
index edcd9be..b83a84f 100644
--- a/packages/ruby-merge/README.md
+++ b/packages/ruby-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/rust-merge/README.md b/packages/rust-merge/README.md
index 8152e76..4788736 100644
--- a/packages/rust-merge/README.md
+++ b/packages/rust-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/toml-merge/README.md b/packages/toml-merge/README.md
index a595f76..a811fb3 100644
--- a/packages/toml-merge/README.md
+++ b/packages/toml-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/tree-haver/README.md b/packages/tree-haver/README.md
index dc5e127..f60496c 100644
--- a/packages/tree-haver/README.md
+++ b/packages/tree-haver/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/typescript-compiler-merge/README.md b/packages/typescript-compiler-merge/README.md
index a1ea418..dccaccc 100644
--- a/packages/typescript-compiler-merge/README.md
+++ b/packages/typescript-compiler-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/typescript-merge/README.md b/packages/typescript-merge/README.md
index 225f0ca..173e59b 100644
--- a/packages/typescript-merge/README.md
+++ b/packages/typescript-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/yaml-merge/README.md b/packages/yaml-merge/README.md
index e83c1ec..227691b 100644
--- a/packages/yaml-merge/README.md
+++ b/packages/yaml-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |
diff --git a/packages/zip-merge/README.md b/packages/zip-merge/README.md
index 1b93e77..9ae71b7 100644
--- a/packages/zip-merge/README.md
+++ b/packages/zip-merge/README.md
@@ -32,6 +32,8 @@ JSONC migration note: JSONC is handled by `json-merge` as the `jsonc` dialect. T
 
 YAML provider note: `yaml-merge` is the canonical YAML family package. Ruby's `psych-merge` package is the Psych provider for that family, not a separate YAML family; old `Psych::Merge::*` examples remain provider-specific until portable fixtures cover the behavior.
 
+Markdown provider note: `markdown-merge` is the canonical Markdown family package. Provider packages own parser-specific docs and backend defaults: Go `goldmarkmerge`, Ruby `commonmarker-merge`, `markly-merge`, and `kramdown-merge`, Rust `pulldown-cmark-merge`, and TypeScript `@structuredmerge/markdown-it-merge`.
+
 | Backend | Languages | Families | Note |
 |---|---|---|---|
 | tree-sitter-language-pack | Go, Ruby, Rust, TypeScript | markdown, toml, yaml, source | Preferred cross-language parser substrate where a family has language-pack support. |

From ec8dd1e66c4d794c289fb69aa85013b339566f8a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 15:20:07 -0600
Subject: [PATCH 014/130] Support draft 02 compact ruleset directives

---
 packages/ast-merge/src/contracts.ts | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 9d60d1d..50e07bf 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -125,9 +125,14 @@ const compactRulesetSingletonDirectives = new Set([
   'read',
   'attach',
   'comment_style',
-  'render'
+  'render',
+  'render_strategy'
 ]);
 const compactRulesetRepeatableKeyedDirectives = new Set([
+  'backend',
+  'node_role',
+  'atomic',
+  'child_group',
   'capability',
   'logical_owner',
   'repair',
@@ -206,7 +211,7 @@ export function parseCompactRuleset(source: string): ParseResult<CompactRuleset>
       );
     }
     if (compactRulesetRepeatableKeyedDirectives.has(name)) {
-      const key = `${name}\u0000${args[0]}`;
+      const key = compactRulesetRepeatableKey(name, args);
       if (seenRepeatableKeys.has(key)) {
         diagnostics.push(
           compactRulesetDiagnostic(
@@ -251,6 +256,13 @@ function compactRulesetKnownDirective(name: string): boolean {
   );
 }
 
+function compactRulesetRepeatableKey(name: string, args: readonly string[]): string {
+  if (name === 'child_group' && args.length > 1) {
+    return `${name}\u0000${args[0]}\u0000${args[1]}`;
+  }
+  return `${name}\u0000${args[0]}`;
+}
+
 function compactRulesetDiagnostic(message: string, path?: string): Diagnostic {
   return {
     severity: 'error',

From 22250c7b9522d66c5240da70deafb4ba6115bd1f Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 15:27:06 -0600
Subject: [PATCH 015/130] Add compact ruleset profile extraction

---
 packages/ast-merge/src/contracts.ts           | 147 ++++++++++++++++++
 packages/ast-merge/src/index.ts               |   9 ++
 .../ast-merge/test/compact-ruleset.test.ts    |  35 ++++-
 3 files changed, 190 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 50e07bf..242f796 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -115,6 +115,62 @@ export interface CompactRuleset {
   readonly comments: readonly string[];
 }
 
+export interface CompactRulesetBackendDeclaration {
+  readonly backend: string;
+  readonly support: string;
+}
+
+export interface CompactRulesetNodeRole {
+  readonly selector: string;
+  readonly role: string;
+}
+
+export interface CompactRulesetAtomicNode {
+  readonly selector: string;
+  readonly atomic: boolean;
+}
+
+export interface CompactRulesetChildGroup {
+  readonly parent_selector: string;
+  readonly name: string;
+  readonly policy: string;
+}
+
+export interface CompactRulesetNamedValue {
+  readonly name: string;
+  readonly value: string;
+}
+
+export interface CompactRulesetSurfaceDeclaration {
+  readonly name: string;
+  readonly selector: string;
+}
+
+export interface CompactRulesetDelegateDeclaration {
+  readonly surface: string;
+  readonly policy: string;
+}
+
+export interface CompactRulesetProfile {
+  readonly format: string;
+  readonly owners: string;
+  readonly match: string;
+  readonly read: string;
+  readonly attach: string;
+  readonly comment_style?: string;
+  readonly render?: string;
+  readonly render_strategy?: string;
+  readonly backends: readonly CompactRulesetBackendDeclaration[];
+  readonly node_roles: readonly CompactRulesetNodeRole[];
+  readonly atomic_nodes: readonly CompactRulesetAtomicNode[];
+  readonly child_groups: readonly CompactRulesetChildGroup[];
+  readonly capabilities: readonly CompactRulesetNamedValue[];
+  readonly logical_owners: readonly CompactRulesetNamedValue[];
+  readonly repairs: readonly CompactRulesetNamedValue[];
+  readonly surfaces: readonly CompactRulesetSurfaceDeclaration[];
+  readonly delegates: readonly CompactRulesetDelegateDeclaration[];
+}
+
 const compactRulesetIdentifierPattern = /^[A-Za-z][A-Za-z0-9_.-]*$/;
 const compactRulesetTokenPattern = /^[\x21\x24-\x7e]+$/;
 const compactRulesetRequiredDirectives = ['format', 'owners', 'match', 'read', 'attach'] as const;
@@ -250,6 +306,97 @@ export function parseCompactRuleset(source: string): ParseResult<CompactRuleset>
     : { ok: false, diagnostics, policies: [] };
 }
 
+export function compactRulesetFeatureProfile(ruleset: CompactRuleset): CompactRulesetProfile {
+  const profile: MutableCompactRulesetProfile = {
+    format: '',
+    owners: '',
+    match: '',
+    read: '',
+    attach: '',
+    backends: [],
+    node_roles: [],
+    atomic_nodes: [],
+    child_groups: [],
+    capabilities: [],
+    logical_owners: [],
+    repairs: [],
+    surfaces: [],
+    delegates: []
+  };
+
+  for (const directive of ruleset.directives) {
+    const args = directive.arguments;
+    if (args.length === 0) continue;
+    switch (directive.name) {
+      case 'format':
+        profile.format = args[0];
+        break;
+      case 'owners':
+        profile.owners = args[0];
+        break;
+      case 'match':
+        profile.match = args[0];
+        break;
+      case 'read':
+        profile.read = args[0];
+        break;
+      case 'attach':
+        profile.attach = args[0];
+        break;
+      case 'comment_style':
+        profile.comment_style = args[0];
+        break;
+      case 'render':
+        profile.render = args[0];
+        break;
+      case 'render_strategy':
+        profile.render_strategy = args[0];
+        break;
+      case 'backend':
+        if (args.length > 1) profile.backends.push({ backend: args[0], support: args[1] });
+        break;
+      case 'node_role':
+        if (args.length > 1) profile.node_roles.push({ selector: args[0], role: args[1] });
+        break;
+      case 'atomic':
+        if (args.length > 1) profile.atomic_nodes.push({ selector: args[0], atomic: args[1] === 'true' });
+        break;
+      case 'child_group':
+        if (args.length > 2) {
+          profile.child_groups.push({
+            parent_selector: args[0],
+            name: args[1],
+            policy: args[2]
+          });
+        }
+        break;
+      case 'capability':
+        if (args.length > 1) profile.capabilities.push({ name: args[0], value: args[1] });
+        break;
+      case 'logical_owner':
+        if (args.length > 1) profile.logical_owners.push({ name: args[0], value: args[1] });
+        break;
+      case 'repair':
+        if (args.length > 1) profile.repairs.push({ name: args[0], value: args[1] });
+        break;
+      case 'surface':
+        if (args.length > 1) profile.surfaces.push({ name: args[0], selector: args[1] });
+        break;
+      case 'delegate':
+        if (args.length > 1) profile.delegates.push({ surface: args[0], policy: args[1] });
+        break;
+    }
+  }
+
+  return profile;
+}
+
+type MutableCompactRulesetProfile = {
+  -readonly [K in keyof CompactRulesetProfile]: CompactRulesetProfile[K] extends readonly (infer T)[]
+    ? T[]
+    : CompactRulesetProfile[K];
+};
+
 function compactRulesetKnownDirective(name: string): boolean {
   return (
     compactRulesetSingletonDirectives.has(name) || compactRulesetRepeatableKeyedDirectives.has(name)
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index a04881a..67aba6a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -35,7 +35,15 @@ export type {
   DiagnosticCategory,
   DiagnosticSeverity,
   CompactRuleset,
+  CompactRulesetAtomicNode,
+  CompactRulesetBackendDeclaration,
+  CompactRulesetChildGroup,
+  CompactRulesetDelegateDeclaration,
   CompactRulesetDirective,
+  CompactRulesetNamedValue,
+  CompactRulesetNodeRole,
+  CompactRulesetProfile,
+  CompactRulesetSurfaceDeclaration,
   DiscoveredSurface,
   DelegatedChildOperation,
   ReviewDiagnosticReason,
@@ -246,6 +254,7 @@ export {
   STRUCTURED_EDIT_TRANSPORT_VERSION,
   REVIEW_TRANSPORT_VERSION,
   conformanceManifestReplayContext,
+  compactRulesetFeatureProfile,
   parseCompactRuleset,
   conformanceManifestReviewStateEnvelope,
   conformanceManifestReviewRequestIds,
diff --git a/packages/ast-merge/test/compact-ruleset.test.ts b/packages/ast-merge/test/compact-ruleset.test.ts
index 55705c5..d7c324a 100644
--- a/packages/ast-merge/test/compact-ruleset.test.ts
+++ b/packages/ast-merge/test/compact-ruleset.test.ts
@@ -1,7 +1,7 @@
 import { readdirSync, readFileSync, statSync } from 'node:fs';
 import path from 'node:path';
 import { describe, expect, it } from 'vitest';
-import { parseCompactRuleset } from '../src/index';
+import { compactRulesetFeatureProfile, parseCompactRuleset } from '../src/index';
 
 function rulesetFixtures(root: string): string[] {
   return readdirSync(root).flatMap((entry) => {
@@ -40,4 +40,37 @@ describe('parseCompactRuleset', () => {
       expect(result.diagnostics.length, name).toBeGreaterThan(0);
     }
   });
+
+  it('derives the shared compact ruleset feature profile fixture', () => {
+    const fixture = JSON.parse(
+      readFileSync(
+        path.resolve(
+          import.meta.dirname,
+          '..',
+          '..',
+          '..',
+          '..',
+          'fixtures',
+          'diagnostics',
+          'slice-781-compact-ruleset-profile',
+          'module-profile.json'
+        ),
+        'utf8'
+      )
+    ) as { ruleset_path: string[]; profile: unknown };
+
+    const rulesetPath = path.resolve(
+      import.meta.dirname,
+      '..',
+      '..',
+      '..',
+      '..',
+      'fixtures',
+      ...fixture.ruleset_path
+    );
+    const result = parseCompactRuleset(readFileSync(rulesetPath, 'utf8'));
+    expect(result.ok, JSON.stringify(result.diagnostics)).toBe(true);
+    expect(result.analysis).toBeDefined();
+    expect(compactRulesetFeatureProfile(result.analysis!)).toEqual(fixture.profile);
+  });
 });

From 847039fe009360e954565feb804db5cf1135271d Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 15:35:04 -0600
Subject: [PATCH 016/130] Add normalized tree node contract

---
 packages/tree-haver/src/contracts.ts          | 39 ++++++++++++
 packages/tree-haver/src/index.ts              |  3 +
 .../test/fixtures.integration.test.ts         | 61 +++++++++++++++++++
 3 files changed, 103 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 8efa295..c013732 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -103,6 +103,45 @@ export interface SourceSpan {
   readonly endPoint: SourcePoint;
 }
 
+export type NodeRole =
+  | 'structural'
+  | 'token'
+  | 'trivia'
+  | 'comment'
+  | 'delimiter'
+  | 'separator'
+  | 'virtual'
+  | 'error'
+  | 'opaque';
+
+export interface NormalizedTreeNode {
+  readonly id: string;
+  readonly kind: string;
+  readonly role: NodeRole;
+  readonly parentId?: string;
+  readonly childIds: readonly string[];
+  readonly span: SourceSpan;
+  readonly fieldName?: string;
+  readonly named: boolean;
+  readonly anonymous: boolean;
+  readonly hasSourceText: boolean;
+  readonly sourceFragment: string;
+}
+
+export function nodeRoles(): readonly NodeRole[] {
+  return [
+    'structural',
+    'token',
+    'trivia',
+    'comment',
+    'delimiter',
+    'separator',
+    'virtual',
+    'error',
+    'opaque'
+  ];
+}
+
 export interface ByteEditSpan {
   readonly startByte: number;
   readonly oldEndByte: number;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index ffacdd6..338c738 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -22,6 +22,8 @@ export type {
   KaitaiTreeNode,
   LanguagePackAnalysis,
   LanguagePackProcessAnalysis,
+  NodeRole,
+  NormalizedTreeNode,
   ParserAdapter,
   ParserDiagnostics,
   ParserRequest,
@@ -59,6 +61,7 @@ export {
   kaitaiFeatureProfile,
   KREUZBERG_LANGUAGE_PACK_BACKEND,
   languagePackAdapterInfo,
+  nodeRoles,
   PEGGY_BACKEND,
   peggyAdapterInfo,
   peggyFeatureProfile,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 370cb99..eb3db81 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -12,6 +12,7 @@ import type {
   BinaryScalarValue,
   ByteEditSpan,
   FeatureProfile,
+  NormalizedTreeNode,
   ParserRequest,
   PolicyReference,
   ZipUnsafeEntry
@@ -34,6 +35,7 @@ import {
   PEGGY_BACKEND,
   peggyAdapterInfo,
   peggyFeatureProfile,
+  nodeRoles,
   registerBackend,
   registeredBackends,
   sliceByteRange,
@@ -193,6 +195,24 @@ interface ConformanceManifest {
   >;
 }
 
+interface NormalizedTreeNodeFixture {
+  readonly id: string;
+  readonly kind: string;
+  readonly role: NormalizedTreeNode['role'];
+  readonly parent_id: string | null;
+  readonly child_ids: readonly string[];
+  readonly span: {
+    readonly range: { readonly start_byte: number; readonly end_byte: number };
+    readonly start_point: { readonly row: number; readonly column: number };
+    readonly end_point: { readonly row: number; readonly column: number };
+  };
+  readonly field_name: string | null;
+  readonly named: boolean;
+  readonly anonymous: boolean;
+  readonly has_source_text: boolean;
+  readonly source_fragment: string;
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -214,6 +234,29 @@ function diagnosticsFixturePath(role: string): string[] {
   return [...entry.path];
 }
 
+function normalizedTreeNode(fixture: NormalizedTreeNodeFixture): NormalizedTreeNode {
+  return {
+    id: fixture.id,
+    kind: fixture.kind,
+    role: fixture.role,
+    parentId: fixture.parent_id ?? undefined,
+    childIds: fixture.child_ids,
+    span: {
+      range: {
+        startByte: fixture.span.range.start_byte,
+        endByte: fixture.span.range.end_byte
+      },
+      startPoint: fixture.span.start_point,
+      endPoint: fixture.span.end_point
+    },
+    fieldName: fixture.field_name ?? undefined,
+    named: fixture.named,
+    anonymous: fixture.anonymous,
+    hasSourceText: fixture.has_source_text,
+    sourceFragment: fixture.source_fragment
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -236,6 +279,24 @@ describe('tree-haver shared fixtures', () => {
     }).toEqual(fixture.adapter_info);
   });
 
+  it('conforms to the slice-782 normalized tree node fixture', () => {
+    const fixture = readFixture<{
+      node_roles: string[];
+      node: NormalizedTreeNodeFixture;
+      child: NormalizedTreeNodeFixture;
+    }>('diagnostics', 'slice-782-normalized-tree-node', 'normalized-tree-node.json');
+
+    expect(nodeRoles()).toEqual(fixture.node_roles);
+    const node = normalizedTreeNode(fixture.node);
+    const child = normalizedTreeNode(fixture.child);
+
+    expect(node.role).toBe('structural');
+    expect(node.childIds[1]).toBe(child.id);
+    expect(child.parentId).toBe(node.id);
+    expect(child.fieldName).toBe('declaration');
+    expect(child.hasSourceText).toBe(true);
+  });
+
   it('conforms to the slice-19 adapter policy support fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(
       ...diagnosticsFixturePath('adapter_policy_support')

From 5d69706d20dea48418e21aea991cf06dfe0a3c6b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 15:37:36 -0600
Subject: [PATCH 017/130] Add backend capability contract

---
 packages/tree-haver/src/contracts.ts          | 26 ++++++++
 packages/tree-haver/src/index.ts              |  3 +-
 .../test/fixtures.integration.test.ts         | 60 +++++++++++++++++++
 3 files changed, 88 insertions(+), 1 deletion(-)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index c013732..addecb2 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -62,6 +62,32 @@ export interface FeatureProfile {
   readonly supportedPolicies?: readonly PolicyReference[];
 }
 
+export interface ParserIdentity {
+  readonly name: string;
+  readonly version: string;
+  readonly implementation: string;
+}
+
+export interface LanguageVersion {
+  readonly version: string;
+  readonly dialect?: string;
+}
+
+export interface BackendCapability {
+  readonly backendRef: BackendReference;
+  readonly language: string;
+  readonly parserIdentity: ParserIdentity;
+  readonly languageVersion: LanguageVersion;
+  readonly parseErrorBehavior: string;
+  readonly sourceSpanSupport: string;
+  readonly sourceFragmentSupport: string;
+  readonly renderStrategies: readonly string[];
+  readonly semanticRoleSupport: string;
+  readonly normalizedTreeSupport: boolean;
+  readonly nativeNodeAccess: boolean;
+  readonly diagnostics: readonly string[];
+}
+
 export interface ParserAdapter<TAnalysis extends AnalysisHandle> {
   readonly info: AdapterInfo;
   parse(request: ParserRequest): ParseResult<TAnalysis>;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 338c738..5c2c6fd 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -3,6 +3,8 @@ export const packageName = '@structuredmerge/tree-haver';
 export type {
   AdapterInfo,
   AnalysisHandle,
+  BackendCapability,
+  BackendReference,
   BinaryDiagnostic,
   BinaryMergeReport,
   BinaryNestedDispatch,
@@ -10,7 +12,6 @@ export type {
   BinaryRawPayload,
   BinaryRenderPolicy,
   BinaryScalarValue,
-  BackendReference,
   ByteEditSpan,
   ByteRange,
   Diagnostic,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index eb3db81..4a3765b 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -3,6 +3,7 @@ import path from 'node:path';
 import { describe, expect, it } from 'vitest';
 import type {
   AdapterInfo,
+  BackendCapability,
   BackendReference,
   BinaryDiagnostic,
   BinaryMergeReport,
@@ -213,6 +214,28 @@ interface NormalizedTreeNodeFixture {
   readonly source_fragment: string;
 }
 
+interface BackendCapabilityFixture {
+  readonly backend_ref: BackendReference;
+  readonly language: string;
+  readonly parser_identity: {
+    readonly name: string;
+    readonly version: string;
+    readonly implementation: string;
+  };
+  readonly language_version: {
+    readonly version: string;
+    readonly dialect: string | null;
+  };
+  readonly parse_error_behavior: string;
+  readonly source_span_support: string;
+  readonly source_fragment_support: string;
+  readonly render_strategies: readonly string[];
+  readonly semantic_role_support: string;
+  readonly normalized_tree_support: boolean;
+  readonly native_node_access: boolean;
+  readonly diagnostics: readonly string[];
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -257,6 +280,26 @@ function normalizedTreeNode(fixture: NormalizedTreeNodeFixture): NormalizedTreeN
   };
 }
 
+function backendCapability(fixture: BackendCapabilityFixture): BackendCapability {
+  return {
+    backendRef: fixture.backend_ref,
+    language: fixture.language,
+    parserIdentity: fixture.parser_identity,
+    languageVersion: {
+      version: fixture.language_version.version,
+      dialect: fixture.language_version.dialect ?? undefined
+    },
+    parseErrorBehavior: fixture.parse_error_behavior,
+    sourceSpanSupport: fixture.source_span_support,
+    sourceFragmentSupport: fixture.source_fragment_support,
+    renderStrategies: fixture.render_strategies,
+    semanticRoleSupport: fixture.semantic_role_support,
+    normalizedTreeSupport: fixture.normalized_tree_support,
+    nativeNodeAccess: fixture.native_node_access,
+    diagnostics: fixture.diagnostics
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -297,6 +340,23 @@ describe('tree-haver shared fixtures', () => {
     expect(child.hasSourceText).toBe(true);
   });
 
+  it('conforms to the slice-783 backend capability report fixture', () => {
+    const fixture = readFixture<{ capability: BackendCapabilityFixture }>(
+      'diagnostics',
+      'slice-783-backend-capability-report',
+      'backend-capability-report.json'
+    );
+    const capability = backendCapability(fixture.capability);
+
+    expect(capability.backendRef).toEqual({ id: 'go-dst', family: 'native' });
+    expect(capability.language).toBe('go');
+    expect(capability.parserIdentity.name).toBe('github.com/dave/dst');
+    expect(capability.parseErrorBehavior).toBe('diagnostic_and_partial_tree');
+    expect(capability.renderStrategies[0]).toBe('source_fragment_reuse');
+    expect(capability.normalizedTreeSupport).toBe(true);
+    expect(capability.nativeNodeAccess).toBe(true);
+  });
+
   it('conforms to the slice-19 adapter policy support fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(
       ...diagnosticsFixturePath('adapter_policy_support')

From bfff40c0e8810f63503b73758359e05f80dd2b9f Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 15:40:47 -0600
Subject: [PATCH 018/130] Add source fragment extraction contract

---
 packages/tree-haver/src/contracts.ts          | 37 +++++++++++++++
 packages/tree-haver/src/index.ts              |  2 +
 .../test/fixtures.integration.test.ts         | 45 +++++++++++++++++++
 3 files changed, 84 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index addecb2..3fa8da6 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -154,6 +154,15 @@ export interface NormalizedTreeNode {
   readonly sourceFragment: string;
 }
 
+export interface SourceFragment {
+  readonly text: string;
+  readonly span: SourceSpan;
+  readonly available: boolean;
+  readonly strategy: string;
+  readonly byteLength: number;
+  readonly diagnostics: readonly string[];
+}
+
 export function nodeRoles(): readonly NodeRole[] {
   return [
     'structural',
@@ -319,6 +328,34 @@ export function sliceByteRange(source: string, range: ByteRange): string {
   return sourceBytes.subarray(range.startByte, range.endByte).toString('utf8');
 }
 
+export function extractSourceFragment(
+  source: string,
+  span: SourceSpan,
+  strategy: string
+): SourceFragment {
+  try {
+    const text = sliceByteRange(source, span.range);
+
+    return {
+      text,
+      span,
+      available: true,
+      strategy,
+      byteLength: Buffer.from(text, 'utf8').length,
+      diagnostics: []
+    };
+  } catch (error) {
+    return {
+      text: '',
+      span,
+      available: false,
+      strategy,
+      byteLength: 0,
+      diagnostics: [error instanceof Error ? error.message : String(error)]
+    };
+  }
+}
+
 export function byteOffsetForPoint(source: string, point: SourcePoint): number {
   if (point.row < 0 || point.column < 0) {
     throw new RangeError(`invalid source point (${point.row}, ${point.column})`);
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 5c2c6fd..f40216b 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -36,6 +36,7 @@ export type {
   ProcessRequest,
   ProcessSpan,
   ProcessStructureItem,
+  SourceFragment,
   SourcePoint,
   SourceSpan,
   ZipArchiveEntry,
@@ -57,6 +58,7 @@ export {
   byteRangeOverlaps,
   createPeggyParser,
   currentBackendId,
+  extractSourceFragment,
   KAITAI_STRUCT_BACKEND,
   kaitaiAdapterInfo,
   kaitaiFeatureProfile,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 4a3765b..c4eaac3 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -16,6 +16,7 @@ import type {
   NormalizedTreeNode,
   ParserRequest,
   PolicyReference,
+  SourceSpan,
   ZipUnsafeEntry
 } from '../src/index';
 import { processWithLanguagePack } from '../src/index';
@@ -28,6 +29,7 @@ import {
   byteRangeLength,
   byteRangeOverlaps,
   currentBackendId,
+  extractSourceFragment,
   kaitaiAdapterInfo,
   kaitaiFeatureProfile,
   KAITAI_STRUCT_BACKEND,
@@ -236,6 +238,23 @@ interface BackendCapabilityFixture {
   readonly diagnostics: readonly string[];
 }
 
+interface SourceFragmentExtractionFixture {
+  readonly source: string;
+  readonly strategy: string;
+  readonly span: {
+    readonly range: { readonly start_byte: number; readonly end_byte: number };
+    readonly start_point: { readonly row: number; readonly column: number };
+    readonly end_point: { readonly row: number; readonly column: number };
+  };
+  readonly fragment: {
+    readonly text: string;
+    readonly available: boolean;
+    readonly strategy: string;
+    readonly byte_length: number;
+    readonly diagnostics: readonly string[];
+  };
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -300,6 +319,17 @@ function backendCapability(fixture: BackendCapabilityFixture): BackendCapability
   };
 }
 
+function sourceSpan(fixture: SourceFragmentExtractionFixture['span']): SourceSpan {
+  return {
+    range: {
+      startByte: fixture.range.start_byte,
+      endByte: fixture.range.end_byte
+    },
+    startPoint: fixture.start_point,
+    endPoint: fixture.end_point
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -357,6 +387,21 @@ describe('tree-haver shared fixtures', () => {
     expect(capability.nativeNodeAccess).toBe(true);
   });
 
+  it('conforms to the slice-784 source fragment extraction fixture', () => {
+    const fixture = readFixture<SourceFragmentExtractionFixture>(
+      'diagnostics',
+      'slice-784-source-fragment-extraction',
+      'source-fragment-extraction.json'
+    );
+    const fragment = extractSourceFragment(fixture.source, sourceSpan(fixture.span), fixture.strategy);
+
+    expect(fragment.text).toBe(fixture.fragment.text);
+    expect(fragment.available).toBe(fixture.fragment.available);
+    expect(fragment.strategy).toBe(fixture.fragment.strategy);
+    expect(fragment.byteLength).toBe(fixture.fragment.byte_length);
+    expect(fragment.diagnostics).toHaveLength(fixture.fragment.diagnostics.length);
+  });
+
   it('conforms to the slice-19 adapter policy support fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(
       ...diagnosticsFixturePath('adapter_policy_support')

From a3829245decbeceffd736de248c97f2a50c1c892 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 15:42:41 -0600
Subject: [PATCH 019/130] Add parse error tolerance contract

---
 packages/tree-haver/src/contracts.ts          | 15 +++++++
 packages/tree-haver/src/index.ts              |  1 +
 .../test/fixtures.integration.test.ts         | 44 +++++++++++++++++++
 3 files changed, 60 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 3fa8da6..613f480 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -88,6 +88,21 @@ export interface BackendCapability {
   readonly diagnostics: readonly string[];
 }
 
+export interface ParseErrorNode {
+  readonly kind: string;
+  readonly span: SourceSpan;
+  readonly message: string;
+}
+
+export interface ParseErrorTolerance {
+  readonly backendRef: BackendReference;
+  readonly language: string;
+  readonly behavior: string;
+  readonly toleratesErrors: boolean;
+  readonly errorNodes: readonly ParseErrorNode[];
+  readonly diagnostics: readonly string[];
+}
+
 export interface ParserAdapter<TAnalysis extends AnalysisHandle> {
   readonly info: AdapterInfo;
   parse(request: ParserRequest): ParseResult<TAnalysis>;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index f40216b..9be51e0 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -25,6 +25,7 @@ export type {
   LanguagePackProcessAnalysis,
   NodeRole,
   NormalizedTreeNode,
+  ParseErrorTolerance,
   ParserAdapter,
   ParserDiagnostics,
   ParserRequest,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index c4eaac3..32d8b89 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -14,6 +14,7 @@ import type {
   ByteEditSpan,
   FeatureProfile,
   NormalizedTreeNode,
+  ParseErrorTolerance,
   ParserRequest,
   PolicyReference,
   SourceSpan,
@@ -255,6 +256,19 @@ interface SourceFragmentExtractionFixture {
   };
 }
 
+interface ParseErrorToleranceFixture {
+  readonly backend_ref: BackendReference;
+  readonly language: string;
+  readonly behavior: string;
+  readonly tolerates_errors: boolean;
+  readonly error_nodes: Array<{
+    readonly kind: string;
+    readonly span: SourceFragmentExtractionFixture['span'];
+    readonly message: string;
+  }>;
+  readonly diagnostics: readonly string[];
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -330,6 +344,21 @@ function sourceSpan(fixture: SourceFragmentExtractionFixture['span']): SourceSpa
   };
 }
 
+function parseErrorTolerance(fixture: ParseErrorToleranceFixture): ParseErrorTolerance {
+  return {
+    backendRef: fixture.backend_ref,
+    language: fixture.language,
+    behavior: fixture.behavior,
+    toleratesErrors: fixture.tolerates_errors,
+    errorNodes: fixture.error_nodes.map((node) => ({
+      kind: node.kind,
+      span: sourceSpan(node.span),
+      message: node.message
+    })),
+    diagnostics: fixture.diagnostics
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -402,6 +431,21 @@ describe('tree-haver shared fixtures', () => {
     expect(fragment.diagnostics).toHaveLength(fixture.fragment.diagnostics.length);
   });
 
+  it('conforms to the slice-785 parse error tolerance fixture', () => {
+    const fixture = readFixture<{ parse_error_tolerance: ParseErrorToleranceFixture }>(
+      'diagnostics',
+      'slice-785-parse-error-tolerance',
+      'parse-error-tolerance.json'
+    );
+    const tolerance = parseErrorTolerance(fixture.parse_error_tolerance);
+
+    expect(tolerance.backendRef.id).toBe('tree-sitter-go');
+    expect(tolerance.behavior).toBe('diagnostic_and_partial_tree');
+    expect(tolerance.toleratesErrors).toBe(true);
+    expect(tolerance.errorNodes[0]?.span.range.startByte).toBe(27);
+    expect(tolerance.diagnostics[0]).toBe('partial tree contains parser error nodes');
+  });
+
   it('conforms to the slice-19 adapter policy support fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(
       ...diagnosticsFixturePath('adapter_policy_support')

From 180fed13e319e721d48044e87e08d953caef7843 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:02:02 -0600
Subject: [PATCH 020/130] Add progressive node metadata contract

---
 packages/tree-haver/src/contracts.ts          |  5 ++++
 .../test/fixtures.integration.test.ts         | 28 ++++++++++++++++++-
 2 files changed, 32 insertions(+), 1 deletion(-)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 613f480..a64c3c9 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -167,6 +167,11 @@ export interface NormalizedTreeNode {
   readonly anonymous: boolean;
   readonly hasSourceText: boolean;
   readonly sourceFragment: string;
+  readonly backendKind?: string;
+  readonly semanticRoles: readonly string[];
+  readonly backendRoles: readonly string[];
+  readonly unsupportedFeatures: readonly string[];
+  readonly metadata: Readonly<Record<string, Readonly<Record<string, string>>>>;
 }
 
 export interface SourceFragment {
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 32d8b89..5e3c6dc 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -215,6 +215,11 @@ interface NormalizedTreeNodeFixture {
   readonly anonymous: boolean;
   readonly has_source_text: boolean;
   readonly source_fragment: string;
+  readonly backend_kind?: string;
+  readonly semantic_roles?: readonly string[];
+  readonly backend_roles?: readonly string[];
+  readonly unsupported_features?: readonly string[];
+  readonly metadata?: Readonly<Record<string, Readonly<Record<string, string>>>>;
 }
 
 interface BackendCapabilityFixture {
@@ -309,7 +314,12 @@ function normalizedTreeNode(fixture: NormalizedTreeNodeFixture): NormalizedTreeN
     named: fixture.named,
     anonymous: fixture.anonymous,
     hasSourceText: fixture.has_source_text,
-    sourceFragment: fixture.source_fragment
+    sourceFragment: fixture.source_fragment,
+    backendKind: fixture.backend_kind,
+    semanticRoles: fixture.semantic_roles ?? [],
+    backendRoles: fixture.backend_roles ?? [],
+    unsupportedFeatures: fixture.unsupported_features ?? [],
+    metadata: fixture.metadata ?? {}
   };
 }
 
@@ -399,6 +409,22 @@ describe('tree-haver shared fixtures', () => {
     expect(child.hasSourceText).toBe(true);
   });
 
+  it('conforms to the slice-786 progressive node metadata fixture', () => {
+    const fixture = readFixture<{
+      enhanced_node: NormalizedTreeNodeFixture;
+      limited_node: NormalizedTreeNodeFixture;
+    }>('diagnostics', 'slice-786-progressive-node-metadata', 'progressive-node-metadata.json');
+    const enhanced = normalizedTreeNode(fixture.enhanced_node);
+    const limited = normalizedTreeNode(fixture.limited_node);
+
+    expect(enhanced.backendKind).toBe('FuncDecl');
+    expect(enhanced.semanticRoles[0]).toBe('declaration');
+    expect(enhanced.metadata.go_dst?.node_path).toBe('decls[0]');
+    expect(limited.hasSourceText).toBe(false);
+    expect(limited.unsupportedFeatures[1]).toBe('source_fragment');
+    expect(limited.metadata.psych?.location_support).toBe('line_column_only');
+  });
+
   it('conforms to the slice-783 backend capability report fixture', () => {
     const fixture = readFixture<{ capability: BackendCapabilityFixture }>(
       'diagnostics',

From e3ac3a5a19c612711e3d0962144ef7be2d8a5c55 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:24:20 -0600
Subject: [PATCH 021/130] Add native parser adapter contract

---
 packages/tree-haver/src/contracts.ts          | 21 ++++++
 packages/tree-haver/src/index.ts              |  2 +
 .../test/fixtures.integration.test.ts         | 65 +++++++++++++++++++
 3 files changed, 88 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index a64c3c9..28663f8 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -103,6 +103,27 @@ export interface ParseErrorTolerance {
   readonly diagnostics: readonly string[];
 }
 
+export interface NativeParserProvider {
+  readonly id: string;
+  readonly family: string;
+  readonly language: string;
+  readonly operations: readonly string[];
+  readonly retainsNativeTree: boolean;
+  readonly nativeTreeVisibility: string;
+  readonly metadataPolicy: string;
+}
+
+export interface NormalizedParseResult {
+  readonly ok: boolean;
+  readonly backendCapability: BackendCapability;
+  readonly rootId: string;
+  readonly nodes: readonly NormalizedTreeNode[];
+  readonly parseErrorTolerance: ParseErrorTolerance;
+  readonly sourceFragmentsAvailable: boolean;
+  readonly diagnostics: readonly string[];
+  readonly metadata: Readonly<Record<string, Readonly<Record<string, string>>>>;
+}
+
 export interface ParserAdapter<TAnalysis extends AnalysisHandle> {
   readonly info: AdapterInfo;
   parse(request: ParserRequest): ParseResult<TAnalysis>;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 9be51e0..865f88f 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -23,6 +23,8 @@ export type {
   KaitaiTreeNode,
   LanguagePackAnalysis,
   LanguagePackProcessAnalysis,
+  NativeParserProvider,
+  NormalizedParseResult,
   NodeRole,
   NormalizedTreeNode,
   ParseErrorTolerance,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 5e3c6dc..4b13aca 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -13,6 +13,8 @@ import type {
   BinaryScalarValue,
   ByteEditSpan,
   FeatureProfile,
+  NativeParserProvider,
+  NormalizedParseResult,
   NormalizedTreeNode,
   ParseErrorTolerance,
   ParserRequest,
@@ -274,6 +276,27 @@ interface ParseErrorToleranceFixture {
   readonly diagnostics: readonly string[];
 }
 
+interface NativeParserProviderFixture {
+  readonly id: string;
+  readonly family: string;
+  readonly language: string;
+  readonly operations: readonly string[];
+  readonly retains_native_tree: boolean;
+  readonly native_tree_visibility: string;
+  readonly metadata_policy: string;
+}
+
+interface NormalizedParseResultFixture {
+  readonly ok: boolean;
+  readonly backend_capability: BackendCapabilityFixture;
+  readonly root_id: string;
+  readonly nodes: readonly NormalizedTreeNodeFixture[];
+  readonly parse_error_tolerance: ParseErrorToleranceFixture;
+  readonly source_fragments_available: boolean;
+  readonly diagnostics: readonly string[];
+  readonly metadata: Readonly<Record<string, Readonly<Record<string, string>>>>;
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -369,6 +392,31 @@ function parseErrorTolerance(fixture: ParseErrorToleranceFixture): ParseErrorTol
   };
 }
 
+function nativeParserProvider(fixture: NativeParserProviderFixture): NativeParserProvider {
+  return {
+    id: fixture.id,
+    family: fixture.family,
+    language: fixture.language,
+    operations: fixture.operations,
+    retainsNativeTree: fixture.retains_native_tree,
+    nativeTreeVisibility: fixture.native_tree_visibility,
+    metadataPolicy: fixture.metadata_policy
+  };
+}
+
+function normalizedParseResult(fixture: NormalizedParseResultFixture): NormalizedParseResult {
+  return {
+    ok: fixture.ok,
+    backendCapability: backendCapability(fixture.backend_capability),
+    rootId: fixture.root_id,
+    nodes: fixture.nodes.map(normalizedTreeNode),
+    parseErrorTolerance: parseErrorTolerance(fixture.parse_error_tolerance),
+    sourceFragmentsAvailable: fixture.source_fragments_available,
+    diagnostics: fixture.diagnostics,
+    metadata: fixture.metadata
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -425,6 +473,23 @@ describe('tree-haver shared fixtures', () => {
     expect(limited.metadata.psych?.location_support).toBe('line_column_only');
   });
 
+  it('conforms to the slice-787 native parser adapter contract fixture', () => {
+    const fixture = readFixture<{
+      provider: NativeParserProviderFixture;
+      parse_result: NormalizedParseResultFixture;
+    }>('diagnostics', 'slice-787-native-parser-adapter-contract', 'native-parser-adapter-contract.json');
+    const provider = nativeParserProvider(fixture.provider);
+    const result = normalizedParseResult(fixture.parse_result);
+
+    expect(provider.id).toBe('go-dst');
+    expect(provider.retainsNativeTree).toBe(true);
+    expect(provider.nativeTreeVisibility).toBe('provider_internal');
+    expect(result.rootId).toBe(result.nodes[0]?.id);
+    expect(result.nodes[1]?.semanticRoles[1]).toBe('function');
+    expect(result.metadata.go_dst?.native_tree_visibility).toBe('provider_internal');
+    expect(result.sourceFragmentsAvailable).toBe(true);
+  });
+
   it('conforms to the slice-783 backend capability report fixture', () => {
     const fixture = readFixture<{ capability: BackendCapabilityFixture }>(
       'diagnostics',

From 15ddef07b5dd6cbda920bccc276aeae0b326ef94 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:26:51 -0600
Subject: [PATCH 022/130] Add tree-haver profile contract

---
 packages/tree-haver/src/contracts.ts          | 14 ++++++
 packages/tree-haver/src/index.ts              |  1 +
 .../test/fixtures.integration.test.ts         | 48 +++++++++++++++++++
 3 files changed, 63 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 28663f8..34d77cc 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -124,6 +124,20 @@ export interface NormalizedParseResult {
   readonly metadata: Readonly<Record<string, Readonly<Record<string, string>>>>;
 }
 
+export interface TreeHaverProfile {
+  readonly profileId: string;
+  readonly language: string;
+  readonly backendRef: BackendReference;
+  readonly providerId: string;
+  readonly nodeRoles: readonly NodeRole[];
+  readonly normalizedNodeFields: readonly string[];
+  readonly optionalNodeFeatures: readonly string[];
+  readonly unsupportedDefaults: Readonly<Record<string, string>>;
+  readonly capability: BackendCapability;
+  readonly fixtureSlices: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export interface ParserAdapter<TAnalysis extends AnalysisHandle> {
   readonly info: AdapterInfo;
   parse(request: ParserRequest): ParseResult<TAnalysis>;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 865f88f..2487780 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -42,6 +42,7 @@ export type {
   SourceFragment,
   SourcePoint,
   SourceSpan,
+  TreeHaverProfile,
   ZipArchiveEntry,
   ZipArchiveInfo,
   ZipFamilyReport,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 4b13aca..d35c618 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -20,6 +20,7 @@ import type {
   ParserRequest,
   PolicyReference,
   SourceSpan,
+  TreeHaverProfile,
   ZipUnsafeEntry
 } from '../src/index';
 import { processWithLanguagePack } from '../src/index';
@@ -297,6 +298,20 @@ interface NormalizedParseResultFixture {
   readonly metadata: Readonly<Record<string, Readonly<Record<string, string>>>>;
 }
 
+interface TreeHaverProfileFixture {
+  readonly profile_id: string;
+  readonly language: string;
+  readonly backend_ref: BackendReference;
+  readonly provider_id: string;
+  readonly node_roles: readonly NormalizedTreeNode['role'][];
+  readonly normalized_node_fields: readonly string[];
+  readonly optional_node_features: readonly string[];
+  readonly unsupported_defaults: Readonly<Record<string, string>>;
+  readonly capability: BackendCapabilityFixture;
+  readonly fixture_slices: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -417,6 +432,22 @@ function normalizedParseResult(fixture: NormalizedParseResultFixture): Normalize
   };
 }
 
+function treeHaverProfile(fixture: TreeHaverProfileFixture): TreeHaverProfile {
+  return {
+    profileId: fixture.profile_id,
+    language: fixture.language,
+    backendRef: fixture.backend_ref,
+    providerId: fixture.provider_id,
+    nodeRoles: fixture.node_roles,
+    normalizedNodeFields: fixture.normalized_node_fields,
+    optionalNodeFeatures: fixture.optional_node_features,
+    unsupportedDefaults: fixture.unsupported_defaults,
+    capability: backendCapability(fixture.capability),
+    fixtureSlices: fixture.fixture_slices,
+    diagnostics: fixture.diagnostics
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -490,6 +521,23 @@ describe('tree-haver shared fixtures', () => {
     expect(result.sourceFragmentsAvailable).toBe(true);
   });
 
+  it('conforms to the slice-788 tree-haver profile fixture', () => {
+    const fixture = readFixture<{ profile: TreeHaverProfileFixture }>(
+      'diagnostics',
+      'slice-788-tree-haver-profile',
+      'tree-haver-profile.json'
+    );
+    const profile = treeHaverProfile(fixture.profile);
+
+    expect(profile.profileId).toBe('go-dst-normalized-tree-v1');
+    expect(profile.backendRef.id).toBe('go-dst');
+    expect(profile.nodeRoles[0]).toBe('structural');
+    expect(profile.normalizedNodeFields.at(-1)).toBe('metadata');
+    expect(profile.unsupportedDefaults.field_name).toBe('null');
+    expect(profile.capability.parserIdentity.name).toBe('github.com/dave/dst');
+    expect(profile.fixtureSlices[0]).toBe('slice-782-normalized-tree-node');
+  });
+
   it('conforms to the slice-783 backend capability report fixture', () => {
     const fixture = readFixture<{ capability: BackendCapabilityFixture }>(
       'diagnostics',

From 1b654b32dc4b1ede1d8f3ae8ba23bb01cf5d541b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:33:29 -0600
Subject: [PATCH 023/130] Add ordered tree primitives contract

---
 packages/tree-haver/src/contracts.ts          | 14 +++++
 packages/tree-haver/src/index.ts              |  2 +
 .../test/fixtures.integration.test.ts         | 60 ++++++++++++++++++-
 3 files changed, 74 insertions(+), 2 deletions(-)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 34d77cc..89c457a 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -138,6 +138,20 @@ export interface TreeHaverProfile {
   readonly diagnostics: readonly string[];
 }
 
+export interface OrderedSiblingEdge {
+  readonly parentId: string;
+  readonly nodeId: string;
+  readonly previousSiblingId?: string;
+  readonly nextSiblingId?: string;
+}
+
+export interface OrderedTreePrimitives {
+  readonly rootId: string;
+  readonly childOrder: Readonly<Record<string, readonly string[]>>;
+  readonly siblingEdges: readonly OrderedSiblingEdge[];
+  readonly diagnostics: readonly string[];
+}
+
 export interface ParserAdapter<TAnalysis extends AnalysisHandle> {
   readonly info: AdapterInfo;
   parse(request: ParserRequest): ParseResult<TAnalysis>;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 2487780..352b695 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -27,6 +27,8 @@ export type {
   NormalizedParseResult,
   NodeRole,
   NormalizedTreeNode,
+  OrderedSiblingEdge,
+  OrderedTreePrimitives,
   ParseErrorTolerance,
   ParserAdapter,
   ParserDiagnostics,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index d35c618..8a4fa2f 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -16,6 +16,7 @@ import type {
   NativeParserProvider,
   NormalizedParseResult,
   NormalizedTreeNode,
+  OrderedTreePrimitives,
   ParseErrorTolerance,
   ParserRequest,
   PolicyReference,
@@ -312,6 +313,18 @@ interface TreeHaverProfileFixture {
   readonly diagnostics: readonly string[];
 }
 
+interface OrderedTreePrimitivesFixture {
+  readonly root_id: string;
+  readonly child_order: Readonly<Record<string, readonly string[]>>;
+  readonly sibling_edges: readonly {
+    readonly parent_id: string;
+    readonly node_id: string;
+    readonly previous_sibling_id: string | null;
+    readonly next_sibling_id: string | null;
+  }[];
+  readonly diagnostics: readonly string[];
+}
+
 function readFixture<T>(...segments: string[]): T {
   const fixturePath = path.resolve(process.cwd(), '..', 'fixtures', ...segments);
 
@@ -448,6 +461,20 @@ function treeHaverProfile(fixture: TreeHaverProfileFixture): TreeHaverProfile {
   };
 }
 
+function orderedTreePrimitives(fixture: OrderedTreePrimitivesFixture): OrderedTreePrimitives {
+  return {
+    rootId: fixture.root_id,
+    childOrder: fixture.child_order,
+    siblingEdges: fixture.sibling_edges.map((edge) => ({
+      parentId: edge.parent_id,
+      nodeId: edge.node_id,
+      previousSiblingId: edge.previous_sibling_id ?? undefined,
+      nextSiblingId: edge.next_sibling_id ?? undefined
+    })),
+    diagnostics: fixture.diagnostics
+  };
+}
+
 describe('tree-haver shared fixtures', () => {
   it('conforms to the slice-06 parser request fixture', () => {
     const fixture = readFixture<ParserAdapterFixture>(...diagnosticsFixturePath('parser_request'));
@@ -508,7 +535,11 @@ describe('tree-haver shared fixtures', () => {
     const fixture = readFixture<{
       provider: NativeParserProviderFixture;
       parse_result: NormalizedParseResultFixture;
-    }>('diagnostics', 'slice-787-native-parser-adapter-contract', 'native-parser-adapter-contract.json');
+    }>(
+      'diagnostics',
+      'slice-787-native-parser-adapter-contract',
+      'native-parser-adapter-contract.json'
+    );
     const provider = nativeParserProvider(fixture.provider);
     const result = normalizedParseResult(fixture.parse_result);
 
@@ -538,6 +569,27 @@ describe('tree-haver shared fixtures', () => {
     expect(profile.fixtureSlices[0]).toBe('slice-782-normalized-tree-node');
   });
 
+  it('conforms to the slice-789 ordered tree primitives fixture', () => {
+    const fixture = readFixture<{
+      root_id: string;
+      ordered_tree: OrderedTreePrimitivesFixture;
+      forbidden_merge_terms: readonly string[];
+    }>('diagnostics', 'slice-789-ordered-tree-primitives', 'ordered-tree-primitives.json');
+    const ordered = orderedTreePrimitives(fixture.ordered_tree);
+
+    for (const diagnostic of ordered.diagnostics) {
+      for (const term of fixture.forbidden_merge_terms) {
+        expect(diagnostic.toLowerCase()).not.toContain(term.toLowerCase());
+      }
+    }
+
+    expect(ordered.rootId).toBe(fixture.root_id);
+    expect(ordered.childOrder.file?.[0]).toBe('imports');
+    expect(ordered.childOrder.imports?.[1]).toBe('import-strings');
+    expect(ordered.siblingEdges[2]?.previousSiblingId).toBeUndefined();
+    expect(ordered.siblingEdges[2]?.nextSiblingId).toBe('import-strings');
+  });
+
   it('conforms to the slice-783 backend capability report fixture', () => {
     const fixture = readFixture<{ capability: BackendCapabilityFixture }>(
       'diagnostics',
@@ -561,7 +613,11 @@ describe('tree-haver shared fixtures', () => {
       'slice-784-source-fragment-extraction',
       'source-fragment-extraction.json'
     );
-    const fragment = extractSourceFragment(fixture.source, sourceSpan(fixture.span), fixture.strategy);
+    const fragment = extractSourceFragment(
+      fixture.source,
+      sourceSpan(fixture.span),
+      fixture.strategy
+    );
 
     expect(fragment.text).toBe(fixture.fragment.text);
     expect(fragment.available).toBe(fixture.fragment.available);

From ca87d6e4ca533b6850975e08c0de7dc285937f89 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:38:13 -0600
Subject: [PATCH 024/130] Add generic merge IR contract

---
 packages/ast-merge/src/contracts.ts           | 40 ++++++++++++++++++-
 packages/ast-merge/src/index.ts               |  4 ++
 .../test/fixtures.integration.test.ts         | 21 ++++++++++
 3 files changed, 64 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 242f796..ff083f9 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -359,7 +359,8 @@ export function compactRulesetFeatureProfile(ruleset: CompactRuleset): CompactRu
         if (args.length > 1) profile.node_roles.push({ selector: args[0], role: args[1] });
         break;
       case 'atomic':
-        if (args.length > 1) profile.atomic_nodes.push({ selector: args[0], atomic: args[1] === 'true' });
+        if (args.length > 1)
+          profile.atomic_nodes.push({ selector: args[0], atomic: args[1] === 'true' });
         break;
       case 'child_group':
         if (args.length > 2) {
@@ -426,6 +427,43 @@ export interface MergeResult<TOutput> {
   readonly policies?: readonly PolicyReference[];
 }
 
+export interface MergeIRNodeClass {
+  readonly class_id: string;
+  readonly signature: string;
+  readonly node_ids: Readonly<Record<string, string>>;
+  readonly roles: readonly string[];
+}
+
+export interface MergeIROrderedNode {
+  readonly node_id: string;
+  readonly parent_id: string;
+  readonly child_ids: readonly string[];
+  readonly previous_sibling_id: string | null;
+  readonly next_sibling_id: string | null;
+}
+
+export interface MergeIRChange {
+  readonly change_id: string;
+  readonly side: string;
+  readonly kind: string;
+  readonly node_id: string;
+  readonly class_id: string | null;
+  readonly parent_id: string;
+  readonly previous_sibling_id: string | null;
+  readonly next_sibling_id: string | null;
+  readonly content_hash: string;
+}
+
+export interface MergeIR {
+  readonly version: string;
+  readonly tree_id: string;
+  readonly source: string;
+  readonly node_classes: readonly MergeIRNodeClass[];
+  readonly ordered_nodes: readonly MergeIROrderedNode[];
+  readonly changes: readonly MergeIRChange[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 67aba6a..2631bfa 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -47,6 +47,10 @@ export type {
   DiscoveredSurface,
   DelegatedChildOperation,
   ReviewDiagnosticReason,
+  MergeIR,
+  MergeIRChange,
+  MergeIRNodeClass,
+  MergeIROrderedNode,
   MergeResult,
   FamilyFeatureProfile,
   StructuredEditStructureProfile,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index d7f490e..0735d47 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -37,6 +37,7 @@ import type {
   DiagnosticSeverity,
   DiscoveredSurface,
   FamilyFeatureProfile,
+  MergeIR,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -5562,6 +5563,26 @@ function normalizeProjectedChildReviewGroupProgress(
 }
 
 describe('ast-merge shared fixtures', () => {
+  it('conforms to the slice-790 generic merge IR fixture', () => {
+    const fixture = readFixture<{
+      merge_ir: MergeIR;
+      expected: {
+        version: string;
+        node_class_count: number;
+        change_kinds: readonly string[];
+        ordered_node_count: number;
+      };
+    }>('diagnostics', 'slice-790-generic-merge-ir', 'generic-merge-ir.json');
+    const mergeIR = fixture.merge_ir;
+
+    expect(mergeIR.version).toBe(fixture.expected.version);
+    expect(mergeIR.node_classes).toHaveLength(fixture.expected.node_class_count);
+    expect(mergeIR.ordered_nodes).toHaveLength(fixture.expected.ordered_node_count);
+    expect(mergeIR.changes.map((change) => change.kind)).toEqual(fixture.expected.change_kinds);
+    expect(mergeIR.node_classes[0]?.node_ids.left).toBe('left-import-fmt');
+    expect(mergeIR.changes[1]?.class_id).toBe('class-import-strings');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From ea83bd10245d3d58e761daf864f2c611c484e671 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:41:11 -0600
Subject: [PATCH 025/130] Add pairwise matching contract

---
 packages/ast-merge/src/contracts.ts           | 18 ++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 24 +++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index ff083f9..e17fed7 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -464,6 +464,24 @@ export interface MergeIR {
   readonly diagnostics: readonly string[];
 }
 
+export interface PairwiseNodeMatch {
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly class_id: string;
+  readonly strategy: string;
+  readonly confidence: number;
+  readonly diagnostics: readonly string[];
+}
+
+export interface PairwiseMatching {
+  readonly matching_id: string;
+  readonly from_revision: string;
+  readonly to_revision: string;
+  readonly matches: readonly PairwiseNodeMatch[];
+  readonly unmatched_from: readonly string[];
+  readonly unmatched_to: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 2631bfa..2ee1b1a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -52,6 +52,8 @@ export type {
   MergeIRNodeClass,
   MergeIROrderedNode,
   MergeResult,
+  PairwiseMatching,
+  PairwiseNodeMatch,
   FamilyFeatureProfile,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 0735d47..57b817b 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -38,6 +38,7 @@ import type {
   DiscoveredSurface,
   FamilyFeatureProfile,
   MergeIR,
+  PairwiseMatching,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -5583,6 +5584,29 @@ describe('ast-merge shared fixtures', () => {
     expect(mergeIR.changes[1]?.class_id).toBe('class-import-strings');
   });
 
+  it('conforms to the slice-791 pairwise matchings fixture', () => {
+    const fixture = readFixture<{
+      pairwise_matchings: readonly PairwiseMatching[];
+      expected: {
+        matching_ids: readonly string[];
+        total_match_count: number;
+        unmatched_insertions: readonly string[];
+        unmatched_deletions: readonly string[];
+      };
+    }>('diagnostics', 'slice-791-pairwise-matchings', 'pairwise-matchings.json');
+    const matchings = fixture.pairwise_matchings;
+
+    expect(matchings.map((matching) => matching.matching_id)).toEqual(
+      fixture.expected.matching_ids
+    );
+    expect(matchings.reduce((sum, matching) => sum + matching.matches.length, 0)).toBe(
+      fixture.expected.total_match_count
+    );
+    expect(matchings[0]?.unmatched_to[0]).toBe('left-import-os');
+    expect(matchings[1]?.unmatched_from[0]).toBe('base-decl-greet');
+    expect(matchings[2]?.matches[1]?.diagnostics[0]).toBe('sibling position changed');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From d918034fc3177e4051b38898886287fa8de99568 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:43:42 -0600
Subject: [PATCH 026/130] Add class mapping contract

---
 packages/ast-merge/src/contracts.ts           | 23 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  3 +++
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index e17fed7..74b628d 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -482,6 +482,29 @@ export interface PairwiseMatching {
   readonly unmatched_to: readonly string[];
 }
 
+export interface ClassMappingNodeClass {
+  readonly class_id: string;
+  readonly signature: string;
+  readonly node_ids: Readonly<Record<string, string>>;
+  readonly matching_ids: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
+export interface ClassMappingDiagnostic {
+  readonly severity: string;
+  readonly category: string;
+  readonly class_id: string;
+  readonly message: string;
+  readonly matching_ids: readonly string[];
+}
+
+export interface ClassMappingReport {
+  readonly mapping_id: string;
+  readonly source_matching_ids: readonly string[];
+  readonly node_classes: readonly ClassMappingNodeClass[];
+  readonly diagnostics: readonly ClassMappingDiagnostic[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 2ee1b1a..c6169d9 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -1,6 +1,9 @@
 export const packageName = '@structuredmerge/ast-merge';
 
 export type {
+  ClassMappingDiagnostic,
+  ClassMappingNodeClass,
+  ClassMappingReport,
   ConformanceCaseRef,
   ConformanceCaseRun,
   ConformanceCaseRequirements,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 57b817b..ee6f5c4 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -36,6 +36,7 @@ import type {
   DiagnosticCategory,
   DiagnosticSeverity,
   DiscoveredSurface,
+  ClassMappingReport,
   FamilyFeatureProfile,
   MergeIR,
   PairwiseMatching,
@@ -5607,6 +5608,28 @@ describe('ast-merge shared fixtures', () => {
     expect(matchings[2]?.matches[1]?.diagnostics[0]).toBe('sibling position changed');
   });
 
+  it('conforms to the slice-792 class mapping fixture', () => {
+    const fixture = readFixture<{
+      class_mapping: ClassMappingReport;
+      expected: {
+        class_count: number;
+        diagnostic_categories: readonly string[];
+        conflicted_class_ids: readonly string[];
+      };
+    }>('diagnostics', 'slice-792-class-mapping', 'class-mapping.json');
+    const report = fixture.class_mapping;
+
+    expect(report.node_classes).toHaveLength(fixture.expected.class_count);
+    expect(report.diagnostics.map((diagnostic) => diagnostic.category)).toEqual(
+      fixture.expected.diagnostic_categories
+    );
+    expect(report.diagnostics.map((diagnostic) => diagnostic.class_id)).toEqual(
+      fixture.expected.conflicted_class_ids
+    );
+    expect(report.node_classes[2]?.node_ids.right).toBeUndefined();
+    expect(report.diagnostics[1]?.category).toBe('delete_edit_disagreement');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From cf12482894355bd9159cb6837c722c5279fe0c16 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:52:23 -0600
Subject: [PATCH 027/130] Add PCS change-set contract

---
 packages/ast-merge/src/contracts.ts           | 33 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  4 +++
 .../test/fixtures.integration.test.ts         | 29 ++++++++++++++++
 3 files changed, 66 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 74b628d..cde0d18 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -505,6 +505,39 @@ export interface ClassMappingReport {
   readonly diagnostics: readonly ClassMappingDiagnostic[];
 }
 
+export interface PCSConstraint {
+  readonly constraint_id: string;
+  readonly revision: string;
+  readonly parent_class_id: string;
+  readonly predecessor_class_id: string | null;
+  readonly successor_class_id: string | null;
+  readonly relation: string;
+}
+
+export interface PCS {
+  readonly pcs_id: string;
+  readonly tree_id: string;
+  readonly base_revision: string;
+  readonly constraints: readonly PCSConstraint[];
+}
+
+export interface ChangeSetChange {
+  readonly change_id: string;
+  readonly kind: string;
+  readonly class_id: string;
+  readonly parent_class_id: string;
+  readonly predecessor_class_id: string | null;
+  readonly successor_class_id: string | null;
+  readonly content_hash: string;
+}
+
+export interface ChangeSet {
+  readonly change_set_id: string;
+  readonly side: string;
+  readonly changes: readonly ChangeSetChange[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index c6169d9..806499d 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -1,6 +1,8 @@
 export const packageName = '@structuredmerge/ast-merge';
 
 export type {
+  ChangeSet,
+  ChangeSetChange,
   ClassMappingDiagnostic,
   ClassMappingNodeClass,
   ClassMappingReport,
@@ -57,6 +59,8 @@ export type {
   MergeResult,
   PairwiseMatching,
   PairwiseNodeMatch,
+  PCS,
+  PCSConstraint,
   FamilyFeatureProfile,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index ee6f5c4..f95a695 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -36,10 +36,12 @@ import type {
   DiagnosticCategory,
   DiagnosticSeverity,
   DiscoveredSurface,
+  ChangeSet,
   ClassMappingReport,
   FamilyFeatureProfile,
   MergeIR,
   PairwiseMatching,
+  PCS,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -5630,6 +5632,33 @@ describe('ast-merge shared fixtures', () => {
     expect(report.diagnostics[1]?.category).toBe('delete_edit_disagreement');
   });
 
+  it('conforms to the slice-793 PCS change-set generation fixture', () => {
+    const fixture = readFixture<{
+      pcs: PCS;
+      change_sets: readonly ChangeSet[];
+      expected: {
+        pcs_constraint_count: number;
+        change_set_count: number;
+        change_kinds: readonly string[];
+        diagnostic_count: number;
+      };
+    }>('diagnostics', 'slice-793-pcs-change-set-generation', 'pcs-change-set-generation.json');
+    const changeKinds = fixture.change_sets.flatMap((changeSet) =>
+      changeSet.changes.map((change) => change.kind)
+    );
+    const diagnosticCount = fixture.change_sets.reduce(
+      (sum, changeSet) => sum + changeSet.diagnostics.length,
+      0
+    );
+
+    expect(fixture.pcs.constraints).toHaveLength(fixture.expected.pcs_constraint_count);
+    expect(fixture.change_sets).toHaveLength(fixture.expected.change_set_count);
+    expect(changeKinds).toEqual(fixture.expected.change_kinds);
+    expect(diagnosticCount).toBe(fixture.expected.diagnostic_count);
+    expect(fixture.pcs.constraints[2]?.predecessor_class_id).toBe('class-import-strings');
+    expect(fixture.change_sets[1]?.changes[1]?.kind).toBe('delete');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From b2644c7568e34e88299982f81214dc7586cb187d Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:54:55 -0600
Subject: [PATCH 028/130] Add raw merge union contract

---
 packages/ast-merge/src/contracts.ts           | 19 ++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 30 +++++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index cde0d18..78bc0ec 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -538,6 +538,25 @@ export interface ChangeSet {
   readonly diagnostics: readonly string[];
 }
 
+export interface RawMergeChange {
+  readonly change_id: string;
+  readonly source_change_set_id: string;
+  readonly side: string;
+  readonly kind: string;
+  readonly class_id: string;
+  readonly parent_class_id: string;
+  readonly predecessor_class_id: string | null;
+  readonly successor_class_id: string | null;
+  readonly content_hash: string;
+}
+
+export interface RawMerge {
+  readonly raw_merge_id: string;
+  readonly input_change_set_ids: readonly string[];
+  readonly changes: readonly RawMergeChange[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 806499d..f32ff1f 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -61,6 +61,8 @@ export type {
   PairwiseNodeMatch,
   PCS,
   PCSConstraint,
+  RawMerge,
+  RawMergeChange,
   FamilyFeatureProfile,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index f95a695..5443266 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -42,6 +42,7 @@ import type {
   MergeIR,
   PairwiseMatching,
   PCS,
+  RawMerge,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -5659,6 +5660,35 @@ describe('ast-merge shared fixtures', () => {
     expect(fixture.change_sets[1]?.changes[1]?.kind).toBe('delete');
   });
 
+  it('conforms to the slice-794 raw merge change-set union fixture', () => {
+    const fixture = readFixture<{
+      raw_merge: RawMerge;
+      expected: {
+        raw_change_count: number;
+        input_change_set_count: number;
+        sides: readonly string[];
+        conflicting_class_candidates: readonly string[];
+      };
+    }>('diagnostics', 'slice-794-raw-merge-change-set-union', 'raw-merge-change-set-union.json');
+    const sides = fixture.raw_merge.changes.reduce<string[]>((memo, change) => {
+      if (!memo.includes(change.side)) memo.push(change.side);
+      return memo;
+    }, []);
+    const classDeclGreetCount = fixture.raw_merge.changes.filter(
+      (change) => change.class_id === 'class-decl-greet'
+    ).length;
+
+    expect(fixture.raw_merge.changes).toHaveLength(fixture.expected.raw_change_count);
+    expect(fixture.raw_merge.input_change_set_ids).toHaveLength(
+      fixture.expected.input_change_set_count
+    );
+    expect(sides).toEqual(fixture.expected.sides);
+    expect(classDeclGreetCount).toBe(2);
+    expect(fixture.raw_merge.diagnostics[0]).toBe(
+      'raw merge intentionally preserves both sides before inconsistency detection'
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From b303806f156a967d20b72de1b33f0564f9706a60 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:56:51 -0600
Subject: [PATCH 029/130] Add inconsistency detection contract

---
 packages/ast-merge/src/contracts.ts           | 16 ++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 22 +++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 78bc0ec..40aeccb 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -557,6 +557,22 @@ export interface RawMerge {
   readonly diagnostics: readonly string[];
 }
 
+export interface MergeInconsistency {
+  readonly inconsistency_id: string;
+  readonly category: string;
+  readonly severity: string;
+  readonly class_ids: readonly string[];
+  readonly change_ids: readonly string[];
+  readonly message: string;
+}
+
+export interface InconsistencyReport {
+  readonly report_id: string;
+  readonly raw_merge_id: string;
+  readonly inconsistencies: readonly MergeInconsistency[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index f32ff1f..674a9c2 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -39,6 +39,8 @@ export type {
   Diagnostic,
   DiagnosticCategory,
   DiagnosticSeverity,
+  InconsistencyReport,
+  MergeInconsistency,
   CompactRuleset,
   CompactRulesetAtomicNode,
   CompactRulesetBackendDeclaration,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 5443266..7911683 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -39,6 +39,7 @@ import type {
   ChangeSet,
   ClassMappingReport,
   FamilyFeatureProfile,
+  InconsistencyReport,
   MergeIR,
   PairwiseMatching,
   PCS,
@@ -5689,6 +5690,27 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-795 inconsistency detection fixture', () => {
+    const fixture = readFixture<{
+      inconsistency_report: InconsistencyReport;
+      expected: {
+        inconsistency_count: number;
+        categories: readonly string[];
+        blocking_count: number;
+      };
+    }>('diagnostics', 'slice-795-inconsistency-detection', 'inconsistency-detection.json');
+    const report = fixture.inconsistency_report;
+
+    expect(report.inconsistencies).toHaveLength(fixture.expected.inconsistency_count);
+    expect(report.inconsistencies.map((item) => item.category)).toEqual(
+      fixture.expected.categories
+    );
+    expect(report.inconsistencies.filter((item) => item.severity === 'error')).toHaveLength(
+      fixture.expected.blocking_count
+    );
+    expect(report.inconsistencies[1]?.change_ids[1]).toBe('right-delete-greet');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From c8e5f4a15b29b207e3c5fd6f896999a0f3bfc83a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 17:59:15 -0600
Subject: [PATCH 030/130] Add merge IR comparison contract

---
 packages/ast-merge/src/contracts.ts           | 26 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  3 +++
 .../test/fixtures.integration.test.ts         | 20 ++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 40aeccb..d01e1bb 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -573,6 +573,32 @@ export interface InconsistencyReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface MergeIRComparisonCase {
+  readonly case_id: string;
+  readonly family: string;
+  readonly scenario: string;
+  readonly owner_path_outcome: string;
+  readonly merge_ir_outcome: string;
+  readonly merge_ir_advantage: string;
+  readonly diagnostics: readonly string[];
+}
+
+export interface MergeIRComparisonSummary {
+  readonly owner_path_wins: number;
+  readonly merge_ir_wins: number;
+  readonly neutral: number;
+  readonly defer: number;
+  readonly recommendation: string;
+}
+
+export interface MergeIRComparisonReport {
+  readonly comparison_id: string;
+  readonly baseline: string;
+  readonly prototype: string;
+  readonly cases: readonly MergeIRComparisonCase[];
+  readonly summary: MergeIRComparisonSummary;
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 674a9c2..2f14eba 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -41,6 +41,9 @@ export type {
   DiagnosticSeverity,
   InconsistencyReport,
   MergeInconsistency,
+  MergeIRComparisonCase,
+  MergeIRComparisonReport,
+  MergeIRComparisonSummary,
   CompactRuleset,
   CompactRulesetAtomicNode,
   CompactRulesetBackendDeclaration,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 7911683..06fbf9a 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -41,6 +41,7 @@ import type {
   FamilyFeatureProfile,
   InconsistencyReport,
   MergeIR,
+  MergeIRComparisonReport,
   PairwiseMatching,
   PCS,
   RawMerge,
@@ -5711,6 +5712,25 @@ describe('ast-merge shared fixtures', () => {
     expect(report.inconsistencies[1]?.change_ids[1]).toBe('right-delete-greet');
   });
 
+  it('conforms to the slice-796 merge IR comparison fixture', () => {
+    const fixture = readFixture<{
+      comparison: MergeIRComparisonReport;
+      expected: {
+        case_count: number;
+        families: readonly string[];
+        merge_ir_wins: number;
+        recommendation: string;
+      };
+    }>('diagnostics', 'slice-796-merge-ir-comparison', 'merge-ir-comparison.json');
+    const report = fixture.comparison;
+
+    expect(report.cases).toHaveLength(fixture.expected.case_count);
+    expect(report.cases.map((testCase) => testCase.family)).toEqual(fixture.expected.families);
+    expect(report.summary.merge_ir_wins).toBe(fixture.expected.merge_ir_wins);
+    expect(report.summary.recommendation).toBe(fixture.expected.recommendation);
+    expect(report.cases[4]?.merge_ir_advantage).toBe('defer');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 0ca1cbc64fe9c3d9132db562b6fe4383be0aadd2 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:03:04 -0600
Subject: [PATCH 031/130] Add structural matching baseline contract

---
 packages/ast-merge/src/contracts.ts           | 19 ++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 26 +++++++++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index d01e1bb..17c263b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -599,6 +599,25 @@ export interface MergeIRComparisonReport {
   readonly summary: MergeIRComparisonSummary;
 }
 
+export interface StructuralPathMatch {
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly confidence: number;
+}
+
+export interface StructuralMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly from_revision: string;
+  readonly to_revision: string;
+  readonly matches: readonly StructuralPathMatch[];
+  readonly unmatched_from: readonly string[];
+  readonly unmatched_to: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 2f14eba..b9adc45 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -44,6 +44,8 @@ export type {
   MergeIRComparisonCase,
   MergeIRComparisonReport,
   MergeIRComparisonSummary,
+  StructuralMatchingReport,
+  StructuralPathMatch,
   CompactRuleset,
   CompactRulesetAtomicNode,
   CompactRulesetBackendDeclaration,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 06fbf9a..da412b2 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -45,6 +45,7 @@ import type {
   PairwiseMatching,
   PCS,
   RawMerge,
+  StructuralMatchingReport,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -5731,6 +5732,31 @@ describe('ast-merge shared fixtures', () => {
     expect(report.cases[4]?.merge_ir_advantage).toBe('defer');
   });
 
+  it('conforms to the slice-797 structural matching baseline fixture', () => {
+    const fixture = readFixture<{
+      matching: StructuralMatchingReport;
+      expected: {
+        strategy: string;
+        match_count: number;
+        unmatched_from_count: number;
+        unmatched_to_count: number;
+        move_detection: boolean;
+      };
+    }>(
+      'diagnostics',
+      'slice-797-structural-matching-baseline',
+      'structural-matching-baseline.json'
+    );
+    const report = fixture.matching;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(report.unmatched_from).toHaveLength(fixture.expected.unmatched_from_count);
+    expect(report.unmatched_to).toHaveLength(fixture.expected.unmatched_to_count);
+    expect(fixture.expected.move_detection).toBe(false);
+    expect(report.matches[1]?.from_path).toBe('/declarations/Greet');
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From b1361252d5760d18ac6156008ecc40928f2f83cc Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:06:42 -0600
Subject: [PATCH 032/130] Add signature matching commutative parent contract

---
 packages/ast-merge/src/contracts.ts           | 33 +++++++++++++++++
 packages/ast-merge/src/index.ts               |  3 ++
 .../test/fixtures.integration.test.ts         | 36 +++++++++++++++++++
 3 files changed, 72 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 17c263b..f8e941c 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -618,6 +618,39 @@ export interface StructuralMatchingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface SignatureMatchingParent {
+  readonly kind: string;
+  readonly role: string;
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly child_order: string;
+}
+
+export interface SignatureNodeMatch {
+  readonly signature: string;
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly confidence: number;
+  readonly diagnostics: readonly string[];
+}
+
+export interface SignatureMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly parent_policy: string;
+  readonly signature_components: readonly string[];
+  readonly from_revision: string;
+  readonly to_revision: string;
+  readonly matches: readonly SignatureNodeMatch[];
+  readonly unmatched_from: readonly string[];
+  readonly unmatched_to: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index b9adc45..6645c5f 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -44,6 +44,9 @@ export type {
   MergeIRComparisonCase,
   MergeIRComparisonReport,
   MergeIRComparisonSummary,
+  SignatureMatchingParent,
+  SignatureMatchingReport,
+  SignatureNodeMatch,
   StructuralMatchingReport,
   StructuralPathMatch,
   CompactRuleset,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index da412b2..1dff872 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -45,6 +45,8 @@ import type {
   PairwiseMatching,
   PCS,
   RawMerge,
+  SignatureMatchingParent,
+  SignatureMatchingReport,
   StructuralMatchingReport,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
@@ -5757,6 +5759,40 @@ describe('ast-merge shared fixtures', () => {
     expect(report.matches[1]?.from_path).toBe('/declarations/Greet');
   });
 
+  it('conforms to the slice-798 signature matching commutative parent fixture', () => {
+    const fixture = readFixture<{
+      parent: SignatureMatchingParent;
+      matching: SignatureMatchingReport;
+      expected: {
+        strategy: string;
+        parent_policy: string;
+        signature_components: readonly string[];
+        match_count: number;
+        unmatched_from_count: number;
+        unmatched_to_count: number;
+        order_sensitive: boolean;
+        first_match_signature: string;
+        first_match_to_path: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-798-signature-matching-commutative-parent',
+      'signature-matching-commutative-parent.json'
+    );
+    const report = fixture.matching;
+
+    expect(fixture.parent.child_order).toBe(fixture.expected.parent_policy);
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.parent_policy).toBe(fixture.expected.parent_policy);
+    expect(report.signature_components).toEqual(fixture.expected.signature_components);
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(report.unmatched_from).toHaveLength(fixture.expected.unmatched_from_count);
+    expect(report.unmatched_to).toHaveLength(fixture.expected.unmatched_to_count);
+    expect(fixture.expected.order_sensitive).toBe(false);
+    expect(report.matches[0]?.signature).toBe(fixture.expected.first_match_signature);
+    expect(report.matches[0]?.to_path).toBe(fixture.expected.first_match_to_path);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From c72825734a23c9b545df3a0072f18f2489d2bb77 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:09:40 -0600
Subject: [PATCH 033/130] Add source text normalized matching contract

---
 packages/ast-merge/src/contracts.ts           | 25 ++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 33 +++++++++++++++++++
 3 files changed, 60 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index f8e941c..562ef77 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -651,6 +651,31 @@ export interface SignatureMatchingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface SourceTextNormalizedMatch {
+  readonly normalized_text: string;
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly from_source_text: string;
+  readonly to_source_text: string;
+  readonly confidence: number;
+  readonly diagnostics: readonly string[];
+}
+
+export interface SourceTextNormalizedMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly from_revision: string;
+  readonly to_revision: string;
+  readonly normalization: readonly string[];
+  readonly leaf_kinds: readonly string[];
+  readonly matches: readonly SourceTextNormalizedMatch[];
+  readonly unmatched_from: readonly string[];
+  readonly unmatched_to: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 6645c5f..080f833 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -47,6 +47,8 @@ export type {
   SignatureMatchingParent,
   SignatureMatchingReport,
   SignatureNodeMatch,
+  SourceTextNormalizedMatch,
+  SourceTextNormalizedMatchingReport,
   StructuralMatchingReport,
   StructuralPathMatch,
   CompactRuleset,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 1dff872..6d327b2 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -47,6 +47,7 @@ import type {
   RawMerge,
   SignatureMatchingParent,
   SignatureMatchingReport,
+  SourceTextNormalizedMatchingReport,
   StructuralMatchingReport,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
@@ -5793,6 +5794,38 @@ describe('ast-merge shared fixtures', () => {
     expect(report.matches[0]?.to_path).toBe(fixture.expected.first_match_to_path);
   });
 
+  it('conforms to the slice-799 source-text normalized leaf matching fixture', () => {
+    const fixture = readFixture<{
+      matching: SourceTextNormalizedMatchingReport;
+      expected: {
+        strategy: string;
+        normalization: readonly string[];
+        leaf_kinds: readonly string[];
+        match_count: number;
+        unmatched_from_count: number;
+        unmatched_to_count: number;
+        first_match_normalized_text: string;
+        minimum_confidence: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-799-source-text-normalized-leaf-matching',
+      'source-text-normalized-leaf-matching.json'
+    );
+    const report = fixture.matching;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.normalization).toEqual(fixture.expected.normalization);
+    expect(report.leaf_kinds).toEqual(fixture.expected.leaf_kinds);
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(report.unmatched_from).toHaveLength(fixture.expected.unmatched_from_count);
+    expect(report.unmatched_to).toHaveLength(fixture.expected.unmatched_to_count);
+    expect(report.matches[0]?.normalized_text).toBe(fixture.expected.first_match_normalized_text);
+    expect(report.matches[0]?.confidence).toBeGreaterThanOrEqual(
+      fixture.expected.minimum_confidence
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From a63cc6f30fb7122ad9cac9aac72186805dc1708b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:12:57 -0600
Subject: [PATCH 034/130] Add move detection opt-in contract

---
 packages/ast-merge/src/contracts.ts           | 34 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  3 ++
 .../test/fixtures.integration.test.ts         | 34 +++++++++++++++++++
 3 files changed, 71 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 562ef77..4f9788a 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -676,6 +676,40 @@ export interface SourceTextNormalizedMatchingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface MoveDetectionCapability {
+  readonly name: string;
+  readonly enabled: boolean;
+  readonly default_enabled: boolean;
+  readonly requires_stable_node_identity: boolean;
+}
+
+export interface MoveDetectionMatch {
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly signature: string;
+  readonly moved: boolean;
+  readonly from_parent_path: string;
+  readonly to_parent_path: string;
+  readonly from_index: number;
+  readonly to_index: number;
+  readonly confidence: number;
+  readonly diagnostics: readonly string[];
+}
+
+export interface MoveDetectionMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly from_revision: string;
+  readonly to_revision: string;
+  readonly capability: MoveDetectionCapability;
+  readonly matches: readonly MoveDetectionMatch[];
+  readonly unmatched_from: readonly string[];
+  readonly unmatched_to: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 080f833..be72b0b 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -44,6 +44,9 @@ export type {
   MergeIRComparisonCase,
   MergeIRComparisonReport,
   MergeIRComparisonSummary,
+  MoveDetectionCapability,
+  MoveDetectionMatch,
+  MoveDetectionMatchingReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SignatureNodeMatch,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 6d327b2..7d02024 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -42,6 +42,7 @@ import type {
   InconsistencyReport,
   MergeIR,
   MergeIRComparisonReport,
+  MoveDetectionMatchingReport,
   PairwiseMatching,
   PCS,
   RawMerge,
@@ -5826,6 +5827,39 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-800 move detection opt-in fixture', () => {
+    const fixture = readFixture<{
+      matching: MoveDetectionMatchingReport;
+      expected: {
+        strategy: string;
+        capability: string;
+        enabled: boolean;
+        default_enabled: boolean;
+        requires_stable_node_identity: boolean;
+        match_count: number;
+        move_count: number;
+        first_moved_signature: string;
+        first_moved_from_index: number;
+        first_moved_to_index: number;
+      };
+    }>('diagnostics', 'slice-800-move-detection-opt-in', 'move-detection-opt-in.json');
+    const report = fixture.matching;
+    const moveCount = report.matches.filter((match) => match.moved).length;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.capability.name).toBe(fixture.expected.capability);
+    expect(report.capability.enabled).toBe(fixture.expected.enabled);
+    expect(report.capability.default_enabled).toBe(fixture.expected.default_enabled);
+    expect(report.capability.requires_stable_node_identity).toBe(
+      fixture.expected.requires_stable_node_identity
+    );
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(moveCount).toBe(fixture.expected.move_count);
+    expect(report.matches[0]?.signature).toBe(fixture.expected.first_moved_signature);
+    expect(report.matches[0]?.from_index).toBe(fixture.expected.first_moved_from_index);
+    expect(report.matches[0]?.to_index).toBe(fixture.expected.first_moved_to_index);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 29976a8a6e8aa34b0881c3a7fe2c739664d1baab Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:15:47 -0600
Subject: [PATCH 035/130] Add rename-aware matching gated contract

---
 packages/ast-merge/src/contracts.ts           | 34 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  3 ++
 .../test/fixtures.integration.test.ts         | 33 ++++++++++++++++++
 3 files changed, 70 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 4f9788a..db27321 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -710,6 +710,40 @@ export interface MoveDetectionMatchingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface RenameAwareCapability {
+  readonly name: string;
+  readonly status: string;
+  readonly enabled: boolean;
+  readonly requires_explicit_profile: boolean;
+  readonly requires_diagnostics: boolean;
+}
+
+export interface RenameAwareCandidate {
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly from_signature: string;
+  readonly to_signature: string;
+  readonly stable_body_hash: string;
+  readonly rename_distance: number;
+  readonly selected: boolean;
+  readonly diagnostics: readonly string[];
+}
+
+export interface RenameAwareMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly from_revision: string;
+  readonly to_revision: string;
+  readonly capability: RenameAwareCapability;
+  readonly candidates: readonly RenameAwareCandidate[];
+  readonly matches: readonly SignatureNodeMatch[];
+  readonly unmatched_from: readonly string[];
+  readonly unmatched_to: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index be72b0b..48cee93 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -47,6 +47,9 @@ export type {
   MoveDetectionCapability,
   MoveDetectionMatch,
   MoveDetectionMatchingReport,
+  RenameAwareCapability,
+  RenameAwareCandidate,
+  RenameAwareMatchingReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SignatureNodeMatch,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 7d02024..42b7e04 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -46,6 +46,7 @@ import type {
   PairwiseMatching,
   PCS,
   RawMerge,
+  RenameAwareMatchingReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SourceTextNormalizedMatchingReport,
@@ -5860,6 +5861,38 @@ describe('ast-merge shared fixtures', () => {
     expect(report.matches[0]?.to_index).toBe(fixture.expected.first_moved_to_index);
   });
 
+  it('conforms to the slice-801 rename-aware matching gated fixture', () => {
+    const fixture = readFixture<{
+      matching: RenameAwareMatchingReport;
+      expected: {
+        strategy: string;
+        capability: string;
+        status: string;
+        enabled: boolean;
+        requires_explicit_profile: boolean;
+        requires_diagnostics: boolean;
+        candidate_count: number;
+        match_count: number;
+        first_candidate_selected: boolean;
+        first_candidate_body_hash: string;
+      };
+    }>('diagnostics', 'slice-801-rename-aware-matching-gated', 'rename-aware-matching-gated.json');
+    const report = fixture.matching;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.capability.name).toBe(fixture.expected.capability);
+    expect(report.capability.status).toBe(fixture.expected.status);
+    expect(report.capability.enabled).toBe(fixture.expected.enabled);
+    expect(report.capability.requires_explicit_profile).toBe(
+      fixture.expected.requires_explicit_profile
+    );
+    expect(report.capability.requires_diagnostics).toBe(fixture.expected.requires_diagnostics);
+    expect(report.candidates).toHaveLength(fixture.expected.candidate_count);
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(report.candidates[0]?.selected).toBe(fixture.expected.first_candidate_selected);
+    expect(report.candidates[0]?.stable_body_hash).toBe(fixture.expected.first_candidate_body_hash);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 6ab6123651d414422a7c50f70132f219ad983a36 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:19:00 -0600
Subject: [PATCH 036/130] Add ambiguity diagnostics contract

---
 packages/ast-merge/src/contracts.ts           | 20 +++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 29 +++++++++++++++++++
 3 files changed, 51 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index db27321..33c8715 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -744,6 +744,26 @@ export interface RenameAwareMatchingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface MatchingAmbiguity {
+  readonly signature: string;
+  readonly scope_path: string;
+  readonly from_candidates: readonly string[];
+  readonly to_candidates: readonly string[];
+  readonly selected: boolean;
+  readonly reason: string;
+  readonly diagnostics: readonly string[];
+}
+
+export interface AmbiguityMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly scope_path: string;
+  readonly ambiguous: boolean;
+  readonly matches: readonly SignatureNodeMatch[];
+  readonly ambiguities: readonly MatchingAmbiguity[];
+  readonly diagnostics: readonly Diagnostic[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 48cee93..24b3e08 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -1,6 +1,7 @@
 export const packageName = '@structuredmerge/ast-merge';
 
 export type {
+  AmbiguityMatchingReport,
   ChangeSet,
   ChangeSetChange,
   ClassMappingDiagnostic,
@@ -44,6 +45,7 @@ export type {
   MergeIRComparisonCase,
   MergeIRComparisonReport,
   MergeIRComparisonSummary,
+  MatchingAmbiguity,
   MoveDetectionCapability,
   MoveDetectionMatch,
   MoveDetectionMatchingReport,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 42b7e04..bb061b2 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -7,6 +7,7 @@ import { mergeMarkdown } from '../../markdown-merge/src/index';
 import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
 import type {
+  AmbiguityMatchingReport,
   ConformanceCaseRef,
   ConformanceCaseRun,
   ConformanceCaseExecution,
@@ -5893,6 +5894,34 @@ describe('ast-merge shared fixtures', () => {
     expect(report.candidates[0]?.stable_body_hash).toBe(fixture.expected.first_candidate_body_hash);
   });
 
+  it('conforms to the slice-802 ambiguity diagnostics fixture', () => {
+    const fixture = readFixture<{
+      matching: AmbiguityMatchingReport;
+      expected: {
+        strategy: string;
+        scope_path: string;
+        ambiguous: boolean;
+        match_count: number;
+        ambiguity_count: number;
+        diagnostic_category: string;
+        first_ambiguity_signature: string;
+        first_ambiguity_reason: string;
+        first_ambiguity_selected: boolean;
+      };
+    }>('diagnostics', 'slice-802-ambiguity-diagnostics', 'ambiguity-diagnostics.json');
+    const report = fixture.matching;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.scope_path).toBe(fixture.expected.scope_path);
+    expect(report.ambiguous).toBe(fixture.expected.ambiguous);
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(report.ambiguities).toHaveLength(fixture.expected.ambiguity_count);
+    expect(report.diagnostics[0]?.category).toBe(fixture.expected.diagnostic_category);
+    expect(report.ambiguities[0]?.signature).toBe(fixture.expected.first_ambiguity_signature);
+    expect(report.ambiguities[0]?.reason).toBe(fixture.expected.first_ambiguity_reason);
+    expect(report.ambiguities[0]?.selected).toBe(fixture.expected.first_ambiguity_selected);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From d28d7185559af8e81b057c3ba752934eddb7cc48 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:22:16 -0600
Subject: [PATCH 037/130] Add duplicate signature tie-break contract

---
 packages/ast-merge/src/contracts.ts           | 28 +++++++++++++++
 packages/ast-merge/src/index.ts               |  3 ++
 .../test/fixtures.integration.test.ts         | 35 +++++++++++++++++++
 3 files changed, 66 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 33c8715..920d9d8 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -764,6 +764,34 @@ export interface AmbiguityMatchingReport {
   readonly diagnostics: readonly Diagnostic[];
 }
 
+export interface RejectedTieBreakCandidate {
+  readonly from_path: string;
+  readonly from_node_id: string;
+  readonly confidence: number;
+  readonly rejected_by: string;
+}
+
+export interface TieBreakMatch {
+  readonly signature: string;
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly from_node_id: string;
+  readonly to_node_id: string;
+  readonly confidence: number;
+  readonly selected_by: string;
+  readonly rejected_candidates: readonly RejectedTieBreakCandidate[];
+  readonly diagnostics: readonly string[];
+}
+
+export interface TieBreakMatchingReport {
+  readonly matching_id: string;
+  readonly strategy: string;
+  readonly scope_path: string;
+  readonly tie_break_rules: readonly string[];
+  readonly matches: readonly TieBreakMatch[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 24b3e08..080f2e1 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -52,6 +52,7 @@ export type {
   RenameAwareCapability,
   RenameAwareCandidate,
   RenameAwareMatchingReport,
+  RejectedTieBreakCandidate,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SignatureNodeMatch,
@@ -59,6 +60,8 @@ export type {
   SourceTextNormalizedMatchingReport,
   StructuralMatchingReport,
   StructuralPathMatch,
+  TieBreakMatch,
+  TieBreakMatchingReport,
   CompactRuleset,
   CompactRulesetAtomicNode,
   CompactRulesetBackendDeclaration,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index bb061b2..eb35742 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -52,6 +52,7 @@ import type {
   SignatureMatchingReport,
   SourceTextNormalizedMatchingReport,
   StructuralMatchingReport,
+  TieBreakMatchingReport,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -5922,6 +5923,40 @@ describe('ast-merge shared fixtures', () => {
     expect(report.ambiguities[0]?.selected).toBe(fixture.expected.first_ambiguity_selected);
   });
 
+  it('conforms to the slice-803 duplicate signature tie-break fixture', () => {
+    const fixture = readFixture<{
+      matching: TieBreakMatchingReport;
+      expected: {
+        strategy: string;
+        scope_path: string;
+        tie_break_rules: readonly string[];
+        match_count: number;
+        first_match_signature: string;
+        first_match_selected_by: string;
+        rejected_candidate_count: number;
+        first_rejected_by: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-803-duplicate-signature-tie-break',
+      'duplicate-signature-tie-break.json'
+    );
+    const report = fixture.matching;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.scope_path).toBe(fixture.expected.scope_path);
+    expect(report.tie_break_rules).toEqual(fixture.expected.tie_break_rules);
+    expect(report.matches).toHaveLength(fixture.expected.match_count);
+    expect(report.matches[0]?.signature).toBe(fixture.expected.first_match_signature);
+    expect(report.matches[0]?.selected_by).toBe(fixture.expected.first_match_selected_by);
+    expect(report.matches[0]?.rejected_candidates).toHaveLength(
+      fixture.expected.rejected_candidate_count
+    );
+    expect(report.matches[0]?.rejected_candidates[0]?.rejected_by).toBe(
+      fixture.expected.first_rejected_by
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 3368938e914b77016d03a4fdf33a78be2c0a02c7 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:25:13 -0600
Subject: [PATCH 038/130] Add matching debug artifacts contract

---
 packages/ast-merge/src/contracts.ts           | 37 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  5 +++
 .../test/fixtures.integration.test.ts         | 23 ++++++++++++
 3 files changed, 65 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 920d9d8..52ec598 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -792,6 +792,43 @@ export interface TieBreakMatchingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface MatchingDebugOwnerSet {
+  readonly owner_id: string;
+  readonly scope_path: string;
+  readonly node_paths: readonly string[];
+}
+
+export interface MatchingDebugCandidate {
+  readonly candidate_id: string;
+  readonly signature: string;
+  readonly from_path: string;
+  readonly to_path: string;
+  readonly confidence: number;
+  readonly reason: string;
+}
+
+export interface MatchingDebugSelectedMatch {
+  readonly candidate_id: string;
+  readonly selected_by: string;
+}
+
+export interface MatchingDebugRejectedMatch {
+  readonly candidate_id: string;
+  readonly rejected_by: string;
+  readonly reason: string;
+}
+
+export interface MatchingDebugArtifacts {
+  readonly artifact_id: string;
+  readonly matching_id: string;
+  readonly enabled: boolean;
+  readonly owner_sets: readonly MatchingDebugOwnerSet[];
+  readonly candidates: readonly MatchingDebugCandidate[];
+  readonly selected_matches: readonly MatchingDebugSelectedMatch[];
+  readonly rejected_matches: readonly MatchingDebugRejectedMatch[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 080f2e1..9da7e1d 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -45,6 +45,11 @@ export type {
   MergeIRComparisonCase,
   MergeIRComparisonReport,
   MergeIRComparisonSummary,
+  MatchingDebugArtifacts,
+  MatchingDebugCandidate,
+  MatchingDebugOwnerSet,
+  MatchingDebugRejectedMatch,
+  MatchingDebugSelectedMatch,
   MatchingAmbiguity,
   MoveDetectionCapability,
   MoveDetectionMatch,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index eb35742..b6b0d0f 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -41,6 +41,7 @@ import type {
   ClassMappingReport,
   FamilyFeatureProfile,
   InconsistencyReport,
+  MatchingDebugArtifacts,
   MergeIR,
   MergeIRComparisonReport,
   MoveDetectionMatchingReport,
@@ -5957,6 +5958,28 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-804 matching debug artifacts fixture', () => {
+    const fixture = readFixture<{
+      debug_artifacts: MatchingDebugArtifacts;
+      expected: {
+        enabled: boolean;
+        owner_set_count: number;
+        candidate_count: number;
+        selected_count: number;
+        rejected_count: number;
+        first_rejection_reason: string;
+      };
+    }>('diagnostics', 'slice-804-matching-debug-artifacts', 'matching-debug-artifacts.json');
+    const artifacts = fixture.debug_artifacts;
+
+    expect(artifacts.enabled).toBe(fixture.expected.enabled);
+    expect(artifacts.owner_sets).toHaveLength(fixture.expected.owner_set_count);
+    expect(artifacts.candidates).toHaveLength(fixture.expected.candidate_count);
+    expect(artifacts.selected_matches).toHaveLength(fixture.expected.selected_count);
+    expect(artifacts.rejected_matches).toHaveLength(fixture.expected.rejected_count);
+    expect(artifacts.rejected_matches[0]?.reason).toBe(fixture.expected.first_rejection_reason);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 807f9344f80898f1b8dc9541d238e83910bb9baa Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:41:56 -0600
Subject: [PATCH 039/130] Add fallback scopes contract

---
 packages/ast-merge/src/contracts.ts           | 17 ++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 52ec598..97370b5 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -829,6 +829,23 @@ export interface MatchingDebugArtifacts {
   readonly diagnostics: readonly string[];
 }
 
+export interface FallbackScopeDefinition {
+  readonly scope: string;
+  readonly path: string;
+  readonly owner_path: string;
+  readonly covers_children: boolean;
+  readonly requires_source_span: boolean;
+  readonly description: string;
+}
+
+export interface FallbackScopeReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly scopes: readonly FallbackScopeDefinition[];
+  readonly default_order: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 9da7e1d..52d57cb 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -40,6 +40,8 @@ export type {
   Diagnostic,
   DiagnosticCategory,
   DiagnosticSeverity,
+  FallbackScopeDefinition,
+  FallbackScopeReport,
   InconsistencyReport,
   MergeInconsistency,
   MergeIRComparisonCase,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index b6b0d0f..1f85870 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -37,6 +37,7 @@ import type {
   DiagnosticCategory,
   DiagnosticSeverity,
   DiscoveredSurface,
+  FallbackScopeReport,
   ChangeSet,
   ClassMappingReport,
   FamilyFeatureProfile,
@@ -5980,6 +5981,28 @@ describe('ast-merge shared fixtures', () => {
     expect(artifacts.rejected_matches[0]?.reason).toBe(fixture.expected.first_rejection_reason);
   });
 
+  it('conforms to the slice-805 fallback scopes fixture', () => {
+    const fixture = readFixture<{
+      fallback: FallbackScopeReport;
+      expected: {
+        scope_count: number;
+        default_order: readonly string[];
+        first_scope: string;
+        last_scope: string;
+        whole_file_requires_source_span: boolean;
+      };
+    }>('diagnostics', 'slice-805-fallback-scopes', 'fallback-scopes.json');
+    const report = fixture.fallback;
+
+    expect(report.scopes).toHaveLength(fixture.expected.scope_count);
+    expect(report.default_order).toEqual(fixture.expected.default_order);
+    expect(report.scopes[0]?.scope).toBe(fixture.expected.first_scope);
+    expect(report.scopes.at(-1)?.scope).toBe(fixture.expected.last_scope);
+    expect(report.scopes.at(-1)?.requires_source_span).toBe(
+      fixture.expected.whole_file_requires_source_span
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From b3193f8e3cc7095ab38ad48ce684b79c4f341e50 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:44:35 -0600
Subject: [PATCH 040/130] Add conflict categories contract

---
 packages/ast-merge/src/contracts.ts           | 16 ++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 22 +++++++++++++++++++
 3 files changed, 40 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 97370b5..b644c5b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -846,6 +846,22 @@ export interface FallbackScopeReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface MergeConflict {
+  readonly conflict_id: string;
+  readonly category: string;
+  readonly path: string;
+  readonly fallback_scope: string;
+  readonly message: string;
+}
+
+export interface ConflictCategoryReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly categories: readonly string[];
+  readonly conflicts: readonly MergeConflict[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 52d57cb..c7b797e 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -7,6 +7,7 @@ export type {
   ClassMappingDiagnostic,
   ClassMappingNodeClass,
   ClassMappingReport,
+  ConflictCategoryReport,
   ConformanceCaseRef,
   ConformanceCaseRun,
   ConformanceCaseRequirements,
@@ -43,6 +44,7 @@ export type {
   FallbackScopeDefinition,
   FallbackScopeReport,
   InconsistencyReport,
+  MergeConflict,
   MergeInconsistency,
   MergeIRComparisonCase,
   MergeIRComparisonReport,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 1f85870..8b42e4d 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -40,6 +40,7 @@ import type {
   FallbackScopeReport,
   ChangeSet,
   ClassMappingReport,
+  ConflictCategoryReport,
   FamilyFeatureProfile,
   InconsistencyReport,
   MatchingDebugArtifacts,
@@ -6003,6 +6004,27 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-806 conflict categories fixture', () => {
+    const fixture = readFixture<{
+      conflicts: ConflictCategoryReport;
+      expected: {
+        category_count: number;
+        conflict_count: number;
+        first_category: string;
+        last_category: string;
+        parse_limited_fallback_scope: string;
+      };
+    }>('diagnostics', 'slice-806-conflict-categories', 'conflict-categories.json');
+    const report = fixture.conflicts;
+    const parseLimited = report.conflicts.find((conflict) => conflict.category === 'parse_limited');
+
+    expect(report.categories).toHaveLength(fixture.expected.category_count);
+    expect(report.conflicts).toHaveLength(fixture.expected.conflict_count);
+    expect(report.categories[0]).toBe(fixture.expected.first_category);
+    expect(report.categories.at(-1)).toBe(fixture.expected.last_category);
+    expect(parseLimited?.fallback_scope).toBe(fixture.expected.parse_limited_fallback_scope);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 6c7bf2479b0c0e284c8b71f7e21d3b2412a7283d Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:47:26 -0600
Subject: [PATCH 041/130] Add local line fallback contract

---
 packages/ast-merge/src/contracts.ts           | 19 ++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 29 +++++++++++++++++++
 3 files changed, 50 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index b644c5b..1f82550 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -862,6 +862,25 @@ export interface ConflictCategoryReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface LineSpan {
+  readonly start_line: number;
+  readonly end_line: number;
+}
+
+export interface LocalLineFallbackReport {
+  readonly fallback_id: string;
+  readonly strategy: string;
+  readonly scope: string;
+  readonly path: string;
+  readonly owner_path: string;
+  readonly base_span: LineSpan;
+  readonly left_span: LineSpan;
+  readonly right_span: LineSpan;
+  readonly result: string;
+  readonly conflict_category: string;
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index c7b797e..2da41af 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -44,6 +44,8 @@ export type {
   FallbackScopeDefinition,
   FallbackScopeReport,
   InconsistencyReport,
+  LineSpan,
+  LocalLineFallbackReport,
   MergeConflict,
   MergeInconsistency,
   MergeIRComparisonCase,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 8b42e4d..570c3da 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -43,6 +43,7 @@ import type {
   ConflictCategoryReport,
   FamilyFeatureProfile,
   InconsistencyReport,
+  LocalLineFallbackReport,
   MatchingDebugArtifacts,
   MergeIR,
   MergeIRComparisonReport,
@@ -6025,6 +6026,34 @@ describe('ast-merge shared fixtures', () => {
     expect(parseLimited?.fallback_scope).toBe(fixture.expected.parse_limited_fallback_scope);
   });
 
+  it('conforms to the slice-807 local line-based fallback fixture', () => {
+    const fixture = readFixture<{
+      fallback: LocalLineFallbackReport;
+      expected: {
+        strategy: string;
+        scope: string;
+        path: string;
+        result: string;
+        conflict_category: string;
+        left_line_count: number;
+        right_line_count: number;
+      };
+    }>('diagnostics', 'slice-807-local-line-based-fallback', 'local-line-based-fallback.json');
+    const report = fixture.fallback;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.scope).toBe(fixture.expected.scope);
+    expect(report.path).toBe(fixture.expected.path);
+    expect(report.result).toBe(fixture.expected.result);
+    expect(report.conflict_category).toBe(fixture.expected.conflict_category);
+    expect(report.left_span.end_line - report.left_span.start_line + 1).toBe(
+      fixture.expected.left_line_count
+    );
+    expect(report.right_span.end_line - report.right_span.start_line + 1).toBe(
+      fixture.expected.right_line_count
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From e972e2d6eb5bceeb1a417463c7021cdd563500a1 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:49:47 -0600
Subject: [PATCH 042/130] Add conflict marker rendering contract

---
 packages/ast-merge/src/contracts.ts           | 13 ++++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 25 +++++++++++++++++++
 3 files changed, 39 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 1f82550..9a74ad1 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -881,6 +881,19 @@ export interface LocalLineFallbackReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface ConflictMarkerRenderingReport {
+  readonly render_id: string;
+  readonly strategy: string;
+  readonly marker_size: number;
+  readonly path_label: string;
+  readonly left_label: string;
+  readonly base_label: string;
+  readonly right_label: string;
+  readonly include_base: boolean;
+  readonly output: string;
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 2da41af..1b04fdf 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -8,6 +8,7 @@ export type {
   ClassMappingNodeClass,
   ClassMappingReport,
   ConflictCategoryReport,
+  ConflictMarkerRenderingReport,
   ConformanceCaseRef,
   ConformanceCaseRun,
   ConformanceCaseRequirements,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 570c3da..de3f108 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -41,6 +41,7 @@ import type {
   ChangeSet,
   ClassMappingReport,
   ConflictCategoryReport,
+  ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
   InconsistencyReport,
   LocalLineFallbackReport,
@@ -6054,6 +6055,30 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-808 conflict marker rendering fixture', () => {
+    const fixture = readFixture<{
+      rendering: ConflictMarkerRenderingReport;
+      expected: {
+        strategy: string;
+        marker_size: number;
+        path_label: string;
+        include_base: boolean;
+        starts_with: string;
+        contains_base_marker: string;
+        ends_with: string;
+      };
+    }>('diagnostics', 'slice-808-conflict-marker-rendering', 'conflict-marker-rendering.json');
+    const report = fixture.rendering;
+
+    expect(report.strategy).toBe(fixture.expected.strategy);
+    expect(report.marker_size).toBe(fixture.expected.marker_size);
+    expect(report.path_label).toBe(fixture.expected.path_label);
+    expect(report.include_base).toBe(fixture.expected.include_base);
+    expect(report.output.startsWith(fixture.expected.starts_with)).toBe(true);
+    expect(report.output.includes(fixture.expected.contains_base_marker)).toBe(true);
+    expect(report.output.endsWith(fixture.expected.ends_with)).toBe(true);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From a43f36f85a199530430a9f13c1cde96f8f3d60bf Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 18:52:26 -0600
Subject: [PATCH 043/130] Add typed conflict handler contract

---
 packages/ast-merge/src/contracts.ts           | 16 +++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 24 +++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 9a74ad1..7ec9b78 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -894,6 +894,22 @@ export interface ConflictMarkerRenderingReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface ConflictHandlerRegistration {
+  readonly handler_id: string;
+  readonly conflict_category: string;
+  readonly fallback_scope: string;
+  readonly node_roles: readonly string[];
+  readonly capability: string;
+  readonly enabled: boolean;
+}
+
+export interface ConflictHandlerRegistryReport {
+  readonly registry_id: string;
+  readonly version: string;
+  readonly handlers: readonly ConflictHandlerRegistration[];
+  readonly diagnostics: readonly string[];
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 1b04fdf..bd9c99d 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -8,6 +8,8 @@ export type {
   ClassMappingNodeClass,
   ClassMappingReport,
   ConflictCategoryReport,
+  ConflictHandlerRegistration,
+  ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   ConformanceCaseRef,
   ConformanceCaseRun,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index de3f108..fb32744 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -41,6 +41,7 @@ import type {
   ChangeSet,
   ClassMappingReport,
   ConflictCategoryReport,
+  ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
   InconsistencyReport,
@@ -6079,6 +6080,29 @@ describe('ast-merge shared fixtures', () => {
     expect(report.output.endsWith(fixture.expected.ends_with)).toBe(true);
   });
 
+  it('conforms to the slice-809 typed conflict handler extension points fixture', () => {
+    const fixture = readFixture<{
+      handlers: ConflictHandlerRegistryReport;
+      expected: {
+        handler_count: number;
+        enabled_count: number;
+        first_handler_category: string;
+        second_handler_scope: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-809-typed-conflict-handler-extension-points',
+      'typed-conflict-handler-extension-points.json'
+    );
+    const report = fixture.handlers;
+    const enabledCount = report.handlers.filter((handler) => handler.enabled).length;
+
+    expect(report.handlers).toHaveLength(fixture.expected.handler_count);
+    expect(enabledCount).toBe(fixture.expected.enabled_count);
+    expect(report.handlers[0]?.conflict_category).toBe(fixture.expected.first_handler_category);
+    expect(report.handlers[1]?.fallback_scope).toBe(fixture.expected.second_handler_scope);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 988a640eea0696844619d228a45f8950bbb34239 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:14:38 -0600
Subject: [PATCH 044/130] Add generic conflict handler execution

---
 packages/ast-merge/src/contracts.ts           | 124 ++++++++++++++++++
 packages/ast-merge/src/index.ts               |   6 +
 .../test/fixtures.integration.test.ts         |  38 ++++++
 3 files changed, 168 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 7ec9b78..69f641b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -910,6 +910,130 @@ export interface ConflictHandlerRegistryReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface HandlerChildNode {
+  readonly node_id: string;
+  readonly signature: string;
+  readonly source: string;
+}
+
+export interface HandlerKeyedMember {
+  readonly key: string;
+  readonly value: string;
+}
+
+export interface GenericConflictHandlerResult {
+  readonly resolved: boolean;
+  readonly merged_children?: readonly HandlerChildNode[];
+  readonly merged_members?: readonly HandlerKeyedMember[];
+  readonly diagnostics: readonly string[];
+}
+
+export interface GenericConflictHandlerCase {
+  readonly case_id: string;
+  readonly handler_id: string;
+  readonly conflict_category: string;
+  readonly parent_policy?: string;
+  readonly base_children?: readonly HandlerChildNode[];
+  readonly left_insertions?: readonly HandlerChildNode[];
+  readonly right_insertions?: readonly HandlerChildNode[];
+  readonly base_members?: readonly HandlerKeyedMember[];
+  readonly left_edits?: readonly HandlerKeyedMember[];
+  readonly right_edits?: readonly HandlerKeyedMember[];
+  readonly expected_result: GenericConflictHandlerResult;
+}
+
+export interface GenericConflictHandlerExecution {
+  readonly execution_id: string;
+  readonly version: string;
+  readonly cases: readonly GenericConflictHandlerCase[];
+  readonly diagnostics: readonly string[];
+}
+
+export const genericIndependentCommutativeInsertionsHandler =
+  'generic-independent-commutative-insertions';
+export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
+
+export function executeGenericConflictHandler(
+  handlerCase: GenericConflictHandlerCase
+): GenericConflictHandlerResult {
+  if (handlerCase.handler_id === genericIndependentCommutativeInsertionsHandler) {
+    return executeIndependentCommutativeInsertions(handlerCase);
+  }
+  if (handlerCase.handler_id === genericKeyedMemberEditHandler) {
+    return executeIndependentKeyedMemberEdits(handlerCase);
+  }
+
+  return {
+    resolved: false,
+    diagnostics: ['unsupported generic conflict handler']
+  };
+}
+
+function executeIndependentCommutativeInsertions(
+  handlerCase: GenericConflictHandlerCase
+): GenericConflictHandlerResult {
+  if (handlerCase.parent_policy !== 'commutative') {
+    return {
+      resolved: false,
+      diagnostics: ['independent insertion handler requires a commutative parent']
+    };
+  }
+
+  const seen = new Set<string>();
+  const mergedChildren: HandlerChildNode[] = [];
+  const appendUnique = (nodes: readonly HandlerChildNode[] | undefined) => {
+    for (const node of nodes ?? []) {
+      const key = node.signature || node.node_id;
+      if (seen.has(key)) continue;
+      seen.add(key);
+      mergedChildren.push(node);
+    }
+  };
+
+  appendUnique(handlerCase.base_children);
+  appendUnique(handlerCase.left_insertions);
+  appendUnique(handlerCase.right_insertions);
+
+  return {
+    resolved: true,
+    merged_children: mergedChildren,
+    diagnostics: ['independent insertions into a commutative parent were unioned deterministically']
+  };
+}
+
+function executeIndependentKeyedMemberEdits(
+  handlerCase: GenericConflictHandlerCase
+): GenericConflictHandlerResult {
+  const order: string[] = [];
+  const values = new Map<string, string>();
+  const setMember = (member: HandlerKeyedMember) => {
+    if (!values.has(member.key)) order.push(member.key);
+    values.set(member.key, member.value);
+  };
+
+  for (const member of handlerCase.base_members ?? []) setMember(member);
+  for (const member of handlerCase.left_edits ?? []) setMember(member);
+  for (const member of handlerCase.right_edits ?? []) {
+    if (
+      values.has(member.key) &&
+      values.get(member.key) !== member.value &&
+      (handlerCase.left_edits ?? []).some((left) => left.key === member.key)
+    ) {
+      return {
+        resolved: false,
+        diagnostics: ['keyed member was edited differently on both sides']
+      };
+    }
+    setMember(member);
+  }
+
+  return {
+    resolved: true,
+    merged_members: order.map((key) => ({ key, value: values.get(key) ?? '' })),
+    diagnostics: ['independent keyed member edits were merged by key']
+  };
+}
+
 export type PolicySurface = 'fallback' | 'array';
 
 export interface PolicyReference {
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index bd9c99d..c06170b 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -46,6 +46,11 @@ export type {
   DiagnosticSeverity,
   FallbackScopeDefinition,
   FallbackScopeReport,
+  GenericConflictHandlerCase,
+  GenericConflictHandlerExecution,
+  GenericConflictHandlerResult,
+  HandlerChildNode,
+  HandlerKeyedMember,
   InconsistencyReport,
   LineSpan,
   LocalLineFallbackReport,
@@ -374,6 +379,7 @@ export {
   structuredEditProviderBatchExecutionHandoffEnvelope,
   structuredEditProviderBatchExecutionPlanEnvelope,
   structuredEditExecutionReportEnvelope,
+  executeGenericConflictHandler,
   executeNestedMerge,
   executeDelegatedChildApplyPlan,
   executeReviewedNestedMerge,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index fb32744..cde8642 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -6,6 +6,7 @@ import { describe, expect, it } from 'vitest';
 import { mergeMarkdown } from '../../markdown-merge/src/index';
 import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
+import { executeGenericConflictHandler } from '../src/index';
 import type {
   AmbiguityMatchingReport,
   ConformanceCaseRef,
@@ -44,6 +45,7 @@ import type {
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
+  GenericConflictHandlerExecution,
   InconsistencyReport,
   LocalLineFallbackReport,
   MatchingDebugArtifacts,
@@ -6103,6 +6105,42 @@ describe('ast-merge shared fixtures', () => {
     expect(report.handlers[1]?.fallback_scope).toBe(fixture.expected.second_handler_scope);
   });
 
+  it('conforms to the slice-810 generic conflict handler execution fixture', () => {
+    const fixture = readFixture<{
+      execution: GenericConflictHandlerExecution;
+      expected: {
+        case_count: number;
+        resolved_count: number;
+        first_handler_id: string;
+        first_merged_child_count: number;
+        second_handler_id: string;
+        second_merged_member_count: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-810-generic-conflict-handler-execution',
+      'generic-conflict-handler-execution.json'
+    );
+    const execution = fixture.execution;
+    const resolvedCount = execution.cases.filter(
+      (handlerCase) => handlerCase.expected_result.resolved
+    ).length;
+    const results = execution.cases.map((handlerCase) =>
+      executeGenericConflictHandler(handlerCase)
+    );
+
+    execution.cases.forEach((handlerCase, index) => {
+      expect(results[index]).toEqual(handlerCase.expected_result);
+    });
+
+    expect(execution.cases).toHaveLength(fixture.expected.case_count);
+    expect(resolvedCount).toBe(fixture.expected.resolved_count);
+    expect(execution.cases[0]?.handler_id).toBe(fixture.expected.first_handler_id);
+    expect(results[0]?.merged_children).toHaveLength(fixture.expected.first_merged_child_count);
+    expect(execution.cases[1]?.handler_id).toBe(fixture.expected.second_handler_id);
+    expect(results[1]?.merged_members).toHaveLength(fixture.expected.second_merged_member_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From c3b46daf87dcf4a52d3c50f62bb1f03f2b25e27e Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:17:55 -0600
Subject: [PATCH 045/130] Add language profile handler registration contract

---
 packages/ast-merge/src/contracts.ts           | 15 +++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 32 +++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 69f641b..bf2930b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -949,6 +949,21 @@ export interface GenericConflictHandlerExecution {
   readonly diagnostics: readonly string[];
 }
 
+export interface LanguageProfileHandlerRegistration {
+  readonly role: string;
+  readonly handler_id: string;
+  readonly conflict_categories: readonly string[];
+  readonly enabled: boolean;
+}
+
+export interface LanguageProfileHandlerRegistry {
+  readonly profile_id: string;
+  readonly language: string;
+  readonly version: string;
+  readonly registrations: readonly LanguageProfileHandlerRegistration[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index c06170b..67b1c89 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -52,6 +52,8 @@ export type {
   HandlerChildNode,
   HandlerKeyedMember,
   InconsistencyReport,
+  LanguageProfileHandlerRegistration,
+  LanguageProfileHandlerRegistry,
   LineSpan,
   LocalLineFallbackReport,
   MergeConflict,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index cde8642..bc73da5 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -47,6 +47,7 @@ import type {
   FamilyFeatureProfile,
   GenericConflictHandlerExecution,
   InconsistencyReport,
+  LanguageProfileHandlerRegistry,
   LocalLineFallbackReport,
   MatchingDebugArtifacts,
   MergeIR,
@@ -6141,6 +6142,37 @@ describe('ast-merge shared fixtures', () => {
     expect(results[1]?.merged_members).toHaveLength(fixture.expected.second_merged_member_count);
   });
 
+  it('conforms to the slice-811 language profile handler registration fixture', () => {
+    const fixture = readFixture<{
+      profile_handlers: LanguageProfileHandlerRegistry;
+      expected: {
+        language: string;
+        registration_count: number;
+        enabled_count: number;
+        roles: readonly string[];
+        duplicate_member_handler: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-811-language-profile-handler-registration',
+      'language-profile-handler-registration.json'
+    );
+    const registry = fixture.profile_handlers;
+    const enabledCount = registry.registrations.filter(
+      (registration) => registration.enabled
+    ).length;
+    const roles = registry.registrations.map((registration) => registration.role);
+    const duplicateMemberHandler = registry.registrations.find(
+      (registration) => registration.role === 'duplicate_members'
+    )?.handler_id;
+
+    expect(registry.language).toBe(fixture.expected.language);
+    expect(registry.registrations).toHaveLength(fixture.expected.registration_count);
+    expect(enabledCount).toBe(fixture.expected.enabled_count);
+    expect(roles).toEqual(fixture.expected.roles);
+    expect(duplicateMemberHandler).toBe(fixture.expected.duplicate_member_handler);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 2370baa04151d08e81f214724c2c2f56bb28e3d8 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:22:56 -0600
Subject: [PATCH 046/130] Add fallback usage machine output contract

---
 packages/ast-merge/src/contracts.ts           | 35 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  5 +++
 .../test/fixtures.integration.test.ts         | 31 ++++++++++++++++
 3 files changed, 71 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index bf2930b..636b117 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -964,6 +964,41 @@ export interface LanguageProfileHandlerRegistry {
   readonly diagnostics: readonly string[];
 }
 
+export interface FallbackUsageEntry {
+  readonly fallback_id: string;
+  readonly strategy: string;
+  readonly scope: string;
+  readonly path: string;
+  readonly conflict_category: string;
+}
+
+export interface FallbackUsageSummary {
+  readonly fallback_count: number;
+  readonly conflict_count: number;
+  readonly resolved_count: number;
+}
+
+export interface FallbackUsageMachineOutput {
+  readonly fallbacks: readonly FallbackUsageEntry[];
+  readonly summary: FallbackUsageSummary;
+}
+
+export interface GitDriverOutput {
+  readonly stdout: string;
+  readonly stderr: string;
+  readonly exit_code: number;
+}
+
+export interface FallbackUsageReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly mode: string;
+  readonly quiet_by_default: boolean;
+  readonly machine_output: FallbackUsageMachineOutput;
+  readonly git_driver_output: GitDriverOutput;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 67b1c89..e9e0195 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -46,11 +46,16 @@ export type {
   DiagnosticSeverity,
   FallbackScopeDefinition,
   FallbackScopeReport,
+  FallbackUsageEntry,
+  FallbackUsageMachineOutput,
+  FallbackUsageReport,
+  FallbackUsageSummary,
   GenericConflictHandlerCase,
   GenericConflictHandlerExecution,
   GenericConflictHandlerResult,
   HandlerChildNode,
   HandlerKeyedMember,
+  GitDriverOutput,
   InconsistencyReport,
   LanguageProfileHandlerRegistration,
   LanguageProfileHandlerRegistry,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index bc73da5..b14200e 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -39,6 +39,7 @@ import type {
   DiagnosticSeverity,
   DiscoveredSurface,
   FallbackScopeReport,
+  FallbackUsageReport,
   ChangeSet,
   ClassMappingReport,
   ConflictCategoryReport,
@@ -6173,6 +6174,36 @@ describe('ast-merge shared fixtures', () => {
     expect(duplicateMemberHandler).toBe(fixture.expected.duplicate_member_handler);
   });
 
+  it('conforms to the slice-812 fallback usage machine output fixture', () => {
+    const fixture = readFixture<{
+      fallback_usage: FallbackUsageReport;
+      expected: {
+        mode: string;
+        quiet_by_default: boolean;
+        fallback_count: number;
+        conflict_count: number;
+        stdout: string;
+        stderr: string;
+        exit_code: number;
+        first_fallback_scope: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-812-fallback-usage-machine-output',
+      'fallback-usage-machine-output.json'
+    );
+    const report = fixture.fallback_usage;
+
+    expect(report.mode).toBe(fixture.expected.mode);
+    expect(report.quiet_by_default).toBe(fixture.expected.quiet_by_default);
+    expect(report.machine_output.summary.fallback_count).toBe(fixture.expected.fallback_count);
+    expect(report.machine_output.summary.conflict_count).toBe(fixture.expected.conflict_count);
+    expect(report.git_driver_output.stdout).toBe(fixture.expected.stdout);
+    expect(report.git_driver_output.stderr).toBe(fixture.expected.stderr);
+    expect(report.git_driver_output.exit_code).toBe(fixture.expected.exit_code);
+    expect(report.machine_output.fallbacks[0]?.scope).toBe(fixture.expected.first_fallback_scope);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 8a6fe22640727534fa5934b0028684faa115a452 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:25:32 -0600
Subject: [PATCH 047/130] Add render strategy metadata contract

---
 packages/ast-merge/src/contracts.ts           | 21 +++++++++++++++
 packages/ast-merge/src/index.ts               |  3 +++
 .../test/fixtures.integration.test.ts         | 26 +++++++++++++++++++
 3 files changed, 50 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 636b117..0abb2ce 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -999,6 +999,27 @@ export interface FallbackUsageReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface RenderByteSpan {
+  readonly start_byte: number;
+  readonly end_byte: number;
+}
+
+export interface RenderStrategyMetadata {
+  readonly strategy: string;
+  readonly path: string;
+  readonly span: RenderByteSpan | null;
+  readonly preserves_source_fragment: boolean;
+  readonly requires_reparse: boolean;
+}
+
+export interface RenderPlanReport {
+  readonly plan_id: string;
+  readonly version: string;
+  readonly language: string;
+  readonly strategies: readonly RenderStrategyMetadata[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index e9e0195..3f0e09f 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -78,6 +78,9 @@ export type {
   RenameAwareCapability,
   RenameAwareCandidate,
   RenameAwareMatchingReport,
+  RenderByteSpan,
+  RenderPlanReport,
+  RenderStrategyMetadata,
   RejectedTieBreakCandidate,
   SignatureMatchingParent,
   SignatureMatchingReport,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index b14200e..e851b1c 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -58,6 +58,7 @@ import type {
   PCS,
   RawMerge,
   RenameAwareMatchingReport,
+  RenderPlanReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SourceTextNormalizedMatchingReport,
@@ -6204,6 +6205,31 @@ describe('ast-merge shared fixtures', () => {
     expect(report.machine_output.fallbacks[0]?.scope).toBe(fixture.expected.first_fallback_scope);
   });
 
+  it('conforms to the slice-813 render strategy metadata fixture', () => {
+    const fixture = readFixture<{
+      render_plan: RenderPlanReport;
+      expected: {
+        language: string;
+        strategy_count: number;
+        strategies: readonly string[];
+        source_reuse_preserves_fragment: boolean;
+        full_file_requires_reparse: boolean;
+      };
+    }>('diagnostics', 'slice-813-render-strategy-metadata', 'render-strategy-metadata.json');
+    const report = fixture.render_plan;
+    const strategies = report.strategies.map((strategy) => strategy.strategy);
+
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.strategies).toHaveLength(fixture.expected.strategy_count);
+    expect(strategies).toEqual(fixture.expected.strategies);
+    expect(report.strategies[0]?.preserves_source_fragment).toBe(
+      fixture.expected.source_reuse_preserves_fragment
+    );
+    expect(report.strategies.at(-1)?.requires_reparse).toBe(
+      fixture.expected.full_file_requires_reparse
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From f29fadc6d09c26ac5a52d87c6b46e0f6604208ee Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:27:32 -0600
Subject: [PATCH 048/130] Add reparse after render contract

---
 packages/ast-merge/src/contracts.ts           | 13 +++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 29 +++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 0abb2ce..dcc29fd 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1020,6 +1020,19 @@ export interface RenderPlanReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface RenderVerificationReport {
+  readonly verification_id: string;
+  readonly version: string;
+  readonly mode: string;
+  readonly language: string;
+  readonly render_strategy: string;
+  readonly attempted: boolean;
+  readonly passed: boolean;
+  readonly hard_gate: boolean;
+  readonly parse_errors: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 3f0e09f..208d966 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -81,6 +81,7 @@ export type {
   RenderByteSpan,
   RenderPlanReport,
   RenderStrategyMetadata,
+  RenderVerificationReport,
   RejectedTieBreakCandidate,
   SignatureMatchingParent,
   SignatureMatchingReport,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index e851b1c..b8d20f0 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -59,6 +59,7 @@ import type {
   RawMerge,
   RenameAwareMatchingReport,
   RenderPlanReport,
+  RenderVerificationReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SourceTextNormalizedMatchingReport,
@@ -6230,6 +6231,34 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-814 reparse after render verification fixture', () => {
+    const fixture = readFixture<{
+      render_verification: RenderVerificationReport;
+      expected: {
+        mode: string;
+        language: string;
+        attempted: boolean;
+        passed: boolean;
+        hard_gate: boolean;
+        parse_error_count: number;
+        render_strategy: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-814-reparse-after-render-verification',
+      'reparse-after-render-verification.json'
+    );
+    const report = fixture.render_verification;
+
+    expect(report.mode).toBe(fixture.expected.mode);
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.attempted).toBe(fixture.expected.attempted);
+    expect(report.passed).toBe(fixture.expected.passed);
+    expect(report.hard_gate).toBe(fixture.expected.hard_gate);
+    expect(report.parse_errors).toHaveLength(fixture.expected.parse_error_count);
+    expect(report.render_strategy).toBe(fixture.expected.render_strategy);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 2ce2ea7fdb066cd83a6f13d09d17ae3841324ec9 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:29:58 -0600
Subject: [PATCH 049/130] Add formatting preservation metrics contract

---
 packages/ast-merge/src/contracts.ts           | 16 ++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 29 +++++++++++++++++++
 3 files changed, 47 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index dcc29fd..053550b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1033,6 +1033,22 @@ export interface RenderVerificationReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface FormattingPreservationMetrics {
+  readonly expected_output_line_diff_size: number;
+  readonly expected_output_character_diff_size: number;
+  readonly formatting_preservation_score: number;
+}
+
+export interface FormattingPreservationConformanceReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly suite: string;
+  readonly case_id: string;
+  readonly language: string;
+  readonly formatting_metrics: FormattingPreservationMetrics;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 208d966..4e7683b 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -50,6 +50,8 @@ export type {
   FallbackUsageMachineOutput,
   FallbackUsageReport,
   FallbackUsageSummary,
+  FormattingPreservationConformanceReport,
+  FormattingPreservationMetrics,
   GenericConflictHandlerCase,
   GenericConflictHandlerExecution,
   GenericConflictHandlerResult,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index b8d20f0..dc6c900 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -46,6 +46,7 @@ import type {
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
+  FormattingPreservationConformanceReport,
   GenericConflictHandlerExecution,
   InconsistencyReport,
   LanguageProfileHandlerRegistry,
@@ -6259,6 +6260,34 @@ describe('ast-merge shared fixtures', () => {
     expect(report.render_strategy).toBe(fixture.expected.render_strategy);
   });
 
+  it('conforms to the slice-815 formatting preservation metrics fixture', () => {
+    const fixture = readFixture<{
+      conformance_report: FormattingPreservationConformanceReport;
+      expected: {
+        suite: string;
+        language: string;
+        line_diff_size: number;
+        character_diff_size: number;
+        score: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-815-formatting-preservation-metrics',
+      'formatting-preservation-metrics.json'
+    );
+    const report = fixture.conformance_report;
+
+    expect(report.suite).toBe(fixture.expected.suite);
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.formatting_metrics.expected_output_line_diff_size).toBe(
+      fixture.expected.line_diff_size
+    );
+    expect(report.formatting_metrics.expected_output_character_diff_size).toBe(
+      fixture.expected.character_diff_size
+    );
+    expect(report.formatting_metrics.formatting_preservation_score).toBe(fixture.expected.score);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From daa2cb1efb7d0afbb1895be83b9750107e3f1f87 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:32:26 -0600
Subject: [PATCH 050/130] Add formatting recommendation gate contract

---
 packages/ast-merge/src/contracts.ts           | 15 +++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 27 +++++++++++++++++++
 3 files changed, 44 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 053550b..fc9dcbc 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1049,6 +1049,21 @@ export interface FormattingPreservationConformanceReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface FormattingRecommendationWeights {
+  readonly expected_output_line_diff_size: number;
+  readonly expected_output_character_diff_size: number;
+}
+
+export interface FormattingRecommendationGate {
+  readonly gate_id: string;
+  readonly version: string;
+  readonly threshold: number;
+  readonly passed: boolean;
+  readonly weights: FormattingRecommendationWeights;
+  readonly metrics: FormattingPreservationMetrics;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 4e7683b..f9f31b6 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -52,6 +52,8 @@ export type {
   FallbackUsageSummary,
   FormattingPreservationConformanceReport,
   FormattingPreservationMetrics,
+  FormattingRecommendationGate,
+  FormattingRecommendationWeights,
   GenericConflictHandlerCase,
   GenericConflictHandlerExecution,
   GenericConflictHandlerResult,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index dc6c900..ae4b1e2 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -47,6 +47,7 @@ import type {
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
   FormattingPreservationConformanceReport,
+  FormattingRecommendationGate,
   GenericConflictHandlerExecution,
   InconsistencyReport,
   LanguageProfileHandlerRegistry,
@@ -6288,6 +6289,32 @@ describe('ast-merge shared fixtures', () => {
     expect(report.formatting_metrics.formatting_preservation_score).toBe(fixture.expected.score);
   });
 
+  it('conforms to the slice-816 formatting recommendation gate fixture', () => {
+    const fixture = readFixture<{
+      recommendation_gate: FormattingRecommendationGate;
+      expected: {
+        threshold: number;
+        passed: boolean;
+        line_weight: number;
+        character_weight: number;
+        score: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-816-formatting-recommendation-gate',
+      'formatting-recommendation-gate.json'
+    );
+    const gate = fixture.recommendation_gate;
+
+    expect(gate.threshold).toBe(fixture.expected.threshold);
+    expect(gate.passed).toBe(fixture.expected.passed);
+    expect(gate.weights.expected_output_line_diff_size).toBe(fixture.expected.line_weight);
+    expect(gate.weights.expected_output_character_diff_size).toBe(
+      fixture.expected.character_weight
+    );
+    expect(gate.metrics.formatting_preservation_score).toBe(fixture.expected.score);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 6a251ed48a6584a3c51b4f2ac30d30ac39f7ab68 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:35:01 -0600
Subject: [PATCH 051/130] Add formatting hard gates contract

---
 packages/ast-merge/src/contracts.ts           | 13 +++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 38 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index fc9dcbc..4cb0760 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1064,6 +1064,19 @@ export interface FormattingRecommendationGate {
   readonly diagnostics: readonly string[];
 }
 
+export interface FormattingHardGate {
+  readonly name: string;
+  readonly passed: boolean;
+  readonly weighted: boolean;
+}
+
+export interface FormattingHardGateReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly gates: readonly FormattingHardGate[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index f9f31b6..6612746 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -50,6 +50,8 @@ export type {
   FallbackUsageMachineOutput,
   FallbackUsageReport,
   FallbackUsageSummary,
+  FormattingHardGate,
+  FormattingHardGateReport,
   FormattingPreservationConformanceReport,
   FormattingPreservationMetrics,
   FormattingRecommendationGate,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index ae4b1e2..bc7463d 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -46,6 +46,7 @@ import type {
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
+  FormattingHardGateReport,
   FormattingPreservationConformanceReport,
   FormattingRecommendationGate,
   GenericConflictHandlerExecution,
@@ -6315,6 +6316,28 @@ describe('ast-merge shared fixtures', () => {
     expect(gate.metrics.formatting_preservation_score).toBe(fixture.expected.score);
   });
 
+  it('conforms to the slice-817 formatting hard gates fixture', () => {
+    const fixture = readFixture<{
+      hard_gate_report: FormattingHardGateReport;
+      expected: {
+        gate_count: number;
+        all_passed: boolean;
+        weighted_gate_count: number;
+        first_gate: string;
+        second_gate: string;
+      };
+    }>('diagnostics', 'slice-817-formatting-hard-gates', 'formatting-hard-gates.json');
+    const report = fixture.hard_gate_report;
+    const passedCount = report.gates.filter((gate) => gate.passed).length;
+    const weightedCount = report.gates.filter((gate) => gate.weighted).length;
+
+    expect(report.gates).toHaveLength(fixture.expected.gate_count);
+    expect(passedCount === report.gates.length).toBe(fixture.expected.all_passed);
+    expect(weightedCount).toBe(fixture.expected.weighted_gate_count);
+    expect(report.gates[0]?.name).toBe(fixture.expected.first_gate);
+    expect(report.gates[1]?.name).toBe(fixture.expected.second_gate);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 8d46d4fb8b54592afc2e88cda859c6512563cf7d Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:37:16 -0600
Subject: [PATCH 052/130] Add secondary formatting metrics contract

---
 packages/ast-merge/src/contracts.ts           | 10 ++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 4cb0760..702ddfd 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1077,6 +1077,16 @@ export interface FormattingHardGateReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface SecondaryFormattingMetricsReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly unchanged_line_churn: number;
+  readonly output_diff_size: number;
+  readonly source_fragment_retention: number;
+  readonly weighted: boolean;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 6612746..c0c9537 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -89,6 +89,7 @@ export type {
   RenderStrategyMetadata,
   RenderVerificationReport,
   RejectedTieBreakCandidate,
+  SecondaryFormattingMetricsReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SignatureNodeMatch,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index bc7463d..1715375 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -63,6 +63,7 @@ import type {
   RenameAwareMatchingReport,
   RenderPlanReport,
   RenderVerificationReport,
+  SecondaryFormattingMetricsReport,
   SignatureMatchingParent,
   SignatureMatchingReport,
   SourceTextNormalizedMatchingReport,
@@ -6338,6 +6339,28 @@ describe('ast-merge shared fixtures', () => {
     expect(report.gates[1]?.name).toBe(fixture.expected.second_gate);
   });
 
+  it('conforms to the slice-818 secondary formatting metrics fixture', () => {
+    const fixture = readFixture<{
+      secondary_metrics: SecondaryFormattingMetricsReport;
+      expected: {
+        unchanged_line_churn: number;
+        output_diff_size: number;
+        source_fragment_retention: number;
+        weighted: boolean;
+      };
+    }>(
+      'diagnostics',
+      'slice-818-secondary-formatting-metrics',
+      'secondary-formatting-metrics.json'
+    );
+    const report = fixture.secondary_metrics;
+
+    expect(report.unchanged_line_churn).toBe(fixture.expected.unchanged_line_churn);
+    expect(report.output_diff_size).toBe(fixture.expected.output_diff_size);
+    expect(report.source_fragment_retention).toBe(fixture.expected.source_fragment_retention);
+    expect(report.weighted).toBe(fixture.expected.weighted);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 1b3fa946ba6de049d6847d4c4e119a4e0edd1d93 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:39:41 -0600
Subject: [PATCH 053/130] Add token span preservation metrics contract

---
 packages/ast-merge/src/contracts.ts           | 10 ++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 34 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 702ddfd..adb9369 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1087,6 +1087,16 @@ export interface SecondaryFormattingMetricsReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface TokenSpanPreservationMetricsReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly source_spans_available: boolean;
+  readonly token_preservation: number;
+  readonly span_preservation: number;
+  readonly weighted: boolean;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index c0c9537..8a4e1e6 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -99,6 +99,7 @@ export type {
   StructuralPathMatch,
   TieBreakMatch,
   TieBreakMatchingReport,
+  TokenSpanPreservationMetricsReport,
   CompactRuleset,
   CompactRulesetAtomicNode,
   CompactRulesetBackendDeclaration,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 1715375..13625ab 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -69,6 +69,7 @@ import type {
   SourceTextNormalizedMatchingReport,
   StructuralMatchingReport,
   TieBreakMatchingReport,
+  TokenSpanPreservationMetricsReport,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
@@ -6361,6 +6362,28 @@ describe('ast-merge shared fixtures', () => {
     expect(report.weighted).toBe(fixture.expected.weighted);
   });
 
+  it('conforms to the slice-819 token span preservation metrics fixture', () => {
+    const fixture = readFixture<{
+      token_span_metrics: TokenSpanPreservationMetricsReport;
+      expected: {
+        source_spans_available: boolean;
+        token_preservation: number;
+        span_preservation: number;
+        weighted: boolean;
+      };
+    }>(
+      'diagnostics',
+      'slice-819-token-span-preservation-metrics',
+      'token-span-preservation-metrics.json'
+    );
+    const report = fixture.token_span_metrics;
+
+    expect(report.source_spans_available).toBe(fixture.expected.source_spans_available);
+    expect(report.token_preservation).toBe(fixture.expected.token_preservation);
+    expect(report.span_preservation).toBe(fixture.expected.span_preservation);
+    expect(report.weighted).toBe(fixture.expected.weighted);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 1de28b55cc67339c85ab12006d44ae62228257a6 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:42:05 -0600
Subject: [PATCH 054/130] Add formatting edge fixture contract

---
 packages/ast-merge/src/contracts.ts           | 13 ++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 21 +++++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index adb9369..28c26d7 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1097,6 +1097,19 @@ export interface TokenSpanPreservationMetricsReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface FormattingEdgeFixtureCase {
+  readonly case_id: string;
+  readonly category: string;
+  readonly requires_conflict_markers: boolean;
+}
+
+export interface FormattingEdgeFixtureSuite {
+  readonly suite_id: string;
+  readonly version: string;
+  readonly cases: readonly FormattingEdgeFixtureCase[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 8a4e1e6..59cb2ec 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -50,6 +50,8 @@ export type {
   FallbackUsageMachineOutput,
   FallbackUsageReport,
   FallbackUsageSummary,
+  FormattingEdgeFixtureCase,
+  FormattingEdgeFixtureSuite,
   FormattingHardGate,
   FormattingHardGateReport,
   FormattingPreservationConformanceReport,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 13625ab..98ccda9 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -46,6 +46,7 @@ import type {
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
+  FormattingEdgeFixtureSuite,
   FormattingHardGateReport,
   FormattingPreservationConformanceReport,
   FormattingRecommendationGate,
@@ -6384,6 +6385,26 @@ describe('ast-merge shared fixtures', () => {
     expect(report.weighted).toBe(fixture.expected.weighted);
   });
 
+  it('conforms to the slice-820 formatting edge fixtures fixture', () => {
+    const fixture = readFixture<{
+      fixture_suite: FormattingEdgeFixtureSuite;
+      expected: {
+        case_count: number;
+        categories: readonly string[];
+        conflict_marker_case_count: number;
+      };
+    }>('diagnostics', 'slice-820-formatting-edge-fixtures', 'formatting-edge-fixtures.json');
+    const suite = fixture.fixture_suite;
+    const categories = suite.cases.map((fixtureCase) => fixtureCase.category);
+    const conflictMarkerCaseCount = suite.cases.filter(
+      (fixtureCase) => fixtureCase.requires_conflict_markers
+    ).length;
+
+    expect(suite.cases).toHaveLength(fixture.expected.case_count);
+    expect(categories).toEqual(fixture.expected.categories);
+    expect(conflictMarkerCaseCount).toBe(fixture.expected.conflict_marker_case_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 5fd1e5d1f5d78fb6c5937a67e60a2de6b7828b4d Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 19:44:34 -0600
Subject: [PATCH 055/130] Add unsafe render fallback contract

---
 packages/ast-merge/src/contracts.ts           | 10 ++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 25 +++++++++++++++++++
 3 files changed, 36 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 28c26d7..ea6022a 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1110,6 +1110,16 @@ export interface FormattingEdgeFixtureSuite {
   readonly diagnostics: readonly string[];
 }
 
+export interface RenderSafetyReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly provider_id: string;
+  readonly safe_to_render: boolean;
+  readonly outcome: string;
+  readonly fallback_strategy: string;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 59cb2ec..5014f9a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -88,6 +88,7 @@ export type {
   RenameAwareMatchingReport,
   RenderByteSpan,
   RenderPlanReport,
+  RenderSafetyReport,
   RenderStrategyMetadata,
   RenderVerificationReport,
   RejectedTieBreakCandidate,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 98ccda9..490948d 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -63,6 +63,7 @@ import type {
   RawMerge,
   RenameAwareMatchingReport,
   RenderPlanReport,
+  RenderSafetyReport,
   RenderVerificationReport,
   SecondaryFormattingMetricsReport,
   SignatureMatchingParent,
@@ -6405,6 +6406,30 @@ describe('ast-merge shared fixtures', () => {
     expect(conflictMarkerCaseCount).toBe(fixture.expected.conflict_marker_case_count);
   });
 
+  it('conforms to the slice-821 unsafe render fallback or failure fixture', () => {
+    const fixture = readFixture<{
+      render_safety: RenderSafetyReport;
+      expected: {
+        safe_to_render: boolean;
+        allowed_outcomes: readonly string[];
+        outcome: string;
+        fallback_strategy: string;
+        diagnostic_count: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-821-unsafe-render-fallback-or-failure',
+      'unsafe-render-fallback-or-failure.json'
+    );
+    const report = fixture.render_safety;
+
+    expect(report.safe_to_render).toBe(fixture.expected.safe_to_render);
+    expect(fixture.expected.allowed_outcomes).toContain(report.outcome);
+    expect(report.outcome).toBe(fixture.expected.outcome);
+    expect(report.fallback_strategy).toBe(fixture.expected.fallback_strategy);
+    expect(report.diagnostics).toHaveLength(fixture.expected.diagnostic_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From f45752a28d7da69dbe764af260276573e0d46f6a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 20:34:20 -0600
Subject: [PATCH 056/130] Add native provider metadata contracts

---
 packages/ast-merge/src/contracts.ts           | 19 +++++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 33 +++++++++++++++++++
 packages/tree-haver/src/contracts.ts          | 19 +++++++++++
 packages/tree-haver/src/index.ts              |  1 +
 .../test/fixtures.integration.test.ts         | 33 +++++++++++++++++++
 6 files changed, 106 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index ea6022a..4eeaeef 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1120,6 +1120,25 @@ export interface RenderSafetyReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface NativeProviderMetadataReport {
+  readonly provider_id: string;
+  readonly family: string;
+  readonly host_language: string;
+  readonly target_language: string;
+  readonly parser_name: string;
+  readonly parser_version: string;
+  readonly language_version: string;
+  readonly dialect: string;
+  readonly parse_error_behavior: string;
+  readonly source_span_support: string;
+  readonly render_support: string;
+  readonly semantic_role_support: string;
+  readonly retains_native_tree: boolean;
+  readonly native_tree_visibility: string;
+  readonly metadata_policy: string;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 5014f9a..496c410 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -121,6 +121,7 @@ export type {
   MergeIRNodeClass,
   MergeIROrderedNode,
   MergeResult,
+  NativeProviderMetadataReport,
   PairwiseMatching,
   PairwiseNodeMatch,
   PCS,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 490948d..9f74810 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -218,6 +218,7 @@ import type {
   StructuredEditTransportImportError,
   ReviewRequest,
   MergeResult,
+  NativeProviderMetadataReport,
   TemplateTokenConfig,
   TemplateExecutionPlanEntry,
   TemplateDirectoryApplyReport,
@@ -6430,6 +6431,38 @@ describe('ast-merge shared fixtures', () => {
     expect(report.diagnostics).toHaveLength(fixture.expected.diagnostic_count);
   });
 
+  it('conforms to the slice-822 native provider metadata fixture', () => {
+    const fixture = readFixture<{
+      provider_metadata: NativeProviderMetadataReport;
+      expected: {
+        provider_id: string;
+        family: string;
+        host_language: string;
+        target_language: string;
+        parser_name: string;
+        parse_error_behavior: string;
+        source_span_support: string;
+        render_support: string;
+        semantic_role_support: string;
+        retains_native_tree: boolean;
+        metadata_policy: string;
+      };
+    }>('diagnostics', 'slice-822-native-provider-metadata', 'native-provider-metadata.json');
+    const report = fixture.provider_metadata;
+
+    expect(report.provider_id).toBe(fixture.expected.provider_id);
+    expect(report.family).toBe(fixture.expected.family);
+    expect(report.host_language).toBe(fixture.expected.host_language);
+    expect(report.target_language).toBe(fixture.expected.target_language);
+    expect(report.parser_name).toBe(fixture.expected.parser_name);
+    expect(report.parse_error_behavior).toBe(fixture.expected.parse_error_behavior);
+    expect(report.source_span_support).toBe(fixture.expected.source_span_support);
+    expect(report.render_support).toBe(fixture.expected.render_support);
+    expect(report.semantic_role_support).toBe(fixture.expected.semantic_role_support);
+    expect(report.retains_native_tree).toBe(fixture.expected.retains_native_tree);
+    expect(report.metadata_policy).toBe(fixture.expected.metadata_policy);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')
diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 89c457a..a5a6b88 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -113,6 +113,25 @@ export interface NativeParserProvider {
   readonly metadataPolicy: string;
 }
 
+export interface NativeProviderMetadata {
+  readonly provider_id: string;
+  readonly family: string;
+  readonly host_language: string;
+  readonly target_language: string;
+  readonly parser_name: string;
+  readonly parser_version: string;
+  readonly language_version: string;
+  readonly dialect: string;
+  readonly parse_error_behavior: string;
+  readonly source_span_support: string;
+  readonly render_support: string;
+  readonly semantic_role_support: string;
+  readonly retains_native_tree: boolean;
+  readonly native_tree_visibility: string;
+  readonly metadata_policy: string;
+  readonly diagnostics: readonly string[];
+}
+
 export interface NormalizedParseResult {
   readonly ok: boolean;
   readonly backendCapability: BackendCapability;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 352b695..8430f0d 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -24,6 +24,7 @@ export type {
   LanguagePackAnalysis,
   LanguagePackProcessAnalysis,
   NativeParserProvider,
+  NativeProviderMetadata,
   NormalizedParseResult,
   NodeRole,
   NormalizedTreeNode,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 8a4fa2f..a7ecdc2 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -14,6 +14,7 @@ import type {
   ByteEditSpan,
   FeatureProfile,
   NativeParserProvider,
+  NativeProviderMetadata,
   NormalizedParseResult,
   NormalizedTreeNode,
   OrderedTreePrimitives,
@@ -552,6 +553,38 @@ describe('tree-haver shared fixtures', () => {
     expect(result.sourceFragmentsAvailable).toBe(true);
   });
 
+  it('conforms to the slice-822 native provider metadata fixture', () => {
+    const fixture = readFixture<{
+      provider_metadata: NativeProviderMetadata;
+      expected: {
+        provider_id: string;
+        family: string;
+        host_language: string;
+        target_language: string;
+        parser_name: string;
+        parse_error_behavior: string;
+        source_span_support: string;
+        render_support: string;
+        semantic_role_support: string;
+        retains_native_tree: boolean;
+        metadata_policy: string;
+      };
+    }>('diagnostics', 'slice-822-native-provider-metadata', 'native-provider-metadata.json');
+    const metadata = fixture.provider_metadata;
+
+    expect(metadata.provider_id).toBe(fixture.expected.provider_id);
+    expect(metadata.family).toBe(fixture.expected.family);
+    expect(metadata.host_language).toBe(fixture.expected.host_language);
+    expect(metadata.target_language).toBe(fixture.expected.target_language);
+    expect(metadata.parser_name).toBe(fixture.expected.parser_name);
+    expect(metadata.parse_error_behavior).toBe(fixture.expected.parse_error_behavior);
+    expect(metadata.source_span_support).toBe(fixture.expected.source_span_support);
+    expect(metadata.render_support).toBe(fixture.expected.render_support);
+    expect(metadata.semantic_role_support).toBe(fixture.expected.semantic_role_support);
+    expect(metadata.retains_native_tree).toBe(fixture.expected.retains_native_tree);
+    expect(metadata.metadata_policy).toBe(fixture.expected.metadata_policy);
+  });
+
   it('conforms to the slice-788 tree-haver profile fixture', () => {
     const fixture = readFixture<{ profile: TreeHaverProfileFixture }>(
       'diagnostics',

From b37ac9c628a2c29e9326935d4eb81b9db3b7e91a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 20:37:22 -0600
Subject: [PATCH 057/130] Add host language native provider contracts

---
 packages/ast-merge/src/contracts.ts           | 14 ++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 27 +++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 4eeaeef..476b2bb 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1139,6 +1139,20 @@ export interface NativeProviderMetadataReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface HostLanguageNativeProviderContract {
+  readonly provider_id: string;
+  readonly host_language: string;
+  readonly target_language: string;
+  readonly parser_name: string;
+}
+
+export interface HostLanguageNativeProviderContracts {
+  readonly suite_id: string;
+  readonly version: string;
+  readonly providers: readonly HostLanguageNativeProviderContract[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 496c410..a3b40e5 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -63,6 +63,8 @@ export type {
   GenericConflictHandlerResult,
   HandlerChildNode,
   HandlerKeyedMember,
+  HostLanguageNativeProviderContract,
+  HostLanguageNativeProviderContracts,
   GitDriverOutput,
   InconsistencyReport,
   LanguageProfileHandlerRegistration,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 9f74810..9597b1c 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -51,6 +51,7 @@ import type {
   FormattingPreservationConformanceReport,
   FormattingRecommendationGate,
   GenericConflictHandlerExecution,
+  HostLanguageNativeProviderContracts,
   InconsistencyReport,
   LanguageProfileHandlerRegistry,
   LocalLineFallbackReport,
@@ -6463,6 +6464,32 @@ describe('ast-merge shared fixtures', () => {
     expect(report.metadata_policy).toBe(fixture.expected.metadata_policy);
   });
 
+  it('conforms to the slice-823 host language native provider contracts fixture', () => {
+    const fixture = readFixture<{
+      native_provider_contracts: HostLanguageNativeProviderContracts;
+      expected: {
+        provider_count: number;
+        provider_ids: readonly string[];
+        ruby_provider_count: number;
+        first_provider_parser: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-823-host-language-native-provider-contracts',
+      'host-language-native-provider-contracts.json'
+    );
+    const contracts = fixture.native_provider_contracts;
+    const providerIds = contracts.providers.map((provider) => provider.provider_id);
+    const rubyProviderCount = contracts.providers.filter(
+      (provider) => provider.host_language === 'ruby'
+    ).length;
+
+    expect(contracts.providers).toHaveLength(fixture.expected.provider_count);
+    expect(providerIds).toEqual(fixture.expected.provider_ids);
+    expect(rubyProviderCount).toBe(fixture.expected.ruby_provider_count);
+    expect(contracts.providers[0]?.parser_name).toBe(fixture.expected.first_provider_parser);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 6818a743cdf9e62a31ffda9b52a039a76a30e3bb Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 20:40:12 -0600
Subject: [PATCH 058/130] Add Go native proving ground contract

---
 packages/ast-merge/src/contracts.ts           |  9 +++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 19 +++++++++++++++++++
 3 files changed, 29 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 476b2bb..83de22c 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1153,6 +1153,15 @@ export interface HostLanguageNativeProviderContracts {
   readonly diagnostics: readonly string[];
 }
 
+export interface NativeProviderProvingGroundReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly language: string;
+  readonly providers: readonly string[];
+  readonly checks: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index a3b40e5..10d5141 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -124,6 +124,7 @@ export type {
   MergeIROrderedNode,
   MergeResult,
   NativeProviderMetadataReport,
+  NativeProviderProvingGroundReport,
   PairwiseMatching,
   PairwiseNodeMatch,
   PCS,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 9597b1c..59d97b2 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -220,6 +220,7 @@ import type {
   ReviewRequest,
   MergeResult,
   NativeProviderMetadataReport,
+  NativeProviderProvingGroundReport,
   TemplateTokenConfig,
   TemplateExecutionPlanEntry,
   TemplateDirectoryApplyReport,
@@ -6490,6 +6491,24 @@ describe('ast-merge shared fixtures', () => {
     expect(contracts.providers[0]?.parser_name).toBe(fixture.expected.first_provider_parser);
   });
 
+  it('conforms to the slice-824 Go native proving ground fixture', () => {
+    const fixture = readFixture<{
+      proving_ground: NativeProviderProvingGroundReport;
+      expected: {
+        language: string;
+        provider_count: number;
+        providers: readonly string[];
+        checks: readonly string[];
+      };
+    }>('diagnostics', 'slice-824-go-native-proving-ground', 'go-native-proving-ground.json');
+    const report = fixture.proving_ground;
+
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.providers).toHaveLength(fixture.expected.provider_count);
+    expect(report.providers).toEqual(fixture.expected.providers);
+    expect(report.checks).toEqual(fixture.expected.checks);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From ed835c9313c84c0873763bc3e691f8d7b9839bda Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 20:43:33 -0600
Subject: [PATCH 059/130] Add go-dst provider stack contract

---
 packages/ast-merge/src/contracts.ts           | 10 +++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 21 +++++++++++++++++++
 3 files changed, 32 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 83de22c..4d572f2 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1162,6 +1162,16 @@ export interface NativeProviderProvingGroundReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface GoDSTProviderStackReport {
+  readonly provider_id: string;
+  readonly module: string;
+  readonly backend_family: string;
+  readonly language: string;
+  readonly role: string;
+  readonly compares_with: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 10d5141..f2e1d66 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -61,6 +61,7 @@ export type {
   GenericConflictHandlerCase,
   GenericConflictHandlerExecution,
   GenericConflictHandlerResult,
+  GoDSTProviderStackReport,
   HandlerChildNode,
   HandlerKeyedMember,
   HostLanguageNativeProviderContract,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 59d97b2..59d6b22 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -51,6 +51,7 @@ import type {
   FormattingPreservationConformanceReport,
   FormattingRecommendationGate,
   GenericConflictHandlerExecution,
+  GoDSTProviderStackReport,
   HostLanguageNativeProviderContracts,
   InconsistencyReport,
   LanguageProfileHandlerRegistry,
@@ -6509,6 +6510,26 @@ describe('ast-merge shared fixtures', () => {
     expect(report.checks).toEqual(fixture.expected.checks);
   });
 
+  it('conforms to the slice-825 go-dst provider stack fixture', () => {
+    const fixture = readFixture<{
+      provider_stack: GoDSTProviderStackReport;
+      expected: {
+        provider_id: string;
+        module: string;
+        backend_family: string;
+        language: string;
+        comparison_count: number;
+      };
+    }>('diagnostics', 'slice-825-go-dst-provider-stack', 'go-dst-provider-stack.json');
+    const report = fixture.provider_stack;
+
+    expect(report.provider_id).toBe(fixture.expected.provider_id);
+    expect(report.module).toBe(fixture.expected.module);
+    expect(report.backend_family).toBe(fixture.expected.backend_family);
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.compares_with).toHaveLength(fixture.expected.comparison_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 9f59a3aba433b0585f966e243044f7c7ada21bce Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 20:46:54 -0600
Subject: [PATCH 060/130] Add Go provider comparison contract

---
 packages/ast-merge/src/contracts.ts           |  9 ++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 21 +++++++++++++++++++
 3 files changed, 31 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 4d572f2..425c041 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1172,6 +1172,15 @@ export interface GoDSTProviderStackReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface GoProviderComparisonReport {
+  readonly comparison_id: string;
+  readonly version: string;
+  readonly language: string;
+  readonly providers: readonly string[];
+  readonly dimensions: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index f2e1d66..b35896d 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -62,6 +62,7 @@ export type {
   GenericConflictHandlerExecution,
   GenericConflictHandlerResult,
   GoDSTProviderStackReport,
+  GoProviderComparisonReport,
   HandlerChildNode,
   HandlerKeyedMember,
   HostLanguageNativeProviderContract,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 59d6b22..382aea0 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -52,6 +52,7 @@ import type {
   FormattingRecommendationGate,
   GenericConflictHandlerExecution,
   GoDSTProviderStackReport,
+  GoProviderComparisonReport,
   HostLanguageNativeProviderContracts,
   InconsistencyReport,
   LanguageProfileHandlerRegistry,
@@ -6530,6 +6531,26 @@ describe('ast-merge shared fixtures', () => {
     expect(report.compares_with).toHaveLength(fixture.expected.comparison_count);
   });
 
+  it('conforms to the slice-826 Go provider comparison fixture', () => {
+    const fixture = readFixture<{
+      comparison: GoProviderComparisonReport;
+      expected: {
+        language: string;
+        provider_count: number;
+        dimension_count: number;
+        includes_backend_deficiencies: boolean;
+      };
+    }>('diagnostics', 'slice-826-go-provider-comparison', 'go-provider-comparison.json');
+    const report = fixture.comparison;
+
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.providers).toHaveLength(fixture.expected.provider_count);
+    expect(report.dimensions).toHaveLength(fixture.expected.dimension_count);
+    expect(report.dimensions.includes('backend_deficiencies')).toBe(
+      fixture.expected.includes_backend_deficiencies
+    );
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 2c1ef04d3eaca16070c158cc9e7ee065ca11f34e Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 20:58:09 -0600
Subject: [PATCH 061/130] Add backend parity fixture contract

---
 packages/ast-merge/src/contracts.ts           | 15 +++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 25 +++++++++++++++++++
 3 files changed, 42 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 425c041..b3e0117 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1181,6 +1181,21 @@ export interface GoProviderComparisonReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface BackendParityCase {
+  readonly case_id: string;
+  readonly native_provider: string;
+  readonly tree_sitter_provider: string;
+  readonly dimensions: readonly string[];
+}
+
+export interface BackendParitySuite {
+  readonly suite_id: string;
+  readonly version: string;
+  readonly language: string;
+  readonly cases: readonly BackendParityCase[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index b35896d..02d0e29 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -2,6 +2,8 @@ export const packageName = '@structuredmerge/ast-merge';
 
 export type {
   AmbiguityMatchingReport,
+  BackendParityCase,
+  BackendParitySuite,
   ChangeSet,
   ChangeSetChange,
   ClassMappingDiagnostic,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 382aea0..8b9f36b 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -9,6 +9,7 @@ import { mergeRuby } from '../../ruby-merge/src/index';
 import { executeGenericConflictHandler } from '../src/index';
 import type {
   AmbiguityMatchingReport,
+  BackendParitySuite,
   ConformanceCaseRef,
   ConformanceCaseRun,
   ConformanceCaseExecution,
@@ -6551,6 +6552,30 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-827 backend parity fixtures fixture', () => {
+    const fixture = readFixture<{
+      parity_suite: BackendParitySuite;
+      expected: {
+        language: string;
+        case_count: number;
+        native_providers: readonly string[];
+        tree_sitter_provider: string;
+        source_span_case_count: number;
+      };
+    }>('diagnostics', 'slice-827-backend-parity-fixtures', 'backend-parity-fixtures.json');
+    const suite = fixture.parity_suite;
+    const nativeProviders = suite.cases.map((parityCase) => parityCase.native_provider);
+    const sourceSpanCaseCount = suite.cases.filter((parityCase) =>
+      parityCase.dimensions.includes('source_spans')
+    ).length;
+
+    expect(suite.language).toBe(fixture.expected.language);
+    expect(suite.cases).toHaveLength(fixture.expected.case_count);
+    expect(nativeProviders).toEqual(fixture.expected.native_providers);
+    expect(suite.cases[0]?.tree_sitter_provider).toBe(fixture.expected.tree_sitter_provider);
+    expect(sourceSpanCaseCount).toBe(fixture.expected.source_span_case_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 3af2084c0379102eca69ffe48076738ae1edcab5 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:00:50 -0600
Subject: [PATCH 062/130] Add provider richness projection contract

---
 packages/ast-merge/src/contracts.ts           | 19 +++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 27 +++++++++++++++++++
 3 files changed, 48 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index b3e0117..1f6e75f 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1196,6 +1196,25 @@ export interface BackendParitySuite {
   readonly diagnostics: readonly string[];
 }
 
+export interface ProviderRichnessSignature {
+  readonly kind: string;
+  readonly name: string;
+  readonly parameters: readonly string[];
+  readonly result: string;
+}
+
+export interface ProviderRichnessProjection {
+  readonly projection_id: string;
+  readonly version: string;
+  readonly provider_id: string;
+  readonly node_path: string;
+  readonly generic_roles: readonly string[];
+  readonly generic_signature: ProviderRichnessSignature;
+  readonly private_metadata: Readonly<Record<string, Readonly<Record<string, string>>>>;
+  readonly requires_private_fields: boolean;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 02d0e29..eb929f9 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -133,6 +133,8 @@ export type {
   PairwiseNodeMatch,
   PCS,
   PCSConstraint,
+  ProviderRichnessProjection,
+  ProviderRichnessSignature,
   RawMerge,
   RawMergeChange,
   FamilyFeatureProfile,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 8b9f36b..8e31ad1 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -224,6 +224,7 @@ import type {
   MergeResult,
   NativeProviderMetadataReport,
   NativeProviderProvingGroundReport,
+  ProviderRichnessProjection,
   TemplateTokenConfig,
   TemplateExecutionPlanEntry,
   TemplateDirectoryApplyReport,
@@ -6576,6 +6577,32 @@ describe('ast-merge shared fixtures', () => {
     expect(sourceSpanCaseCount).toBe(fixture.expected.source_span_case_count);
   });
 
+  it('conforms to the slice-828 provider richness projection fixture', () => {
+    const fixture = readFixture<{
+      projection: ProviderRichnessProjection;
+      expected: {
+        provider_id: string;
+        role_count: number;
+        signature_kind: string;
+        signature_name: string;
+        requires_private_fields: boolean;
+        private_metadata_namespace: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-828-provider-richness-projection',
+      'provider-richness-projection.json'
+    );
+    const projection = fixture.projection;
+
+    expect(projection.provider_id).toBe(fixture.expected.provider_id);
+    expect(projection.generic_roles).toHaveLength(fixture.expected.role_count);
+    expect(projection.generic_signature.kind).toBe(fixture.expected.signature_kind);
+    expect(projection.generic_signature.name).toBe(fixture.expected.signature_name);
+    expect(projection.requires_private_fields).toBe(fixture.expected.requires_private_fields);
+    expect(projection.private_metadata[fixture.expected.private_metadata_namespace]).toBeDefined();
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 1bf0fc5e02cf0fa9ba0fad506537782f26b36ec8 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:03:25 -0600
Subject: [PATCH 063/130] Add backend gap conformance contract

---
 packages/ast-merge/src/contracts.ts           | 25 ++++++++++++++++
 packages/ast-merge/src/index.ts               |  3 ++
 .../test/fixtures.integration.test.ts         | 29 +++++++++++++++++++
 3 files changed, 57 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 1f6e75f..4f63899 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1215,6 +1215,31 @@ export interface ProviderRichnessProjection {
   readonly diagnostics: readonly string[];
 }
 
+export interface BackendGapConformanceGap {
+  readonly capability: string;
+  readonly status: string;
+  readonly impact: string;
+  readonly diagnostic_code: string;
+  readonly normalized_fallback: string;
+}
+
+export interface BackendGapConformanceSummary {
+  readonly gap_count: number;
+  readonly fallback_count: number;
+  readonly silently_normalized: boolean;
+}
+
+export interface BackendGapConformanceReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly language: string;
+  readonly provider_id: string;
+  readonly compared_provider_id: string;
+  readonly gaps: readonly BackendGapConformanceGap[];
+  readonly summary: BackendGapConformanceSummary;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index eb929f9..229eda1 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -2,6 +2,9 @@ export const packageName = '@structuredmerge/ast-merge';
 
 export type {
   AmbiguityMatchingReport,
+  BackendGapConformanceGap,
+  BackendGapConformanceReport,
+  BackendGapConformanceSummary,
   BackendParityCase,
   BackendParitySuite,
   ChangeSet,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 8e31ad1..969285e 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -9,6 +9,7 @@ import { mergeRuby } from '../../ruby-merge/src/index';
 import { executeGenericConflictHandler } from '../src/index';
 import type {
   AmbiguityMatchingReport,
+  BackendGapConformanceReport,
   BackendParitySuite,
   ConformanceCaseRef,
   ConformanceCaseRun,
@@ -6603,6 +6604,34 @@ describe('ast-merge shared fixtures', () => {
     expect(projection.private_metadata[fixture.expected.private_metadata_namespace]).toBeDefined();
   });
 
+  it('conforms to the slice-829 backend gap conformance report fixture', () => {
+    const fixture = readFixture<{
+      report: BackendGapConformanceReport;
+      expected: {
+        language: string;
+        provider_id: string;
+        compared_provider_id: string;
+        gap_count: number;
+        fallback_count: number;
+        silently_normalized: boolean;
+        first_diagnostic_code: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-829-backend-gap-conformance-report',
+      'backend-gap-conformance-report.json'
+    );
+    const report = fixture.report;
+
+    expect(report.language).toBe(fixture.expected.language);
+    expect(report.provider_id).toBe(fixture.expected.provider_id);
+    expect(report.compared_provider_id).toBe(fixture.expected.compared_provider_id);
+    expect(report.gaps).toHaveLength(fixture.expected.gap_count);
+    expect(report.summary.fallback_count).toBe(fixture.expected.fallback_count);
+    expect(report.summary.silently_normalized).toBe(fixture.expected.silently_normalized);
+    expect(report.gaps[0]?.diagnostic_code).toBe(fixture.expected.first_diagnostic_code);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 0a74346efd6699a829783298a954cde06892c736 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:06:31 -0600
Subject: [PATCH 064/130] Add false textual conflict fixture contract

---
 packages/ast-merge/src/contracts.ts           | 19 +++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 24 +++++++++++++++++++
 3 files changed, 45 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 4f63899..436d48b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1240,6 +1240,25 @@ export interface BackendGapConformanceReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface FalseTextualConflictCase {
+  readonly case_id: string;
+  readonly language: string;
+  readonly category: string;
+  readonly base_path: string;
+  readonly ours_path: string;
+  readonly theirs_path: string;
+  readonly expected_strategy: string;
+  readonly expected_unresolved_conflict: boolean;
+}
+
+export interface FalseTextualConflictSuite {
+  readonly suite_id: string;
+  readonly version: string;
+  readonly source: string;
+  readonly cases: readonly FalseTextualConflictCase[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 229eda1..67fefb0 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -55,6 +55,8 @@ export type {
   FallbackUsageMachineOutput,
   FallbackUsageReport,
   FallbackUsageSummary,
+  FalseTextualConflictCase,
+  FalseTextualConflictSuite,
   FormattingEdgeFixtureCase,
   FormattingEdgeFixtureSuite,
   FormattingHardGate,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 969285e..4205692 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -48,6 +48,7 @@ import type {
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
+  FalseTextualConflictSuite,
   FormattingEdgeFixtureSuite,
   FormattingHardGateReport,
   FormattingPreservationConformanceReport,
@@ -6632,6 +6633,29 @@ describe('ast-merge shared fixtures', () => {
     expect(report.gaps[0]?.diagnostic_code).toBe(fixture.expected.first_diagnostic_code);
   });
 
+  it('conforms to the slice-901 false textual conflicts fixture', () => {
+    const fixture = readFixture<{
+      suite: FalseTextualConflictSuite;
+      expected: {
+        case_count: number;
+        languages: readonly string[];
+        categories: readonly string[];
+        expected_unresolved_conflict_count: number;
+      };
+    }>('diagnostics', 'slice-901-false-textual-conflicts', 'false-textual-conflicts.json');
+    const suite = fixture.suite;
+    const languages = suite.cases.map((conflictCase) => conflictCase.language);
+    const categories = suite.cases.map((conflictCase) => conflictCase.category);
+    const unresolvedConflictCount = suite.cases.filter(
+      (conflictCase) => conflictCase.expected_unresolved_conflict
+    ).length;
+
+    expect(suite.cases).toHaveLength(fixture.expected.case_count);
+    expect(languages).toEqual(fixture.expected.languages);
+    expect(categories).toEqual(fixture.expected.categories);
+    expect(unresolvedConflictCount).toBe(fixture.expected.expected_unresolved_conflict_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 88089d87db8db885c042cb9ce4b7959ad95e7f80 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:10:01 -0600
Subject: [PATCH 065/130] Add git driver smoke fixture contract

---
 packages/ast-merge/src/contracts.ts           | 19 ++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 31 +++++++++++++++++++
 3 files changed, 52 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 436d48b..164615a 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1259,6 +1259,25 @@ export interface FalseTextualConflictSuite {
   readonly diagnostics: readonly string[];
 }
 
+export interface GitDriverSmokeCase {
+  readonly case_id: string;
+  readonly family: string;
+  readonly ancestor_placeholder: string;
+  readonly current_placeholder: string;
+  readonly other_placeholder: string;
+  readonly path_placeholder: string;
+  readonly expected_exit_code: number;
+  readonly expected_current_file_updated: boolean;
+}
+
+export interface GitDriverSmokeSuite {
+  readonly suite_id: string;
+  readonly version: string;
+  readonly driver_name: string;
+  readonly cases: readonly GitDriverSmokeCase[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 67fefb0..92fd557 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -65,6 +65,8 @@ export type {
   FormattingPreservationMetrics,
   FormattingRecommendationGate,
   FormattingRecommendationWeights,
+  GitDriverSmokeCase,
+  GitDriverSmokeSuite,
   GenericConflictHandlerCase,
   GenericConflictHandlerExecution,
   GenericConflictHandlerResult,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 4205692..0dff78a 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -53,6 +53,7 @@ import type {
   FormattingHardGateReport,
   FormattingPreservationConformanceReport,
   FormattingRecommendationGate,
+  GitDriverSmokeSuite,
   GenericConflictHandlerExecution,
   GoDSTProviderStackReport,
   GoProviderComparisonReport,
@@ -6656,6 +6657,36 @@ describe('ast-merge shared fixtures', () => {
     expect(unresolvedConflictCount).toBe(fixture.expected.expected_unresolved_conflict_count);
   });
 
+  it('conforms to the slice-902 git driver smoke fixtures fixture', () => {
+    const fixture = readFixture<{
+      suite: GitDriverSmokeSuite;
+      expected: {
+        driver_name: string;
+        case_count: number;
+        placeholder_set: readonly string[];
+        updated_current_file_count: number;
+      };
+    }>('diagnostics', 'slice-902-git-driver-smoke-fixtures', 'git-driver-smoke-fixtures.json');
+    const suite = fixture.suite;
+    const firstCase = suite.cases[0];
+    const placeholderSet = firstCase
+      ? [
+          firstCase.ancestor_placeholder,
+          firstCase.current_placeholder,
+          firstCase.other_placeholder,
+          firstCase.path_placeholder
+        ]
+      : [];
+    const updatedCurrentFileCount = suite.cases.filter(
+      (smokeCase) => smokeCase.expected_current_file_updated
+    ).length;
+
+    expect(suite.driver_name).toBe(fixture.expected.driver_name);
+    expect(suite.cases).toHaveLength(fixture.expected.case_count);
+    expect(placeholderSet).toEqual(fixture.expected.placeholder_set);
+    expect(updatedCurrentFileCount).toBe(fixture.expected.updated_current_file_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 1081c3f8962b249565cd6b4747637875b00dbf7f Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:12:42 -0600
Subject: [PATCH 066/130] Add diff driver smoke fixture contract

---
 packages/ast-merge/src/contracts.ts           | 16 +++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 164615a..76bcfa3 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1278,6 +1278,22 @@ export interface GitDriverSmokeSuite {
   readonly diagnostics: readonly string[];
 }
 
+export interface DiffDriverSmokeCase {
+  readonly case_id: string;
+  readonly argument_count: number;
+  readonly argument_roles: readonly string[];
+  readonly expected_exit_code: number;
+  readonly expected_output_kind: string;
+}
+
+export interface DiffDriverSmokeSuite {
+  readonly suite_id: string;
+  readonly version: string;
+  readonly driver_name: string;
+  readonly cases: readonly DiffDriverSmokeCase[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 92fd557..f9a725c 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -49,6 +49,8 @@ export type {
   Diagnostic,
   DiagnosticCategory,
   DiagnosticSeverity,
+  DiffDriverSmokeCase,
+  DiffDriverSmokeSuite,
   FallbackScopeDefinition,
   FallbackScopeReport,
   FallbackUsageEntry,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 0dff78a..d7382f8 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -39,6 +39,7 @@ import type {
   DelegatedChildSurfaceOutput,
   DiagnosticCategory,
   DiagnosticSeverity,
+  DiffDriverSmokeSuite,
   DiscoveredSurface,
   FallbackScopeReport,
   FallbackUsageReport,
@@ -6687,6 +6688,28 @@ describe('ast-merge shared fixtures', () => {
     expect(updatedCurrentFileCount).toBe(fixture.expected.updated_current_file_count);
   });
 
+  it('conforms to the slice-903 diff driver smoke fixtures fixture', () => {
+    const fixture = readFixture<{
+      suite: DiffDriverSmokeSuite;
+      expected: {
+        driver_name: string;
+        case_count: number;
+        argument_counts: readonly number[];
+        structured_diff_count: number;
+      };
+    }>('diagnostics', 'slice-903-diff-driver-smoke-fixtures', 'diff-driver-smoke-fixtures.json');
+    const suite = fixture.suite;
+    const argumentCounts = suite.cases.map((smokeCase) => smokeCase.argument_count);
+    const structuredDiffCount = suite.cases.filter(
+      (smokeCase) => smokeCase.expected_output_kind === 'structured_diff'
+    ).length;
+
+    expect(suite.driver_name).toBe(fixture.expected.driver_name);
+    expect(suite.cases).toHaveLength(fixture.expected.case_count);
+    expect(argumentCounts).toEqual(fixture.expected.argument_counts);
+    expect(structuredDiffCount).toBe(fixture.expected.structured_diff_count);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 843babf736d8427accd20a345ad80ea79ccf3650 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:15:41 -0600
Subject: [PATCH 067/130] Add performance guardrails contract

---
 packages/ast-merge/src/contracts.ts           | 18 +++++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 43 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 76bcfa3..e8e2e3e 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1294,6 +1294,24 @@ export interface DiffDriverSmokeSuite {
   readonly diagnostics: readonly string[];
 }
 
+export interface PerformanceTimeoutDiagnostic {
+  readonly severity: string;
+  readonly category: string;
+  readonly code: string;
+  readonly fallback: string;
+}
+
+export interface PerformanceGuardrails {
+  readonly guardrail_id: string;
+  readonly version: string;
+  readonly max_bytes: number;
+  readonly max_nodes: number;
+  readonly max_match_candidates: number;
+  readonly timeout_ms: number;
+  readonly timeout_diagnostic: PerformanceTimeoutDiagnostic;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index f9a725c..d7527b1 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -142,6 +142,8 @@ export type {
   PairwiseNodeMatch,
   PCS,
   PCSConstraint,
+  PerformanceGuardrails,
+  PerformanceTimeoutDiagnostic,
   ProviderRichnessProjection,
   ProviderRichnessSignature,
   RawMerge,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index d7382f8..d64453d 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -68,6 +68,7 @@ import type {
   MoveDetectionMatchingReport,
   PairwiseMatching,
   PCS,
+  PerformanceGuardrails,
   RawMerge,
   RenameAwareMatchingReport,
   RenderPlanReport,
@@ -6710,6 +6711,28 @@ describe('ast-merge shared fixtures', () => {
     expect(structuredDiffCount).toBe(fixture.expected.structured_diff_count);
   });
 
+  it('conforms to the slice-904 performance guardrails fixture', () => {
+    const fixture = readFixture<{
+      guardrails: PerformanceGuardrails;
+      expected: {
+        max_bytes: number;
+        max_nodes: number;
+        max_match_candidates: number;
+        timeout_ms: number;
+        timeout_code: string;
+        fallback: string;
+      };
+    }>('diagnostics', 'slice-904-performance-guardrails', 'performance-guardrails.json');
+    const guardrails = fixture.guardrails;
+
+    expect(guardrails.max_bytes).toBe(fixture.expected.max_bytes);
+    expect(guardrails.max_nodes).toBe(fixture.expected.max_nodes);
+    expect(guardrails.max_match_candidates).toBe(fixture.expected.max_match_candidates);
+    expect(guardrails.timeout_ms).toBe(fixture.expected.timeout_ms);
+    expect(guardrails.timeout_diagnostic.code).toBe(fixture.expected.timeout_code);
+    expect(guardrails.timeout_diagnostic.fallback).toBe(fixture.expected.fallback);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 7ab65f973771fa66dbc1b7f276e2dc7f050281af Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 21:18:35 -0600
Subject: [PATCH 068/130] Add profile conformance report contract

---
 packages/ast-merge/src/contracts.ts           | 16 +++++++++++++
 packages/ast-merge/src/index.ts               |  2 ++
 .../test/fixtures.integration.test.ts         | 23 +++++++++++++++++++
 3 files changed, 41 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index e8e2e3e..f87dde5 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1312,6 +1312,22 @@ export interface PerformanceGuardrails {
   readonly diagnostics: readonly string[];
 }
 
+export interface ProfileSkippedRule {
+  readonly rule: string;
+  readonly reason: string;
+}
+
+export interface ProfileConformanceReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly profile: string;
+  readonly enabled_rules: readonly string[];
+  readonly skipped_rules: readonly ProfileSkippedRule[];
+  readonly fallback_count: number;
+  readonly unresolved_conflict_count: number;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index d7527b1..18f7fe0 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -146,6 +146,8 @@ export type {
   PerformanceTimeoutDiagnostic,
   ProviderRichnessProjection,
   ProviderRichnessSignature,
+  ProfileConformanceReport,
+  ProfileSkippedRule,
   RawMerge,
   RawMergeChange,
   FamilyFeatureProfile,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index d64453d..bcf7744 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -69,6 +69,7 @@ import type {
   PairwiseMatching,
   PCS,
   PerformanceGuardrails,
+  ProfileConformanceReport,
   RawMerge,
   RenameAwareMatchingReport,
   RenderPlanReport,
@@ -6733,6 +6734,28 @@ describe('ast-merge shared fixtures', () => {
     expect(guardrails.timeout_diagnostic.fallback).toBe(fixture.expected.fallback);
   });
 
+  it('conforms to the slice-905 profile conformance reports fixture', () => {
+    const fixture = readFixture<{
+      report: ProfileConformanceReport;
+      expected: {
+        profile: string;
+        enabled_rule_count: number;
+        skipped_rule_count: number;
+        fallback_count: number;
+        unresolved_conflict_count: number;
+        skipped_rule: string;
+      };
+    }>('diagnostics', 'slice-905-profile-conformance-reports', 'profile-conformance-reports.json');
+    const report = fixture.report;
+
+    expect(report.profile).toBe(fixture.expected.profile);
+    expect(report.enabled_rules).toHaveLength(fixture.expected.enabled_rule_count);
+    expect(report.skipped_rules).toHaveLength(fixture.expected.skipped_rule_count);
+    expect(report.fallback_count).toBe(fixture.expected.fallback_count);
+    expect(report.unresolved_conflict_count).toBe(fixture.expected.unresolved_conflict_count);
+    expect(report.skipped_rules[0]?.rule).toBe(fixture.expected.skipped_rule);
+  });
+
   it('conforms to the slice-02 diagnostic vocabulary fixture', () => {
     const fixture = readFixture<DiagnosticFixture>(
       ...diagnosticsFixturePath('diagnostic_vocabulary')

From 8bf222c8061dbe8b3640c4dc823c21e50d5bf770 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 22:32:05 -0600
Subject: [PATCH 069/130] Add merge engine suite setting contract

---
 packages/ast-merge/src/contracts.ts           | 79 ++++++++++++++++---
 packages/ast-merge/src/index.ts               |  5 ++
 .../test/fixtures.integration.test.ts         | 76 ++++++++++++++++++
 3 files changed, 148 insertions(+), 12 deletions(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index f87dde5..8447740 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -3,6 +3,20 @@ import path from 'node:path';
 
 export type DiagnosticSeverity = 'info' | 'warning' | 'error';
 
+export type MergeEngine = 'owner_path' | 'merge_ir_experimental';
+
+export const mergeEngineEnvironmentVariable = 'SMORG_MERGE_ENGINE';
+
+export function normalizeMergeEngine(engine?: string): MergeEngine {
+  return engine === 'merge_ir_experimental' ? 'merge_ir_experimental' : 'owner_path';
+}
+
+export function mergeEngineFromEnvironment(
+  env: Readonly<Record<string, string | undefined>>
+): MergeEngine {
+  return normalizeMergeEngine(env[mergeEngineEnvironmentVariable]);
+}
+
 export type DiagnosticCategory =
   | 'parse_error'
   | 'destination_parse_error'
@@ -2578,6 +2592,7 @@ export interface ConformanceCaseRun {
   readonly requirements: ConformanceCaseRequirements;
   readonly familyProfile: FamilyFeatureProfile;
   readonly featureProfile?: ConformanceFeatureProfileView;
+  readonly mergeEngine?: MergeEngine;
 }
 
 export interface ConformanceCaseExecution {
@@ -2625,6 +2640,7 @@ export interface NamedConformanceSuiteReport {
 export interface ConformanceFamilyPlanContext {
   readonly familyProfile: FamilyFeatureProfile;
   readonly featureProfile?: ConformanceFeatureProfileView;
+  readonly mergeEngine?: MergeEngine;
 }
 
 export interface NamedConformanceSuitePlan {
@@ -2646,6 +2662,7 @@ export interface ConformanceManifestPlanningOptions {
   readonly contexts?: Readonly<Record<string, ConformanceFamilyPlanContext>>;
   readonly familyProfiles?: Readonly<Record<string, FamilyFeatureProfile>>;
   readonly requireExplicitContexts?: boolean;
+  readonly mergeEngine?: MergeEngine;
 }
 
 export interface ConformanceManifestReport {
@@ -2843,6 +2860,7 @@ export interface ConformanceSuitePlanEntry {
 
 export interface ConformanceSuitePlan {
   readonly family: string;
+  readonly mergeEngine?: MergeEngine;
   readonly entries: readonly ConformanceSuitePlanEntry[];
   readonly missingRoles: readonly string[];
 }
@@ -6691,6 +6709,20 @@ export function defaultConformanceFamilyContext(
   };
 }
 
+function applyPlanningMergeEngine(
+  context: ConformanceFamilyPlanContext,
+  options: ConformanceManifestPlanningOptions
+): ConformanceFamilyPlanContext {
+  if (context.mergeEngine || !options.mergeEngine) {
+    return context;
+  }
+
+  return {
+    ...context,
+    mergeEngine: normalizeMergeEngine(options.mergeEngine)
+  };
+}
+
 export function reviewRequestIdForFamilyContext(family: string): string {
   return `family_context:${family}`;
 }
@@ -7369,7 +7401,7 @@ export function resolveConformanceFamilyContext(
 
   if (explicitContext) {
     return {
-      context: explicitContext,
+      context: applyPlanningMergeEngine(explicitContext, options),
       diagnostics: []
     };
   }
@@ -7401,7 +7433,7 @@ export function resolveConformanceFamilyContext(
   }
 
   return {
-    context: defaultConformanceFamilyContext(familyProfile),
+    context: applyPlanningMergeEngine(defaultConformanceFamilyContext(familyProfile), options),
     diagnostics: [
       {
         severity: 'warning',
@@ -7874,6 +7906,23 @@ export function planConformanceSuite(
   roles: readonly string[],
   familyProfile: FamilyFeatureProfile,
   featureProfile?: ConformanceFeatureProfileView
+): ConformanceSuitePlan {
+  return planConformanceSuiteWithMergeEngine(
+    manifest,
+    family,
+    roles,
+    familyProfile,
+    featureProfile
+  );
+}
+
+export function planConformanceSuiteWithMergeEngine(
+  manifest: ConformanceManifest,
+  family: string,
+  roles: readonly string[],
+  familyProfile: FamilyFeatureProfile,
+  featureProfile?: ConformanceFeatureProfileView,
+  mergeEngine?: MergeEngine
 ): ConformanceSuitePlan {
   const entries: ConformanceSuitePlanEntry[] = [];
   const missingRoles: string[] = [];
@@ -7901,13 +7950,15 @@ export function planConformanceSuite(
         ref,
         requirements: entry.requirements ?? {},
         familyProfile,
-        featureProfile
+        featureProfile,
+        mergeEngine
       }
     });
   }
 
   return {
     family,
+    mergeEngine,
     entries,
     missingRoles
   };
@@ -7925,7 +7976,7 @@ export function planNamedConformanceSuite(
     return undefined;
   }
 
-  return planConformanceSuite(
+  return planConformanceSuiteWithMergeEngine(
     manifest,
     definition.subject.grammar,
     definition.roles,
@@ -7939,19 +7990,23 @@ export function planNamedConformanceSuiteEntry(
   suiteSelector: ConformanceSuiteSelector,
   context: ConformanceFamilyPlanContext
 ): NamedConformanceSuitePlan | undefined {
-  const plan = planNamedConformanceSuite(
-    manifest,
-    suiteSelector,
-    context.familyProfile,
-    context.featureProfile
-  );
+  const definition = conformanceSuiteDefinition(manifest, suiteSelector);
 
-  if (!plan) {
+  if (!definition) {
     return undefined;
   }
 
+  const plan = planConformanceSuiteWithMergeEngine(
+    manifest,
+    definition.subject.grammar,
+    definition.roles,
+    context.familyProfile,
+    context.featureProfile,
+    context.mergeEngine
+  );
+
   return {
-    suite: conformanceSuiteDefinition(manifest, suiteSelector)!,
+    suite: definition,
     plan
   };
 }
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 18f7fe0..ae6690d 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -49,6 +49,7 @@ export type {
   Diagnostic,
   DiagnosticCategory,
   DiagnosticSeverity,
+  MergeEngine,
   DiffDriverSmokeCase,
   DiffDriverSmokeSuite,
   FallbackScopeDefinition,
@@ -471,7 +472,11 @@ export {
   conformanceSuiteDefinition,
   conformanceSuiteSelectors,
   defaultConformanceFamilyContext,
+  mergeEngineEnvironmentVariable,
+  mergeEngineFromEnvironment,
+  normalizeMergeEngine,
   planConformanceSuite,
+  planConformanceSuiteWithMergeEngine,
   planNamedConformanceSuiteEntry,
   planNamedConformanceSuitesWithDiagnostics,
   planNamedConformanceSuites,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index bcf7744..9570927 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -228,6 +228,7 @@ import type {
   StructuredEditTransportImportError,
   ReviewRequest,
   MergeResult,
+  MergeEngine,
   NativeProviderMetadataReport,
   NativeProviderProvingGroundReport,
   ProviderRichnessProjection,
@@ -347,6 +348,9 @@ import {
   conformanceSuiteDefinition,
   conformanceSuiteSelectors,
   defaultConformanceFamilyContext,
+  mergeEngineEnvironmentVariable,
+  mergeEngineFromEnvironment,
+  normalizeMergeEngine,
   planConformanceSuite,
   planNamedConformanceSuiteEntry,
   planNamedConformanceSuitesWithDiagnostics,
@@ -5630,6 +5634,78 @@ describe('ast-merge shared fixtures', () => {
     expect(mergeIR.changes[1]?.class_id).toBe('class-import-strings');
   });
 
+  it('conforms to the slice-906 merge engine suite setting fixture', () => {
+    const fixture = readFixture<{
+      settings: {
+        default_engine: MergeEngine;
+        experimental_engine: MergeEngine;
+        supported_engines: readonly MergeEngine[];
+        environment_variable: string;
+        experimental_policy: string;
+        runs_same_suite: boolean;
+      };
+      expected: {
+        default_engine: MergeEngine;
+        experimental_engine: MergeEngine;
+        supported_engine_count: number;
+        environment_variable: string;
+        experimental_policy: string;
+        runs_same_suite: boolean;
+      };
+    }>('diagnostics', 'slice-906-merge-engine-suite-setting', 'merge-engine-suite-setting.json');
+
+    expect(normalizeMergeEngine()).toBe(fixture.expected.default_engine);
+    expect(normalizeMergeEngine(fixture.settings.experimental_engine)).toBe(
+      fixture.expected.experimental_engine
+    );
+    expect(fixture.settings.supported_engines).toHaveLength(
+      fixture.expected.supported_engine_count
+    );
+    expect(mergeEngineEnvironmentVariable).toBe(fixture.expected.environment_variable);
+    expect(fixture.settings.experimental_policy).toBe(fixture.expected.experimental_policy);
+    expect(fixture.settings.runs_same_suite).toBe(fixture.expected.runs_same_suite);
+    expect(
+      mergeEngineFromEnvironment({
+        [mergeEngineEnvironmentVariable]: fixture.settings.experimental_engine
+      })
+    ).toBe('merge_ir_experimental');
+
+    const plan = planNamedConformanceSuitesWithDiagnostics(
+      {
+        family_feature_profiles: [],
+        suite_descriptors: [
+          {
+            kind: 'family',
+            subject: { grammar: 'go' },
+            roles: ['case']
+          }
+        ],
+        families: {
+          go: [
+            {
+              role: 'case',
+              path: ['go', 'case.json']
+            }
+          ]
+        }
+      },
+      {
+        familyProfiles: {
+          go: {
+            family: 'go',
+            supportedDialects: [],
+            supportedPolicies: []
+          }
+        },
+        mergeEngine: 'merge_ir_experimental'
+      }
+    );
+
+    expect(plan.entries).toHaveLength(1);
+    expect(plan.entries[0]?.plan.mergeEngine).toBe('merge_ir_experimental');
+    expect(plan.entries[0]?.plan.entries[0]?.run.mergeEngine).toBe('merge_ir_experimental');
+  });
+
   it('conforms to the slice-791 pairwise matchings fixture', () => {
     const fixture = readFixture<{
       pairwise_matchings: readonly PairwiseMatching[];

From 713604bba47610b91a981fe8f96112e98b611911 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 22:41:00 -0600
Subject: [PATCH 070/130] Evaluate merge IR change sets behind engine flag

---
 packages/ast-merge/src/contracts.ts           | 129 ++++++++++++++++++
 packages/ast-merge/src/index.ts               |   4 +
 .../test/fixtures.integration.test.ts         |  45 ++++++
 3 files changed, 178 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 8447740..58a23a2 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -587,6 +587,14 @@ export interface InconsistencyReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface MergeIREvaluationReport {
+  readonly merge_engine: MergeEngine;
+  readonly raw_merge: RawMerge;
+  readonly inconsistency_report: InconsistencyReport;
+  readonly outcome: string;
+  readonly diagnostics: readonly string[];
+}
+
 export interface MergeIRComparisonCase {
   readonly case_id: string;
   readonly family: string;
@@ -613,6 +621,127 @@ export interface MergeIRComparisonReport {
   readonly summary: MergeIRComparisonSummary;
 }
 
+export function rawMergeChangeSets(rawMergeId: string, changeSets: readonly ChangeSet[]): RawMerge {
+  return {
+    raw_merge_id: rawMergeId,
+    input_change_set_ids: changeSets.map((changeSet) => changeSet.change_set_id),
+    changes: changeSets.flatMap((changeSet) =>
+      changeSet.changes.map((change) => ({
+        change_id: change.change_id,
+        source_change_set_id: changeSet.change_set_id,
+        side: changeSet.side,
+        kind: change.kind,
+        class_id: change.class_id,
+        parent_class_id: change.parent_class_id,
+        predecessor_class_id: change.predecessor_class_id,
+        successor_class_id: change.successor_class_id,
+        content_hash: change.content_hash
+      }))
+    ),
+    diagnostics: ['raw merge intentionally preserves both sides before inconsistency detection']
+  };
+}
+
+export function detectRawMergeInconsistencies(
+  reportId: string,
+  rawMerge: RawMerge
+): InconsistencyReport {
+  const changesByClass = new Map<string, RawMergeChange[]>();
+  for (const change of rawMerge.changes) {
+    changesByClass.set(change.class_id, [...(changesByClass.get(change.class_id) ?? []), change]);
+  }
+
+  const inconsistencies: MergeInconsistency[] = [];
+  for (const change of rawMerge.changes) {
+    if (change.kind === 'move') {
+      inconsistencies.push({
+        inconsistency_id: `order-${change.class_id}`,
+        category: 'order_conflict',
+        severity: 'warning',
+        class_ids: [change.class_id],
+        change_ids: [change.change_id],
+        message: 'branch changes predecessor/successor ordering relation'
+      });
+    }
+  }
+
+  for (const [classId, changes] of changesByClass) {
+    const changesOfKind = (kind: string) => changes.filter((change) => change.kind === kind);
+    const hashesOfKind = (kind: string) =>
+      new Set(changesOfKind(kind).map((change) => change.content_hash));
+    const insertions = changesOfKind('insert');
+    const deletes = changesOfKind('delete');
+    const contentChanges = changesOfKind('content_change');
+
+    if (insertions.length > 1 && hashesOfKind('insert').size > 1) {
+      inconsistencies.push({
+        inconsistency_id: `duplicate-${classId}`,
+        category: 'duplicate_insertion_conflict',
+        severity: 'error',
+        class_ids: [classId],
+        change_ids: insertions.map((change) => change.change_id),
+        message: 'branches insert the same class with incompatible content hashes'
+      });
+    }
+    if (deletes.length > 0 && contentChanges.length > 0) {
+      inconsistencies.push({
+        inconsistency_id: `delete-edit-${classId}`,
+        category: 'delete_edit_conflict',
+        severity: 'error',
+        class_ids: [classId],
+        change_ids: [
+          ...contentChanges.map((change) => change.change_id),
+          ...deletes.map((change) => change.change_id)
+        ],
+        message: 'one branch edits a class that another branch deletes'
+      });
+    }
+    if (contentChanges.length > 1 && hashesOfKind('content_change').size > 1) {
+      inconsistencies.push({
+        inconsistency_id: `content-${classId}`,
+        category: 'content_conflict',
+        severity: 'error',
+        class_ids: [classId],
+        change_ids: contentChanges.map((change) => change.change_id),
+        message: 'branches change class content differently'
+      });
+    }
+  }
+
+  return {
+    report_id: reportId,
+    raw_merge_id: rawMerge.raw_merge_id,
+    inconsistencies,
+    diagnostics: [
+      'inconsistency detection classifies raw merge candidates before any conflict rendering'
+    ]
+  };
+}
+
+export function evaluateMergeIRChangeSets(
+  engine: MergeEngine | undefined,
+  rawMergeId: string,
+  reportId: string,
+  changeSets: readonly ChangeSet[]
+): MergeIREvaluationReport {
+  const mergeEngine = normalizeMergeEngine(engine);
+  const rawMerge = rawMergeChangeSets(rawMergeId, changeSets);
+  const inconsistencyReport = detectRawMergeInconsistencies(reportId, rawMerge);
+  const blockingCount = inconsistencyReport.inconsistencies.filter(
+    (inconsistency) => inconsistency.severity === 'error'
+  ).length;
+
+  return {
+    merge_engine: mergeEngine,
+    raw_merge: rawMerge,
+    inconsistency_report: inconsistencyReport,
+    outcome: blockingCount > 0 ? 'blocked_by_inconsistency' : 'clean',
+    diagnostics: [
+      'merge_ir_experimental evaluates PCS-style change sets behind the opt-in engine flag'
+    ]
+  };
+}
+
 export interface StructuralPathMatch {
   readonly from_path: string;
   readonly to_path: string;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index ae6690d..781c012 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -50,6 +50,7 @@ export type {
   DiagnosticCategory,
   DiagnosticSeverity,
   MergeEngine,
+  MergeIREvaluationReport,
   DiffDriverSmokeCase,
   DiffDriverSmokeSuite,
   FallbackScopeDefinition,
@@ -475,6 +476,9 @@ export {
   mergeEngineEnvironmentVariable,
   mergeEngineFromEnvironment,
   normalizeMergeEngine,
+  detectRawMergeInconsistencies,
+  evaluateMergeIRChangeSets,
+  rawMergeChangeSets,
   planConformanceSuite,
   planConformanceSuiteWithMergeEngine,
   planNamedConformanceSuiteEntry,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 9570927..4f129a1 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -351,6 +351,7 @@ import {
   mergeEngineEnvironmentVariable,
   mergeEngineFromEnvironment,
   normalizeMergeEngine,
+  evaluateMergeIRChangeSets,
   planConformanceSuite,
   planNamedConformanceSuiteEntry,
   planNamedConformanceSuitesWithDiagnostics,
@@ -5828,6 +5829,50 @@ describe('ast-merge shared fixtures', () => {
     expect(report.inconsistencies[1]?.change_ids[1]).toBe('right-delete-greet');
   });
 
+  it('conforms to the slice-907 merge IR experimental evaluation fixture', () => {
+    const fixture = readFixture<{
+      request: {
+        merge_engine: MergeEngine;
+        raw_merge_id: string;
+        report_id: string;
+        change_sets: readonly ChangeSet[];
+      };
+      expected: {
+        merge_engine: MergeEngine;
+        raw_change_count: number;
+        input_change_set_count: number;
+        categories: readonly string[];
+        blocking_count: number;
+        outcome: string;
+      };
+    }>(
+      'diagnostics',
+      'slice-907-merge-ir-experimental-evaluation',
+      'merge-ir-experimental-evaluation.json'
+    );
+    const report = evaluateMergeIRChangeSets(
+      fixture.request.merge_engine,
+      fixture.request.raw_merge_id,
+      fixture.request.report_id,
+      fixture.request.change_sets
+    );
+    const categories = report.inconsistency_report.inconsistencies.map(
+      (inconsistency) => inconsistency.category
+    );
+    const blockingCount = report.inconsistency_report.inconsistencies.filter(
+      (inconsistency) => inconsistency.severity === 'error'
+    ).length;
+
+    expect(report.merge_engine).toBe(fixture.expected.merge_engine);
+    expect(report.raw_merge.changes).toHaveLength(fixture.expected.raw_change_count);
+    expect(report.raw_merge.input_change_set_ids).toHaveLength(
+      fixture.expected.input_change_set_count
+    );
+    expect(categories).toEqual(fixture.expected.categories);
+    expect(blockingCount).toBe(fixture.expected.blocking_count);
+    expect(report.outcome).toBe(fixture.expected.outcome);
+  });
+
   it('conforms to the slice-796 merge IR comparison fixture', () => {
     const fixture = readFixture<{
       comparison: MergeIRComparisonReport;

From a7863e9e5c0fb6cbe5edf177dc8317215a7f8995 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 23:06:15 -0600
Subject: [PATCH 071/130] Add smorg-ts git command surface

---
 README.md                          |  19 ++
 packages/smorg-ts/package.json     |  25 ++
 packages/smorg-ts/src/cli.ts       | 520 +++++++++++++++++++++++++++++
 packages/smorg-ts/test/cli.test.ts | 170 ++++++++++
 tsconfig.json                      |   1 +
 vitest.config.ts                   |   3 +
 6 files changed, 738 insertions(+)
 create mode 100644 packages/smorg-ts/package.json
 create mode 100644 packages/smorg-ts/src/cli.ts
 create mode 100644 packages/smorg-ts/test/cli.test.ts

diff --git a/README.md b/README.md
index 32a482c..1754b0f 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,25 @@ pnpm add @structuredmerge/ast-merge @structuredmerge/json-merge
 
 The packages are published under the `@structuredmerge` npm scope.
 
+## Command
+
+The TypeScript implementation ships the implementation-specific `smorg-ts`
+command. Use that name in git configuration unless a package manager or local
+install has provided a `smorg` symlink.
+
+```sh
+git config merge.smorg-ts.driver 'smorg-ts merge-driver %O %A %B %P'
+git config diff.smorg-ts.command 'smorg-ts diff-driver'
+smorg-ts conflicts diff path/to/file-with-conflicts.go
+smorg-ts languages --gitattributes
+```
+
+`merge-driver` updates Git's `%A` file by default, or writes to `--output` when
+used outside git. `diff-driver` accepts both the two-argument local form and the
+seven- or nine-argument forms Git passes to external diff commands.
+`conflicts diff` reports conflict-marker regions in a file that already contains
+Git conflict markers.
+
 ## Packages
 
 Core:
diff --git a/packages/smorg-ts/package.json b/packages/smorg-ts/package.json
new file mode 100644
index 0000000..26c8252
--- /dev/null
+++ b/packages/smorg-ts/package.json
@@ -0,0 +1,25 @@
+{
+  "name": "@structuredmerge/smorg-ts",
+  "version": "0.2.0",
+  "private": false,
+  "type": "module",
+  "main": "./src/cli.ts",
+  "bin": {
+    "smorg-ts": "./src/cli.ts"
+  },
+  "author": "Peter H. Boling",
+  "homepage": "https://structuredmerge.org",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/structuredmerge/structuredmerge-typescript.git"
+  },
+  "bugs": {
+    "url": "https://github.com/structuredmerge/structuredmerge-typescript/issues"
+  },
+  "dependencies": {
+    "@structuredmerge/ast-merge": "workspace:*",
+    "@structuredmerge/go-merge": "workspace:*",
+    "@structuredmerge/json-merge": "workspace:*",
+    "@structuredmerge/plain-merge": "workspace:*"
+  }
+}
diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
new file mode 100644
index 0000000..1a9cae1
--- /dev/null
+++ b/packages/smorg-ts/src/cli.ts
@@ -0,0 +1,520 @@
+#!/usr/bin/env node
+import { readFileSync, writeFileSync } from 'node:fs';
+import path from 'node:path';
+
+import type { MergeResult } from '@structuredmerge/ast-merge';
+import { mergeGo } from '@structuredmerge/go-merge';
+import { mergeJson } from '@structuredmerge/json-merge';
+import { mergeText } from '@structuredmerge/plain-merge';
+
+export const exitSuccess = 0;
+export const exitUnresolvedConflict = 1;
+export const exitUserError = 2;
+export const exitInternalError = 3;
+
+interface MergeDriverOptions {
+  readonly ancestor: string;
+  readonly current: string;
+  readonly other: string;
+  readonly pathName?: string;
+  readonly output?: string;
+  readonly strict: boolean;
+  readonly fallback: string;
+  readonly checkOnly: boolean;
+  readonly exitCode: boolean;
+}
+
+interface DiffDriverOptions {
+  readonly pathName?: string;
+  readonly oldPath: string;
+  readonly newPath: string;
+}
+
+interface ConflictDiffOptions {
+  readonly pathName?: string;
+  readonly filePath: string;
+  readonly exitCode: boolean;
+}
+
+interface PathSettings {
+  language?: string;
+  conflictMarkerSize: number;
+}
+
+interface ConflictRegion {
+  readonly startLine: number;
+  readonly separatorLine: number;
+  readonly endLine: number;
+}
+
+export function run(
+  args: readonly string[],
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  const [command, ...rest] = args;
+  switch (command) {
+    case 'merge-driver':
+      return runMergeDriver(rest, stderr);
+    case 'diff-driver':
+      return runDiffDriver(rest, stdout, stderr);
+    case 'conflicts':
+      return runConflicts(rest, stdout, stderr);
+    case 'languages':
+      return runLanguages(rest, stdout, stderr);
+    case 'help':
+    case '-h':
+    case '--help':
+      printUsage(stdout);
+      return exitSuccess;
+    default:
+      if (command) {
+        stderr.write(`unknown command ${JSON.stringify(command)}\n`);
+      }
+      printUsage(stderr);
+      return exitUserError;
+  }
+}
+
+function printUsage(out: Pick<NodeJS.WriteStream, 'write'>): void {
+  out.write(
+    [
+      'usage: smorg-ts merge-driver [--path-name PATH] [--output PATH] [--strict] [--fallback=none|line|local|full-file] %O %A %B [%P]',
+      '       smorg-ts merge-driver --ancestor %O --current %A --other %B --path-name %P',
+      '       smorg-ts diff-driver [--path-name PATH] OLD NEW',
+      '       smorg-ts diff-driver PATH OLD-FILE OLD-HEX OLD-MODE NEW-FILE NEW-HEX NEW-MODE [OLD-PREFIX NEW-PREFIX]',
+      '       smorg-ts conflicts diff [--path-name PATH] [--exit-code] FILE',
+      '       smorg-ts languages --gitattributes'
+    ].join('\n') + '\n'
+  );
+}
+
+function runMergeDriver(
+  args: readonly string[],
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  const options = parseMergeDriverOptions(args, stderr);
+  if (!options) return exitUserError;
+
+  let ancestorSource: string;
+  let currentSource: string;
+  let otherSource: string;
+  try {
+    ancestorSource = readFileSync(options.ancestor, 'utf8');
+    currentSource = readFileSync(options.current, 'utf8');
+    otherSource = readFileSync(options.other, 'utf8');
+  } catch (error) {
+    stderr.write(`read merge input: ${String(error)}\n`);
+    return exitUserError;
+  }
+  void ancestorSource;
+
+  const effectivePath = options.pathName ?? options.current;
+  const settings = loadPathSettings(effectivePath);
+  const result = mergeByPath(effectivePath, settings.language, otherSource, currentSource);
+  let output = result.output;
+  if (!result.ok || output === undefined) {
+    if (options.strict || options.fallback === 'none') {
+      printDiagnostics(stderr, result);
+      return exitUnresolvedConflict;
+    }
+    output = currentSource;
+  }
+
+  if (options.checkOnly) {
+    return options.exitCode && output !== currentSource ? exitUnresolvedConflict : exitSuccess;
+  }
+
+  try {
+    writeFileSync(options.output ?? options.current, output);
+  } catch (error) {
+    stderr.write(`write output: ${String(error)}\n`);
+    return exitInternalError;
+  }
+  return exitSuccess;
+}
+
+function parseMergeDriverOptions(
+  args: readonly string[],
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): MergeDriverOptions | undefined {
+  let ancestor: string | undefined;
+  let current: string | undefined;
+  let other: string | undefined;
+  let pathName: string | undefined;
+  let output: string | undefined;
+  let strict = false;
+  let fallback = 'full-file';
+  let checkOnly = false;
+  let exitCode = false;
+  const positionals: string[] = [];
+
+  for (let index = 0; index < args.length; index += 1) {
+    const value = args[index];
+    switch (value) {
+      case '--ancestor':
+        ancestor = args[++index];
+        break;
+      case '--current':
+        current = args[++index];
+        break;
+      case '--other':
+        other = args[++index];
+        break;
+      case '--path-name':
+        pathName = args[++index];
+        break;
+      case '--output':
+        output = args[++index];
+        break;
+      case '--strict':
+        strict = true;
+        break;
+      case '--check-only':
+        checkOnly = true;
+        break;
+      case '--exit-code':
+        exitCode = true;
+        break;
+      case '--fallback':
+        fallback = args[++index] ?? '';
+        break;
+      default:
+        if (value.startsWith('--fallback=')) {
+          fallback = value.slice('--fallback='.length);
+        } else if (value.startsWith('--')) {
+          stderr.write(`unknown merge-driver option ${JSON.stringify(value)}\n`);
+          return undefined;
+        } else {
+          positionals.push(value);
+        }
+    }
+  }
+
+  ancestor ??= positionals[0];
+  current ??= positionals[1];
+  other ??= positionals[2];
+  pathName ??= positionals[3];
+
+  if (!ancestor || !current || !other) {
+    stderr.write('merge-driver requires ancestor, current, and other paths\n');
+    return undefined;
+  }
+  if (!['none', 'line', 'local', 'full-file'].includes(fallback)) {
+    stderr.write(`unsupported fallback mode ${JSON.stringify(fallback)}\n`);
+    return undefined;
+  }
+  return { ancestor, current, other, pathName, output, strict, fallback, checkOnly, exitCode };
+}
+
+function runDiffDriver(
+  args: readonly string[],
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  const options = parseDiffDriverOptions(args, stderr);
+  if (!options) return exitUserError;
+  try {
+    printStructuredDiff(
+      stdout,
+      options.pathName ?? options.newPath,
+      readFileSync(options.oldPath, 'utf8'),
+      readFileSync(options.newPath, 'utf8')
+    );
+  } catch (error) {
+    stderr.write(`read diff input: ${String(error)}\n`);
+    return exitUserError;
+  }
+  return exitSuccess;
+}
+
+function parseDiffDriverOptions(
+  args: readonly string[],
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): DiffDriverOptions | undefined {
+  let pathName: string | undefined;
+  const positionals: string[] = [];
+  for (let index = 0; index < args.length; index += 1) {
+    const value = args[index];
+    if (value === '--path-name') {
+      pathName = args[++index];
+    } else if (value.startsWith('--')) {
+      stderr.write(`unknown diff-driver option ${JSON.stringify(value)}\n`);
+      return undefined;
+    } else {
+      positionals.push(value);
+    }
+  }
+
+  if (positionals.length === 2) {
+    return { pathName, oldPath: positionals[0], newPath: positionals[1] };
+  }
+  if (positionals.length === 7 || positionals.length === 9) {
+    return {
+      pathName: pathName ?? positionals[0],
+      oldPath: positionals[1],
+      newPath: positionals[4]
+    };
+  }
+  stderr.write('diff-driver requires either 2, 7, or 9 positional arguments\n');
+  return undefined;
+}
+
+function printStructuredDiff(
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  pathName: string,
+  oldSource: string,
+  newSource: string
+): void {
+  stdout.write(`structured-diff ${pathName}\n`);
+  if (oldSource === newSource) {
+    stdout.write('status unchanged\n');
+    return;
+  }
+  stdout.write(
+    `status changed\nold-lines ${lineCount(oldSource)}\nnew-lines ${lineCount(newSource)}\n`
+  );
+}
+
+function runConflicts(
+  args: readonly string[],
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  const [subcommand, ...rest] = args;
+  if (subcommand !== 'diff') {
+    stderr.write('conflicts requires the diff subcommand\n');
+    return exitUserError;
+  }
+  return runConflictsDiff(rest, stdout, stderr);
+}
+
+function runConflictsDiff(
+  args: readonly string[],
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  const options = parseConflictsDiffOptions(args, stderr);
+  if (!options) return exitUserError;
+  const effectivePath = options.pathName ?? options.filePath;
+  try {
+    const settings = loadPathSettings(effectivePath);
+    const regions = findConflictRegions(
+      readFileSync(options.filePath, 'utf8'),
+      settings.conflictMarkerSize
+    );
+    printConflictDiff(stdout, effectivePath, regions);
+    return options.exitCode && regions.length > 0 ? exitUnresolvedConflict : exitSuccess;
+  } catch (error) {
+    stderr.write(`read conflicted file: ${String(error)}\n`);
+    return exitUserError;
+  }
+}
+
+function parseConflictsDiffOptions(
+  args: readonly string[],
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): ConflictDiffOptions | undefined {
+  let pathName: string | undefined;
+  let exitCode = false;
+  const positionals: string[] = [];
+  for (let index = 0; index < args.length; index += 1) {
+    const value = args[index];
+    if (value === '--path-name') {
+      pathName = args[++index];
+    } else if (value === '--exit-code') {
+      exitCode = true;
+    } else if (value.startsWith('--')) {
+      stderr.write(`unknown conflicts diff option ${JSON.stringify(value)}\n`);
+      return undefined;
+    } else {
+      positionals.push(value);
+    }
+  }
+  if (positionals.length !== 1) {
+    stderr.write('conflicts diff requires exactly one file path\n');
+    return undefined;
+  }
+  return { pathName, filePath: positionals[0], exitCode };
+}
+
+function runLanguages(
+  args: readonly string[],
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  if (args.length !== 1 || args[0] !== '--gitattributes') {
+    stderr.write('languages currently requires --gitattributes\n');
+    return exitUserError;
+  }
+  for (const line of [
+    '*.go merge=smorg-ts diff=smorg-ts smorg.language=go',
+    '*.json merge=smorg-ts diff=smorg-ts smorg.language=json',
+    '*.jsonc merge=smorg-ts diff=smorg-ts smorg.language=jsonc'
+  ]) {
+    stdout.write(`${line}\n`);
+  }
+  return exitSuccess;
+}
+
+function mergeByPath(
+  pathName: string,
+  language: string | undefined,
+  otherSource: string,
+  currentSource: string
+): MergeResult<string> {
+  switch (normalizeLanguage(language, pathName)) {
+    case 'go':
+      return mergeGo(otherSource, currentSource, 'go');
+    case 'json':
+      return mergeJson(otherSource, currentSource, 'json');
+    case 'jsonc':
+      return mergeJson(otherSource, currentSource, 'jsonc');
+    default:
+      return mergeText(otherSource, currentSource);
+  }
+}
+
+function normalizeLanguage(language: string | undefined, pathName: string): string {
+  switch (language?.trim().toLowerCase()) {
+    case 'go':
+    case 'golang':
+      return 'go';
+    case 'json':
+      return 'json';
+    case 'jsonc':
+    case 'json with comments':
+      return 'jsonc';
+    case 'plain':
+    case 'text':
+    case 'plaintext':
+    case 'text/plain':
+      return 'text';
+  }
+  switch (path.extname(pathName).toLowerCase()) {
+    case '.go':
+      return 'go';
+    case '.json':
+      return 'json';
+    case '.jsonc':
+      return 'jsonc';
+    default:
+      return 'text';
+  }
+}
+
+function loadPathSettings(pathName: string): PathSettings {
+  const settings: PathSettings = { conflictMarkerSize: 7 };
+  for (const attributesPath of attributeFilesForPath(pathName)) {
+    try {
+      applyAttributes(settings, pathName, readFileSync(attributesPath, 'utf8'));
+    } catch {
+      // Missing .gitattributes files are expected.
+    }
+  }
+  return settings;
+}
+
+function attributeFilesForPath(pathName: string): string[] {
+  const cleanPath = path.normalize(pathName);
+  const dir = path.dirname(cleanPath);
+  if (dir === '.' || path.isAbsolute(cleanPath) || cleanPath.startsWith('..')) {
+    return ['.gitattributes'];
+  }
+  const files = ['.gitattributes'];
+  const parts = dir.split(path.sep).filter(Boolean);
+  for (let index = 0; index < parts.length; index += 1) {
+    files.push(path.join(...parts.slice(0, index + 1), '.gitattributes'));
+  }
+  return files;
+}
+
+function applyAttributes(settings: PathSettings, pathName: string, source: string): void {
+  for (const rawLine of source.split('\n')) {
+    const line = rawLine.trim();
+    if (!line || line.startsWith('#')) continue;
+    const [pattern, ...fields] = line.split(/\s+/u);
+    if (!pattern || fields.length === 0 || !attributePatternMatches(pattern, pathName)) continue;
+    for (const field of fields) {
+      const [key, value] = field.split('=', 2);
+      if (!value) continue;
+      if (key === 'smorg.language' || key === 'linguist-language') {
+        settings.language = value;
+      } else if (key === 'conflict-marker-size') {
+        const markerSize = Number.parseInt(value, 10);
+        if (markerSize > 0) settings.conflictMarkerSize = markerSize;
+      }
+    }
+  }
+}
+
+function attributePatternMatches(pattern: string, pathName: string): boolean {
+  if (pattern === pathName) return true;
+  if (!pattern.includes('/')) {
+    return simpleGlobMatches(pattern, path.basename(pathName));
+  }
+  return simpleGlobMatches(pattern, pathName);
+}
+
+function simpleGlobMatches(pattern: string, value: string): boolean {
+  if (pattern === '*') return true;
+  const wildcard = pattern.indexOf('*');
+  if (wildcard < 0) return pattern === value;
+  return (
+    value.startsWith(pattern.slice(0, wildcard)) && value.endsWith(pattern.slice(wildcard + 1))
+  );
+}
+
+function findConflictRegions(source: string, markerSize: number): ConflictRegion[] {
+  const width = Math.max(1, markerSize);
+  const startPrefix = '<'.repeat(width);
+  const separatorPrefix = '='.repeat(width);
+  const endPrefix = '>'.repeat(width);
+  const regions: ConflictRegion[] = [];
+  let current: { startLine: number; separatorLine: number } | undefined;
+
+  source.split('\n').forEach((line, index) => {
+    const lineNumber = index + 1;
+    if (line.startsWith(startPrefix)) {
+      current = { startLine: lineNumber, separatorLine: 0 };
+    } else if (current && current.separatorLine === 0 && line.startsWith(separatorPrefix)) {
+      current.separatorLine = lineNumber;
+    } else if (current && line.startsWith(endPrefix)) {
+      regions.push({ ...current, endLine: lineNumber });
+      current = undefined;
+    }
+  });
+  return regions;
+}
+
+function printConflictDiff(
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  pathName: string,
+  regions: readonly ConflictRegion[]
+): void {
+  stdout.write(`conflicts ${pathName}\n`);
+  stdout.write(`count ${regions.length}\n`);
+  regions.forEach((region, index) => {
+    stdout.write(
+      `conflict ${index + 1} lines ${region.startLine}-${region.endLine} separator ${region.separatorLine}\n`
+    );
+  });
+}
+
+function lineCount(source: string): number {
+  if (source.length === 0) return 0;
+  return source.endsWith('\n') ? source.split('\n').length - 1 : source.split('\n').length;
+}
+
+function printDiagnostics(
+  stderr: Pick<NodeJS.WriteStream, 'write'>,
+  result: MergeResult<string>
+): void {
+  result.diagnostics.forEach((diagnostic) => {
+    stderr.write(`${diagnostic.category}: ${diagnostic.message}\n`);
+  });
+}
+
+if (import.meta.url === `file://${process.argv[1]}`) {
+  process.exit(run(process.argv.slice(2), process.stdout, process.stderr));
+}
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
new file mode 100644
index 0000000..719ec5f
--- /dev/null
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -0,0 +1,170 @@
+import { mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
+import { tmpdir } from 'node:os';
+import path from 'node:path';
+
+import { afterEach, beforeEach, describe, expect, it } from 'vitest';
+
+import { exitSuccess, exitUnresolvedConflict, run } from '../src/cli';
+
+function writer() {
+  let output = '';
+  return {
+    stream: {
+      write: (chunk: string) => {
+        output += chunk;
+        return true;
+      }
+    },
+    output: () => output
+  };
+}
+
+describe('smorg-ts cli', () => {
+  let previousCwd: string;
+  let dir: string;
+
+  beforeEach(() => {
+    previousCwd = process.cwd();
+    dir = mkdtempSync(path.join(tmpdir(), 'smorg-ts-test-'));
+    process.chdir(dir);
+  });
+
+  afterEach(() => {
+    process.chdir(previousCwd);
+    rmSync(dir, { force: true, recursive: true });
+  });
+
+  function write(name: string, source: string): string {
+    const filePath = path.join(dir, name);
+    writeFileSync(filePath, source);
+    return filePath;
+  }
+
+  it('updates the current file in merge-driver mode', () => {
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.tmp', '{"name":"structuredmerge","current":true}');
+    const other = write('other.tmp', '{"name":"structuredmerge","other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', '--path-name', 'package.json', ancestor, current, other],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit, stderr.output()).toBe(exitSuccess);
+    const merged = readFileSync(current, 'utf8');
+    expect(merged).toContain('"current":true');
+    expect(merged).toContain('"other":true');
+    expect(stdout.output()).toBe('');
+  });
+
+  it('uses smorg.language from gitattributes', () => {
+    writeFileSync('.gitattributes', '*.data smorg.language=json\n');
+    const ancestor = write('ancestor.tmp', '{"name":"structuredmerge"}');
+    const current = write('current.tmp', '{"name":"structuredmerge","current":true}');
+    const other = write('other.tmp', '{"name":"structuredmerge","other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', ancestor, current, other, 'package.data'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit, stderr.output()).toBe(exitSuccess);
+    const merged = readFileSync(current, 'utf8');
+    expect(merged).toContain('"current":true');
+    expect(merged).toContain('"other":true');
+  });
+
+  it('returns conflict exit code for strict merge failures', () => {
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.json', '{"name":');
+    const other = write('other.json', '{"other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', '--strict', ancestor, current, other, 'package.json'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUnresolvedConflict);
+    expect(stderr.output()).toContain('destination_parse_error');
+  });
+
+  it('supports check-only exit-code without writing', () => {
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.json', '{"name":"structuredmerge","current":true}');
+    const other = write('other.json', '{"name":"structuredmerge","other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', '--check-only', '--exit-code', ancestor, current, other, 'package.json'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUnresolvedConflict);
+    expect(readFileSync(current, 'utf8')).not.toContain('"other":true');
+  });
+
+  it('supports diff-driver git arities', () => {
+    for (const argumentCount of [7, 9]) {
+      const oldPath = write(`old-${argumentCount}.json`, '{"old":true}');
+      const newPath = write(`new-${argumentCount}.json`, '{"new":true}');
+      const args = [
+        'diff-driver',
+        'package.json',
+        oldPath,
+        'abc123',
+        '100644',
+        newPath,
+        'def456',
+        '100644'
+      ];
+      if (argumentCount === 9) args.push('a/', 'b/');
+      const stdout = writer();
+      const stderr = writer();
+
+      const exit = run(args, stdout.stream, stderr.stream);
+
+      expect(exit, stderr.output()).toBe(exitSuccess);
+      expect(stdout.output()).toContain('structured-diff package.json');
+    }
+  });
+
+  it('reports conflict regions', () => {
+    const conflicted = write(
+      'conflicted.go',
+      'package main\n<<<<<<< ours\nfunc Current() {}\n=======\nfunc Other() {}\n>>>>>>> theirs\n'
+    );
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['conflicts', 'diff', '--path-name', 'main.go', '--exit-code', conflicted],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUnresolvedConflict);
+    expect(stdout.output()).toContain('conflicts main.go');
+    expect(stdout.output()).toContain('conflict 1 lines 2-6 separator 4');
+  });
+
+  it('prints gitattributes', () => {
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(['languages', '--gitattributes'], stdout.stream, stderr.stream);
+
+    expect(exit, stderr.output()).toBe(exitSuccess);
+    expect(stdout.output()).toContain('*.go merge=smorg-ts diff=smorg-ts smorg.language=go');
+  });
+});
diff --git a/tsconfig.json b/tsconfig.json
index cc0c9be..b966149 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -8,6 +8,7 @@
       "@structuredmerge/tree-haver": ["./packages/tree-haver/src/index.ts"],
       "@structuredmerge/plain-merge": ["./packages/plain-merge/src/index.ts"],
       "@structuredmerge/json-merge": ["./packages/json-merge/src/index.ts"],
+      "@structuredmerge/go-merge": ["./packages/go-merge/src/index.ts"],
       "@structuredmerge/toml-merge": ["./packages/toml-merge/src/index.ts"],
       "@structuredmerge/peggy-toml-merge": ["./packages/peggy-toml-merge/src/index.ts"],
       "@structuredmerge/typescript-merge": ["./packages/typescript-merge/src/index.ts"],
diff --git a/vitest.config.ts b/vitest.config.ts
index 2552365..ec7ac66 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -18,6 +18,9 @@ export default defineConfig({
       '@structuredmerge/json-merge': fileURLToPath(
         new URL('./packages/json-merge/src/index.ts', import.meta.url)
       ),
+      '@structuredmerge/go-merge': fileURLToPath(
+        new URL('./packages/go-merge/src/index.ts', import.meta.url)
+      ),
       '@structuredmerge/toml-merge': fileURLToPath(
         new URL('./packages/toml-merge/src/index.ts', import.meta.url)
       ),

From 639b55cd5f2cdca1c3185a88a96bb6013fed5442 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 23:11:18 -0600
Subject: [PATCH 072/130] Document smorg-ts symlink guidance

---
 README.md | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/README.md b/README.md
index 1754b0f..913300d 100644
--- a/README.md
+++ b/README.md
@@ -31,6 +31,13 @@ The TypeScript implementation ships the implementation-specific `smorg-ts`
 command. Use that name in git configuration unless a package manager or local
 install has provided a `smorg` symlink.
 
+Package-manager formulas may expose the selected implementation as `smorg`.
+For a local user-created symlink:
+
+```sh
+ln -s "$(command -v smorg-ts)" ~/.local/bin/smorg
+```
+
 ```sh
 git config merge.smorg-ts.driver 'smorg-ts merge-driver %O %A %B %P'
 git config diff.smorg-ts.command 'smorg-ts diff-driver'

From 2c2033f2bf787983de5124150de6341d4babeb12 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 23:17:35 -0600
Subject: [PATCH 073/130] Add language backend profile schema

---
 packages/ast-merge/src/contracts.ts           | 73 +++++++++++++++++++
 packages/ast-merge/src/index.ts               | 10 +++
 .../test/fixtures.integration.test.ts         | 32 ++++++++
 3 files changed, 115 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 58a23a2..5faae59 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1569,6 +1569,79 @@ export interface FamilyFeatureProfile {
   readonly supportedPolicies: readonly PolicyReference[];
 }
 
+export interface ParserIdentity {
+  readonly parser: string;
+  readonly backend: string;
+  readonly backend_family: string;
+  readonly parser_version: string;
+  readonly language_version: string;
+}
+
+export interface GitAttributeProfile {
+  readonly attribute_namespace: string;
+  readonly language_attributes: readonly string[];
+  readonly language: string;
+  readonly merge_driver: string;
+  readonly diff_driver: string;
+  readonly conflict_marker_size_attribute: string;
+}
+
+export interface BackendProfile {
+  readonly backend: string;
+  readonly family: string;
+  readonly default: boolean;
+  readonly capabilities: readonly string[];
+}
+
+export interface AtomicNodeRule {
+  readonly selector: string;
+  readonly reason: string;
+}
+
+export interface SignatureDefinition {
+  readonly name: string;
+  readonly selector: string;
+  readonly extractor: string;
+}
+
+export interface CommutativeParentDefinition {
+  readonly selector: string;
+  readonly child_group: string;
+}
+
+export interface ChildGroupDefinition {
+  readonly name: string;
+  readonly separator: string;
+  readonly delimiter: string | null;
+}
+
+export interface CommentAttachmentRule {
+  readonly selector: string;
+  readonly strategy: string;
+}
+
+export interface LanguageBackendProfileRules {
+  readonly node_roles: readonly string[];
+  readonly atomic_nodes: readonly AtomicNodeRule[];
+  readonly signatures: readonly SignatureDefinition[];
+  readonly commutative_parents: readonly CommutativeParentDefinition[];
+  readonly child_groups: readonly ChildGroupDefinition[];
+  readonly comment_attachment: readonly CommentAttachmentRule[];
+}
+
+export interface LanguageBackendProfile {
+  readonly profile_id: string;
+  readonly family: string;
+  readonly version: string;
+  readonly parser_identity: ParserIdentity;
+  readonly extensions: readonly string[];
+  readonly aliases: readonly string[];
+  readonly git_attributes: GitAttributeProfile;
+  readonly supported_dialects: readonly string[];
+  readonly backends: readonly BackendProfile[];
+  readonly rules: LanguageBackendProfileRules;
+}
+
 export interface StructuredEditStructureProfile {
   readonly ownerScope: string;
   readonly ownerSelector: string;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 781c012..3f56eac 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -2,11 +2,13 @@ export const packageName = '@structuredmerge/ast-merge';
 
 export type {
   AmbiguityMatchingReport,
+  AtomicNodeRule,
   BackendGapConformanceGap,
   BackendGapConformanceReport,
   BackendGapConformanceSummary,
   BackendParityCase,
   BackendParitySuite,
+  BackendProfile,
   ChangeSet,
   ChangeSetChange,
   ClassMappingDiagnostic,
@@ -16,6 +18,9 @@ export type {
   ConflictHandlerRegistration,
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
+  ChildGroupDefinition,
+  CommentAttachmentRule,
+  CommutativeParentDefinition,
   ConformanceCaseRef,
   ConformanceCaseRun,
   ConformanceCaseRequirements,
@@ -82,6 +87,8 @@ export type {
   HostLanguageNativeProviderContracts,
   GitDriverOutput,
   InconsistencyReport,
+  LanguageBackendProfile,
+  LanguageBackendProfileRules,
   LanguageProfileHandlerRegistration,
   LanguageProfileHandlerRegistry,
   LineSpan,
@@ -146,6 +153,7 @@ export type {
   PCSConstraint,
   PerformanceGuardrails,
   PerformanceTimeoutDiagnostic,
+  ParserIdentity,
   ProviderRichnessProjection,
   ProviderRichnessSignature,
   ProfileConformanceReport,
@@ -153,6 +161,8 @@ export type {
   RawMerge,
   RawMergeChange,
   FamilyFeatureProfile,
+  GitAttributeProfile,
+  SignatureDefinition,
   StructuredEditStructureProfile,
   StructuredEditSelectionProfile,
   StructuredEditTargetSelection,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 4f129a1..e30891a 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -60,6 +60,7 @@ import type {
   GoProviderComparisonReport,
   HostLanguageNativeProviderContracts,
   InconsistencyReport,
+  LanguageBackendProfile,
   LanguageProfileHandlerRegistry,
   LocalLineFallbackReport,
   MatchingDebugArtifacts,
@@ -489,6 +490,18 @@ interface FamilyFeatureProfileFixture {
   };
 }
 
+interface LanguageBackendProfileSchemaFixture {
+  profile: LanguageBackendProfile;
+  expected: {
+    profile_id: string;
+    family: string;
+    default_backend: string;
+    primary_language_attribute: string;
+    first_signature: string;
+    first_commutative_parent: string;
+  };
+}
+
 interface TemplateSourcePathMappingFixture {
   cases: Array<{
     template_source_path: string;
@@ -6965,6 +6978,25 @@ describe('ast-merge shared fixtures', () => {
     }).toEqual(fixture.feature_profile);
   });
 
+  it('conforms to the slice-908 language backend profile schema fixture', () => {
+    const fixture = readFixture<LanguageBackendProfileSchemaFixture>(
+      'diagnostics',
+      'slice-908-language-backend-profile-schema',
+      'language-backend-profile-schema.json'
+    );
+
+    expect(fixture.profile.profile_id).toBe(fixture.expected.profile_id);
+    expect(fixture.profile.family).toBe(fixture.expected.family);
+    expect(fixture.profile.backends[0]?.backend).toBe(fixture.expected.default_backend);
+    expect(fixture.profile.git_attributes.language_attributes[0]).toBe(
+      fixture.expected.primary_language_attribute
+    );
+    expect(fixture.profile.rules.signatures[0]?.name).toBe(fixture.expected.first_signature);
+    expect(fixture.profile.rules.commutative_parents[0]?.selector).toBe(
+      fixture.expected.first_commutative_parent
+    );
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',

From 4780a97d945d3e1aa8bdfcb4c224df4dd515e1fa Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 23:34:00 -0600
Subject: [PATCH 074/130] Validate language backend profiles

---
 packages/ast-merge/src/contracts.ts           | 135 ++++++++++++++++++
 packages/ast-merge/src/index.ts               |   6 +-
 .../test/fixtures.integration.test.ts         |  52 ++++++-
 packages/tree-haver/src/contracts.ts          |   3 +
 4 files changed, 194 insertions(+), 2 deletions(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 5faae59..0975c34 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1642,6 +1642,141 @@ export interface LanguageBackendProfile {
   readonly rules: LanguageBackendProfileRules;
 }
 
+export interface BackendGrammarInventory {
+  readonly backend_ref: {
+    readonly id: string;
+    readonly family: string;
+  };
+  readonly known_node_kinds?: readonly string[];
+  readonly known_fields?: readonly string[];
+  readonly grammar_inventory?: string;
+}
+
+export interface ProfileValidationDiagnostic {
+  readonly severity: 'error' | 'warning';
+  readonly message: string;
+}
+
+export interface ProfileValidationResult {
+  readonly ok: boolean;
+  readonly errors: readonly ProfileValidationDiagnostic[];
+  readonly warnings: readonly ProfileValidationDiagnostic[];
+  readonly diagnostics: readonly ProfileValidationDiagnostic[];
+}
+
+export function validateLanguageBackendProfile(
+  profile: LanguageBackendProfile,
+  capability?: BackendGrammarInventory
+): ProfileValidationResult {
+  const errors: ProfileValidationDiagnostic[] = [];
+  const warnings: ProfileValidationDiagnostic[] = [];
+  const diagnostics: ProfileValidationDiagnostic[] = [];
+  const addError = (message: string) => {
+    const diagnostic: ProfileValidationDiagnostic = { severity: 'error', message };
+    errors.push(diagnostic);
+    diagnostics.push(diagnostic);
+  };
+  const addWarning = (message: string) => {
+    const diagnostic: ProfileValidationDiagnostic = { severity: 'warning', message };
+    warnings.push(diagnostic);
+    diagnostics.push(diagnostic);
+  };
+
+  const validRoles = new Set([
+    'structural',
+    'token',
+    'trivia',
+    'comment',
+    'delimiter',
+    'separator',
+    'virtual',
+    'error',
+    'opaque'
+  ]);
+  profile.rules.node_roles.forEach((role) => {
+    if (!validRoles.has(role)) addError(`invalid node role ${role}`);
+  });
+
+  const signatureNames = new Set<string>();
+  profile.rules.signatures.forEach((signature) => {
+    if (!signature.name) addError('signature name is required');
+    else if (signatureNames.has(signature.name))
+      addError(`duplicate signature name ${signature.name}`);
+    signatureNames.add(signature.name);
+    if (!signature.selector) addError('signature selector is required');
+    if (!validSignatureExtractor(signature.extractor)) {
+      addError(`unsupported signature extractor ${signature.extractor}`);
+    }
+  });
+
+  const childGroups = new Set<string>();
+  profile.rules.child_groups.forEach((group) => {
+    if (!group.name) addError('child group name is required');
+    else if (childGroups.has(group.name)) addError(`duplicate child group name ${group.name}`);
+    childGroups.add(group.name);
+  });
+  profile.rules.commutative_parents.forEach((parent) => {
+    if (!parent.selector) addError('commutative parent selector is required');
+    if (!childGroups.has(parent.child_group)) {
+      addError(
+        `commutative parent ${parent.selector} references unknown child group ${parent.child_group}`
+      );
+    }
+  });
+  profile.rules.atomic_nodes.forEach((atomic) => {
+    if (!atomic.selector) addError('atomic node selector is required');
+  });
+  profile.rules.comment_attachment.forEach((attachment) => {
+    if (!attachment.selector) addError('comment attachment selector is required');
+    if (!attachment.strategy) addError('comment attachment strategy is required');
+  });
+
+  if (capability?.grammar_inventory) {
+    validateBackendInventory(profile, capability, addError, addWarning);
+  }
+
+  return { ok: errors.length === 0, errors, warnings, diagnostics };
+}
+
+function validSignatureExtractor(extractor: string): boolean {
+  return (
+    extractor === 'text' ||
+    extractor.startsWith('field:') ||
+    extractor.startsWith('kind:') ||
+    extractor.startsWith('custom:')
+  );
+}
+
+function validateBackendInventory(
+  profile: LanguageBackendProfile,
+  capability: BackendGrammarInventory,
+  addError: (message: string) => void,
+  addWarning: (message: string) => void
+): void {
+  const nodeKinds = new Set(capability.known_node_kinds ?? []);
+  const fields = new Set(capability.known_fields ?? []);
+  const report = capability.grammar_inventory === 'exhaustive' ? addError : addWarning;
+  const checkSelector = (prefix: string, selector: string) => {
+    if (selector && nodeKinds.size > 0 && !nodeKinds.has(selector)) report(`${prefix} ${selector}`);
+  };
+  profile.rules.atomic_nodes.forEach((atomic) => {
+    checkSelector('unknown atomic node selector', atomic.selector);
+  });
+  profile.rules.signatures.forEach((signature) => {
+    checkSelector('unknown signature selector', signature.selector);
+    if (signature.extractor.startsWith('field:')) {
+      const field = signature.extractor.slice('field:'.length);
+      if (fields.size > 0 && !fields.has(field)) report(`unknown signature field ${field}`);
+    }
+  });
+  profile.rules.commutative_parents.forEach((parent) => {
+    checkSelector('unknown commutative parent selector', parent.selector);
+  });
+  profile.rules.comment_attachment.forEach((attachment) => {
+    checkSelector('unknown comment attachment selector', attachment.selector);
+  });
+}
+
 export interface StructuredEditStructureProfile {
   readonly ownerScope: string;
   readonly ownerSelector: string;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 3f56eac..06ebb80 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -6,6 +6,7 @@ export type {
   BackendGapConformanceGap,
   BackendGapConformanceReport,
   BackendGapConformanceSummary,
+  BackendGrammarInventory,
   BackendParityCase,
   BackendParitySuite,
   BackendProfile,
@@ -157,6 +158,8 @@ export type {
   ProviderRichnessProjection,
   ProviderRichnessSignature,
   ProfileConformanceReport,
+  ProfileValidationDiagnostic,
+  ProfileValidationResult,
   ProfileSkippedRule,
   RawMerge,
   RawMergeChange,
@@ -583,5 +586,6 @@ export {
   resolveConformanceFamilyContext,
   selectConformanceCase,
   summarizeNamedConformanceSuiteReports,
-  summarizeConformanceResults
+  summarizeConformanceResults,
+  validateLanguageBackendProfile
 } from './contracts';
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index e30891a..7495658 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -6,9 +6,10 @@ import { describe, expect, it } from 'vitest';
 import { mergeMarkdown } from '../../markdown-merge/src/index';
 import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
-import { executeGenericConflictHandler } from '../src/index';
+import { executeGenericConflictHandler, validateLanguageBackendProfile } from '../src/index';
 import type {
   AmbiguityMatchingReport,
+  BackendGrammarInventory,
   BackendGapConformanceReport,
   BackendParitySuite,
   ConformanceCaseRef,
@@ -71,6 +72,7 @@ import type {
   PCS,
   PerformanceGuardrails,
   ProfileConformanceReport,
+  ProfileValidationDiagnostic,
   RawMerge,
   RenameAwareMatchingReport,
   RenderPlanReport,
@@ -502,6 +504,24 @@ interface LanguageBackendProfileSchemaFixture {
   };
 }
 
+interface ProfileValidationFixture {
+  structural_profile: LanguageBackendProfile;
+  backend_metadata: BackendGrammarInventory;
+  partial_backend_metadata: BackendGrammarInventory;
+  unknown_selector_profile: LanguageBackendProfile;
+  expected: {
+    structural_errors: string[];
+    exhaustive_backend_errors: string[];
+    partial_backend_warnings: string[];
+  };
+}
+
+function sortedProfileValidationMessages(
+  diagnostics: readonly ProfileValidationDiagnostic[]
+): string[] {
+  return diagnostics.map((diagnostic) => diagnostic.message).sort();
+}
+
 interface TemplateSourcePathMappingFixture {
   cases: Array<{
     template_source_path: string;
@@ -6997,6 +7017,36 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-909 profile validation fixture', () => {
+    const fixture = readFixture<ProfileValidationFixture>(
+      'diagnostics',
+      'slice-909-profile-validation',
+      'profile-validation.json'
+    );
+
+    const structural = validateLanguageBackendProfile(fixture.structural_profile);
+    expect(sortedProfileValidationMessages(structural.errors)).toEqual(
+      [...fixture.expected.structural_errors].sort()
+    );
+
+    const exhaustive = validateLanguageBackendProfile(
+      fixture.unknown_selector_profile,
+      fixture.backend_metadata
+    );
+    expect(sortedProfileValidationMessages(exhaustive.errors)).toEqual(
+      [...fixture.expected.exhaustive_backend_errors].sort()
+    );
+
+    const partial = validateLanguageBackendProfile(
+      fixture.unknown_selector_profile,
+      fixture.partial_backend_metadata
+    );
+    expect(partial.errors).toHaveLength(0);
+    expect(sortedProfileValidationMessages(partial.warnings)).toEqual(
+      [...fixture.expected.partial_backend_warnings].sort()
+    );
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',
diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index a5a6b88..085df2d 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -85,6 +85,9 @@ export interface BackendCapability {
   readonly semanticRoleSupport: string;
   readonly normalizedTreeSupport: boolean;
   readonly nativeNodeAccess: boolean;
+  readonly knownNodeKinds?: readonly string[];
+  readonly knownFields?: readonly string[];
+  readonly grammarInventory?: string;
   readonly diagnostics: readonly string[];
 }
 

From 4e7cb6e4ad99c5dd4c7a2be5fee328f1ec77294a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 23:40:24 -0600
Subject: [PATCH 075/130] Expose active profile reporting contracts

---
 packages/ast-merge/src/contracts.ts           | 36 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  4 +++
 .../test/fixtures.integration.test.ts         | 35 ++++++++++++++++++
 3 files changed, 75 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 0975c34..588f24b 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1460,10 +1460,40 @@ export interface ProfileSkippedRule {
   readonly reason: string;
 }
 
+export interface ActiveProfileRuleCounts {
+  readonly node_roles: number;
+  readonly atomic_nodes: number;
+  readonly signatures: number;
+  readonly commutative_parents: number;
+  readonly child_groups: number;
+  readonly comment_attachment: number;
+}
+
+export interface ActiveProfileValidationSummary {
+  readonly ok: boolean;
+  readonly error_count: number;
+  readonly warning_count: number;
+}
+
+export interface ActiveProfileView {
+  readonly profile_id: string;
+  readonly family: string;
+  readonly backend: string;
+  readonly backend_family: string;
+  readonly parser: string;
+  readonly parser_version: string;
+  readonly language_version: string;
+  readonly dialect: string;
+  readonly supported_dialects: readonly string[];
+  readonly rule_counts: ActiveProfileRuleCounts;
+  readonly validation: ActiveProfileValidationSummary;
+}
+
 export interface ProfileConformanceReport {
   readonly report_id: string;
   readonly version: string;
   readonly profile: string;
+  readonly active_profile?: ActiveProfileView;
   readonly enabled_rules: readonly string[];
   readonly skipped_rules: readonly ProfileSkippedRule[];
   readonly fallback_count: number;
@@ -1471,6 +1501,12 @@ export interface ProfileConformanceReport {
   readonly diagnostics: readonly string[];
 }
 
+export interface ProfileDebugOutput {
+  readonly mode: string;
+  readonly active_profile: ActiveProfileView;
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 06ebb80..2297216 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -1,6 +1,9 @@
 export const packageName = '@structuredmerge/ast-merge';
 
 export type {
+  ActiveProfileRuleCounts,
+  ActiveProfileValidationSummary,
+  ActiveProfileView,
   AmbiguityMatchingReport,
   AtomicNodeRule,
   BackendGapConformanceGap,
@@ -158,6 +161,7 @@ export type {
   ProviderRichnessProjection,
   ProviderRichnessSignature,
   ProfileConformanceReport,
+  ProfileDebugOutput,
   ProfileValidationDiagnostic,
   ProfileValidationResult,
   ProfileSkippedRule,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 7495658..fa488d8 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -8,6 +8,7 @@ import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
 import { executeGenericConflictHandler, validateLanguageBackendProfile } from '../src/index';
 import type {
+  ActiveProfileView,
   AmbiguityMatchingReport,
   BackendGrammarInventory,
   BackendGapConformanceReport,
@@ -72,6 +73,7 @@ import type {
   PCS,
   PerformanceGuardrails,
   ProfileConformanceReport,
+  ProfileDebugOutput,
   ProfileValidationDiagnostic,
   RawMerge,
   RenameAwareMatchingReport,
@@ -516,6 +518,21 @@ interface ProfileValidationFixture {
   };
 }
 
+interface ActiveProfileReportingFixture {
+  active_profile: ActiveProfileView;
+  conformance_report: ProfileConformanceReport;
+  debug_output: ProfileDebugOutput;
+  expected: {
+    profile_id: string;
+    family: string;
+    backend: string;
+    parser: string;
+    signature_count: number;
+    validation_ok: boolean;
+    debug_mode: string;
+  };
+}
+
 function sortedProfileValidationMessages(
   diagnostics: readonly ProfileValidationDiagnostic[]
 ): string[] {
@@ -7047,6 +7064,24 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-910 active profile reporting fixture', () => {
+    const fixture = readFixture<ActiveProfileReportingFixture>(
+      'diagnostics',
+      'slice-910-active-profile-reporting',
+      'active-profile-reporting.json'
+    );
+
+    expect(fixture.active_profile.profile_id).toBe(fixture.expected.profile_id);
+    expect(fixture.active_profile.family).toBe(fixture.expected.family);
+    expect(fixture.active_profile.backend).toBe(fixture.expected.backend);
+    expect(fixture.active_profile.parser).toBe(fixture.expected.parser);
+    expect(fixture.active_profile.rule_counts.signatures).toBe(fixture.expected.signature_count);
+    expect(fixture.active_profile.validation.ok).toBe(fixture.expected.validation_ok);
+    expect(fixture.conformance_report.active_profile?.profile_id).toBe(fixture.expected.profile_id);
+    expect(fixture.debug_output.mode).toBe(fixture.expected.debug_mode);
+    expect(fixture.debug_output.active_profile.profile_id).toBe(fixture.expected.profile_id);
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',

From f51fa2b72400f6f181654a6b5f78ca6e817ef00a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Thu, 14 May 2026 23:59:22 -0600
Subject: [PATCH 076/130] Add profile promotion reporting contracts

---
 packages/ast-merge/src/contracts.ts           | 39 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  4 ++
 .../test/fixtures.integration.test.ts         | 36 +++++++++++++++++
 3 files changed, 79 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 588f24b..6964291 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1507,6 +1507,45 @@ export interface ProfileDebugOutput {
   readonly diagnostics: readonly string[];
 }
 
+export type ProfilePromotionStatus =
+  | 'experimental'
+  | 'available'
+  | 'recommended'
+  | 'default'
+  | 'disabled';
+
+export interface ProfilePromotionHardGate {
+  readonly name: string;
+  readonly passed: boolean;
+  readonly required: boolean;
+  readonly diagnostics: readonly string[];
+}
+
+export interface ProfilePromotionMetrics {
+  readonly required_fixture_count: number;
+  readonly passed_fixture_count: number;
+  readonly formatting_preservation_score: number;
+  readonly formatting_threshold: number;
+  readonly fallback_count: number;
+  readonly fallback_threshold: number;
+  readonly unresolved_conflict_count: number;
+  readonly backend_parity_passed: boolean;
+}
+
+export interface ProfilePromotionReport {
+  readonly report_id: string;
+  readonly version: string;
+  readonly profile_id: string;
+  readonly backend: string;
+  readonly status: ProfilePromotionStatus;
+  readonly active_profile?: ActiveProfileView;
+  readonly hard_gates: readonly ProfilePromotionHardGate[];
+  readonly metrics: ProfilePromotionMetrics;
+  readonly required_suites: readonly string[];
+  readonly blocking_reasons: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 2297216..d61310f 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -162,6 +162,10 @@ export type {
   ProviderRichnessSignature,
   ProfileConformanceReport,
   ProfileDebugOutput,
+  ProfilePromotionHardGate,
+  ProfilePromotionMetrics,
+  ProfilePromotionReport,
+  ProfilePromotionStatus,
   ProfileValidationDiagnostic,
   ProfileValidationResult,
   ProfileSkippedRule,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index fa488d8..93d92ec 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -74,6 +74,7 @@ import type {
   PerformanceGuardrails,
   ProfileConformanceReport,
   ProfileDebugOutput,
+  ProfilePromotionReport,
   ProfileValidationDiagnostic,
   RawMerge,
   RenameAwareMatchingReport,
@@ -533,6 +534,20 @@ interface ActiveProfileReportingFixture {
   };
 }
 
+interface ProfilePromotionReportFixture {
+  report: ProfilePromotionReport;
+  blocked_report: ProfilePromotionReport;
+  expected: {
+    profile_id: string;
+    recommended_status: string;
+    blocked_status: string;
+    hard_gate_count: number;
+    required_fixture_count: number;
+    formatting_threshold: number;
+    blocking_reason_count: number;
+  };
+}
+
 function sortedProfileValidationMessages(
   diagnostics: readonly ProfileValidationDiagnostic[]
 ): string[] {
@@ -7082,6 +7097,27 @@ describe('ast-merge shared fixtures', () => {
     expect(fixture.debug_output.active_profile.profile_id).toBe(fixture.expected.profile_id);
   });
 
+  it('conforms to the slice-911 profile promotion report fixture', () => {
+    const fixture = readFixture<ProfilePromotionReportFixture>(
+      'diagnostics',
+      'slice-911-profile-promotion-report',
+      'profile-promotion-report.json'
+    );
+
+    expect(fixture.report.profile_id).toBe(fixture.expected.profile_id);
+    expect(fixture.report.status).toBe(fixture.expected.recommended_status);
+    expect(fixture.report.hard_gates).toHaveLength(fixture.expected.hard_gate_count);
+    expect(fixture.report.metrics.required_fixture_count).toBe(
+      fixture.expected.required_fixture_count
+    );
+    expect(fixture.report.metrics.formatting_threshold).toBe(fixture.expected.formatting_threshold);
+    expect(fixture.report.active_profile?.profile_id).toBe(fixture.expected.profile_id);
+    expect(fixture.blocked_report.status).toBe(fixture.expected.blocked_status);
+    expect(fixture.blocked_report.blocking_reasons).toHaveLength(
+      fixture.expected.blocking_reason_count
+    );
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',

From 411ddd9b750e4123937195019730cdba713b2532 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 00:53:06 -0600
Subject: [PATCH 077/130] Add profile promotion policy contracts

---
 packages/ast-merge/src/contracts.ts           | 37 +++++++++++++
 packages/ast-merge/src/index.ts               |  5 ++
 .../test/fixtures.integration.test.ts         | 55 +++++++++++++++++++
 3 files changed, 97 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 6964291..6528688 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1546,6 +1546,43 @@ export interface ProfilePromotionReport {
   readonly diagnostics: readonly string[];
 }
 
+export type ProfilePromotionScope = 'data_format' | 'source_subprofile';
+
+export interface ProfileRecommendationGate {
+  readonly required_fixture_count: number;
+  readonly formatting_threshold: number;
+  readonly fallback_threshold: number;
+  readonly unresolved_conflict_threshold: number;
+  readonly requires_backend_parity: boolean;
+  readonly requires_cross_implementation_parity: boolean;
+}
+
+export interface ProfileDefaultGate {
+  readonly requires_recommended_status: boolean;
+  readonly requires_explicit_package_rollout: boolean;
+  readonly minimum_recommended_days: number;
+  readonly requires_narrow_scope: boolean;
+}
+
+export interface ProfilePromotionPolicyEntry {
+  readonly profile_id: string;
+  readonly family: string;
+  readonly scope: ProfilePromotionScope;
+  readonly eligible_statuses: readonly ProfilePromotionStatus[];
+  readonly recommendation_gate: ProfileRecommendationGate;
+  readonly default_gate: ProfileDefaultGate;
+  readonly required_suites: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
+export interface ProfilePromotionPolicy {
+  readonly policy_id: string;
+  readonly version: string;
+  readonly global_hard_gates: readonly string[];
+  readonly profiles: readonly ProfilePromotionPolicyEntry[];
+  readonly diagnostics: readonly string[];
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index d61310f..1e29e86 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -164,8 +164,13 @@ export type {
   ProfileDebugOutput,
   ProfilePromotionHardGate,
   ProfilePromotionMetrics,
+  ProfilePromotionPolicy,
+  ProfilePromotionPolicyEntry,
   ProfilePromotionReport,
+  ProfilePromotionScope,
   ProfilePromotionStatus,
+  ProfileRecommendationGate,
+  ProfileDefaultGate,
   ProfileValidationDiagnostic,
   ProfileValidationResult,
   ProfileSkippedRule,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 93d92ec..878edc0 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -74,6 +74,7 @@ import type {
   PerformanceGuardrails,
   ProfileConformanceReport,
   ProfileDebugOutput,
+  ProfilePromotionPolicy,
   ProfilePromotionReport,
   ProfileValidationDiagnostic,
   RawMerge,
@@ -548,6 +549,21 @@ interface ProfilePromotionReportFixture {
   };
 }
 
+interface ProfilePromotionPolicyFixture {
+  policy: ProfilePromotionPolicy;
+  expected: {
+    policy_id: string;
+    profile_count: number;
+    global_hard_gate_count: number;
+    recommended_eligible_count: number;
+    default_eligible_count: number;
+    source_subprofile_count: number;
+    json_requires_cross_implementation_parity: boolean;
+    ruby_requires_backend_parity: boolean;
+    formatting_threshold: number;
+  };
+}
+
 function sortedProfileValidationMessages(
   diagnostics: readonly ProfileValidationDiagnostic[]
 ): string[] {
@@ -7118,6 +7134,45 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-912 profile promotion policy fixture', () => {
+    const fixture = readFixture<ProfilePromotionPolicyFixture>(
+      'diagnostics',
+      'slice-912-profile-promotion-policy',
+      'profile-promotion-policy.json'
+    );
+    const recommendedEligible = fixture.policy.profiles.filter((entry) =>
+      entry.eligible_statuses.includes('recommended')
+    ).length;
+    const defaultEligible = fixture.policy.profiles.filter((entry) =>
+      entry.eligible_statuses.includes('default')
+    ).length;
+    const sourceSubprofiles = fixture.policy.profiles.filter(
+      (entry) => entry.scope === 'source_subprofile'
+    ).length;
+    const jsonPolicy = fixture.policy.profiles.find(
+      (entry) => entry.profile_id === 'json.keyed-object'
+    );
+    const rubyPolicy = fixture.policy.profiles.find(
+      (entry) => entry.profile_id === 'ruby.gemspec-dependencies'
+    );
+
+    expect(fixture.policy.policy_id).toBe(fixture.expected.policy_id);
+    expect(fixture.policy.profiles).toHaveLength(fixture.expected.profile_count);
+    expect(fixture.policy.global_hard_gates).toHaveLength(fixture.expected.global_hard_gate_count);
+    expect(recommendedEligible).toBe(fixture.expected.recommended_eligible_count);
+    expect(defaultEligible).toBe(fixture.expected.default_eligible_count);
+    expect(sourceSubprofiles).toBe(fixture.expected.source_subprofile_count);
+    expect(jsonPolicy?.recommendation_gate.requires_cross_implementation_parity).toBe(
+      fixture.expected.json_requires_cross_implementation_parity
+    );
+    expect(rubyPolicy?.recommendation_gate.requires_backend_parity).toBe(
+      fixture.expected.ruby_requires_backend_parity
+    );
+    expect(jsonPolicy?.recommendation_gate.formatting_threshold).toBe(
+      fixture.expected.formatting_threshold
+    );
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',

From c3ebc267895599ba3bb5d54544368d069863430b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 00:57:26 -0600
Subject: [PATCH 078/130] Evaluate profile promotion policies

---
 packages/ast-merge/src/contracts.ts           | 64 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  2 +
 .../test/fixtures.integration.test.ts         | 45 ++++++++++++-
 3 files changed, 110 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 6528688..a9143b7 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1583,6 +1583,70 @@ export interface ProfilePromotionPolicy {
   readonly diagnostics: readonly string[];
 }
 
+export interface ProfilePromotionEvaluation {
+  readonly profile_id: string;
+  readonly status: ProfilePromotionStatus;
+  readonly blocking_reasons: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
+export function evaluateProfilePromotion(
+  policy: ProfilePromotionPolicy,
+  report: ProfilePromotionReport
+): ProfilePromotionEvaluation {
+  const entry = policy.profiles.find((profile) => profile.profile_id === report.profile_id);
+  if (!entry) {
+    return {
+      profile_id: report.profile_id,
+      status: 'experimental',
+      blocking_reasons: ['profile has no promotion policy'],
+      diagnostics: []
+    };
+  }
+  const blockingReasons = profilePromotionBlockingReasons(entry, report);
+  const status =
+    blockingReasons.length === 0 && entry.eligible_statuses.includes('recommended')
+      ? 'recommended'
+      : 'available';
+  return {
+    profile_id: report.profile_id,
+    status,
+    blocking_reasons: blockingReasons,
+    diagnostics: []
+  };
+}
+
+function profilePromotionBlockingReasons(
+  entry: ProfilePromotionPolicyEntry,
+  report: ProfilePromotionReport
+): string[] {
+  const reasons: string[] = [];
+  report.hard_gates.forEach((gate) => {
+    if (gate.required && !gate.passed) reasons.push(`required hard gate ${gate.name} failed`);
+  });
+  if (report.metrics.passed_fixture_count < entry.recommendation_gate.required_fixture_count) {
+    reasons.push('passed fixture count is below required fixture count');
+  }
+  if (
+    report.metrics.formatting_preservation_score < entry.recommendation_gate.formatting_threshold
+  ) {
+    reasons.push('formatting preservation score is below threshold');
+  }
+  if (report.metrics.fallback_count > entry.recommendation_gate.fallback_threshold) {
+    reasons.push('fallback count exceeds threshold');
+  }
+  if (
+    report.metrics.unresolved_conflict_count >
+    entry.recommendation_gate.unresolved_conflict_threshold
+  ) {
+    reasons.push('unresolved conflict count exceeds threshold');
+  }
+  if (entry.recommendation_gate.requires_backend_parity && !report.metrics.backend_parity_passed) {
+    reasons.push('backend parity did not pass');
+  }
+  return reasons;
+}
+
 export const genericIndependentCommutativeInsertionsHandler =
   'generic-independent-commutative-insertions';
 export const genericKeyedMemberEditHandler = 'generic-keyed-member-edit';
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 1e29e86..562883c 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -163,6 +163,7 @@ export type {
   ProfileConformanceReport,
   ProfileDebugOutput,
   ProfilePromotionHardGate,
+  ProfilePromotionEvaluation,
   ProfilePromotionMetrics,
   ProfilePromotionPolicy,
   ProfilePromotionPolicyEntry,
@@ -600,5 +601,6 @@ export {
   selectConformanceCase,
   summarizeNamedConformanceSuiteReports,
   summarizeConformanceResults,
+  evaluateProfilePromotion,
   validateLanguageBackendProfile
 } from './contracts';
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 878edc0..b8383eb 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -6,7 +6,11 @@ import { describe, expect, it } from 'vitest';
 import { mergeMarkdown } from '../../markdown-merge/src/index';
 import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
-import { executeGenericConflictHandler, validateLanguageBackendProfile } from '../src/index';
+import {
+  evaluateProfilePromotion,
+  executeGenericConflictHandler,
+  validateLanguageBackendProfile
+} from '../src/index';
 import type {
   ActiveProfileView,
   AmbiguityMatchingReport,
@@ -564,6 +568,20 @@ interface ProfilePromotionPolicyFixture {
   };
 }
 
+interface ProfilePromotionEvaluationFixture {
+  policy: ProfilePromotionPolicy;
+  recommended_report: ProfilePromotionReport;
+  blocked_report: ProfilePromotionReport;
+  expected: {
+    recommended_status: string;
+    recommended_blocking_reason_count: number;
+    blocked_status: string;
+    blocked_blocking_reason_count: number;
+    first_blocking_reason: string;
+    unknown_profile_status: string;
+  };
+}
+
 function sortedProfileValidationMessages(
   diagnostics: readonly ProfileValidationDiagnostic[]
 ): string[] {
@@ -7173,6 +7191,31 @@ describe('ast-merge shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-913 profile promotion evaluation fixture', () => {
+    const fixture = readFixture<ProfilePromotionEvaluationFixture>(
+      'diagnostics',
+      'slice-913-profile-promotion-evaluation',
+      'profile-promotion-evaluation.json'
+    );
+
+    const recommended = evaluateProfilePromotion(fixture.policy, fixture.recommended_report);
+    expect(recommended.status).toBe(fixture.expected.recommended_status);
+    expect(recommended.blocking_reasons).toHaveLength(
+      fixture.expected.recommended_blocking_reason_count
+    );
+
+    const blocked = evaluateProfilePromotion(fixture.policy, fixture.blocked_report);
+    expect(blocked.status).toBe(fixture.expected.blocked_status);
+    expect(blocked.blocking_reasons).toHaveLength(fixture.expected.blocked_blocking_reason_count);
+    expect(blocked.blocking_reasons[0]).toBe(fixture.expected.first_blocking_reason);
+
+    const unknown = evaluateProfilePromotion(fixture.policy, {
+      ...fixture.recommended_report,
+      profile_id: 'unknown.profile'
+    });
+    expect(unknown.status).toBe(fixture.expected.unknown_profile_status);
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',

From 2dbaf5f5ecf475434c5295125ef9783e8b73f0ab Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 01:20:25 -0600
Subject: [PATCH 079/130] Use canonical promotion policy profile ids

---
 packages/ast-merge/test/fixtures.integration.test.ts | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index b8383eb..3b91ed7 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -7171,7 +7171,7 @@ describe('ast-merge shared fixtures', () => {
       (entry) => entry.profile_id === 'json.keyed-object'
     );
     const rubyPolicy = fixture.policy.profiles.find(
-      (entry) => entry.profile_id === 'ruby.gemspec-dependencies'
+      (entry) => entry.profile_id === 'ruby.gemspec-dependency-declarations'
     );
 
     expect(fixture.policy.policy_id).toBe(fixture.expected.policy_id);

From aadec88df368e019a03c43949bc8f90e277bc2bd Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 01:23:13 -0600
Subject: [PATCH 080/130] Expose canonical promotion profile ids

---
 packages/ast-merge/src/contracts.ts                  | 7 +++++++
 packages/ast-merge/src/index.ts                      | 5 +++++
 packages/ast-merge/test/fixtures.integration.test.ts | 6 ++++--
 3 files changed, 16 insertions(+), 2 deletions(-)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index a9143b7..890b010 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1548,6 +1548,13 @@ export interface ProfilePromotionReport {
 
 export type ProfilePromotionScope = 'data_format' | 'source_subprofile';
 
+export const promotionProfileJsonKeyedObject = 'json.keyed-object';
+export const promotionProfileGoImportDeclarations = 'go.import-declarations';
+export const promotionProfileRustUseDeclarations = 'rust.use-declarations';
+export const promotionProfileTypeScriptImportDeclarations = 'typescript.import-declarations';
+export const promotionProfileRubyGemspecDependencyDeclarations =
+  'ruby.gemspec-dependency-declarations';
+
 export interface ProfileRecommendationGate {
   readonly required_fixture_count: number;
   readonly formatting_threshold: number;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 562883c..e90327a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -602,5 +602,10 @@ export {
   summarizeNamedConformanceSuiteReports,
   summarizeConformanceResults,
   evaluateProfilePromotion,
+  promotionProfileGoImportDeclarations,
+  promotionProfileJsonKeyedObject,
+  promotionProfileRubyGemspecDependencyDeclarations,
+  promotionProfileRustUseDeclarations,
+  promotionProfileTypeScriptImportDeclarations,
   validateLanguageBackendProfile
 } from './contracts';
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 3b91ed7..89b8dbe 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -9,6 +9,8 @@ import { mergeRuby } from '../../ruby-merge/src/index';
 import {
   evaluateProfilePromotion,
   executeGenericConflictHandler,
+  promotionProfileJsonKeyedObject,
+  promotionProfileRubyGemspecDependencyDeclarations,
   validateLanguageBackendProfile
 } from '../src/index';
 import type {
@@ -7168,10 +7170,10 @@ describe('ast-merge shared fixtures', () => {
       (entry) => entry.scope === 'source_subprofile'
     ).length;
     const jsonPolicy = fixture.policy.profiles.find(
-      (entry) => entry.profile_id === 'json.keyed-object'
+      (entry) => entry.profile_id === promotionProfileJsonKeyedObject
     );
     const rubyPolicy = fixture.policy.profiles.find(
-      (entry) => entry.profile_id === 'ruby.gemspec-dependency-declarations'
+      (entry) => entry.profile_id === promotionProfileRubyGemspecDependencyDeclarations
     );
 
     expect(fixture.policy.policy_id).toBe(fixture.expected.policy_id);

From 50f5afa81955ea175272be553f803457ba706a4b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 01:26:42 -0600
Subject: [PATCH 081/130] Expose initial profile promotion policy

---
 packages/ast-merge/src/contracts.ts           | 88 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         |  2 +
 3 files changed, 91 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 890b010..9657dbb 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1590,6 +1590,94 @@ export interface ProfilePromotionPolicy {
   readonly diagnostics: readonly string[];
 }
 
+export function initialProfilePromotionPolicy(): ProfilePromotionPolicy {
+  const sourceSubprofile = (profileId: string, family: string): ProfilePromotionPolicyEntry => ({
+    profile_id: profileId,
+    family,
+    scope: 'source_subprofile',
+    eligible_statuses: ['available', 'recommended'],
+    recommendation_gate: {
+      required_fixture_count: 16,
+      formatting_threshold: 0.95,
+      fallback_threshold: 2,
+      unresolved_conflict_threshold: 0,
+      requires_backend_parity: true,
+      requires_cross_implementation_parity: false
+    },
+    default_gate: {
+      requires_recommended_status: true,
+      requires_explicit_package_rollout: true,
+      minimum_recommended_days: 30,
+      requires_narrow_scope: true
+    },
+    required_suites: [
+      'slice-827-backend-parity-fixtures',
+      'slice-815-formatting-preservation-metrics'
+    ],
+    diagnostics: ['source-language profile is narrow and not language-wide']
+  });
+  const rubyProfile = sourceSubprofile(promotionProfileRubyGemspecDependencyDeclarations, 'ruby');
+  return {
+    policy_id: 'initial-profile-promotion-policy',
+    version: '1',
+    global_hard_gates: [
+      'parse_or_fail_closed',
+      'render_or_fail_closed',
+      'coherent_conflict_markers',
+      'performance_guardrails'
+    ],
+    profiles: [
+      {
+        profile_id: promotionProfileJsonKeyedObject,
+        family: 'json',
+        scope: 'data_format',
+        eligible_statuses: ['available', 'recommended', 'default'],
+        recommendation_gate: {
+          required_fixture_count: 12,
+          formatting_threshold: 0.95,
+          fallback_threshold: 1,
+          unresolved_conflict_threshold: 0,
+          requires_backend_parity: true,
+          requires_cross_implementation_parity: true
+        },
+        default_gate: {
+          requires_recommended_status: true,
+          requires_explicit_package_rollout: true,
+          minimum_recommended_days: 30,
+          requires_narrow_scope: true
+        },
+        required_suites: [
+          'slice-901-false-textual-conflicts',
+          'slice-902-git-driver-smoke-fixtures',
+          'slice-815-formatting-preservation-metrics'
+        ],
+        diagnostics: ['data-format profile may become default after recommendation soak time']
+      },
+      sourceSubprofile(promotionProfileGoImportDeclarations, 'go'),
+      sourceSubprofile(promotionProfileRustUseDeclarations, 'rust'),
+      sourceSubprofile(promotionProfileTypeScriptImportDeclarations, 'typescript'),
+      {
+        ...rubyProfile,
+        recommendation_gate: {
+          ...rubyProfile.recommendation_gate,
+          required_fixture_count: 10,
+          fallback_threshold: 1,
+          requires_backend_parity: false
+        },
+        required_suites: [
+          'slice-702-ruby-gemspec-signature-merge-acceptance',
+          'slice-703-ruby-gemspec-field-policy-acceptance',
+          'slice-704-ruby-gemspec-dependency-section-policy-acceptance'
+        ],
+        diagnostics: ['Ruby source subprofile is limited to dependency declarations']
+      }
+    ],
+    diagnostics: [
+      'default status is allowed only after recommendation status and explicit package rollout'
+    ]
+  };
+}
+
 export interface ProfilePromotionEvaluation {
   readonly profile_id: string;
   readonly status: ProfilePromotionStatus;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index e90327a..ba4253c 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -602,6 +602,7 @@ export {
   summarizeNamedConformanceSuiteReports,
   summarizeConformanceResults,
   evaluateProfilePromotion,
+  initialProfilePromotionPolicy,
   promotionProfileGoImportDeclarations,
   promotionProfileJsonKeyedObject,
   promotionProfileRubyGemspecDependencyDeclarations,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 89b8dbe..4670cb6 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -9,6 +9,7 @@ import { mergeRuby } from '../../ruby-merge/src/index';
 import {
   evaluateProfilePromotion,
   executeGenericConflictHandler,
+  initialProfilePromotionPolicy,
   promotionProfileJsonKeyedObject,
   promotionProfileRubyGemspecDependencyDeclarations,
   validateLanguageBackendProfile
@@ -7191,6 +7192,7 @@ describe('ast-merge shared fixtures', () => {
     expect(jsonPolicy?.recommendation_gate.formatting_threshold).toBe(
       fixture.expected.formatting_threshold
     );
+    expect(initialProfilePromotionPolicy()).toEqual(fixture.policy);
   });
 
   it('conforms to the slice-913 profile promotion evaluation fixture', () => {

From 6126ea71f44615974b7bfa5bdf7eaa4f37b567a4 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 08:34:44 -0600
Subject: [PATCH 082/130] Add profile selection enforcement contract

---
 packages/ast-merge/src/contracts.ts           | 80 +++++++++++++++++++
 packages/ast-merge/src/index.ts               |  4 +
 .../test/fixtures.integration.test.ts         | 67 ++++++++++++++++
 3 files changed, 151 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 9657dbb..8aa8506 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -1685,6 +1685,31 @@ export interface ProfilePromotionEvaluation {
   readonly diagnostics: readonly string[];
 }
 
+export type ProfileSelectionEnforcementMode = 'advisory' | 'required';
+
+export interface ProfileSelectionRequirement {
+  readonly profile_id: string;
+  readonly promotion_policy_id: string;
+  readonly minimum_profile_status: ProfilePromotionStatus;
+  readonly enforcement_mode: ProfileSelectionEnforcementMode;
+}
+
+export interface ProfileSelectionDecision {
+  readonly profile_id: string;
+  readonly promotion_policy_id: string;
+  readonly minimum_profile_status: ProfilePromotionStatus;
+  readonly evaluated_status: ProfilePromotionStatus;
+  readonly enforcement_mode: ProfileSelectionEnforcementMode;
+  readonly satisfied: boolean;
+  readonly enforced: boolean;
+  readonly allowed: boolean;
+  readonly rejection_code?: string;
+  readonly active_profile?: ActiveProfileView;
+  readonly profile_promotion_evaluation: ProfilePromotionEvaluation;
+  readonly blocking_reasons: readonly string[];
+  readonly diagnostics: readonly string[];
+}
+
 export function evaluateProfilePromotion(
   policy: ProfilePromotionPolicy,
   report: ProfilePromotionReport
@@ -1711,6 +1736,61 @@ export function evaluateProfilePromotion(
   };
 }
 
+export function evaluateProfileSelectionRequirement(
+  requirement: ProfileSelectionRequirement,
+  activeProfile: ActiveProfileView | undefined,
+  evaluation: ProfilePromotionEvaluation
+): ProfileSelectionDecision {
+  const satisfied =
+    profilePromotionStatusRank(evaluation.status) >=
+      profilePromotionStatusRank(requirement.minimum_profile_status) &&
+    evaluation.status !== 'disabled';
+  const enforced = requirement.enforcement_mode === 'required';
+  const allowed = satisfied || !enforced;
+  const blockingReasons = [...evaluation.blocking_reasons];
+  let rejectionCode = '';
+  if (!satisfied) {
+    blockingReasons.unshift(
+      `profile status ${evaluation.status} is below required ${requirement.minimum_profile_status}`
+    );
+    if (enforced) rejectionCode = 'profile_status_unmet';
+  }
+  const diagnostics = [...evaluation.diagnostics];
+  if (requirement.profile_id !== evaluation.profile_id) {
+    diagnostics.push('selected profile does not match promotion evaluation profile');
+  }
+  return {
+    profile_id: requirement.profile_id,
+    promotion_policy_id: requirement.promotion_policy_id,
+    minimum_profile_status: requirement.minimum_profile_status,
+    evaluated_status: evaluation.status,
+    enforcement_mode: requirement.enforcement_mode,
+    satisfied,
+    enforced,
+    allowed,
+    rejection_code: rejectionCode,
+    active_profile: activeProfile,
+    profile_promotion_evaluation: evaluation,
+    blocking_reasons: blockingReasons,
+    diagnostics
+  };
+}
+
+function profilePromotionStatusRank(status: ProfilePromotionStatus): number {
+  switch (status) {
+    case 'experimental':
+      return 1;
+    case 'available':
+      return 2;
+    case 'recommended':
+      return 3;
+    case 'default':
+      return 4;
+    default:
+      return 0;
+  }
+}
+
 function profilePromotionBlockingReasons(
   entry: ProfilePromotionPolicyEntry,
   report: ProfilePromotionReport
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index ba4253c..e533375 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -170,6 +170,9 @@ export type {
   ProfilePromotionReport,
   ProfilePromotionScope,
   ProfilePromotionStatus,
+  ProfileSelectionDecision,
+  ProfileSelectionEnforcementMode,
+  ProfileSelectionRequirement,
   ProfileRecommendationGate,
   ProfileDefaultGate,
   ProfileValidationDiagnostic,
@@ -602,6 +605,7 @@ export {
   summarizeNamedConformanceSuiteReports,
   summarizeConformanceResults,
   evaluateProfilePromotion,
+  evaluateProfileSelectionRequirement,
   initialProfilePromotionPolicy,
   promotionProfileGoImportDeclarations,
   promotionProfileJsonKeyedObject,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 4670cb6..95a8e2b 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -8,6 +8,7 @@ import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
 import {
   evaluateProfilePromotion,
+  evaluateProfileSelectionRequirement,
   executeGenericConflictHandler,
   initialProfilePromotionPolicy,
   promotionProfileJsonKeyedObject,
@@ -81,8 +82,10 @@ import type {
   PerformanceGuardrails,
   ProfileConformanceReport,
   ProfileDebugOutput,
+  ProfilePromotionEvaluation,
   ProfilePromotionPolicy,
   ProfilePromotionReport,
+  ProfileSelectionRequirement,
   ProfileValidationDiagnostic,
   RawMerge,
   RenameAwareMatchingReport,
@@ -585,6 +588,30 @@ interface ProfilePromotionEvaluationFixture {
   };
 }
 
+interface ProfileSelectionEnforcementFixture {
+  active_profile: ActiveProfileView;
+  available_evaluation: ProfilePromotionEvaluation;
+  recommended_evaluation: ProfilePromotionEvaluation;
+  advisory_requirement: ProfileSelectionRequirement;
+  required_requirement: ProfileSelectionRequirement;
+  satisfied_requirement: ProfileSelectionRequirement;
+  expected: {
+    advisory_allowed: boolean;
+    advisory_satisfied: boolean;
+    advisory_enforced: boolean;
+    advisory_rejection_code: string;
+    required_allowed: boolean;
+    required_satisfied: boolean;
+    required_enforced: boolean;
+    required_rejection_code: string;
+    required_first_blocking_reason: string;
+    satisfied_allowed: boolean;
+    satisfied_satisfied: boolean;
+    satisfied_enforced: boolean;
+    satisfied_rejection_code: string;
+  };
+}
+
 function sortedProfileValidationMessages(
   diagnostics: readonly ProfileValidationDiagnostic[]
 ): string[] {
@@ -7220,6 +7247,46 @@ describe('ast-merge shared fixtures', () => {
     expect(unknown.status).toBe(fixture.expected.unknown_profile_status);
   });
 
+  it('conforms to the slice-914 profile selection enforcement fixture', () => {
+    const fixture = readFixture<ProfileSelectionEnforcementFixture>(
+      'diagnostics',
+      'slice-914-profile-selection-enforcement',
+      'profile-selection-enforcement.json'
+    );
+
+    const advisory = evaluateProfileSelectionRequirement(
+      fixture.advisory_requirement,
+      fixture.active_profile,
+      fixture.available_evaluation
+    );
+    expect(advisory.allowed).toBe(fixture.expected.advisory_allowed);
+    expect(advisory.satisfied).toBe(fixture.expected.advisory_satisfied);
+    expect(advisory.enforced).toBe(fixture.expected.advisory_enforced);
+    expect(advisory.rejection_code).toBe(fixture.expected.advisory_rejection_code);
+
+    const required = evaluateProfileSelectionRequirement(
+      fixture.required_requirement,
+      fixture.active_profile,
+      fixture.available_evaluation
+    );
+    expect(required.allowed).toBe(fixture.expected.required_allowed);
+    expect(required.satisfied).toBe(fixture.expected.required_satisfied);
+    expect(required.enforced).toBe(fixture.expected.required_enforced);
+    expect(required.rejection_code).toBe(fixture.expected.required_rejection_code);
+    expect(required.blocking_reasons[0]).toBe(fixture.expected.required_first_blocking_reason);
+
+    const satisfied = evaluateProfileSelectionRequirement(
+      fixture.satisfied_requirement,
+      fixture.active_profile,
+      fixture.recommended_evaluation
+    );
+    expect(satisfied.allowed).toBe(fixture.expected.satisfied_allowed);
+    expect(satisfied.satisfied).toBe(fixture.expected.satisfied_satisfied);
+    expect(satisfied.enforced).toBe(fixture.expected.satisfied_enforced);
+    expect(satisfied.rejection_code).toBe(fixture.expected.satisfied_rejection_code);
+    expect(satisfied.blocking_reasons).toHaveLength(0);
+  });
+
   it('conforms to the template source path mapping fixture', () => {
     const manifest = readFixture<ConformanceManifest>(
       'conformance',

From cd644a737a5696ac5ff8d1c5d38cbf06cdf42503 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 08:42:29 -0600
Subject: [PATCH 083/130] Expose profile promotion transport fields

---
 packages/ast-merge/src/contracts.ts           | 21 +++++++
 packages/ast-merge/src/index.ts               |  1 +
 .../test/fixtures.integration.test.ts         | 59 +++++++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 8aa8506..9100d58 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -2278,6 +2278,9 @@ export interface StructuredEditApplicationEnvelope {
 export interface StructuredEditRequestEnvelope {
   readonly kind: 'structured_edit_request';
   readonly version: typeof STRUCTURED_EDIT_TRANSPORT_VERSION;
+  readonly profile_id?: string;
+  readonly minimum_profile_status?: ProfilePromotionStatus;
+  readonly promotion_policy_id?: string;
   readonly request: StructuredEditRequest;
 }
 
@@ -2285,6 +2288,10 @@ export interface StructuredEditExecutionReport {
   readonly application: StructuredEditApplication;
   readonly providerFamily: string;
   readonly providerBackend?: string;
+  readonly active_profile?: ActiveProfileView;
+  readonly profile_promotion_evaluation?: ProfilePromotionEvaluation;
+  readonly profile_selection_decision?: ProfileSelectionDecision;
+  readonly profile_blocking_reasons?: readonly string[];
   readonly diagnostics: readonly Diagnostic[];
   readonly metadata?: Readonly<Record<string, unknown>>;
 }
@@ -3655,6 +3662,20 @@ export function structuredEditRequestEnvelope(
   };
 }
 
+export function profileSelectionRequirementFromRequestEnvelope(
+  envelope: StructuredEditRequestEnvelope
+): ProfileSelectionRequirement | undefined {
+  if (!envelope.profile_id && !envelope.minimum_profile_status && !envelope.promotion_policy_id) {
+    return undefined;
+  }
+  return {
+    profile_id: envelope.profile_id ?? '',
+    promotion_policy_id: envelope.promotion_policy_id ?? '',
+    minimum_profile_status: envelope.minimum_profile_status ?? 'available',
+    enforcement_mode: 'required'
+  };
+}
+
 export function importStructuredEditRequestEnvelope(value: unknown): {
   request?: StructuredEditRequest;
   error?: StructuredEditTransportImportError;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index e533375..e55a06a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -607,6 +607,7 @@ export {
   evaluateProfilePromotion,
   evaluateProfileSelectionRequirement,
   initialProfilePromotionPolicy,
+  profileSelectionRequirementFromRequestEnvelope,
   promotionProfileGoImportDeclarations,
   promotionProfileJsonKeyedObject,
   promotionProfileRubyGemspecDependencyDeclarations,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 95a8e2b..4d0af6d 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -85,6 +85,7 @@ import type {
   ProfilePromotionEvaluation,
   ProfilePromotionPolicy,
   ProfilePromotionReport,
+  ProfileSelectionDecision,
   ProfileSelectionRequirement,
   ProfileValidationDiagnostic,
   RawMerge,
@@ -227,6 +228,7 @@ import type {
   StructuredEditKettleJemPrimitiveGapReport,
   StructuredEditExecutionReport,
   StructuredEditExecutionReportEnvelope,
+  ProfileSelectionRequirement,
   PolicyReference,
   PolicySurface,
   Diagnostic,
@@ -447,6 +449,7 @@ import {
   importStructuredEditProviderBatchExecutionHandoffEnvelope,
   importStructuredEditProviderBatchExecutionPlanEnvelope,
   importStructuredEditExecutionReportEnvelope,
+  profileSelectionRequirementFromRequestEnvelope,
   reviewReplayBundleInputs,
   reviewReplayBundleEnvelope,
   reviewedNestedExecution,
@@ -1395,6 +1398,9 @@ interface StructuredEditRequestEnvelopeFixture {
   expected_envelope: {
     kind: StructuredEditRequestEnvelope['kind'];
     version: number;
+    profile_id?: string;
+    minimum_profile_status?: StructuredEditRequestEnvelope['minimum_profile_status'];
+    promotion_policy_id?: string;
     request: StructuredEditRequestFixture['cases'][number]['request'];
   };
 }
@@ -1428,6 +1434,10 @@ interface StructuredEditExecutionReportFixture {
       application: StructuredEditApplicationFixture['cases'][number]['application'];
       provider_family: string;
       provider_backend?: string | null;
+      active_profile?: ActiveProfileView;
+      profile_promotion_evaluation?: ProfilePromotionEvaluation;
+      profile_selection_decision?: ProfileSelectionDecision;
+      profile_blocking_reasons?: readonly string[];
       diagnostics: DiagnosticFixture['diagnostics'];
       metadata?: Record<string, unknown>;
     };
@@ -2672,6 +2682,18 @@ interface StructuredEditExecutionReportEnvelopeFixture {
   };
 }
 
+interface StructuredEditProfilePromotionEnvelopeFixture {
+  structured_edit_request: StructuredEditRequestFixture['cases'][number]['request'];
+  profile_selection_requirement: ProfileSelectionRequirement;
+  expected_request_envelope: StructuredEditRequestEnvelopeFixture['expected_envelope'];
+  structured_edit_execution_report: StructuredEditExecutionReportFixture['cases'][number]['report'];
+  expected_execution_report_envelope: StructuredEditExecutionReportEnvelopeFixture['expected_envelope'];
+  expected: {
+    rejection_code: string;
+    profile_blocking_reason_count: number;
+  };
+}
+
 interface StructuredEditExecutionReportEnvelopeRejectionFixture {
   cases: Array<{
     label: string;
@@ -4349,6 +4371,9 @@ function normalizeStructuredEditRequestEnvelope(
   return {
     kind: raw.kind,
     version: STRUCTURED_EDIT_TRANSPORT_VERSION,
+    profile_id: raw.profile_id,
+    minimum_profile_status: raw.minimum_profile_status,
+    promotion_policy_id: raw.promotion_policy_id,
     request: normalizeStructuredEditRequest(raw.request)
   };
 }
@@ -4360,6 +4385,10 @@ function normalizeStructuredEditExecutionReport(
     application: normalizeStructuredEditApplication(raw.application),
     providerFamily: raw.provider_family,
     providerBackend: raw.provider_backend ?? undefined,
+    active_profile: raw.active_profile,
+    profile_promotion_evaluation: raw.profile_promotion_evaluation,
+    profile_selection_decision: raw.profile_selection_decision,
+    profile_blocking_reasons: raw.profile_blocking_reasons,
     diagnostics: raw.diagnostics.map((diagnostic) => normalizeDiagnostic(diagnostic)),
     metadata: raw.metadata
   };
@@ -11088,6 +11117,36 @@ describe('ast-merge shared fixtures', () => {
     }
   });
 
+  it('conforms to the slice-915 structured-edit profile promotion envelope fixture', () => {
+    const fixture = readFixture<StructuredEditProfilePromotionEnvelopeFixture>(
+      'diagnostics',
+      'slice-915-structured-edit-profile-promotion-envelope',
+      'structured-edit-profile-promotion-envelope.json'
+    );
+    const request = normalizeStructuredEditRequest(fixture.structured_edit_request);
+    const requestEnvelope = {
+      ...structuredEditRequestEnvelope(request),
+      profile_id: fixture.expected_request_envelope.profile_id,
+      minimum_profile_status: fixture.expected_request_envelope.minimum_profile_status,
+      promotion_policy_id: fixture.expected_request_envelope.promotion_policy_id
+    };
+    expect(requestEnvelope).toEqual(
+      normalizeStructuredEditRequestEnvelope(fixture.expected_request_envelope)
+    );
+    expect(profileSelectionRequirementFromRequestEnvelope(requestEnvelope)).toEqual(
+      fixture.profile_selection_requirement
+    );
+
+    const report = normalizeStructuredEditExecutionReport(fixture.structured_edit_execution_report);
+    expect(structuredEditExecutionReportEnvelope(report)).toEqual(
+      normalizeStructuredEditExecutionReportEnvelope(fixture.expected_execution_report_envelope)
+    );
+    expect(report.profile_selection_decision?.rejection_code).toBe(fixture.expected.rejection_code);
+    expect(report.profile_blocking_reasons).toHaveLength(
+      fixture.expected.profile_blocking_reason_count
+    );
+  });
+
   it('conforms to the slice-438 structured-edit execution report fixture', () => {
     const fixture = readFixture<StructuredEditExecutionReportFixture>(
       ...diagnosticsFixturePath('structured_edit_execution_report')

From 4920679925d21ac7f2e98e42bc5c64d7150d604a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 08:46:16 -0600
Subject: [PATCH 084/130] Add profile promotion CLI flags

---
 packages/smorg-ts/src/cli.ts       | 81 ++++++++++++++++++++++++++++--
 packages/smorg-ts/test/cli.test.ts | 31 +++++++++++-
 2 files changed, 108 insertions(+), 4 deletions(-)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 1a9cae1..8cf3781 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -2,7 +2,12 @@
 import { readFileSync, writeFileSync } from 'node:fs';
 import path from 'node:path';
 
-import type { MergeResult } from '@structuredmerge/ast-merge';
+import {
+  evaluateProfileSelectionRequirement,
+  initialProfilePromotionPolicy,
+  promotionProfileJsonKeyedObject
+} from '@structuredmerge/ast-merge';
+import type { MergeResult, ProfilePromotionStatus } from '@structuredmerge/ast-merge';
 import { mergeGo } from '@structuredmerge/go-merge';
 import { mergeJson } from '@structuredmerge/json-merge';
 import { mergeText } from '@structuredmerge/plain-merge';
@@ -22,6 +27,9 @@ interface MergeDriverOptions {
   readonly fallback: string;
   readonly checkOnly: boolean;
   readonly exitCode: boolean;
+  readonly profileId?: string;
+  readonly profileReport: boolean;
+  readonly requireProfileStatus?: string;
 }
 
 interface DiffDriverOptions {
@@ -55,7 +63,7 @@ export function run(
   const [command, ...rest] = args;
   switch (command) {
     case 'merge-driver':
-      return runMergeDriver(rest, stderr);
+      return runMergeDriver(rest, stdout, stderr);
     case 'diff-driver':
       return runDiffDriver(rest, stdout, stderr);
     case 'conflicts':
@@ -91,10 +99,19 @@ function printUsage(out: Pick<NodeJS.WriteStream, 'write'>): void {
 
 function runMergeDriver(
   args: readonly string[],
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
   stderr: Pick<NodeJS.WriteStream, 'write'>
 ): number {
   const options = parseMergeDriverOptions(args, stderr);
   if (!options) return exitUserError;
+  const profileExit = reportAndEnforceProfile(
+    options.profileId,
+    options.profileReport,
+    options.requireProfileStatus,
+    stdout,
+    stderr
+  );
+  if (profileExit !== exitSuccess) return profileExit;
 
   let ancestorSource: string;
   let currentSource: string;
@@ -147,6 +164,9 @@ function parseMergeDriverOptions(
   let fallback = 'full-file';
   let checkOnly = false;
   let exitCode = false;
+  let profileId: string | undefined;
+  let profileReport = false;
+  let requireProfileStatus: string | undefined;
   const positionals: string[] = [];
 
   for (let index = 0; index < args.length; index += 1) {
@@ -176,6 +196,15 @@ function parseMergeDriverOptions(
       case '--exit-code':
         exitCode = true;
         break;
+      case '--profile':
+        profileId = args[++index];
+        break;
+      case '--profile-report':
+        profileReport = true;
+        break;
+      case '--require-profile-status':
+        requireProfileStatus = args[++index];
+        break;
       case '--fallback':
         fallback = args[++index] ?? '';
         break;
@@ -204,7 +233,53 @@ function parseMergeDriverOptions(
     stderr.write(`unsupported fallback mode ${JSON.stringify(fallback)}\n`);
     return undefined;
   }
-  return { ancestor, current, other, pathName, output, strict, fallback, checkOnly, exitCode };
+  return {
+    ancestor,
+    current,
+    other,
+    pathName,
+    output,
+    strict,
+    fallback,
+    checkOnly,
+    exitCode,
+    profileId,
+    profileReport,
+    requireProfileStatus
+  };
+}
+
+function reportAndEnforceProfile(
+  profileId: string | undefined,
+  profileReport: boolean,
+  requireStatus: string | undefined,
+  stdout: Pick<NodeJS.WriteStream, 'write'>,
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  if (!profileId && !profileReport && !requireStatus) return exitSuccess;
+  const selectedProfile = profileId ?? promotionProfileJsonKeyedObject;
+  const evaluation = {
+    profile_id: selectedProfile,
+    status: 'available' as ProfilePromotionStatus,
+    blocking_reasons: ['profile promotion evidence is not loaded by this CLI command'],
+    diagnostics: []
+  };
+  const decision = evaluateProfileSelectionRequirement(
+    {
+      profile_id: selectedProfile,
+      promotion_policy_id: initialProfilePromotionPolicy().policy_id,
+      minimum_profile_status: (requireStatus ?? 'available') as ProfilePromotionStatus,
+      enforcement_mode: requireStatus ? 'required' : 'advisory'
+    },
+    undefined,
+    evaluation
+  );
+  if (profileReport) stdout.write(`${JSON.stringify(decision)}\n`);
+  if (!decision.allowed) {
+    stderr.write(`${decision.blocking_reasons[0]}\n`);
+    return exitUserError;
+  }
+  return exitSuccess;
 }
 
 function runDiffDriver(
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 719ec5f..c56e440 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -4,7 +4,7 @@ import path from 'node:path';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
-import { exitSuccess, exitUnresolvedConflict, run } from '../src/cli';
+import { exitSuccess, exitUnresolvedConflict, exitUserError, run } from '../src/cli';
 
 function writer() {
   let output = '';
@@ -114,6 +114,35 @@ describe('smorg-ts cli', () => {
     expect(readFileSync(current, 'utf8')).not.toContain('"other":true');
   });
 
+  it('prints profile report and blocks unmet required profile status', () => {
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.json', '{"name":"structuredmerge","current":true}');
+    const other = write('other.json', '{"name":"structuredmerge","other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      [
+        'merge-driver',
+        '--profile',
+        'json.keyed-object',
+        '--profile-report',
+        '--require-profile-status',
+        'recommended',
+        ancestor,
+        current,
+        other,
+        'package.json'
+      ],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUserError);
+    expect(stdout.output()).toContain('"rejection_code":"profile_status_unmet"');
+    expect(stderr.output()).toContain('profile status available is below required recommended');
+  });
+
   it('supports diff-driver git arities', () => {
     for (const argumentCount of [7, 9]) {
       const oldPath = write(`old-${argumentCount}.json`, '{"old":true}');

From 9f479439e04b8632c5d1870aace331819fea3d50 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 08:48:38 -0600
Subject: [PATCH 085/130] Support profile promotion git attributes

---
 packages/smorg-ts/src/cli.ts       | 22 ++++++++++++++--------
 packages/smorg-ts/test/cli.test.ts | 22 ++++++++++++++++++++++
 2 files changed, 36 insertions(+), 8 deletions(-)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 8cf3781..2f23dfe 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -47,6 +47,8 @@ interface ConflictDiffOptions {
 interface PathSettings {
   language?: string;
   conflictMarkerSize: number;
+  profileId?: string;
+  requireProfileStatus?: string;
 }
 
 interface ConflictRegion {
@@ -104,14 +106,6 @@ function runMergeDriver(
 ): number {
   const options = parseMergeDriverOptions(args, stderr);
   if (!options) return exitUserError;
-  const profileExit = reportAndEnforceProfile(
-    options.profileId,
-    options.profileReport,
-    options.requireProfileStatus,
-    stdout,
-    stderr
-  );
-  if (profileExit !== exitSuccess) return profileExit;
 
   let ancestorSource: string;
   let currentSource: string;
@@ -128,6 +122,14 @@ function runMergeDriver(
 
   const effectivePath = options.pathName ?? options.current;
   const settings = loadPathSettings(effectivePath);
+  const profileExit = reportAndEnforceProfile(
+    options.profileId ?? settings.profileId,
+    options.profileReport,
+    options.requireProfileStatus ?? settings.requireProfileStatus,
+    stdout,
+    stderr
+  );
+  if (profileExit !== exitSuccess) return profileExit;
   const result = mergeByPath(effectivePath, settings.language, otherSource, currentSource);
   let output = result.output;
   if (!result.ok || output === undefined) {
@@ -515,6 +517,10 @@ function applyAttributes(settings: PathSettings, pathName: string, source: strin
       if (!value) continue;
       if (key === 'smorg.language' || key === 'linguist-language') {
         settings.language = value;
+      } else if (key === 'smorg.profile') {
+        settings.profileId = value;
+      } else if (key === 'smorg.requireProfileStatus') {
+        settings.requireProfileStatus = value;
       } else if (key === 'conflict-marker-size') {
         const markerSize = Number.parseInt(value, 10);
         if (markerSize > 0) settings.conflictMarkerSize = markerSize;
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index c56e440..93d645a 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -143,6 +143,28 @@ describe('smorg-ts cli', () => {
     expect(stderr.output()).toContain('profile status available is below required recommended');
   });
 
+  it('uses smorg profile attributes', () => {
+    writeFileSync(
+      '.gitattributes',
+      '*.json smorg.profile=json.keyed-object smorg.requireProfileStatus=recommended\n'
+    );
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.json', '{"name":"structuredmerge","current":true}');
+    const other = write('other.json', '{"name":"structuredmerge","other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', '--profile-report', ancestor, current, other, 'package.json'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUserError);
+    expect(stdout.output()).toContain('"profile_id":"json.keyed-object"');
+    expect(stdout.output()).toContain('"rejection_code":"profile_status_unmet"');
+  });
+
   it('supports diff-driver git arities', () => {
     for (const argumentCount of [7, 9]) {
       const oldPath = write(`old-${argumentCount}.json`, '{"old":true}');

From fd2f2c8f34e6add365d7d6afc19bc4b1e2b1df32 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:13:25 -0600
Subject: [PATCH 086/130] Add ast-crispr package scaffold

---
 packages/ast-crispr/package.json              | 20 +++++
 packages/ast-crispr/src/index.ts              | 81 +++++++++++++++++++
 packages/ast-crispr/test/boundary.test.ts     | 28 +++++++
 .../test/fixtures.integration.test.ts         |  1 -
 pnpm-lock.yaml                                | 21 +++++
 tsconfig.json                                 |  1 +
 6 files changed, 151 insertions(+), 1 deletion(-)
 create mode 100644 packages/ast-crispr/package.json
 create mode 100644 packages/ast-crispr/src/index.ts
 create mode 100644 packages/ast-crispr/test/boundary.test.ts

diff --git a/packages/ast-crispr/package.json b/packages/ast-crispr/package.json
new file mode 100644
index 0000000..d98fb3b
--- /dev/null
+++ b/packages/ast-crispr/package.json
@@ -0,0 +1,20 @@
+{
+  "name": "@structuredmerge/ast-crispr",
+  "version": "0.2.0",
+  "private": false,
+  "type": "module",
+  "main": "./src/index.ts",
+  "author": "Peter H. Boling",
+  "homepage": "https://structuredmerge.org",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/structuredmerge/structuredmerge-typescript.git"
+  },
+  "bugs": {
+    "url": "https://github.com/structuredmerge/structuredmerge-typescript/issues"
+  },
+  "dependencies": {
+    "@structuredmerge/ast-merge": "workspace:*"
+  }
+}
+
diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
new file mode 100644
index 0000000..124c346
--- /dev/null
+++ b/packages/ast-crispr/src/index.ts
@@ -0,0 +1,81 @@
+import type { StructuredEditCrisprExampleParityReport } from '@structuredmerge/ast-merge';
+
+export const packageName = '@structuredmerge/ast-crispr';
+
+export function astMergeContractAnchor(): string {
+  const _anchor: StructuredEditCrisprExampleParityReport | null = null;
+  void _anchor;
+  return 'StructuredEditCrisprExampleParityReport';
+}
+
+export function boundaryReport(): Readonly<Record<string, unknown>> {
+  return {
+    package: 'ast-crispr',
+    layer: 'structural_edit_tool',
+    status: 'active_thin_package',
+    base_contract_package: 'ast-merge',
+    relationship: {
+      ast_merge: [
+        'owns portable structured-edit envelope contracts',
+        'owns transport, report, replay, review, and provider handoff vocabulary',
+        'remains the substrate for provider-neutral fixtures'
+      ],
+      ast_crispr: [
+        'owns ergonomic structural-edit selectors, profiles, and operation helpers',
+        'wraps ast-merge contracts instead of forking them',
+        'may grow compatibility helpers for old ast-crispr concepts after fixture-backed review'
+      ],
+      provider_packages: [
+        'own parser-specific execution and metadata projection',
+        'may expose provider adapters consumed by ast-crispr',
+        'keep raw parser details behind normalized tree metadata or semantic sidecars'
+      ],
+      ast_template: [
+        'orchestrates template and directory workflows',
+        'invokes structural edits through ast-merge or ast-crispr registries/envelopes',
+        'does not own parser-specific selectors'
+      ]
+    },
+    implementations: [
+      {
+        language: 'go',
+        package_name: 'astcrispr',
+        import: 'github.com/structuredmerge/structuredmerge-go/astcrispr'
+      },
+      {
+        language: 'ruby',
+        package_name: 'ast-crispr',
+        require: 'ast/crispr'
+      },
+      {
+        language: 'rust',
+        package_name: 'ast-crispr',
+        crate: 'ast_crispr'
+      },
+      {
+        language: 'typescript',
+        package_name: '@structuredmerge/ast-crispr',
+        import: '@structuredmerge/ast-crispr'
+      }
+    ],
+    initial_exports: [
+      'package identity',
+      'boundary report',
+      'ast-merge structured-edit contract anchor'
+    ],
+    future_exports: [
+      'limit helpers',
+      'match profile helpers',
+      'selection profile helpers',
+      'destination profile helpers',
+      'operation profile helpers',
+      'replace/delete/insert/move helpers',
+      'batch operation helpers'
+    ],
+    metadata: {
+      source: 'legacy_crispr_reference',
+      decision:
+        'Keep ast-merge as the base contract layer and revive ast-crispr as a separate thin package in every implementation.'
+    }
+  };
+}
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
new file mode 100644
index 0000000..7d1b922
--- /dev/null
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -0,0 +1,28 @@
+import { readFileSync } from 'node:fs';
+import path from 'node:path';
+import { describe, expect, it } from 'vitest';
+import { astMergeContractAnchor, boundaryReport } from '../src/index';
+
+interface BoundaryFixture {
+  boundary: Readonly<Record<string, unknown>>;
+}
+
+function readFixture(): BoundaryFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-916-ast-crispr-package-boundary',
+    'ast-crispr-package-boundary.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as BoundaryFixture;
+}
+
+describe('@structuredmerge/ast-crispr', () => {
+  it('conforms to the package boundary fixture', () => {
+    expect(boundaryReport()).toEqual(readFixture().boundary);
+    expect(astMergeContractAnchor()).toBe('StructuredEditCrisprExampleParityReport');
+  });
+});
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 4d0af6d..0446be2 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -228,7 +228,6 @@ import type {
   StructuredEditKettleJemPrimitiveGapReport,
   StructuredEditExecutionReport,
   StructuredEditExecutionReportEnvelope,
-  ProfileSelectionRequirement,
   PolicyReference,
   PolicySurface,
   Diagnostic,
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 20ec660..a6f711b 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -39,6 +39,12 @@ importers:
         specifier: ^3.2.4
         version: 3.2.4(@types/node@24.12.2)(yaml@2.8.3)
 
+  packages/ast-crispr:
+    dependencies:
+      '@structuredmerge/ast-merge':
+        specifier: workspace:*
+        version: link:../ast-merge
+
   packages/ast-merge:
     devDependencies:
       '@structuredmerge/markdown-merge':
@@ -174,6 +180,21 @@ importers:
         specifier: workspace:*
         version: link:../tree-haver
 
+  packages/smorg-ts:
+    dependencies:
+      '@structuredmerge/ast-merge':
+        specifier: workspace:*
+        version: link:../ast-merge
+      '@structuredmerge/go-merge':
+        specifier: workspace:*
+        version: link:../go-merge
+      '@structuredmerge/json-merge':
+        specifier: workspace:*
+        version: link:../json-merge
+      '@structuredmerge/plain-merge':
+        specifier: workspace:*
+        version: link:../plain-merge
+
   packages/toml-merge:
     dependencies:
       '@structuredmerge/ast-merge':
diff --git a/tsconfig.json b/tsconfig.json
index b966149..595ab0e 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,6 +5,7 @@
     "noEmit": true,
     "paths": {
       "@structuredmerge/ast-merge": ["./packages/ast-merge/src/index.ts"],
+      "@structuredmerge/ast-crispr": ["./packages/ast-crispr/src/index.ts"],
       "@structuredmerge/tree-haver": ["./packages/tree-haver/src/index.ts"],
       "@structuredmerge/plain-merge": ["./packages/plain-merge/src/index.ts"],
       "@structuredmerge/json-merge": ["./packages/json-merge/src/index.ts"],

From f44490060a5d4141e1cc1f98c1eb5b4912a400a2 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:30:47 -0600
Subject: [PATCH 087/130] Add ast-crispr limit helpers

---
 packages/ast-crispr/src/index.ts          | 120 +++++++++++++++++++++-
 packages/ast-crispr/test/boundary.test.ts |  50 ++++++++-
 2 files changed, 167 insertions(+), 3 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index 124c346..bb89be1 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -2,6 +2,122 @@ import type { StructuredEditCrisprExampleParityReport } from '@structuredmerge/a
 
 export const packageName = '@structuredmerge/ast-crispr';
 
+export class AstCrisprError extends Error {
+  readonly code: string;
+
+  constructor(message: string, code: string) {
+    super(message);
+    this.name = 'AstCrisprError';
+    this.code = code;
+  }
+}
+
+type Predicate = (count: number) => boolean;
+
+interface LimitConstraint {
+  readonly description: string;
+  readonly predicate: Predicate;
+}
+
+export class Limit {
+  private readonly constraints: readonly LimitConstraint[];
+
+  constructor(spec: unknown = null) {
+    this.constraints = normalizeLimit(spec === null || spec === undefined ? { exactly: 1 } : spec);
+  }
+
+  allows(count: number): boolean {
+    return this.constraints.every((constraint) => constraint.predicate(count));
+  }
+
+  describe(): string {
+    return this.constraints.map((constraint) => constraint.description).join(' and ');
+  }
+}
+
+export function limit(spec: unknown = null): Limit {
+  return spec instanceof Limit ? spec : new Limit(spec);
+}
+
+function normalizeLimit(spec: unknown): readonly LimitConstraint[] {
+  if (spec instanceof Limit) {
+    return normalizeLimit({ exactly: 1 });
+  }
+  if (Array.isArray(spec)) {
+    return spec.flatMap((entry) => normalizeLimit(entry));
+  }
+  if (typeof spec === 'string') {
+    return [constraintForOperator(spec)];
+  }
+  if (spec && typeof spec === 'object') {
+    return normalizeLimitRecord(spec as Readonly<Record<string, unknown>>);
+  }
+  throw new AstCrisprError(
+    'Unsupported ast-crispr limit specification',
+    'ast_crispr_limit_unsupported'
+  );
+}
+
+function normalizeLimitRecord(spec: Readonly<Record<string, unknown>>): readonly LimitConstraint[] {
+  const constraints: LimitConstraint[] = [];
+  if (typeof spec.exactly === 'number') {
+    const value = spec.exactly;
+    constraints.push({ description: `== ${value}`, predicate: (count) => count === value });
+  }
+  if (typeof spec.at_most === 'number') {
+    const value = spec.at_most;
+    constraints.push({ description: `<= ${value}`, predicate: (count) => count <= value });
+  }
+  if (typeof spec.at_least === 'number') {
+    const value = spec.at_least;
+    constraints.push({ description: `>= ${value}`, predicate: (count) => count >= value });
+  }
+  if (spec.none_or_one === true) {
+    constraints.push({ description: '<= 1', predicate: (count) => count <= 1 });
+  }
+  if (constraints.length === 0) {
+    throw new AstCrisprError(
+      'ast-crispr limit must define at least one constraint',
+      'ast_crispr_limit_empty'
+    );
+  }
+
+  return constraints;
+}
+
+function constraintForOperator(spec: string): LimitConstraint {
+  const match = /^(==|!=|<=|>=|<|>)\s*(\d+)$/u.exec(spec.trim());
+  if (!match) {
+    throw new AstCrisprError(
+      'Invalid ast-crispr limit expression',
+      'ast_crispr_limit_invalid_expression'
+    );
+  }
+  const operator = match[1];
+  const value = Number.parseInt(match[2], 10);
+  return {
+    description: `${operator} ${value}`,
+    predicate: (count) => {
+      switch (operator) {
+        case '==':
+          return count === value;
+        case '!=':
+          return count !== value;
+        case '<=':
+          return count <= value;
+        case '>=':
+          return count >= value;
+        case '<':
+          return count < value;
+        case '>':
+          return count > value;
+        default:
+          return false;
+      }
+    }
+  };
+}
+
 export function astMergeContractAnchor(): string {
   const _anchor: StructuredEditCrisprExampleParityReport | null = null;
   void _anchor;
@@ -61,10 +177,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
     initial_exports: [
       'package identity',
       'boundary report',
-      'ast-merge structured-edit contract anchor'
+      'ast-merge structured-edit contract anchor',
+      'limit helpers'
     ],
     future_exports: [
-      'limit helpers',
       'match profile helpers',
       'selection profile helpers',
       'destination profile helpers',
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index 7d1b922..b30a88e 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -1,7 +1,7 @@
 import { readFileSync } from 'node:fs';
 import path from 'node:path';
 import { describe, expect, it } from 'vitest';
-import { astMergeContractAnchor, boundaryReport } from '../src/index';
+import { AstCrisprError, Limit, astMergeContractAnchor, boundaryReport } from '../src/index';
 
 interface BoundaryFixture {
   boundary: Readonly<Record<string, unknown>>;
@@ -20,9 +20,57 @@ function readFixture(): BoundaryFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as BoundaryFixture;
 }
 
+interface LimitFixture {
+  cases: Array<{
+    name: string;
+    spec: unknown;
+    expected_description: string;
+    expectations: Array<{ count: number; allowed: boolean }>;
+  }>;
+  invalid_cases: Array<{
+    name: string;
+    spec: unknown;
+    expected_error: string;
+  }>;
+}
+
+function readLimitFixture(): LimitFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-917-ast-crispr-limit-helpers',
+    'ast-crispr-limit-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as LimitFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
     expect(astMergeContractAnchor()).toBe('StructuredEditCrisprExampleParityReport');
   });
+
+  it('conforms to the limit helper fixture', () => {
+    const fixture = readLimitFixture();
+
+    for (const testCase of fixture.cases) {
+      const limit = new Limit(testCase.spec);
+      expect(limit.describe()).toBe(testCase.expected_description);
+      for (const expectation of testCase.expectations) {
+        expect(limit.allows(expectation.count)).toBe(expectation.allowed);
+      }
+    }
+
+    for (const testCase of fixture.invalid_cases) {
+      expect(() => new Limit(testCase.spec)).toThrow(AstCrisprError);
+      try {
+        new Limit(testCase.spec);
+      } catch (error) {
+        expect((error as AstCrisprError).code).toBe(testCase.expected_error);
+      }
+    }
+  });
 });

From db38552e53b041c8f73c77310c7b462eddfb61db Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:34:27 -0600
Subject: [PATCH 088/130] Add ast-crispr match profile helpers

---
 packages/ast-crispr/src/index.ts          | 81 ++++++++++++++++++++++-
 packages/ast-crispr/test/boundary.test.ts | 41 +++++++++++-
 2 files changed, 119 insertions(+), 3 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index bb89be1..7fb4941 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -35,6 +35,83 @@ export class Limit {
   }
 }
 
+export interface MatchProfileReport {
+  readonly start_boundary: string;
+  readonly start_boundary_family: string;
+  readonly known_start_boundary: boolean;
+  readonly end_boundary: string;
+  readonly end_boundary_family: string;
+  readonly known_end_boundary: boolean;
+  readonly payload_kind: string;
+  readonly payload_family: string;
+  readonly known_payload_kind: boolean;
+  readonly comment_anchored: boolean;
+  readonly trailing_gap_extended: boolean;
+}
+
+interface ProfileDescriptor {
+  readonly family: string;
+}
+
+const KNOWN_START_BOUNDARIES: Readonly<Record<string, ProfileDescriptor>> = {
+  owner_start: { family: 'structural_owner' },
+  comment_region_start: { family: 'comment_anchor' }
+};
+
+const KNOWN_END_BOUNDARIES: Readonly<Record<string, ProfileDescriptor>> = {
+  owner_end: { family: 'structural_owner' },
+  owner_end_plus_trailing_gap: { family: 'gap_extension' }
+};
+
+const KNOWN_PAYLOAD_KINDS: Readonly<Record<string, ProfileDescriptor>> = {
+  structural_owner_body: { family: 'owner_body' },
+  comment_owned_body: { family: 'comment_owned' },
+  section_branch: { family: 'section_branch' }
+};
+
+export class MatchProfile {
+  readonly startBoundary: string;
+  readonly endBoundary: string;
+  readonly payloadKind: string;
+
+  constructor({
+    start_boundary = 'owner_start',
+    end_boundary = 'owner_end',
+    payload_kind = 'structural_owner_body'
+  }: {
+    readonly start_boundary?: string;
+    readonly end_boundary?: string;
+    readonly payload_kind?: string;
+  } = {}) {
+    this.startBoundary = start_boundary;
+    this.endBoundary = end_boundary;
+    this.payloadKind = payload_kind;
+  }
+
+  report(): MatchProfileReport {
+    const startFamily = KNOWN_START_BOUNDARIES[this.startBoundary]?.family ?? 'unknown';
+    const endFamily = KNOWN_END_BOUNDARIES[this.endBoundary]?.family ?? 'unknown';
+    const payloadFamily = KNOWN_PAYLOAD_KINDS[this.payloadKind]?.family ?? 'unknown';
+    return {
+      start_boundary: this.startBoundary,
+      start_boundary_family: startFamily,
+      known_start_boundary: this.startBoundary in KNOWN_START_BOUNDARIES,
+      end_boundary: this.endBoundary,
+      end_boundary_family: endFamily,
+      known_end_boundary: this.endBoundary in KNOWN_END_BOUNDARIES,
+      payload_kind: this.payloadKind,
+      payload_family: payloadFamily,
+      known_payload_kind: this.payloadKind in KNOWN_PAYLOAD_KINDS,
+      comment_anchored: startFamily === 'comment_anchor' || payloadFamily === 'comment_owned',
+      trailing_gap_extended: endFamily === 'gap_extension'
+    };
+  }
+}
+
+export function matchProfile(profile: ConstructorParameters<typeof MatchProfile>[0]): MatchProfile {
+  return new MatchProfile(profile);
+}
+
 export function limit(spec: unknown = null): Limit {
   return spec instanceof Limit ? spec : new Limit(spec);
 }
@@ -178,10 +255,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
       'package identity',
       'boundary report',
       'ast-merge structured-edit contract anchor',
-      'limit helpers'
+      'limit helpers',
+      'match profile helpers'
     ],
     future_exports: [
-      'match profile helpers',
       'selection profile helpers',
       'destination profile helpers',
       'operation profile helpers',
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index b30a88e..ee21e7a 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -1,7 +1,13 @@
 import { readFileSync } from 'node:fs';
 import path from 'node:path';
 import { describe, expect, it } from 'vitest';
-import { AstCrisprError, Limit, astMergeContractAnchor, boundaryReport } from '../src/index';
+import {
+  AstCrisprError,
+  Limit,
+  MatchProfile,
+  astMergeContractAnchor,
+  boundaryReport
+} from '../src/index';
 
 interface BoundaryFixture {
   boundary: Readonly<Record<string, unknown>>;
@@ -47,6 +53,31 @@ function readLimitFixture(): LimitFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as LimitFixture;
 }
 
+interface MatchProfileFixture {
+  cases: Array<{
+    name: string;
+    profile: {
+      start_boundary: string;
+      end_boundary: string;
+      payload_kind: string;
+    };
+    expected: Readonly<Record<string, unknown>>;
+  }>;
+}
+
+function readMatchProfileFixture(): MatchProfileFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-918-ast-crispr-match-profile-helpers',
+    'ast-crispr-match-profile-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as MatchProfileFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
@@ -73,4 +104,12 @@ describe('@structuredmerge/ast-crispr', () => {
       }
     }
   });
+
+  it('conforms to the match profile helper fixture', () => {
+    const fixture = readMatchProfileFixture();
+
+    for (const testCase of fixture.cases) {
+      expect(new MatchProfile(testCase.profile).report()).toEqual(testCase.expected);
+    }
+  });
 });

From 6a585cc6580a4b44c6d7aca3d09423d2801b69ce Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:38:35 -0600
Subject: [PATCH 089/130] Add ast-crispr selection profile helpers

---
 packages/ast-crispr/src/index.ts          | 116 +++++++++++++++++++++-
 packages/ast-crispr/test/boundary.test.ts |  30 ++++++
 2 files changed, 144 insertions(+), 2 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index 7fb4941..57430be 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -49,6 +49,24 @@ export interface MatchProfileReport {
   readonly trailing_gap_extended: boolean;
 }
 
+export interface SelectionProfileReport {
+  readonly owner_scope: string;
+  readonly owner_selector: string;
+  readonly owner_selector_family: string;
+  readonly known_owner_selector: boolean;
+  readonly selector_kind: string;
+  readonly selector_kind_family: string;
+  readonly known_selector_kind: boolean;
+  readonly selection_intent: string;
+  readonly selection_intent_family: string;
+  readonly known_selection_intent: boolean;
+  readonly comment_region: string | null;
+  readonly comment_region_family: string;
+  readonly known_comment_region: boolean;
+  readonly comment_anchored: boolean;
+  readonly include_trailing_gap: boolean;
+}
+
 interface ProfileDescriptor {
   readonly family: string;
 }
@@ -69,6 +87,29 @@ const KNOWN_PAYLOAD_KINDS: Readonly<Record<string, ProfileDescriptor>> = {
   section_branch: { family: 'section_branch' }
 };
 
+const KNOWN_OWNER_SELECTORS: Readonly<Record<string, ProfileDescriptor>> = {
+  line_bound_statements: { family: 'line_oriented' },
+  heading_sections: { family: 'section' }
+};
+
+const KNOWN_SELECTOR_KINDS: Readonly<Record<string, ProfileDescriptor>> = {
+  owner_filter: { family: 'owner_filter' },
+  comment_region_owner: { family: 'comment_anchor' },
+  heading_section: { family: 'section_branch' }
+};
+
+const KNOWN_SELECTION_INTENTS: Readonly<Record<string, ProfileDescriptor>> = {
+  predicate_filter: { family: 'predicate' },
+  comment_region_filter: { family: 'comment' },
+  section_heading: { family: 'section' }
+};
+
+const KNOWN_COMMENT_REGIONS: Readonly<Record<string, ProfileDescriptor>> = {
+  leading: { family: 'leading' },
+  trailing: { family: 'trailing' },
+  inline: { family: 'inline' }
+};
+
 export class MatchProfile {
   readonly startBoundary: string;
   readonly endBoundary: string;
@@ -108,10 +149,81 @@ export class MatchProfile {
   }
 }
 
+export class SelectionProfile {
+  readonly ownerScope: string;
+  readonly ownerSelector: string;
+  readonly selectorKind: string;
+  readonly selectionIntent: string;
+  readonly commentRegion: string | null;
+  readonly includeTrailingGap: boolean;
+
+  constructor({
+    owner_scope = 'shared_default',
+    owner_selector = 'line_bound_statements',
+    selector_kind = 'owner_filter',
+    selection_intent = 'predicate_filter',
+    comment_region = null,
+    include_trailing_gap = false
+  }: {
+    readonly owner_scope?: string;
+    readonly owner_selector?: string;
+    readonly selector_kind?: string;
+    readonly selection_intent?: string;
+    readonly comment_region?: string | null;
+    readonly include_trailing_gap?: boolean;
+  } = {}) {
+    this.ownerScope = owner_scope;
+    this.ownerSelector = owner_selector;
+    this.selectorKind = selector_kind;
+    this.selectionIntent = selection_intent;
+    this.commentRegion = comment_region;
+    this.includeTrailingGap = include_trailing_gap;
+  }
+
+  report(): SelectionProfileReport {
+    const ownerSelectorFamily = KNOWN_OWNER_SELECTORS[this.ownerSelector]?.family ?? 'unknown';
+    const selectorKindFamily = KNOWN_SELECTOR_KINDS[this.selectorKind]?.family ?? 'unknown';
+    const selectionIntentFamily =
+      KNOWN_SELECTION_INTENTS[this.selectionIntent]?.family ?? 'unknown';
+    const commentRegionFamily =
+      this.commentRegion === null
+        ? 'none'
+        : (KNOWN_COMMENT_REGIONS[this.commentRegion]?.family ?? 'unknown');
+    const knownCommentRegion =
+      this.commentRegion !== null && this.commentRegion in KNOWN_COMMENT_REGIONS;
+    return {
+      owner_scope: this.ownerScope,
+      owner_selector: this.ownerSelector,
+      owner_selector_family: ownerSelectorFamily,
+      known_owner_selector: this.ownerSelector in KNOWN_OWNER_SELECTORS,
+      selector_kind: this.selectorKind,
+      selector_kind_family: selectorKindFamily,
+      known_selector_kind: this.selectorKind in KNOWN_SELECTOR_KINDS,
+      selection_intent: this.selectionIntent,
+      selection_intent_family: selectionIntentFamily,
+      known_selection_intent: this.selectionIntent in KNOWN_SELECTION_INTENTS,
+      comment_region: this.commentRegion,
+      comment_region_family: commentRegionFamily,
+      known_comment_region: knownCommentRegion,
+      comment_anchored:
+        selectorKindFamily === 'comment_anchor' ||
+        selectionIntentFamily === 'comment' ||
+        knownCommentRegion,
+      include_trailing_gap: this.includeTrailingGap
+    };
+  }
+}
+
 export function matchProfile(profile: ConstructorParameters<typeof MatchProfile>[0]): MatchProfile {
   return new MatchProfile(profile);
 }
 
+export function selectionProfile(
+  profile: ConstructorParameters<typeof SelectionProfile>[0]
+): SelectionProfile {
+  return new SelectionProfile(profile);
+}
+
 export function limit(spec: unknown = null): Limit {
   return spec instanceof Limit ? spec : new Limit(spec);
 }
@@ -256,10 +368,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
       'boundary report',
       'ast-merge structured-edit contract anchor',
       'limit helpers',
-      'match profile helpers'
+      'match profile helpers',
+      'selection profile helpers'
     ],
     future_exports: [
-      'selection profile helpers',
       'destination profile helpers',
       'operation profile helpers',
       'replace/delete/insert/move helpers',
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index ee21e7a..a3015c3 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -5,6 +5,7 @@ import {
   AstCrisprError,
   Limit,
   MatchProfile,
+  SelectionProfile,
   astMergeContractAnchor,
   boundaryReport
 } from '../src/index';
@@ -78,6 +79,27 @@ function readMatchProfileFixture(): MatchProfileFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as MatchProfileFixture;
 }
 
+interface SelectionProfileFixture {
+  cases: Array<{
+    name: string;
+    profile: ConstructorParameters<typeof SelectionProfile>[0];
+    expected: Readonly<Record<string, unknown>>;
+  }>;
+}
+
+function readSelectionProfileFixture(): SelectionProfileFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-919-ast-crispr-selection-profile-helpers',
+    'ast-crispr-selection-profile-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as SelectionProfileFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
@@ -112,4 +134,12 @@ describe('@structuredmerge/ast-crispr', () => {
       expect(new MatchProfile(testCase.profile).report()).toEqual(testCase.expected);
     }
   });
+
+  it('conforms to the selection profile helper fixture', () => {
+    const fixture = readSelectionProfileFixture();
+
+    for (const testCase of fixture.cases) {
+      expect(new SelectionProfile(testCase.profile).report()).toEqual(testCase.expected);
+    }
+  });
 });

From c304205bf9c773a03aa5cbec51ddcf1a0e0e6085 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:41:59 -0600
Subject: [PATCH 090/130] Add ast-crispr destination profile helpers

---
 packages/ast-crispr/src/index.ts          | 86 ++++++++++++++++++++++-
 packages/ast-crispr/test/boundary.test.ts | 30 ++++++++
 2 files changed, 114 insertions(+), 2 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index 57430be..3186c1f 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -67,6 +67,21 @@ export interface SelectionProfileReport {
   readonly include_trailing_gap: boolean;
 }
 
+export interface DestinationProfileReport {
+  readonly resolution_kind: string;
+  readonly resolution_family: string;
+  readonly known_resolution_kind: boolean;
+  readonly resolution_source: string;
+  readonly resolution_source_family: string;
+  readonly known_resolution_source: boolean;
+  readonly anchor_boundary: string;
+  readonly anchor_boundary_family: string;
+  readonly known_anchor_boundary: boolean;
+  readonly used_if_missing: boolean;
+  readonly append_fallback: boolean;
+  readonly anchored: boolean;
+}
+
 interface ProfileDescriptor {
   readonly family: string;
 }
@@ -110,6 +125,22 @@ const KNOWN_COMMENT_REGIONS: Readonly<Record<string, ProfileDescriptor>> = {
   inline: { family: 'inline' }
 };
 
+const KNOWN_RESOLUTION_KINDS: Readonly<Record<string, ProfileDescriptor>> = {
+  append_fallback: { family: 'append' },
+  anchor_after_statement: { family: 'anchored' }
+};
+
+const KNOWN_RESOLUTION_SOURCES: Readonly<Record<string, ProfileDescriptor>> = {
+  none: { family: 'implicit' },
+  callable: { family: 'callable' },
+  selector: { family: 'selector' }
+};
+
+const KNOWN_ANCHOR_BOUNDARIES: Readonly<Record<string, ProfileDescriptor>> = {
+  none: { family: 'none' },
+  statement_end_plus_following_gap: { family: 'gap_preserving_statement' }
+};
+
 export class MatchProfile {
   readonly startBoundary: string;
   readonly endBoundary: string;
@@ -214,10 +245,61 @@ export class SelectionProfile {
   }
 }
 
+export class DestinationProfile {
+  readonly resolutionKind: string;
+  readonly resolutionSource: string;
+  readonly anchorBoundary: string;
+  readonly usedIfMissing: boolean;
+
+  constructor({
+    resolution_kind = 'append_fallback',
+    resolution_source = 'none',
+    anchor_boundary = 'none',
+    used_if_missing = false
+  }: {
+    readonly resolution_kind?: string;
+    readonly resolution_source?: string;
+    readonly anchor_boundary?: string;
+    readonly used_if_missing?: boolean;
+  } = {}) {
+    this.resolutionKind = resolution_kind;
+    this.resolutionSource = resolution_source;
+    this.anchorBoundary = anchor_boundary;
+    this.usedIfMissing = used_if_missing;
+  }
+
+  report(): DestinationProfileReport {
+    const resolutionFamily = KNOWN_RESOLUTION_KINDS[this.resolutionKind]?.family ?? 'unknown';
+    const resolutionSourceFamily =
+      KNOWN_RESOLUTION_SOURCES[this.resolutionSource]?.family ?? 'unknown';
+    const anchorBoundaryFamily = KNOWN_ANCHOR_BOUNDARIES[this.anchorBoundary]?.family ?? 'unknown';
+    return {
+      resolution_kind: this.resolutionKind,
+      resolution_family: resolutionFamily,
+      known_resolution_kind: this.resolutionKind in KNOWN_RESOLUTION_KINDS,
+      resolution_source: this.resolutionSource,
+      resolution_source_family: resolutionSourceFamily,
+      known_resolution_source: this.resolutionSource in KNOWN_RESOLUTION_SOURCES,
+      anchor_boundary: this.anchorBoundary,
+      anchor_boundary_family: anchorBoundaryFamily,
+      known_anchor_boundary: this.anchorBoundary in KNOWN_ANCHOR_BOUNDARIES,
+      used_if_missing: this.usedIfMissing,
+      append_fallback: this.resolutionKind === 'append_fallback',
+      anchored: resolutionFamily === 'anchored'
+    };
+  }
+}
+
 export function matchProfile(profile: ConstructorParameters<typeof MatchProfile>[0]): MatchProfile {
   return new MatchProfile(profile);
 }
 
+export function destinationProfile(
+  profile: ConstructorParameters<typeof DestinationProfile>[0]
+): DestinationProfile {
+  return new DestinationProfile(profile);
+}
+
 export function selectionProfile(
   profile: ConstructorParameters<typeof SelectionProfile>[0]
 ): SelectionProfile {
@@ -369,10 +451,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
       'ast-merge structured-edit contract anchor',
       'limit helpers',
       'match profile helpers',
-      'selection profile helpers'
+      'selection profile helpers',
+      'destination profile helpers'
     ],
     future_exports: [
-      'destination profile helpers',
       'operation profile helpers',
       'replace/delete/insert/move helpers',
       'batch operation helpers'
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index a3015c3..564d639 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -3,6 +3,7 @@ import path from 'node:path';
 import { describe, expect, it } from 'vitest';
 import {
   AstCrisprError,
+  DestinationProfile,
   Limit,
   MatchProfile,
   SelectionProfile,
@@ -100,6 +101,27 @@ function readSelectionProfileFixture(): SelectionProfileFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as SelectionProfileFixture;
 }
 
+interface DestinationProfileFixture {
+  cases: Array<{
+    name: string;
+    profile: ConstructorParameters<typeof DestinationProfile>[0];
+    expected: Readonly<Record<string, unknown>>;
+  }>;
+}
+
+function readDestinationProfileFixture(): DestinationProfileFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-920-ast-crispr-destination-profile-helpers',
+    'ast-crispr-destination-profile-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as DestinationProfileFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
@@ -142,4 +164,12 @@ describe('@structuredmerge/ast-crispr', () => {
       expect(new SelectionProfile(testCase.profile).report()).toEqual(testCase.expected);
     }
   });
+
+  it('conforms to the destination profile helper fixture', () => {
+    const fixture = readDestinationProfileFixture();
+
+    for (const testCase of fixture.cases) {
+      expect(new DestinationProfile(testCase.profile).report()).toEqual(testCase.expected);
+    }
+  });
 });

From 6e5b1e709498e4813df776b6397d1df6992c4bdf Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:45:03 -0600
Subject: [PATCH 091/130] Add ast-crispr operation profile helpers

---
 packages/ast-crispr/src/index.ts          | 100 ++++++++++++++++++++--
 packages/ast-crispr/test/boundary.test.ts |  30 +++++++
 2 files changed, 124 insertions(+), 6 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index 3186c1f..ca643a4 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -82,6 +82,26 @@ export interface DestinationProfileReport {
   readonly anchored: boolean;
 }
 
+export interface OperationProfileReport {
+  readonly operation_kind: string;
+  readonly operation_family: string;
+  readonly known_operation_kind: boolean;
+  readonly source_requirement: string;
+  readonly known_source_requirement: boolean;
+  readonly destination_requirement: string;
+  readonly known_destination_requirement: boolean;
+  readonly replacement_source: string;
+  readonly known_replacement_source: boolean;
+  readonly captures_source_text: boolean;
+  readonly supports_if_missing: boolean;
+  readonly selects_source: boolean;
+  readonly requires_source: boolean;
+  readonly supports_destination: boolean;
+  readonly requires_destination: boolean;
+  readonly explicit_replacement: boolean;
+  readonly may_reuse_captured_text: boolean;
+}
+
 interface ProfileDescriptor {
   readonly family: string;
 }
@@ -141,6 +161,16 @@ const KNOWN_ANCHOR_BOUNDARIES: Readonly<Record<string, ProfileDescriptor>> = {
   statement_end_plus_following_gap: { family: 'gap_preserving_statement' }
 };
 
+const KNOWN_OPERATION_KINDS: Readonly<Record<string, ProfileDescriptor>> = {
+  replace: { family: 'rewrite' },
+  delete: { family: 'removal' },
+  insert: { family: 'insertion' },
+  move: { family: 'relocation' }
+};
+
+const KNOWN_REQUIREMENTS = new Set(['none', 'optional', 'required']);
+const KNOWN_REPLACEMENT_SOURCES = new Set(['none', 'explicit_text', 'captured_text_or_explicit']);
+
 export class MatchProfile {
   readonly startBoundary: string;
   readonly endBoundary: string;
@@ -290,6 +320,61 @@ export class DestinationProfile {
   }
 }
 
+export class OperationProfile {
+  readonly operationKind: string;
+  readonly sourceRequirement: string;
+  readonly destinationRequirement: string;
+  readonly replacementSource: string;
+  readonly capturesSourceText: boolean;
+  readonly supportsIfMissing: boolean;
+
+  constructor({
+    operation_kind = 'replace',
+    source_requirement = 'required',
+    destination_requirement = 'none',
+    replacement_source = 'explicit_text',
+    captures_source_text = false,
+    supports_if_missing = false
+  }: {
+    readonly operation_kind?: string;
+    readonly source_requirement?: string;
+    readonly destination_requirement?: string;
+    readonly replacement_source?: string;
+    readonly captures_source_text?: boolean;
+    readonly supports_if_missing?: boolean;
+  } = {}) {
+    this.operationKind = operation_kind;
+    this.sourceRequirement = source_requirement;
+    this.destinationRequirement = destination_requirement;
+    this.replacementSource = replacement_source;
+    this.capturesSourceText = captures_source_text;
+    this.supportsIfMissing = supports_if_missing;
+  }
+
+  report(): OperationProfileReport {
+    const operationFamily = KNOWN_OPERATION_KINDS[this.operationKind]?.family ?? 'unknown';
+    return {
+      operation_kind: this.operationKind,
+      operation_family: operationFamily,
+      known_operation_kind: this.operationKind in KNOWN_OPERATION_KINDS,
+      source_requirement: this.sourceRequirement,
+      known_source_requirement: KNOWN_REQUIREMENTS.has(this.sourceRequirement),
+      destination_requirement: this.destinationRequirement,
+      known_destination_requirement: KNOWN_REQUIREMENTS.has(this.destinationRequirement),
+      replacement_source: this.replacementSource,
+      known_replacement_source: KNOWN_REPLACEMENT_SOURCES.has(this.replacementSource),
+      captures_source_text: this.capturesSourceText,
+      supports_if_missing: this.supportsIfMissing,
+      selects_source: this.sourceRequirement !== 'none',
+      requires_source: this.sourceRequirement === 'required',
+      supports_destination: this.destinationRequirement !== 'none',
+      requires_destination: this.destinationRequirement === 'required',
+      explicit_replacement: this.replacementSource === 'explicit_text',
+      may_reuse_captured_text: this.replacementSource === 'captured_text_or_explicit'
+    };
+  }
+}
+
 export function matchProfile(profile: ConstructorParameters<typeof MatchProfile>[0]): MatchProfile {
   return new MatchProfile(profile);
 }
@@ -300,6 +385,12 @@ export function destinationProfile(
   return new DestinationProfile(profile);
 }
 
+export function operationProfile(
+  profile: ConstructorParameters<typeof OperationProfile>[0]
+): OperationProfile {
+  return new OperationProfile(profile);
+}
+
 export function selectionProfile(
   profile: ConstructorParameters<typeof SelectionProfile>[0]
 ): SelectionProfile {
@@ -452,13 +543,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
       'limit helpers',
       'match profile helpers',
       'selection profile helpers',
-      'destination profile helpers'
-    ],
-    future_exports: [
-      'operation profile helpers',
-      'replace/delete/insert/move helpers',
-      'batch operation helpers'
+      'destination profile helpers',
+      'operation profile helpers'
     ],
+    future_exports: ['replace/delete/insert/move helpers', 'batch operation helpers'],
     metadata: {
       source: 'legacy_crispr_reference',
       decision:
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index 564d639..81d89ff 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -6,6 +6,7 @@ import {
   DestinationProfile,
   Limit,
   MatchProfile,
+  OperationProfile,
   SelectionProfile,
   astMergeContractAnchor,
   boundaryReport
@@ -122,6 +123,27 @@ function readDestinationProfileFixture(): DestinationProfileFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as DestinationProfileFixture;
 }
 
+interface OperationProfileFixture {
+  cases: Array<{
+    name: string;
+    profile: ConstructorParameters<typeof OperationProfile>[0];
+    expected: Readonly<Record<string, unknown>>;
+  }>;
+}
+
+function readOperationProfileFixture(): OperationProfileFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-921-ast-crispr-operation-profile-helpers',
+    'ast-crispr-operation-profile-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as OperationProfileFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
@@ -172,4 +194,12 @@ describe('@structuredmerge/ast-crispr', () => {
       expect(new DestinationProfile(testCase.profile).report()).toEqual(testCase.expected);
     }
   });
+
+  it('conforms to the operation profile helper fixture', () => {
+    const fixture = readOperationProfileFixture();
+
+    for (const testCase of fixture.cases) {
+      expect(new OperationProfile(testCase.profile).report()).toEqual(testCase.expected);
+    }
+  });
 });

From b1cff161c6fbd01c4accb3d38e6e2816d7bb66bc Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:48:07 -0600
Subject: [PATCH 092/130] Add ast-crispr operation helpers

---
 packages/ast-crispr/src/index.ts          | 49 ++++++++++++++++++++++-
 packages/ast-crispr/test/boundary.test.ts | 41 ++++++++++++++++++-
 2 files changed, 87 insertions(+), 3 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index ca643a4..0462110 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -391,6 +391,50 @@ export function operationProfile(
   return new OperationProfile(profile);
 }
 
+export function replaceOperation(): OperationProfile {
+  return new OperationProfile({
+    operation_kind: 'replace',
+    source_requirement: 'required',
+    destination_requirement: 'none',
+    replacement_source: 'explicit_text',
+    captures_source_text: true,
+    supports_if_missing: false
+  });
+}
+
+export function deleteOperation(): OperationProfile {
+  return new OperationProfile({
+    operation_kind: 'delete',
+    source_requirement: 'required',
+    destination_requirement: 'none',
+    replacement_source: 'none',
+    captures_source_text: true,
+    supports_if_missing: false
+  });
+}
+
+export function insertOperation(): OperationProfile {
+  return new OperationProfile({
+    operation_kind: 'insert',
+    source_requirement: 'none',
+    destination_requirement: 'optional',
+    replacement_source: 'explicit_text',
+    captures_source_text: false,
+    supports_if_missing: true
+  });
+}
+
+export function moveOperation(): OperationProfile {
+  return new OperationProfile({
+    operation_kind: 'move',
+    source_requirement: 'optional',
+    destination_requirement: 'optional',
+    replacement_source: 'captured_text_or_explicit',
+    captures_source_text: true,
+    supports_if_missing: true
+  });
+}
+
 export function selectionProfile(
   profile: ConstructorParameters<typeof SelectionProfile>[0]
 ): SelectionProfile {
@@ -544,9 +588,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
       'match profile helpers',
       'selection profile helpers',
       'destination profile helpers',
-      'operation profile helpers'
+      'operation profile helpers',
+      'replace/delete/insert/move helpers'
     ],
-    future_exports: ['replace/delete/insert/move helpers', 'batch operation helpers'],
+    future_exports: ['batch operation helpers'],
     metadata: {
       source: 'legacy_crispr_reference',
       decision:
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index 81d89ff..ae734c8 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -9,7 +9,11 @@ import {
   OperationProfile,
   SelectionProfile,
   astMergeContractAnchor,
-  boundaryReport
+  boundaryReport,
+  deleteOperation,
+  insertOperation,
+  moveOperation,
+  replaceOperation
 } from '../src/index';
 
 interface BoundaryFixture {
@@ -144,6 +148,27 @@ function readOperationProfileFixture(): OperationProfileFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as OperationProfileFixture;
 }
 
+interface OperationHelperFixture {
+  cases: Array<{
+    name: string;
+    helper: 'replace' | 'delete' | 'insert' | 'move';
+    expected_operation_profile: Readonly<Record<string, unknown>>;
+  }>;
+}
+
+function readOperationHelperFixture(): OperationHelperFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-922-ast-crispr-operation-helpers',
+    'ast-crispr-operation-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as OperationHelperFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
@@ -202,4 +227,18 @@ describe('@structuredmerge/ast-crispr', () => {
       expect(new OperationProfile(testCase.profile).report()).toEqual(testCase.expected);
     }
   });
+
+  it('conforms to the operation helper fixture', () => {
+    const fixture = readOperationHelperFixture();
+    const helpers = {
+      replace: replaceOperation,
+      delete: deleteOperation,
+      insert: insertOperation,
+      move: moveOperation
+    };
+
+    for (const testCase of fixture.cases) {
+      expect(helpers[testCase.helper]().report()).toEqual(testCase.expected_operation_profile);
+    }
+  });
 });

From a0ae5097d2605ac82ed1651da2f3ae2c0fdc8eb7 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:52:01 -0600
Subject: [PATCH 093/130] Add ast-crispr batch operation helpers

---
 packages/ast-crispr/src/index.ts          | 19 ++++++++++--
 packages/ast-crispr/test/boundary.test.ts | 37 +++++++++++++++++++++++
 2 files changed, 54 insertions(+), 2 deletions(-)

diff --git a/packages/ast-crispr/src/index.ts b/packages/ast-crispr/src/index.ts
index 0462110..afd1cbe 100644
--- a/packages/ast-crispr/src/index.ts
+++ b/packages/ast-crispr/src/index.ts
@@ -102,6 +102,12 @@ export interface OperationProfileReport {
   readonly may_reuse_captured_text: boolean;
 }
 
+export interface BatchOperationReport {
+  readonly operation_count: number;
+  readonly operation_kinds: readonly string[];
+  readonly operation_profiles: readonly OperationProfileReport[];
+}
+
 interface ProfileDescriptor {
   readonly family: string;
 }
@@ -435,6 +441,14 @@ export function moveOperation(): OperationProfile {
   });
 }
 
+export function batchOperationReport(profiles: readonly OperationProfile[]): BatchOperationReport {
+  return {
+    operation_count: profiles.length,
+    operation_kinds: profiles.map((profile) => profile.operationKind),
+    operation_profiles: profiles.map((profile) => profile.report())
+  };
+}
+
 export function selectionProfile(
   profile: ConstructorParameters<typeof SelectionProfile>[0]
 ): SelectionProfile {
@@ -589,9 +603,10 @@ export function boundaryReport(): Readonly<Record<string, unknown>> {
       'selection profile helpers',
       'destination profile helpers',
       'operation profile helpers',
-      'replace/delete/insert/move helpers'
+      'replace/delete/insert/move helpers',
+      'batch operation helpers'
     ],
-    future_exports: ['batch operation helpers'],
+    future_exports: [],
     metadata: {
       source: 'legacy_crispr_reference',
       decision:
diff --git a/packages/ast-crispr/test/boundary.test.ts b/packages/ast-crispr/test/boundary.test.ts
index ae734c8..ba0b7bf 100644
--- a/packages/ast-crispr/test/boundary.test.ts
+++ b/packages/ast-crispr/test/boundary.test.ts
@@ -9,6 +9,7 @@ import {
   OperationProfile,
   SelectionProfile,
   astMergeContractAnchor,
+  batchOperationReport,
   boundaryReport,
   deleteOperation,
   insertOperation,
@@ -169,6 +170,27 @@ function readOperationHelperFixture(): OperationHelperFixture {
   return JSON.parse(readFileSync(fixturePath, 'utf8')) as OperationHelperFixture;
 }
 
+interface BatchOperationHelperFixture {
+  cases: Array<{
+    name: string;
+    helpers: Array<'replace' | 'delete' | 'insert' | 'move'>;
+    expected: Readonly<Record<string, unknown>>;
+  }>;
+}
+
+function readBatchOperationHelperFixture(): BatchOperationHelperFixture {
+  const fixturePath = path.resolve(
+    process.cwd(),
+    '..',
+    'fixtures',
+    'diagnostics',
+    'slice-923-ast-crispr-batch-operation-helpers',
+    'ast-crispr-batch-operation-helpers.json'
+  );
+
+  return JSON.parse(readFileSync(fixturePath, 'utf8')) as BatchOperationHelperFixture;
+}
+
 describe('@structuredmerge/ast-crispr', () => {
   it('conforms to the package boundary fixture', () => {
     expect(boundaryReport()).toEqual(readFixture().boundary);
@@ -241,4 +263,19 @@ describe('@structuredmerge/ast-crispr', () => {
       expect(helpers[testCase.helper]().report()).toEqual(testCase.expected_operation_profile);
     }
   });
+
+  it('conforms to the batch operation helper fixture', () => {
+    const fixture = readBatchOperationHelperFixture();
+    const helpers = {
+      replace: replaceOperation,
+      delete: deleteOperation,
+      insert: insertOperation,
+      move: moveOperation
+    };
+
+    for (const testCase of fixture.cases) {
+      const profiles = testCase.helpers.map((helper) => helpers[helper]());
+      expect(batchOperationReport(profiles)).toEqual(testCase.expected);
+    }
+  });
 });

From fbfaec1b17f6cc53284e5e10ad55014193ba0846 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 14:58:23 -0600
Subject: [PATCH 094/130] Add tree-haver edit projection support

---
 packages/tree-haver/src/contracts.ts          | 14 +++++
 packages/tree-haver/src/index.ts              |  1 +
 .../test/fixtures.integration.test.ts         | 59 +++++++++++++++++++
 3 files changed, 74 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 085df2d..965e4a5 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -160,6 +160,20 @@ export interface TreeHaverProfile {
   readonly diagnostics: readonly string[];
 }
 
+export interface EditProjectionSupport {
+  readonly backendRef: BackendReference;
+  readonly language: string;
+  readonly supportsEditProjection: boolean;
+  readonly nativeEditTarget: string;
+  readonly normalizedEditTarget: string;
+  readonly supportedOperations: readonly string[];
+  readonly requiredNodeFields: readonly string[];
+  readonly correlationKeys: readonly string[];
+  readonly preservesSourceFragments: boolean;
+  readonly unsupportedReason?: string;
+  readonly diagnostics: readonly string[];
+}
+
 export interface OrderedSiblingEdge {
   readonly parentId: string;
   readonly nodeId: string;
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 8430f0d..cb2bd66 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -17,6 +17,7 @@ export type {
   Diagnostic,
   DiagnosticCategory,
   DiagnosticSeverity,
+  EditProjectionSupport,
   FeatureProfile,
   KaitaiByteSpan,
   KaitaiTreeAnalysis,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index a7ecdc2..4f6e31c 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -12,6 +12,7 @@ import type {
   BinaryRenderPolicy,
   BinaryScalarValue,
   ByteEditSpan,
+  EditProjectionSupport,
   FeatureProfile,
   NativeParserProvider,
   NativeProviderMetadata,
@@ -76,6 +77,36 @@ interface BackendRegistryFixture {
   backends: BackendReference[];
 }
 
+interface EditProjectionSupportFixture {
+  backend_ref: BackendReference;
+  language: string;
+  supports_edit_projection: boolean;
+  native_edit_target: string;
+  normalized_edit_target: string;
+  supported_operations: string[];
+  required_node_fields: string[];
+  correlation_keys: string[];
+  preserves_source_fragments: boolean;
+  unsupported_reason: string | null;
+  diagnostics: string[];
+}
+
+function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProjectionSupport {
+  return {
+    backendRef: fixture.backend_ref,
+    language: fixture.language,
+    supportsEditProjection: fixture.supports_edit_projection,
+    nativeEditTarget: fixture.native_edit_target,
+    normalizedEditTarget: fixture.normalized_edit_target,
+    supportedOperations: fixture.supported_operations,
+    requiredNodeFields: fixture.required_node_fields,
+    correlationKeys: fixture.correlation_keys,
+    preservesSourceFragments: fixture.preserves_source_fragments,
+    unsupportedReason: fixture.unsupported_reason ?? undefined,
+    diagnostics: fixture.diagnostics
+  };
+}
+
 interface KaitaiSubstrateFixture {
   backend: BackendReference;
   adapter_info: {
@@ -975,6 +1006,34 @@ describe('tree-haver shared fixtures', () => {
     expect(unsafeEntries[2]?.category).toBe('encrypted_member');
   });
 
+  it('conforms to the slice-924 tree_haver edit projection support fixture', () => {
+    const fixture = readFixture<{
+      support: EditProjectionSupportFixture;
+      unsupported: EditProjectionSupportFixture;
+    }>(
+      'diagnostics',
+      'slice-924-tree-haver-edit-projection-support',
+      'edit-projection-support.json'
+    );
+    const support = editProjectionSupport(fixture.support);
+    const unsupported = editProjectionSupport(fixture.unsupported);
+
+    expect(support.supportsEditProjection).toBe(true);
+    expect(support.backendRef.id).toBe('go-dst');
+    expect(support.supportedOperations[0]).toBe('replace_node');
+    expect(support.correlationKeys[1]).toBe('metadata.go_dst.node_path');
+    expect(support.preservesSourceFragments).toBe(true);
+    expect(support.unsupportedReason).toBeUndefined();
+
+    expect(unsupported.supportsEditProjection).toBe(false);
+    expect(unsupported.backendRef.id).toBe('psych');
+    expect(unsupported.unsupportedReason).toBe('backend_does_not_retain_native_tree');
+    expect(unsupported.supportedOperations).toHaveLength(0);
+    expect(unsupported.diagnostics[0]).toBe(
+      'edit projection unavailable: native tree not retained'
+    );
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From dce3e9befe8a4ea8669a1d36c3ccc4636fd5a201 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 15:24:10 -0600
Subject: [PATCH 095/130] Add tree-haver path validation

---
 packages/tree-haver/src/contracts.ts          | 95 +++++++++++++++++++
 packages/tree-haver/src/index.ts              |  8 ++
 .../test/fixtures.integration.test.ts         | 58 +++++++++++
 3 files changed, 161 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 965e4a5..f32979e 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -174,6 +174,12 @@ export interface EditProjectionSupport {
   readonly diagnostics: readonly string[];
 }
 
+export interface LibraryPathValidation {
+  readonly path: string;
+  readonly valid: boolean;
+  readonly errors: readonly string[];
+}
+
 export interface OrderedSiblingEdge {
   readonly parentId: string;
   readonly nodeId: string;
@@ -607,6 +613,13 @@ const backendRegistry = new Map<string, BackendReference>([
 ]);
 let currentBackend: string | undefined;
 
+export const MAX_LIBRARY_PATH_LENGTH = 4096;
+
+const VALID_LIBRARY_FILENAME_PATTERN = /^[A-Za-z0-9][A-Za-z0-9._-]*$/u;
+const VALID_LANGUAGE_NAME_PATTERN = /^[a-z][a-z0-9_]*$/u;
+const VALID_SYMBOL_NAME_PATTERN = /^[A-Za-z_][A-Za-z0-9_]*$/u;
+const VERSIONED_SHARED_OBJECT_PATTERN = /\.so\.\d+$/u;
+
 export function registerBackend(backend: BackendReference): void {
   backendRegistry.set(backend.id, { ...backend });
 }
@@ -621,6 +634,69 @@ export function registeredBackends(): BackendReference[] {
   return [...backendRegistry.values()].map((backend) => ({ ...backend }));
 }
 
+export function validateLibraryPath(libraryPath: string): LibraryPathValidation {
+  const errors = libraryPathErrors(libraryPath);
+
+  return {
+    path: libraryPath,
+    valid: errors.length === 0,
+    errors
+  };
+}
+
+export function libraryPathErrors(libraryPath: string): string[] {
+  const errors: string[] = [];
+
+  if (libraryPath.length === 0) {
+    errors.push('path_empty');
+  }
+  if (libraryPath.length > MAX_LIBRARY_PATH_LENGTH) {
+    errors.push('path_too_long');
+  }
+  if (libraryPath.includes('\0')) {
+    errors.push('path_contains_null_byte');
+  }
+  if (!libraryPath.startsWith('/') && !windowsAbsolutePath(libraryPath)) {
+    errors.push('path_not_absolute');
+  }
+
+  const segments = libraryPath.split(/[\\/]/u);
+  if (segments.includes('..')) {
+    errors.push('path_contains_parent_traversal');
+  }
+  if (segments.includes('.')) {
+    errors.push('path_contains_current_directory_traversal');
+  }
+  if (!hasAllowedLibraryExtension(libraryPath)) {
+    errors.push('path_extension_not_allowed');
+  }
+
+  const filename = libraryFilename(libraryPath);
+  if (!VALID_LIBRARY_FILENAME_PATTERN.test(filename)) {
+    errors.push('filename_contains_invalid_characters');
+  }
+
+  return errors;
+}
+
+export function safeLanguageName(name: string): boolean {
+  return VALID_LANGUAGE_NAME_PATTERN.test(name);
+}
+
+export function sanitizeLanguageName(name: string): string | undefined {
+  const sanitized = name.toLowerCase().replace(/[^a-z0-9_]/gu, '');
+
+  return safeLanguageName(sanitized) ? sanitized : undefined;
+}
+
+export function safeSymbolName(symbol: string): boolean {
+  return VALID_SYMBOL_NAME_PATTERN.test(symbol);
+}
+
+export function safeBackendName(name: string): boolean {
+  return name === 'auto' || backendRegistry.has(name);
+}
+
 export function currentBackendId(): string | undefined {
   return currentBackend;
 }
@@ -639,6 +715,25 @@ export function withBackend<T>(backendId: string, fn: () => T): T {
   }
 }
 
+function windowsAbsolutePath(libraryPath: string): boolean {
+  return /^[A-Za-z]:[\\/]/u.test(libraryPath);
+}
+
+function hasAllowedLibraryExtension(libraryPath: string): boolean {
+  const normalizedPath = libraryPath.toLowerCase();
+
+  return (
+    normalizedPath.endsWith('.so') ||
+    VERSIONED_SHARED_OBJECT_PATTERN.test(normalizedPath) ||
+    normalizedPath.endsWith('.dylib') ||
+    normalizedPath.endsWith('.dll')
+  );
+}
+
+function libraryFilename(libraryPath: string): string {
+  return libraryPath.split(/[\\/]/u).at(-1) ?? '';
+}
+
 export function createPeggyParser(
   grammar: string,
   options?: peggy.ParserBuildOptions
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index cb2bd66..b06820d 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -24,6 +24,7 @@ export type {
   KaitaiTreeNode,
   LanguagePackAnalysis,
   LanguagePackProcessAnalysis,
+  LibraryPathValidation,
   NativeParserProvider,
   NativeProviderMetadata,
   NormalizedParseResult,
@@ -79,8 +80,15 @@ export {
   processWithLanguagePack,
   parseWithLanguagePack,
   parseWithPeggy,
+  libraryPathErrors,
+  MAX_LIBRARY_PATH_LENGTH,
   registerBackend,
   registeredBackends,
+  safeBackendName,
+  safeLanguageName,
+  safeSymbolName,
+  sanitizeLanguageName,
   sliceByteRange,
+  validateLibraryPath,
   withBackend
 } from './contracts';
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 4f6e31c..fdfb6ee 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -37,6 +37,7 @@ import {
   byteRangeOverlaps,
   currentBackendId,
   extractSourceFragment,
+  libraryPathErrors,
   kaitaiAdapterInfo,
   kaitaiFeatureProfile,
   KAITAI_STRUCT_BACKEND,
@@ -48,7 +49,12 @@ import {
   nodeRoles,
   registerBackend,
   registeredBackends,
+  safeBackendName,
+  safeLanguageName,
+  safeSymbolName,
+  sanitizeLanguageName,
   sliceByteRange,
+  validateLibraryPath,
   withBackend
 } from '../src/index';
 
@@ -91,6 +97,27 @@ interface EditProjectionSupportFixture {
   diagnostics: string[];
 }
 
+interface PathValidationCase {
+  name: string;
+  path: string;
+  expected_valid: boolean;
+  expected_errors: string[];
+}
+
+interface NameValidationCase {
+  name: string;
+  value: string;
+  expected_valid: boolean;
+  expected_sanitized?: string | null;
+}
+
+interface PathValidationFixture {
+  library_path_cases: PathValidationCase[];
+  language_name_cases: NameValidationCase[];
+  symbol_name_cases: NameValidationCase[];
+  backend_name_cases: NameValidationCase[];
+}
+
 function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProjectionSupport {
   return {
     backendRef: fixture.backend_ref,
@@ -1034,6 +1061,37 @@ describe('tree-haver shared fixtures', () => {
     );
   });
 
+  it('conforms to the slice-925 tree_haver path validation fixture', () => {
+    const fixture = readFixture<PathValidationFixture>(
+      'diagnostics',
+      'slice-925-tree-haver-path-validation',
+      'path-validation.json'
+    );
+
+    for (const testCase of fixture.library_path_cases) {
+      const validation = validateLibraryPath(testCase.path);
+      expect(validation.path).toBe(testCase.path);
+      expect(validation.valid, testCase.name).toBe(testCase.expected_valid);
+      expect(validation.errors, testCase.name).toEqual(testCase.expected_errors);
+      expect(libraryPathErrors(testCase.path), testCase.name).toEqual(testCase.expected_errors);
+    }
+
+    for (const testCase of fixture.language_name_cases) {
+      expect(safeLanguageName(testCase.value), testCase.name).toBe(testCase.expected_valid);
+      expect(sanitizeLanguageName(testCase.value), testCase.name).toBe(
+        testCase.expected_sanitized ?? undefined
+      );
+    }
+
+    for (const testCase of fixture.symbol_name_cases) {
+      expect(safeSymbolName(testCase.value), testCase.name).toBe(testCase.expected_valid);
+    }
+
+    for (const testCase of fixture.backend_name_cases) {
+      expect(safeBackendName(testCase.value), testCase.name).toBe(testCase.expected_valid);
+    }
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 4d45a5e21c193a9dd53d66df84f5f928af08b645 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 15:28:22 -0600
Subject: [PATCH 096/130] Add tree-haver backend availability reports

---
 packages/tree-haver/src/contracts.ts          | 41 +++++++++++++++++++
 packages/tree-haver/src/index.ts              |  4 ++
 .../test/fixtures.integration.test.ts         | 36 ++++++++++++++++
 3 files changed, 81 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index f32979e..d51ed83 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -180,6 +180,22 @@ export interface LibraryPathValidation {
   readonly errors: readonly string[];
 }
 
+export type BackendAvailabilityStatus = 'available' | 'unavailable' | 'unknown';
+
+export interface BackendAvailabilityCheck {
+  readonly name: string;
+  readonly status: BackendAvailabilityStatus;
+  readonly required: boolean;
+  readonly diagnostics: readonly string[];
+}
+
+export interface BackendAvailabilityReport {
+  readonly backendRef: BackendReference;
+  readonly status: BackendAvailabilityStatus;
+  readonly checks: readonly BackendAvailabilityCheck[];
+  readonly diagnostics: readonly string[];
+}
+
 export interface OrderedSiblingEdge {
   readonly parentId: string;
   readonly nodeId: string;
@@ -697,6 +713,31 @@ export function safeBackendName(name: string): boolean {
   return name === 'auto' || backendRegistry.has(name);
 }
 
+export function buildBackendAvailabilityReport(
+  backendRef: BackendReference,
+  checks: readonly BackendAvailabilityCheck[]
+): BackendAvailabilityReport {
+  if (checks.length === 0) {
+    return {
+      backendRef,
+      status: 'unknown',
+      checks,
+      diagnostics: ['backend availability unknown: no checks supplied']
+    };
+  }
+
+  const diagnostics: string[] = [];
+  let status: BackendAvailabilityStatus = 'available';
+  for (const check of checks) {
+    if (check.required && check.status !== 'available') {
+      status = 'unavailable';
+      diagnostics.push(`backend unavailable: required check ${check.name} is ${check.status}`);
+    }
+  }
+
+  return { backendRef, status, checks, diagnostics };
+}
+
 export function currentBackendId(): string | undefined {
   return currentBackend;
 }
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index b06820d..992b7eb 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -3,6 +3,9 @@ export const packageName = '@structuredmerge/tree-haver';
 export type {
   AdapterInfo,
   AnalysisHandle,
+  BackendAvailabilityCheck,
+  BackendAvailabilityReport,
+  BackendAvailabilityStatus,
   BackendCapability,
   BackendReference,
   BinaryDiagnostic,
@@ -56,6 +59,7 @@ export type {
 } from './contracts';
 export {
   backendReference,
+  buildBackendAvailabilityReport,
   byteEditDelta,
   byteEditNewRange,
   byteEditOldRange,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index fdfb6ee..6036b15 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -3,6 +3,8 @@ import path from 'node:path';
 import { describe, expect, it } from 'vitest';
 import type {
   AdapterInfo,
+  BackendAvailabilityCheck,
+  BackendAvailabilityReport,
   BackendCapability,
   BackendReference,
   BinaryDiagnostic,
@@ -28,6 +30,7 @@ import type {
 } from '../src/index';
 import { processWithLanguagePack } from '../src/index';
 import {
+  buildBackendAvailabilityReport,
   byteEditDelta,
   byteEditNewRange,
   byteEditOldRange,
@@ -118,6 +121,13 @@ interface PathValidationFixture {
   backend_name_cases: NameValidationCase[];
 }
 
+interface BackendAvailabilityReportFixture {
+  backend_ref: BackendReference;
+  status: 'available' | 'unavailable' | 'unknown';
+  checks: BackendAvailabilityCheck[];
+  diagnostics: string[];
+}
+
 function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProjectionSupport {
   return {
     backendRef: fixture.backend_ref,
@@ -134,6 +144,17 @@ function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProje
   };
 }
 
+function backendAvailabilityReport(
+  fixture: BackendAvailabilityReportFixture
+): BackendAvailabilityReport {
+  return {
+    backendRef: fixture.backend_ref,
+    status: fixture.status,
+    checks: fixture.checks,
+    diagnostics: fixture.diagnostics
+  };
+}
+
 interface KaitaiSubstrateFixture {
   backend: BackendReference;
   adapter_info: {
@@ -1092,6 +1113,21 @@ describe('tree-haver shared fixtures', () => {
     }
   });
 
+  it('conforms to the slice-926 tree_haver backend availability fixture', () => {
+    const fixture = readFixture<Record<string, BackendAvailabilityReportFixture>>(
+      'diagnostics',
+      'slice-926-tree-haver-backend-availability',
+      'backend-availability.json'
+    );
+
+    for (const name of ['available_report', 'unavailable_report', 'unknown_report']) {
+      const expected = backendAvailabilityReport(fixture[name]!);
+      expect(buildBackendAvailabilityReport(expected.backendRef, expected.checks)).toEqual(
+        expected
+      );
+    }
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 567274f54f30acc7a149c84e94d7be259fb863bb Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 15:31:58 -0600
Subject: [PATCH 097/130] Add tree-haver provider diagnostics reports

---
 packages/tree-haver/src/contracts.ts          | 39 +++++++++++++++++
 packages/tree-haver/src/index.ts              |  4 ++
 .../test/fixtures.integration.test.ts         | 43 +++++++++++++++++++
 3 files changed, 86 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index d51ed83..33ec477 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -196,6 +196,25 @@ export interface BackendAvailabilityReport {
   readonly diagnostics: readonly string[];
 }
 
+export type ProviderDiagnosticsStatus = 'clean' | 'warning' | 'blocked';
+
+export interface ProviderDiagnostic {
+  readonly severity: DiagnosticSeverity;
+  readonly category: string;
+  readonly code: string;
+  readonly message: string;
+  readonly path: string;
+  readonly blocking: boolean;
+}
+
+export interface ProviderDiagnosticsReport {
+  readonly providerId: string;
+  readonly backendRef: BackendReference;
+  readonly language: string;
+  readonly status: ProviderDiagnosticsStatus;
+  readonly diagnostics: readonly ProviderDiagnostic[];
+}
+
 export interface OrderedSiblingEdge {
   readonly parentId: string;
   readonly nodeId: string;
@@ -738,6 +757,26 @@ export function buildBackendAvailabilityReport(
   return { backendRef, status, checks, diagnostics };
 }
 
+export function buildProviderDiagnosticsReport(
+  providerId: string,
+  backendRef: BackendReference,
+  language: string,
+  diagnostics: readonly ProviderDiagnostic[]
+): ProviderDiagnosticsReport {
+  let status: ProviderDiagnosticsStatus = 'clean';
+  for (const diagnostic of diagnostics) {
+    if (diagnostic.blocking) {
+      status = 'blocked';
+      break;
+    }
+    if (diagnostic.severity === 'warning') {
+      status = 'warning';
+    }
+  }
+
+  return { providerId, backendRef, language, status, diagnostics };
+}
+
 export function currentBackendId(): string | undefined {
   return currentBackend;
 }
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 992b7eb..67cae73 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -42,6 +42,9 @@ export type {
   ParseResult,
   PolicyReference,
   PolicySurface,
+  ProviderDiagnostic,
+  ProviderDiagnosticsReport,
+  ProviderDiagnosticsStatus,
   ProcessDiagnostic,
   ProcessImportInfo,
   ProcessRequest,
@@ -60,6 +63,7 @@ export type {
 export {
   backendReference,
   buildBackendAvailabilityReport,
+  buildProviderDiagnosticsReport,
   byteEditDelta,
   byteEditNewRange,
   byteEditOldRange,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 6036b15..7cb51d3 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -24,6 +24,8 @@ import type {
   ParseErrorTolerance,
   ParserRequest,
   PolicyReference,
+  ProviderDiagnostic,
+  ProviderDiagnosticsReport,
   SourceSpan,
   TreeHaverProfile,
   ZipUnsafeEntry
@@ -31,6 +33,7 @@ import type {
 import { processWithLanguagePack } from '../src/index';
 import {
   buildBackendAvailabilityReport,
+  buildProviderDiagnosticsReport,
   byteEditDelta,
   byteEditNewRange,
   byteEditOldRange,
@@ -128,6 +131,14 @@ interface BackendAvailabilityReportFixture {
   diagnostics: string[];
 }
 
+interface ProviderDiagnosticsReportFixture {
+  provider_id: string;
+  backend_ref: BackendReference;
+  language: string;
+  status: 'clean' | 'warning' | 'blocked';
+  diagnostics: ProviderDiagnostic[];
+}
+
 function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProjectionSupport {
   return {
     backendRef: fixture.backend_ref,
@@ -155,6 +166,18 @@ function backendAvailabilityReport(
   };
 }
 
+function providerDiagnosticsReport(
+  fixture: ProviderDiagnosticsReportFixture
+): ProviderDiagnosticsReport {
+  return {
+    providerId: fixture.provider_id,
+    backendRef: fixture.backend_ref,
+    language: fixture.language,
+    status: fixture.status,
+    diagnostics: fixture.diagnostics
+  };
+}
+
 interface KaitaiSubstrateFixture {
   backend: BackendReference;
   adapter_info: {
@@ -1128,6 +1151,26 @@ describe('tree-haver shared fixtures', () => {
     }
   });
 
+  it('conforms to the slice-927 tree_haver provider diagnostics fixture', () => {
+    const fixture = readFixture<Record<string, ProviderDiagnosticsReportFixture>>(
+      'diagnostics',
+      'slice-927-tree-haver-provider-diagnostics',
+      'provider-diagnostics.json'
+    );
+
+    for (const name of ['clean_report', 'warning_report', 'blocked_report']) {
+      const expected = providerDiagnosticsReport(fixture[name]!);
+      expect(
+        buildProviderDiagnosticsReport(
+          expected.providerId,
+          expected.backendRef,
+          expected.language,
+          expected.diagnostics
+        )
+      ).toEqual(expected);
+    }
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 85053349adb7f40225044e9486839ab1e1bd5da6 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 15:39:13 -0600
Subject: [PATCH 098/130] Add tree-haver edit projection execution contracts

---
 packages/tree-haver/src/contracts.ts          | 54 ++++++++++++++++
 packages/tree-haver/src/index.ts              |  5 ++
 .../test/fixtures.integration.test.ts         | 62 +++++++++++++++++++
 3 files changed, 121 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 33ec477..1b209c2 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -215,6 +215,36 @@ export interface ProviderDiagnosticsReport {
   readonly diagnostics: readonly ProviderDiagnostic[];
 }
 
+export interface EditProjectionOperationRequest {
+  readonly operation: string;
+  readonly targetNodeId: string;
+  readonly targetNodePath: string;
+  readonly replacementSource: string;
+}
+
+export interface EditProjectionExecutionRequest {
+  readonly providerId: string;
+  readonly backendRef: BackendReference;
+  readonly language: string;
+  readonly source: string;
+  readonly operations: readonly EditProjectionOperationRequest[];
+}
+
+export interface AppliedEditProjectionOperation {
+  readonly operation: string;
+  readonly targetNodeId: string;
+  readonly correlationKey: string;
+  readonly correlationValue: string;
+}
+
+export interface EditProjectionExecutionResult {
+  readonly ok: boolean;
+  readonly status: 'applied' | 'rejected';
+  readonly source: string;
+  readonly appliedOperations: readonly AppliedEditProjectionOperation[];
+  readonly diagnostics: readonly ProviderDiagnostic[];
+}
+
 export interface OrderedSiblingEdge {
   readonly parentId: string;
   readonly nodeId: string;
@@ -777,6 +807,30 @@ export function buildProviderDiagnosticsReport(
   return { providerId, backendRef, language, status, diagnostics };
 }
 
+export function buildEditProjectionExecutionResult(
+  source: string,
+  appliedOperations: readonly AppliedEditProjectionOperation[],
+  diagnostics: readonly ProviderDiagnostic[]
+): EditProjectionExecutionResult {
+  if (diagnostics.some((diagnostic) => diagnostic.blocking)) {
+    return {
+      ok: false,
+      status: 'rejected',
+      source,
+      appliedOperations: [],
+      diagnostics
+    };
+  }
+
+  return {
+    ok: true,
+    status: 'applied',
+    source,
+    appliedOperations,
+    diagnostics
+  };
+}
+
 export function currentBackendId(): string | undefined {
   return currentBackend;
 }
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index 67cae73..b0e6530 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -3,6 +3,7 @@ export const packageName = '@structuredmerge/tree-haver';
 export type {
   AdapterInfo,
   AnalysisHandle,
+  AppliedEditProjectionOperation,
   BackendAvailabilityCheck,
   BackendAvailabilityReport,
   BackendAvailabilityStatus,
@@ -20,6 +21,9 @@ export type {
   Diagnostic,
   DiagnosticCategory,
   DiagnosticSeverity,
+  EditProjectionExecutionRequest,
+  EditProjectionExecutionResult,
+  EditProjectionOperationRequest,
   EditProjectionSupport,
   FeatureProfile,
   KaitaiByteSpan,
@@ -63,6 +67,7 @@ export type {
 export {
   backendReference,
   buildBackendAvailabilityReport,
+  buildEditProjectionExecutionResult,
   buildProviderDiagnosticsReport,
   byteEditDelta,
   byteEditNewRange,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 7cb51d3..9e5063e 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -3,6 +3,7 @@ import path from 'node:path';
 import { describe, expect, it } from 'vitest';
 import type {
   AdapterInfo,
+  AppliedEditProjectionOperation,
   BackendAvailabilityCheck,
   BackendAvailabilityReport,
   BackendCapability,
@@ -14,6 +15,7 @@ import type {
   BinaryRenderPolicy,
   BinaryScalarValue,
   ByteEditSpan,
+  EditProjectionExecutionResult,
   EditProjectionSupport,
   FeatureProfile,
   NativeParserProvider,
@@ -33,6 +35,7 @@ import type {
 import { processWithLanguagePack } from '../src/index';
 import {
   buildBackendAvailabilityReport,
+  buildEditProjectionExecutionResult,
   buildProviderDiagnosticsReport,
   byteEditDelta,
   byteEditNewRange,
@@ -139,6 +142,21 @@ interface ProviderDiagnosticsReportFixture {
   diagnostics: ProviderDiagnostic[];
 }
 
+interface AppliedEditProjectionOperationFixture {
+  operation: string;
+  target_node_id: string;
+  correlation_key: string;
+  correlation_value: string;
+}
+
+interface EditProjectionExecutionResultFixture {
+  ok: boolean;
+  status: 'applied' | 'rejected';
+  source: string;
+  applied_operations: AppliedEditProjectionOperationFixture[];
+  diagnostics: ProviderDiagnostic[];
+}
+
 function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProjectionSupport {
   return {
     backendRef: fixture.backend_ref,
@@ -178,6 +196,25 @@ function providerDiagnosticsReport(
   };
 }
 
+function editProjectionExecutionResult(
+  fixture: EditProjectionExecutionResultFixture
+): EditProjectionExecutionResult {
+  return {
+    ok: fixture.ok,
+    status: fixture.status,
+    source: fixture.source,
+    appliedOperations: fixture.applied_operations.map(
+      (operation): AppliedEditProjectionOperation => ({
+        operation: operation.operation,
+        targetNodeId: operation.target_node_id,
+        correlationKey: operation.correlation_key,
+        correlationValue: operation.correlation_value
+      })
+    ),
+    diagnostics: fixture.diagnostics
+  };
+}
+
 interface KaitaiSubstrateFixture {
   backend: BackendReference;
   adapter_info: {
@@ -1171,6 +1208,31 @@ describe('tree-haver shared fixtures', () => {
     }
   });
 
+  it('conforms to the slice-928 edit projection execution contract fixture', () => {
+    const fixture = readFixture<{
+      expected_result: EditProjectionExecutionResultFixture;
+      unsupported_result: EditProjectionExecutionResultFixture;
+    }>(
+      'diagnostics',
+      'slice-928-go-dst-edit-projection-execution',
+      'edit-projection-execution.json'
+    );
+
+    const expected = editProjectionExecutionResult(fixture.expected_result);
+    expect(
+      buildEditProjectionExecutionResult(
+        expected.source,
+        expected.appliedOperations,
+        expected.diagnostics
+      )
+    ).toEqual(expected);
+
+    const unsupported = editProjectionExecutionResult(fixture.unsupported_result);
+    expect(
+      buildEditProjectionExecutionResult(unsupported.source, [], unsupported.diagnostics)
+    ).toEqual(unsupported);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 1a4ad7357660c0228ab1b01c80b7e5aa816fde6b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 15:49:32 -0600
Subject: [PATCH 099/130] Add insert-child edit projection contract fixture

---
 .../test/fixtures.integration.test.ts         | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 9e5063e..07fd65c 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -1233,6 +1233,25 @@ describe('tree-haver shared fixtures', () => {
     ).toEqual(unsupported);
   });
 
+  it('conforms to the slice-929 insert-child edit projection contract fixture', () => {
+    const fixture = readFixture<{
+      expected_result: EditProjectionExecutionResultFixture;
+    }>(
+      'diagnostics',
+      'slice-929-go-dst-insert-child-edit-projection',
+      'insert-child-edit-projection.json'
+    );
+
+    const expected = editProjectionExecutionResult(fixture.expected_result);
+    expect(
+      buildEditProjectionExecutionResult(
+        expected.source,
+        expected.appliedOperations,
+        expected.diagnostics
+      )
+    ).toEqual(expected);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 2364f533e711662626bac45bec7a32ba5b28cfe8 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 18:07:07 -0600
Subject: [PATCH 100/130] Add delete-node edit projection contract fixture

---
 .../test/fixtures.integration.test.ts         | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 07fd65c..25ac766 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -1252,6 +1252,25 @@ describe('tree-haver shared fixtures', () => {
     ).toEqual(expected);
   });
 
+  it('conforms to the slice-930 delete-node edit projection contract fixture', () => {
+    const fixture = readFixture<{
+      expected_result: EditProjectionExecutionResultFixture;
+    }>(
+      'diagnostics',
+      'slice-930-go-dst-delete-node-edit-projection',
+      'delete-node-edit-projection.json'
+    );
+
+    const expected = editProjectionExecutionResult(fixture.expected_result);
+    expect(
+      buildEditProjectionExecutionResult(
+        expected.source,
+        expected.appliedOperations,
+        expected.diagnostics
+      )
+    ).toEqual(expected);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 4e34ca3e66571844cd272dae3a50df06084fb8cc Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 18:11:12 -0600
Subject: [PATCH 101/130] Add go-parser edit projection contract fixture

---
 .../test/fixtures.integration.test.ts         | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 25ac766..009160f 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -1271,6 +1271,25 @@ describe('tree-haver shared fixtures', () => {
     ).toEqual(expected);
   });
 
+  it('conforms to the slice-931 go-parser edit projection contract fixture', () => {
+    const fixture = readFixture<{
+      expected_result: EditProjectionExecutionResultFixture;
+    }>(
+      'diagnostics',
+      'slice-931-go-parser-edit-projection-execution',
+      'edit-projection-execution.json'
+    );
+
+    const expected = editProjectionExecutionResult(fixture.expected_result);
+    expect(
+      buildEditProjectionExecutionResult(
+        expected.source,
+        expected.appliedOperations,
+        expected.diagnostics
+      )
+    ).toEqual(expected);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From c41259718f5ca5ff62a5870618525089fadef14f Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 18:15:36 -0600
Subject: [PATCH 102/130] Add edit projection provider operation matrix

---
 packages/tree-haver/src/contracts.ts          | 35 +++++++++
 packages/tree-haver/src/index.ts              |  5 ++
 .../test/fixtures.integration.test.ts         | 78 +++++++++++++++++++
 3 files changed, 118 insertions(+)

diff --git a/packages/tree-haver/src/contracts.ts b/packages/tree-haver/src/contracts.ts
index 1b209c2..c71e522 100644
--- a/packages/tree-haver/src/contracts.ts
+++ b/packages/tree-haver/src/contracts.ts
@@ -245,6 +245,33 @@ export interface EditProjectionExecutionResult {
   readonly diagnostics: readonly ProviderDiagnostic[];
 }
 
+export type EditProjectionProviderOperationStatus = 'implemented' | 'planned' | 'unsupported';
+
+export interface EditProjectionProviderOperation {
+  readonly operation: string;
+  readonly status: EditProjectionProviderOperationStatus;
+  readonly nodeScope: string;
+  readonly correlationKeys: readonly string[];
+  readonly fixtureSlices: readonly string[];
+  readonly formattingPreservation: string;
+  readonly diagnostics: readonly string[];
+}
+
+export interface EditProjectionProviderMatrixEntry {
+  readonly providerId: string;
+  readonly backendRef: BackendReference;
+  readonly language: string;
+  readonly formattingPreservation: string;
+  readonly preservesSourceFragments: boolean;
+  readonly operations: readonly EditProjectionProviderOperation[];
+}
+
+export interface EditProjectionProviderMatrix {
+  readonly operations: readonly string[];
+  readonly providers: readonly EditProjectionProviderMatrixEntry[];
+  readonly diagnostics: readonly string[];
+}
+
 export interface OrderedSiblingEdge {
   readonly parentId: string;
   readonly nodeId: string;
@@ -831,6 +858,14 @@ export function buildEditProjectionExecutionResult(
   };
 }
 
+export function buildEditProjectionProviderMatrix(
+  operations: readonly string[],
+  providers: readonly EditProjectionProviderMatrixEntry[],
+  diagnostics: readonly string[]
+): EditProjectionProviderMatrix {
+  return { operations, providers, diagnostics };
+}
+
 export function currentBackendId(): string | undefined {
   return currentBackend;
 }
diff --git a/packages/tree-haver/src/index.ts b/packages/tree-haver/src/index.ts
index b0e6530..675abb6 100644
--- a/packages/tree-haver/src/index.ts
+++ b/packages/tree-haver/src/index.ts
@@ -24,6 +24,10 @@ export type {
   EditProjectionExecutionRequest,
   EditProjectionExecutionResult,
   EditProjectionOperationRequest,
+  EditProjectionProviderMatrix,
+  EditProjectionProviderMatrixEntry,
+  EditProjectionProviderOperation,
+  EditProjectionProviderOperationStatus,
   EditProjectionSupport,
   FeatureProfile,
   KaitaiByteSpan,
@@ -68,6 +72,7 @@ export {
   backendReference,
   buildBackendAvailabilityReport,
   buildEditProjectionExecutionResult,
+  buildEditProjectionProviderMatrix,
   buildProviderDiagnosticsReport,
   byteEditDelta,
   byteEditNewRange,
diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 009160f..d145413 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -16,6 +16,9 @@ import type {
   BinaryScalarValue,
   ByteEditSpan,
   EditProjectionExecutionResult,
+  EditProjectionProviderMatrix,
+  EditProjectionProviderMatrixEntry,
+  EditProjectionProviderOperation,
   EditProjectionSupport,
   FeatureProfile,
   NativeParserProvider,
@@ -36,6 +39,7 @@ import { processWithLanguagePack } from '../src/index';
 import {
   buildBackendAvailabilityReport,
   buildEditProjectionExecutionResult,
+  buildEditProjectionProviderMatrix,
   buildProviderDiagnosticsReport,
   byteEditDelta,
   byteEditNewRange,
@@ -157,6 +161,31 @@ interface EditProjectionExecutionResultFixture {
   diagnostics: ProviderDiagnostic[];
 }
 
+interface EditProjectionProviderOperationFixture {
+  operation: string;
+  status: 'implemented' | 'planned' | 'unsupported';
+  node_scope: string;
+  correlation_keys: string[];
+  fixture_slices: string[];
+  formatting_preservation: string;
+  diagnostics: string[];
+}
+
+interface EditProjectionProviderMatrixEntryFixture {
+  provider_id: string;
+  backend_ref: BackendReference;
+  language: string;
+  formatting_preservation: string;
+  preserves_source_fragments: boolean;
+  operations: EditProjectionProviderOperationFixture[];
+}
+
+interface EditProjectionProviderMatrixFixture {
+  operations: string[];
+  providers: EditProjectionProviderMatrixEntryFixture[];
+  diagnostics: string[];
+}
+
 function editProjectionSupport(fixture: EditProjectionSupportFixture): EditProjectionSupport {
   return {
     backendRef: fixture.backend_ref,
@@ -215,6 +244,39 @@ function editProjectionExecutionResult(
   };
 }
 
+function editProjectionProviderMatrixEntry(
+  fixture: EditProjectionProviderMatrixEntryFixture
+): EditProjectionProviderMatrixEntry {
+  return {
+    providerId: fixture.provider_id,
+    backendRef: fixture.backend_ref,
+    language: fixture.language,
+    formattingPreservation: fixture.formatting_preservation,
+    preservesSourceFragments: fixture.preserves_source_fragments,
+    operations: fixture.operations.map(
+      (operation): EditProjectionProviderOperation => ({
+        operation: operation.operation,
+        status: operation.status,
+        nodeScope: operation.node_scope,
+        correlationKeys: operation.correlation_keys,
+        fixtureSlices: operation.fixture_slices,
+        formattingPreservation: operation.formatting_preservation,
+        diagnostics: operation.diagnostics
+      })
+    )
+  };
+}
+
+function editProjectionProviderMatrix(
+  fixture: EditProjectionProviderMatrixFixture
+): EditProjectionProviderMatrix {
+  return {
+    operations: fixture.operations,
+    providers: fixture.providers.map(editProjectionProviderMatrixEntry),
+    diagnostics: fixture.diagnostics
+  };
+}
+
 interface KaitaiSubstrateFixture {
   backend: BackendReference;
   adapter_info: {
@@ -1290,6 +1352,22 @@ describe('tree-haver shared fixtures', () => {
     ).toEqual(expected);
   });
 
+  it('conforms to the slice-932 edit projection provider operation matrix fixture', () => {
+    const fixture = readFixture<{
+      operations: string[];
+      providers: EditProjectionProviderMatrixEntryFixture[];
+      expected_matrix: EditProjectionProviderMatrixFixture;
+    }>(
+      'diagnostics',
+      'slice-932-edit-projection-provider-operation-matrix',
+      'provider-operation-matrix.json'
+    );
+
+    const providers = fixture.providers.map(editProjectionProviderMatrixEntry);
+    const expected = editProjectionProviderMatrix(fixture.expected_matrix);
+    expect(buildEditProjectionProviderMatrix(fixture.operations, providers, [])).toEqual(expected);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From c83e8aa61e6ea9862cb9f74908c8ef90d472306a Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 18:18:41 -0600
Subject: [PATCH 103/130] Add go-parser insert child edit projection contract
 fixture

---
 .../test/fixtures.integration.test.ts         | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index d145413..49d4b9f 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -1368,6 +1368,25 @@ describe('tree-haver shared fixtures', () => {
     expect(buildEditProjectionProviderMatrix(fixture.operations, providers, [])).toEqual(expected);
   });
 
+  it('conforms to the slice-933 go-parser insert-child edit projection contract fixture', () => {
+    const fixture = readFixture<{
+      expected_result: EditProjectionExecutionResultFixture;
+    }>(
+      'diagnostics',
+      'slice-933-go-parser-insert-child-edit-projection',
+      'insert-child-edit-projection.json'
+    );
+
+    const expected = editProjectionExecutionResult(fixture.expected_result);
+    expect(
+      buildEditProjectionExecutionResult(
+        expected.source,
+        expected.appliedOperations,
+        expected.diagnostics
+      )
+    ).toEqual(expected);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From b63dca5463bd33d7cc59f82f91997499caba1f8b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Fri, 15 May 2026 18:20:32 -0600
Subject: [PATCH 104/130] Add go-parser delete node edit projection contract
 fixture

---
 .../test/fixtures.integration.test.ts         | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/packages/tree-haver/test/fixtures.integration.test.ts b/packages/tree-haver/test/fixtures.integration.test.ts
index 49d4b9f..ced7008 100644
--- a/packages/tree-haver/test/fixtures.integration.test.ts
+++ b/packages/tree-haver/test/fixtures.integration.test.ts
@@ -1387,6 +1387,25 @@ describe('tree-haver shared fixtures', () => {
     ).toEqual(expected);
   });
 
+  it('conforms to the slice-934 go-parser delete-node edit projection contract fixture', () => {
+    const fixture = readFixture<{
+      expected_result: EditProjectionExecutionResultFixture;
+    }>(
+      'diagnostics',
+      'slice-934-go-parser-delete-node-edit-projection',
+      'delete-node-edit-projection.json'
+    );
+
+    const expected = editProjectionExecutionResult(fixture.expected_result);
+    expect(
+      buildEditProjectionExecutionResult(
+        expected.source,
+        expected.appliedOperations,
+        expected.diagnostics
+      )
+    ).toEqual(expected);
+  });
+
   it('supports temporary backend context selection', () => {
     expect(currentBackendId()).toBeUndefined();
 

From 06ea243deef592c1fab638ee595432fe755ee0c8 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 14:25:24 -0600
Subject: [PATCH 105/130] Add TypeScript ast merge git merge3

---
 packages/ast-merge-git/package.json           |  19 ++
 packages/ast-merge-git/src/index.ts           | 245 ++++++++++++++++++
 .../test/fixtures.integration.test.ts         |  63 +++++
 packages/smorg-ts/package.json                |   1 +
 packages/smorg-ts/src/cli.ts                  |  40 ++-
 packages/smorg-ts/test/cli.test.ts            |  21 +-
 pnpm-lock.yaml                                |   9 +
 tsconfig.json                                 |   1 +
 vitest.config.ts                              |   3 +
 9 files changed, 395 insertions(+), 7 deletions(-)
 create mode 100644 packages/ast-merge-git/package.json
 create mode 100644 packages/ast-merge-git/src/index.ts
 create mode 100644 packages/ast-merge-git/test/fixtures.integration.test.ts

diff --git a/packages/ast-merge-git/package.json b/packages/ast-merge-git/package.json
new file mode 100644
index 0000000..4d8f20e
--- /dev/null
+++ b/packages/ast-merge-git/package.json
@@ -0,0 +1,19 @@
+{
+  "name": "@structuredmerge/ast-merge-git",
+  "version": "0.2.0",
+  "private": false,
+  "type": "module",
+  "main": "./src/index.ts",
+  "author": "Peter H. Boling",
+  "homepage": "https://structuredmerge.org",
+  "repository": {
+    "type": "git",
+    "url": "git+https://github.com/structuredmerge/structuredmerge-typescript.git"
+  },
+  "bugs": {
+    "url": "https://github.com/structuredmerge/structuredmerge-typescript/issues"
+  },
+  "dependencies": {
+    "@structuredmerge/ast-merge": "workspace:*"
+  }
+}
diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
new file mode 100644
index 0000000..8f2099c
--- /dev/null
+++ b/packages/ast-merge-git/src/index.ts
@@ -0,0 +1,245 @@
+import type { Diagnostic } from '@structuredmerge/ast-merge';
+
+export const packageName = '@structuredmerge/ast-merge-git';
+
+export interface Merge3Request {
+  readonly base_source: string;
+  readonly ours_source: string;
+  readonly theirs_source: string;
+  readonly path_name?: string;
+  readonly language?: string;
+  readonly dialect?: string;
+  readonly profile_id?: string;
+  readonly fallback_policy?: string;
+  readonly conflict_marker_size?: number;
+  readonly render_policy?: string;
+}
+
+export interface Merge3Conflict {
+  readonly conflict_id: string;
+  readonly category: string;
+  readonly path: string;
+  readonly message: string;
+}
+
+export interface Merge3Response {
+  readonly ok: boolean;
+  readonly merged_source?: string;
+  readonly conflicts: readonly Merge3Conflict[];
+  readonly diagnostics: readonly Diagnostic[];
+  readonly fallbacks: readonly string[];
+  readonly profile: Readonly<Record<string, string>>;
+  readonly render_report: {
+    readonly strategy: string;
+  };
+  readonly formatting_preservation: {
+    readonly line_diff_score: number;
+    readonly character_diff_score: number;
+  };
+  readonly reparse_after_render: boolean | null;
+}
+
+const absent = Symbol('absent');
+type MaybeAbsent = unknown | typeof absent;
+
+export function merge3(request: Merge3Request): Merge3Response {
+  switch (normalizeLanguage(request)) {
+    case 'json':
+      return merge3Json(request);
+    default:
+      return response(request, {
+        ok: false,
+        diagnostics: [
+          {
+            severity: 'error',
+            category: 'unsupported_feature',
+            message: 'ast-merge-git currently supports only json merge3.'
+          }
+        ]
+      });
+  }
+}
+
+export function merge3Json(request: Merge3Request): Merge3Response {
+  try {
+    const base = parseJsonRole('base', request.base_source);
+    const ours = parseJsonRole('ours', request.ours_source);
+    const theirs = parseJsonRole('theirs', request.theirs_source);
+    const conflicts: Merge3Conflict[] = [];
+    const merged = mergeJsonValue(base, ours, theirs, '', conflicts);
+    if (conflicts.length > 0) {
+      return response(request, {
+        ok: false,
+        conflicts,
+        diagnostics: [
+          {
+            severity: 'error',
+            category: 'configuration_error',
+            message: `merge_conflict: merge3 found ${conflicts.length} unresolved conflict(s).`
+          }
+        ]
+      });
+    }
+
+    const mergedSource = JSON.stringify(merged);
+    return response(request, {
+      ok: true,
+      merged_source: mergedSource,
+      reparse_after_render: JSON.parse(mergedSource) !== undefined,
+      formatting_preservation: {
+        line_diff_score: 1,
+        character_diff_score: 1
+      }
+    });
+  } catch (error) {
+    return response(request, {
+      ok: false,
+      diagnostics: [
+        {
+          severity: 'error',
+          category: 'parse_error',
+          message: String(error)
+        }
+      ]
+    });
+  }
+}
+
+function response(
+  request: Merge3Request,
+  fields: Partial<Merge3Response> & { readonly ok: boolean }
+): Merge3Response {
+  return {
+    ok: fields.ok,
+    merged_source: fields.merged_source,
+    conflicts: fields.conflicts ?? [],
+    diagnostics: fields.diagnostics ?? [],
+    fallbacks: fields.fallbacks ?? [],
+    profile: {
+      profile_id: request.profile_id ?? '',
+      language: normalizeLanguage(request),
+      dialect: request.dialect ?? ''
+    },
+    render_report: {
+      strategy: request.render_policy || 'canonical'
+    },
+    formatting_preservation: fields.formatting_preservation ?? {
+      line_diff_score: 0,
+      character_diff_score: 0
+    },
+    reparse_after_render: fields.reparse_after_render ?? null
+  };
+}
+
+function parseJsonRole(role: string, source: string): unknown {
+  try {
+    return JSON.parse(source);
+  } catch (error) {
+    throw new Error(`${role} parse error: ${String(error)}`);
+  }
+}
+
+function mergeJsonValue(
+  base: unknown,
+  ours: unknown,
+  theirs: unknown,
+  path: string,
+  conflicts: Merge3Conflict[]
+): unknown {
+  if (jsonEqual(ours, theirs)) return ours;
+  if (jsonEqual(base, ours)) return theirs;
+  if (jsonEqual(base, theirs)) return ours;
+  if (isRecord(base) && isRecord(ours) && isRecord(theirs)) {
+    return mergeJsonObjects(base, ours, theirs, path, conflicts);
+  }
+
+  addConflict(conflicts, 'edit_edit', path, 'value changed differently in ours and theirs');
+  return ours;
+}
+
+function mergeJsonObjects(
+  base: Readonly<Record<string, unknown>>,
+  ours: Readonly<Record<string, unknown>>,
+  theirs: Readonly<Record<string, unknown>>,
+  path: string,
+  conflicts: Merge3Conflict[]
+): Readonly<Record<string, unknown>> {
+  const result: Record<string, unknown> = {};
+  const keys = [...new Set([...Object.keys(base), ...Object.keys(ours), ...Object.keys(theirs)])].sort();
+  for (const key of keys) {
+    const [merged, keep] = mergeJsonEntry(
+      Object.hasOwn(base, key) ? base[key] : absent,
+      Object.hasOwn(ours, key) ? ours[key] : absent,
+      Object.hasOwn(theirs, key) ? theirs[key] : absent,
+      jsonPointerJoin(path, key),
+      conflicts
+    );
+    if (keep) result[key] = merged;
+  }
+  return result;
+}
+
+function mergeJsonEntry(
+  base: MaybeAbsent,
+  ours: MaybeAbsent,
+  theirs: MaybeAbsent,
+  path: string,
+  conflicts: Merge3Conflict[]
+): readonly [unknown, boolean] {
+  const baseAbsent = base === absent;
+  const oursAbsent = ours === absent;
+  const theirsAbsent = theirs === absent;
+  if (baseAbsent && oursAbsent && theirsAbsent) return [undefined, false];
+  if (baseAbsent && oursAbsent) return [theirs, true];
+  if (baseAbsent && theirsAbsent) return [ours, true];
+  if (baseAbsent && jsonEqual(ours, theirs)) return [ours, true];
+  if (baseAbsent) {
+    addConflict(conflicts, 'add_add', path, 'same path added differently in ours and theirs');
+    return [ours, true];
+  }
+  if (oursAbsent && theirsAbsent) return [undefined, false];
+  if (oursAbsent && jsonEqual(base, theirs)) return [undefined, false];
+  if (theirsAbsent && jsonEqual(base, ours)) return [undefined, false];
+  if (oursAbsent) {
+    addConflict(conflicts, 'delete_edit', path, 'ours deleted a value that theirs edited');
+    return [theirs, true];
+  }
+  if (theirsAbsent) {
+    addConflict(conflicts, 'delete_edit', path, 'theirs deleted a value that ours edited');
+    return [ours, true];
+  }
+  return [mergeJsonValue(base, ours, theirs, path, conflicts), true];
+}
+
+function addConflict(
+  conflicts: Merge3Conflict[],
+  category: string,
+  path: string,
+  message: string
+): void {
+  conflicts.push({
+    conflict_id: `conflict-${conflicts.length + 1}`,
+    category,
+    path: path || '/',
+    message
+  });
+}
+
+function jsonPointerJoin(parent: string, token: string): string {
+  const escaped = token.replaceAll('~', '~0').replaceAll('/', '~1');
+  return parent ? `${parent}/${escaped}` : `/${escaped}`;
+}
+
+function jsonEqual(left: unknown, right: unknown): boolean {
+  return JSON.stringify(left) === JSON.stringify(right);
+}
+
+function isRecord(value: unknown): value is Readonly<Record<string, unknown>> {
+  return typeof value === 'object' && value !== null && !Array.isArray(value);
+}
+
+function normalizeLanguage(request: Merge3Request): string {
+  if (request.language?.trim().toLowerCase() === 'json') return 'json';
+  if (request.path_name?.toLowerCase().endsWith('.json')) return 'json';
+  return request.language?.trim().toLowerCase() ?? '';
+}
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
new file mode 100644
index 0000000..0c0a4dd
--- /dev/null
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -0,0 +1,63 @@
+import { readFileSync } from 'node:fs';
+import path from 'node:path';
+import { describe, expect, it } from 'vitest';
+import { merge3, type Merge3Request } from '../src/index';
+
+interface Fixture {
+  readonly contract: {
+    readonly package: string;
+    readonly operation: string;
+  };
+  readonly cases: readonly {
+    readonly case_id: string;
+    readonly request: Merge3Request;
+    readonly expected: {
+      readonly ok: boolean;
+      readonly merged_json: unknown | null;
+      readonly conflict_count: number;
+      readonly conflict_categories?: readonly string[];
+      readonly conflict_paths?: readonly string[];
+      readonly reparse_after_render: boolean | null;
+    };
+  }[];
+}
+
+function readFixture(...parts: readonly string[]): Fixture {
+  const source = readFileSync(path.join('..', 'fixtures', ...parts), 'utf8');
+  return JSON.parse(source) as Fixture;
+}
+
+describe('@structuredmerge/ast-merge-git', () => {
+  it('conforms to the git merge3 contract fixture', () => {
+    const fixture = readFixture(
+      'diagnostics',
+      'slice-950-git-merge3-contract',
+      'git-merge3-contract.json'
+    );
+    expect(fixture.contract.package).toBe('ast-merge-git');
+    expect(fixture.contract.operation).toBe('merge3');
+
+    for (const testCase of fixture.cases) {
+      const result = merge3(testCase.request);
+      expect(result.ok, testCase.case_id).toBe(testCase.expected.ok);
+      expect(result.conflicts, testCase.case_id).toHaveLength(testCase.expected.conflict_count);
+      expect(result.reparse_after_render, testCase.case_id).toBe(
+        testCase.expected.reparse_after_render
+      );
+      if (result.ok) {
+        expect(JSON.parse(result.merged_source ?? ''), testCase.case_id).toEqual(
+          testCase.expected.merged_json
+        );
+      } else {
+        expect(
+          result.conflicts.map((conflict) => conflict.category),
+          testCase.case_id
+        ).toEqual(testCase.expected.conflict_categories);
+        expect(
+          result.conflicts.map((conflict) => conflict.path),
+          testCase.case_id
+        ).toEqual(testCase.expected.conflict_paths);
+      }
+    }
+  });
+});
diff --git a/packages/smorg-ts/package.json b/packages/smorg-ts/package.json
index 26c8252..84e70af 100644
--- a/packages/smorg-ts/package.json
+++ b/packages/smorg-ts/package.json
@@ -18,6 +18,7 @@
   },
   "dependencies": {
     "@structuredmerge/ast-merge": "workspace:*",
+    "@structuredmerge/ast-merge-git": "workspace:*",
     "@structuredmerge/go-merge": "workspace:*",
     "@structuredmerge/json-merge": "workspace:*",
     "@structuredmerge/plain-merge": "workspace:*"
diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 2f23dfe..aaa3ea8 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -8,6 +8,7 @@ import {
   promotionProfileJsonKeyedObject
 } from '@structuredmerge/ast-merge';
 import type { MergeResult, ProfilePromotionStatus } from '@structuredmerge/ast-merge';
+import { merge3 } from '@structuredmerge/ast-merge-git';
 import { mergeGo } from '@structuredmerge/go-merge';
 import { mergeJson } from '@structuredmerge/json-merge';
 import { mergeText } from '@structuredmerge/plain-merge';
@@ -118,8 +119,6 @@ function runMergeDriver(
     stderr.write(`read merge input: ${String(error)}\n`);
     return exitUserError;
   }
-  void ancestorSource;
-
   const effectivePath = options.pathName ?? options.current;
   const settings = loadPathSettings(effectivePath);
   const profileExit = reportAndEnforceProfile(
@@ -130,7 +129,7 @@ function runMergeDriver(
     stderr
   );
   if (profileExit !== exitSuccess) return profileExit;
-  const result = mergeByPath(effectivePath, settings.language, otherSource, currentSource);
+  const result = mergeByPath(effectivePath, settings.language, ancestorSource, currentSource, otherSource);
   let output = result.output;
   if (!result.ok || output === undefined) {
     if (options.strict || options.fallback === 'none') {
@@ -437,14 +436,27 @@ function runLanguages(
 function mergeByPath(
   pathName: string,
   language: string | undefined,
-  otherSource: string,
-  currentSource: string
+  ancestorSource: string,
+  currentSource: string,
+  otherSource: string
 ): MergeResult<string> {
   switch (normalizeLanguage(language, pathName)) {
     case 'go':
       return mergeGo(otherSource, currentSource, 'go');
     case 'json':
-      return mergeJson(otherSource, currentSource, 'json');
+      return merge3Result(
+        merge3({
+          base_source: ancestorSource,
+          ours_source: currentSource,
+          theirs_source: otherSource,
+          path_name: pathName,
+          language: 'json',
+          dialect: 'json',
+          profile_id: 'json.keyed-object',
+          fallback_policy: 'none',
+          render_policy: 'canonical'
+        })
+      );
     case 'jsonc':
       return mergeJson(otherSource, currentSource, 'jsonc');
     default:
@@ -452,6 +464,22 @@ function mergeByPath(
   }
 }
 
+function merge3Result(result: ReturnType<typeof merge3>): MergeResult<string> {
+  if (result.ok && result.merged_source !== undefined) {
+    return {
+      ok: true,
+      diagnostics: result.diagnostics,
+      output: result.merged_source,
+      policies: []
+    };
+  }
+  return {
+    ok: false,
+    diagnostics: result.diagnostics,
+    policies: []
+  };
+}
+
 function normalizeLanguage(language: string | undefined, pathName: string): string {
   switch (language?.trim().toLowerCase()) {
     case 'go':
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 93d645a..7775e50 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -94,7 +94,26 @@ describe('smorg-ts cli', () => {
     );
 
     expect(exit).toBe(exitUnresolvedConflict);
-    expect(stderr.output()).toContain('destination_parse_error');
+    expect(stderr.output()).toContain('parse_error');
+    expect(stderr.output()).toContain('ours parse error');
+  });
+
+  it('uses the ancestor for JSON same-key conflicts', () => {
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.json', '{"name":"ours"}');
+    const other = write('other.json', '{"name":"theirs"}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', '--strict', ancestor, current, other, 'package.json'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUnresolvedConflict);
+    expect(stderr.output()).toContain('merge_conflict');
+    expect(readFileSync(current, 'utf8')).toBe('{"name":"ours"}');
   });
 
   it('supports check-only exit-code without writing', () => {
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index a6f711b..40bf9fd 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -51,6 +51,12 @@ importers:
         specifier: workspace:*
         version: link:../markdown-merge
 
+  packages/ast-merge-git:
+    dependencies:
+      '@structuredmerge/ast-merge':
+        specifier: workspace:*
+        version: link:../ast-merge
+
   packages/ast-template:
     dependencies:
       '@structuredmerge/ast-merge':
@@ -185,6 +191,9 @@ importers:
       '@structuredmerge/ast-merge':
         specifier: workspace:*
         version: link:../ast-merge
+      '@structuredmerge/ast-merge-git':
+        specifier: workspace:*
+        version: link:../ast-merge-git
       '@structuredmerge/go-merge':
         specifier: workspace:*
         version: link:../go-merge
diff --git a/tsconfig.json b/tsconfig.json
index 595ab0e..ea852a4 100644
--- a/tsconfig.json
+++ b/tsconfig.json
@@ -5,6 +5,7 @@
     "noEmit": true,
     "paths": {
       "@structuredmerge/ast-merge": ["./packages/ast-merge/src/index.ts"],
+      "@structuredmerge/ast-merge-git": ["./packages/ast-merge-git/src/index.ts"],
       "@structuredmerge/ast-crispr": ["./packages/ast-crispr/src/index.ts"],
       "@structuredmerge/tree-haver": ["./packages/tree-haver/src/index.ts"],
       "@structuredmerge/plain-merge": ["./packages/plain-merge/src/index.ts"],
diff --git a/vitest.config.ts b/vitest.config.ts
index ec7ac66..bf9e407 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -9,6 +9,9 @@ export default defineConfig({
       '@structuredmerge/ast-merge': fileURLToPath(
         new URL('./packages/ast-merge/src/index.ts', import.meta.url)
       ),
+      '@structuredmerge/ast-merge-git': fileURLToPath(
+        new URL('./packages/ast-merge-git/src/index.ts', import.meta.url)
+      ),
       '@structuredmerge/tree-haver': fileURLToPath(
         new URL('./packages/tree-haver/src/index.ts', import.meta.url)
       ),

From ba15b4a49f1a05de78ee4c666d8592d7a8cc00ef Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 14:31:43 -0600
Subject: [PATCH 106/130] Add TypeScript git driver JSON integration test

---
 packages/smorg-ts/test/cli.test.ts | 95 ++++++++++++++++++++++++++++++
 1 file changed, 95 insertions(+)

diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 7775e50..8dfea1c 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -1,11 +1,14 @@
 import { mkdtempSync, readFileSync, rmSync, writeFileSync } from 'node:fs';
 import { tmpdir } from 'node:os';
 import path from 'node:path';
+import { execFileSync } from 'node:child_process';
 
 import { afterEach, beforeEach, describe, expect, it } from 'vitest';
 
 import { exitSuccess, exitUnresolvedConflict, exitUserError, run } from '../src/cli';
 
+const repoRoot = process.cwd();
+
 function writer() {
   let output = '';
   return {
@@ -19,6 +22,47 @@ function writer() {
   };
 }
 
+interface GitDriverJsonFixture {
+  readonly cases: readonly GitDriverJsonCase[];
+}
+
+interface GitDriverJsonCase {
+  readonly case_id: string;
+  readonly path_name: string;
+  readonly base_source: string;
+  readonly ours_source: string;
+  readonly theirs_source: string;
+  readonly expected: {
+    readonly exit_code: number;
+    readonly merged_json?: unknown;
+    readonly merged_source?: string;
+    readonly stderr_contains: readonly string[];
+  };
+}
+
+function readGitDriverJsonFixture(): GitDriverJsonFixture {
+  const source = readFileSync(
+    path.join(
+      repoRoot,
+      '..',
+      'fixtures',
+      'diagnostics',
+      'slice-951-git-driver-json-integration',
+      'git-driver-json-integration.json'
+    ),
+    'utf8'
+  );
+  return JSON.parse(source) as GitDriverJsonFixture;
+}
+
+function runGit(dir: string, ...args: readonly string[]): void {
+  execFileSync('git', args, {
+    cwd: dir,
+    env: { ...process.env, GIT_CONFIG_NOSYSTEM: '1' },
+    stdio: 'pipe'
+  });
+}
+
 describe('smorg-ts cli', () => {
   let previousCwd: string;
   let dir: string;
@@ -116,6 +160,57 @@ describe('smorg-ts cli', () => {
     expect(readFileSync(current, 'utf8')).toBe('{"name":"ours"}');
   });
 
+  it('conforms to the git-driver JSON integration fixture in a repository', () => {
+    try {
+      execFileSync('git', ['--version'], { stdio: 'pipe' });
+    } catch {
+      return;
+    }
+    const fixture = readGitDriverJsonFixture();
+    for (const testCase of fixture.cases) {
+      const caseDir = mkdtempSync(path.join(tmpdir(), 'smorg-ts-git-driver-'));
+      try {
+        runGit(caseDir, 'init');
+        runGit(caseDir, 'config', 'user.email', 'smorg-ts@example.invalid');
+        runGit(caseDir, 'config', 'user.name', 'smorg-ts test');
+        writeFileSync(path.join(caseDir, '.gitattributes'), '*.json merge=smorg-ts smorg.language=json\n');
+        writeFileSync(path.join(caseDir, testCase.path_name), testCase.base_source);
+        runGit(caseDir, 'add', '.');
+        runGit(caseDir, 'commit', '-m', 'base');
+
+        const ancestor = path.join(caseDir, 'ancestor.tmp');
+        const current = path.join(caseDir, testCase.path_name);
+        const other = path.join(caseDir, 'other.tmp');
+        writeFileSync(ancestor, testCase.base_source);
+        writeFileSync(current, testCase.ours_source);
+        writeFileSync(other, testCase.theirs_source);
+        const stdout = writer();
+        const stderr = writer();
+
+        const exit = run(
+          ['merge-driver', '--strict', ancestor, current, other, testCase.path_name],
+          stdout.stream,
+          stderr.stream
+        );
+
+        expect(exit, `${testCase.case_id} stderr=${stderr.output()}`).toBe(
+          testCase.expected.exit_code
+        );
+        for (const expected of testCase.expected.stderr_contains) {
+          expect(stderr.output(), testCase.case_id).toContain(expected);
+        }
+        const mergedSource = readFileSync(current, 'utf8');
+        if (testCase.expected.merged_json !== undefined) {
+          expect(JSON.parse(mergedSource), testCase.case_id).toEqual(testCase.expected.merged_json);
+        } else if (testCase.expected.merged_source !== undefined) {
+          expect(mergedSource, testCase.case_id).toBe(testCase.expected.merged_source);
+        }
+      } finally {
+        rmSync(caseDir, { force: true, recursive: true });
+      }
+    }
+  });
+
   it('supports check-only exit-code without writing', () => {
     const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
     const current = write('current.json', '{"name":"structuredmerge","current":true}');

From 0e604d5df643306b016f545fe7bdbf4f44e1d975 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 14:41:53 -0600
Subject: [PATCH 107/130] Clarify merge driver semantic coverage

---
 README.md | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/README.md b/README.md
index 913300d..911fb39 100644
--- a/README.md
+++ b/README.md
@@ -51,6 +51,10 @@ seven- or nine-argument forms Git passes to external diff commands.
 `conflicts diff` reports conflict-marker regions in a file that already contains
 Git conflict markers.
 
+Current semantic merge-driver coverage is fixture-backed for JSON. Other
+language and format paths should be treated as git-compatible command surfaces
+until their `ast-merge-git` coverage is promoted.
+
 ## Packages
 
 Core:

From 9e76a196f44972b7a0ae132319bdcb7fd2e8c9f2 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 15:11:40 -0600
Subject: [PATCH 108/130] Write conflicted merge output in smorg-ts

---
 packages/ast-merge-git/src/index.ts           | 23 +++++++++-
 .../test/fixtures.integration.test.ts         |  4 ++
 packages/smorg-ts/src/cli.ts                  | 42 ++++++++++++++++---
 packages/smorg-ts/test/cli.test.ts            |  9 +++-
 4 files changed, 70 insertions(+), 8 deletions(-)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 8f2099c..d9a68ca 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -25,6 +25,7 @@ export interface Merge3Conflict {
 export interface Merge3Response {
   readonly ok: boolean;
   readonly merged_source?: string;
+  readonly conflicted_source?: string;
   readonly conflicts: readonly Merge3Conflict[];
   readonly diagnostics: readonly Diagnostic[];
   readonly fallbacks: readonly string[];
@@ -71,6 +72,10 @@ export function merge3Json(request: Merge3Request): Merge3Response {
       return response(request, {
         ok: false,
         conflicts,
+        conflicted_source: renderConflictSource(request, conflicts),
+        render_report: {
+          strategy: 'full_file_conflict_markers'
+        },
         diagnostics: [
           {
             severity: 'error',
@@ -112,6 +117,7 @@ function response(
   return {
     ok: fields.ok,
     merged_source: fields.merged_source,
+    conflicted_source: fields.conflicted_source,
     conflicts: fields.conflicts ?? [],
     diagnostics: fields.diagnostics ?? [],
     fallbacks: fields.fallbacks ?? [],
@@ -121,7 +127,7 @@ function response(
       dialect: request.dialect ?? ''
     },
     render_report: {
-      strategy: request.render_policy || 'canonical'
+      strategy: fields.render_report?.strategy ?? request.render_policy ?? 'canonical'
     },
     formatting_preservation: fields.formatting_preservation ?? {
       line_diff_score: 0,
@@ -131,6 +137,21 @@ function response(
   };
 }
 
+function renderConflictSource(request: Merge3Request, conflicts: readonly Merge3Conflict[]): string {
+  const markerSize = Math.max(request.conflict_marker_size ?? 7, 1);
+  return [
+    `/* smorg structured conflicts: ${conflicts.length} unresolved */`,
+    `${'<'.repeat(markerSize)} ours`,
+    request.ours_source,
+    `${'|'.repeat(markerSize)} base`,
+    request.base_source,
+    '='.repeat(markerSize),
+    request.theirs_source,
+    `${'>'.repeat(markerSize)} theirs`,
+    ''
+  ].join('\n');
+}
+
 function parseJsonRole(role: string, source: string): unknown {
   try {
     return JSON.parse(source);
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index 0c0a4dd..c1e27c6 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -17,6 +17,7 @@ interface Fixture {
       readonly conflict_count: number;
       readonly conflict_categories?: readonly string[];
       readonly conflict_paths?: readonly string[];
+      readonly conflicted_source_contains?: readonly string[];
       readonly reparse_after_render: boolean | null;
     };
   }[];
@@ -57,6 +58,9 @@ describe('@structuredmerge/ast-merge-git', () => {
           result.conflicts.map((conflict) => conflict.path),
           testCase.case_id
         ).toEqual(testCase.expected.conflict_paths);
+        for (const needle of testCase.expected.conflicted_source_contains ?? []) {
+          expect(result.conflicted_source, testCase.case_id).toContain(needle);
+        }
       }
     }
   });
diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index aaa3ea8..8934018 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -129,14 +129,34 @@ function runMergeDriver(
     stderr
   );
   if (profileExit !== exitSuccess) return profileExit;
-  const result = mergeByPath(effectivePath, settings.language, ancestorSource, currentSource, otherSource);
+  const result = mergeByPath(
+    effectivePath,
+    settings.language,
+    settings.conflictMarkerSize,
+    ancestorSource,
+    currentSource,
+    otherSource
+  );
   let output = result.output;
-  if (!result.ok || output === undefined) {
-    if (options.strict || options.fallback === 'none') {
-      printDiagnostics(stderr, result);
-      return exitUnresolvedConflict;
+  if (!result.ok) {
+    printDiagnostics(stderr, result);
+    if (output === undefined && !options.strict && options.fallback !== 'none') {
+      output = currentSource;
+    }
+    if (options.checkOnly) return exitUnresolvedConflict;
+    if (output !== undefined) {
+      try {
+        writeFileSync(options.output ?? options.current, output);
+      } catch (error) {
+        stderr.write(`write output: ${String(error)}\n`);
+        return exitInternalError;
+      }
     }
-    output = currentSource;
+    return exitUnresolvedConflict;
+  }
+  if (output === undefined) {
+    stderr.write('merge completed without output\n');
+    return exitInternalError;
   }
 
   if (options.checkOnly) {
@@ -436,6 +456,7 @@ function runLanguages(
 function mergeByPath(
   pathName: string,
   language: string | undefined,
+  conflictMarkerSize: number,
   ancestorSource: string,
   currentSource: string,
   otherSource: string
@@ -454,6 +475,7 @@ function mergeByPath(
           dialect: 'json',
           profile_id: 'json.keyed-object',
           fallback_policy: 'none',
+          conflict_marker_size: conflictMarkerSize,
           render_policy: 'canonical'
         })
       );
@@ -473,6 +495,14 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeResult<string> {
       policies: []
     };
   }
+  if (!result.ok && result.conflicted_source !== undefined) {
+    return {
+      ok: false,
+      diagnostics: result.diagnostics,
+      output: result.conflicted_source,
+      policies: []
+    };
+  }
   return {
     ok: false,
     diagnostics: result.diagnostics,
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 8dfea1c..52c4374 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -36,6 +36,7 @@ interface GitDriverJsonCase {
     readonly exit_code: number;
     readonly merged_json?: unknown;
     readonly merged_source?: string;
+    readonly conflicted_source_contains?: readonly string[];
     readonly stderr_contains: readonly string[];
   };
 }
@@ -157,7 +158,10 @@ describe('smorg-ts cli', () => {
 
     expect(exit).toBe(exitUnresolvedConflict);
     expect(stderr.output()).toContain('merge_conflict');
-    expect(readFileSync(current, 'utf8')).toBe('{"name":"ours"}');
+    const currentSource = readFileSync(current, 'utf8');
+    for (const needle of ['<<<<<<< ours', '||||||| base', '=======', '>>>>>>> theirs']) {
+      expect(currentSource).toContain(needle);
+    }
   });
 
   it('conforms to the git-driver JSON integration fixture in a repository', () => {
@@ -205,6 +209,9 @@ describe('smorg-ts cli', () => {
         } else if (testCase.expected.merged_source !== undefined) {
           expect(mergedSource, testCase.case_id).toBe(testCase.expected.merged_source);
         }
+        for (const expected of testCase.expected.conflicted_source_contains ?? []) {
+          expect(mergedSource, testCase.case_id).toContain(expected);
+        }
       } finally {
         rmSync(caseDir, { force: true, recursive: true });
       }

From 7a6c70f5c9fc9a6c26f2d0471da7cce24a845b83 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 15:14:39 -0600
Subject: [PATCH 109/130] Write full-file fallback conflicts in smorg-ts

---
 packages/smorg-ts/src/cli.ts       | 26 +++++++++++++++++++++++++-
 packages/smorg-ts/test/cli.test.ts | 21 +++++++++++++++++++++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 8934018..f76dcce 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -141,7 +141,12 @@ function runMergeDriver(
   if (!result.ok) {
     printDiagnostics(stderr, result);
     if (output === undefined && !options.strict && options.fallback !== 'none') {
-      output = currentSource;
+      output = fullFileConflictOutput(
+        settings.conflictMarkerSize,
+        ancestorSource,
+        currentSource,
+        otherSource
+      );
     }
     if (options.checkOnly) return exitUnresolvedConflict;
     if (output !== undefined) {
@@ -172,6 +177,25 @@ function runMergeDriver(
   return exitSuccess;
 }
 
+function fullFileConflictOutput(
+  markerSize: number,
+  ancestorSource: string,
+  currentSource: string,
+  otherSource: string
+): string {
+  const size = Math.max(markerSize, 1);
+  return [
+    `${'<'.repeat(size)} ours`,
+    currentSource,
+    `${'|'.repeat(size)} base`,
+    ancestorSource,
+    '='.repeat(size),
+    otherSource,
+    `${'>'.repeat(size)} theirs`,
+    ''
+  ].join('\n');
+}
+
 function parseMergeDriverOptions(
   args: readonly string[],
   stderr: Pick<NodeJS.WriteStream, 'write'>
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 52c4374..fd98015 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -143,6 +143,27 @@ describe('smorg-ts cli', () => {
     expect(stderr.output()).toContain('ours parse error');
   });
 
+  it('writes full-file conflict markers for non-strict fallback failures', () => {
+    const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
+    const current = write('current.json', '{"name":');
+    const other = write('other.json', '{"other":true}');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', ancestor, current, other, 'package.json'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUnresolvedConflict);
+    const currentSource = readFileSync(current, 'utf8');
+    for (const needle of ['<<<<<<< ours', '||||||| base', '=======', '>>>>>>> theirs']) {
+      expect(currentSource).toContain(needle);
+    }
+    expect(stderr.output()).toContain('parse_error');
+  });
+
   it('uses the ancestor for JSON same-key conflicts', () => {
     const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
     const current = write('current.json', '{"name":"ours"}');

From 9f372eacdee80d529bdf804ff9101b79e6dc4d48 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 15:18:44 -0600
Subject: [PATCH 110/130] Exercise fallback fixture in smorg-ts

---
 packages/smorg-ts/test/cli.test.ts | 69 ++++++++++++++++++++++++++++++
 1 file changed, 69 insertions(+)

diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index fd98015..2ebf38d 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -41,6 +41,28 @@ interface GitDriverJsonCase {
   };
 }
 
+interface GitDriverFallbackFixture {
+  readonly cases: readonly GitDriverFallbackCase[];
+}
+
+interface GitDriverFallbackCase {
+  readonly case_id: string;
+  readonly path_name: string;
+  readonly base_source: string;
+  readonly ours_source: string;
+  readonly theirs_source: string;
+  readonly options: {
+    readonly strict?: boolean;
+    readonly fallback?: string;
+  };
+  readonly expected: {
+    readonly exit_code: number;
+    readonly merged_source?: string;
+    readonly source_contains?: readonly string[];
+    readonly stderr_contains: readonly string[];
+  };
+}
+
 function readGitDriverJsonFixture(): GitDriverJsonFixture {
   const source = readFileSync(
     path.join(
@@ -56,6 +78,21 @@ function readGitDriverJsonFixture(): GitDriverJsonFixture {
   return JSON.parse(source) as GitDriverJsonFixture;
 }
 
+function readGitDriverFallbackFixture(): GitDriverFallbackFixture {
+  const source = readFileSync(
+    path.join(
+      repoRoot,
+      '..',
+      'fixtures',
+      'diagnostics',
+      'slice-954-git-driver-fallback',
+      'git-driver-fallback.json'
+    ),
+    'utf8'
+  );
+  return JSON.parse(source) as GitDriverFallbackFixture;
+}
+
 function runGit(dir: string, ...args: readonly string[]): void {
   execFileSync('git', args, {
     cwd: dir,
@@ -164,6 +201,38 @@ describe('smorg-ts cli', () => {
     expect(stderr.output()).toContain('parse_error');
   });
 
+  it('conforms to the git-driver fallback fixture', () => {
+    const fixture = readGitDriverFallbackFixture();
+    for (const testCase of fixture.cases) {
+      const ancestor = write('ancestor.json', testCase.base_source);
+      const current = write('current.json', testCase.ours_source);
+      const other = write('other.json', testCase.theirs_source);
+      const args = ['merge-driver'];
+      if (testCase.options.strict) args.push('--strict');
+      if (testCase.options.fallback && testCase.options.fallback !== 'full-file') {
+        args.push('--fallback', testCase.options.fallback);
+      }
+      args.push(ancestor, current, other, testCase.path_name);
+      const stdout = writer();
+      const stderr = writer();
+
+      const exit = run(args, stdout.stream, stderr.stream);
+      const currentSource = readFileSync(current, 'utf8');
+      expect(exit, `${testCase.case_id} stderr=${stderr.output()}`).toBe(
+        testCase.expected.exit_code
+      );
+      if (testCase.expected.merged_source !== undefined) {
+        expect(currentSource, testCase.case_id).toBe(testCase.expected.merged_source);
+      }
+      for (const needle of testCase.expected.source_contains ?? []) {
+        expect(currentSource, testCase.case_id).toContain(needle);
+      }
+      for (const needle of testCase.expected.stderr_contains) {
+        expect(stderr.output(), testCase.case_id).toContain(needle);
+      }
+    }
+  });
+
   it('uses the ancestor for JSON same-key conflicts', () => {
     const ancestor = write('ancestor.json', '{"name":"structuredmerge"}');
     const current = write('current.json', '{"name":"ours"}');

From d54ca377db23d3e0965cfc954f020f96027671b7 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 15:48:17 -0600
Subject: [PATCH 111/130] Port comment trivia attachment contract to TypeScript

---
 packages/ast-merge/src/contracts.ts           | 228 ++++++++++++++++++
 packages/ast-merge/src/index.ts               |  28 +++
 .../test/fixtures.integration.test.ts         | 121 ++++++++++
 3 files changed, 377 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 9100d58..90465ff 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -478,6 +478,234 @@ export interface MergeIR {
   readonly diagnostics: readonly string[];
 }
 
+export interface LineRange {
+  readonly start_line: number;
+  readonly end_line: number;
+}
+
+export interface CommentOwnerNode {
+  readonly id: string;
+  readonly kind: string;
+  readonly semantic_roles: readonly string[];
+  readonly line_range: LineRange;
+}
+
+export interface CommentStyleDefinition {
+  readonly style: string;
+  readonly line_prefix: string | null;
+  readonly block_prefix: string | null;
+  readonly block_suffix: string | null;
+}
+
+export interface CommentLine {
+  readonly text: string;
+  readonly line_number: number;
+  readonly normalized_content: string;
+}
+
+export interface CommentRegion {
+  readonly id: string;
+  readonly kind: string;
+  readonly style: string;
+  readonly owner_id: string;
+  readonly floating: boolean;
+  readonly nodes: readonly CommentLine[];
+}
+
+export function commentRegionStartLine(region: CommentRegion): number | undefined {
+  return region.nodes.reduce<number | undefined>(
+    (start, node) => (start === undefined ? node.line_number : Math.min(start, node.line_number)),
+    undefined
+  );
+}
+
+export function commentRegionEndLine(region: CommentRegion): number | undefined {
+  return region.nodes.reduce<number | undefined>(
+    (end, node) => (end === undefined ? node.line_number : Math.max(end, node.line_number)),
+    undefined
+  );
+}
+
+export function commentRegionText(region: CommentRegion): string {
+  return region.nodes.map((node) => node.text).join('\n');
+}
+
+export function commentRegionNormalizedContent(region: CommentRegion): string {
+  return region.nodes.map((node) => node.normalized_content).join('\n');
+}
+
+export function commentRegionSignature(region: CommentRegion): readonly string[] {
+  return ['comment_region', region.kind, commentRegionNormalizedContent(region).slice(0, 121)];
+}
+
+export function commentRegionFreezeActions(
+  region: CommentRegion,
+  token: string
+): readonly string[] {
+  if (token.length === 0) return [];
+  const prefix = `${token.toLowerCase()}:`;
+  return region.nodes.flatMap((node) => {
+    const lower = node.text.toLowerCase();
+    if (lower.includes(`${prefix}freeze`)) return ['freeze'];
+    if (lower.includes(`${prefix}unfreeze`)) return ['unfreeze'];
+    return [];
+  });
+}
+
+export interface LayoutGap {
+  readonly id: string;
+  readonly kind: string;
+  readonly start_line: number;
+  readonly end_line: number;
+  readonly lines: readonly string[];
+  readonly before_owner_id: string | null;
+  readonly after_owner_id: string | null;
+  readonly controller_side: string;
+  readonly metadata?: Readonly<Record<string, unknown>>;
+}
+
+export function layoutGapLineCount(gap: LayoutGap): number {
+  return gap.end_line - gap.start_line + 1;
+}
+
+export function layoutGapBlankLineCount(gap: LayoutGap): number {
+  return gap.lines.filter((line) => line.trim().length === 0).length;
+}
+
+export function layoutGapOwnerIdFor(gap: LayoutGap, side: string): string | undefined {
+  if (side === 'before') return gap.before_owner_id ?? undefined;
+  if (side === 'after') return gap.after_owner_id ?? undefined;
+  return undefined;
+}
+
+export function layoutGapControllerOwnerId(gap: LayoutGap): string | undefined {
+  return layoutGapOwnerIdFor(gap, gap.controller_side);
+}
+
+export function layoutGapFallbackOwnerId(gap: LayoutGap): string | undefined {
+  if (gap.controller_side === 'before') return gap.after_owner_id ?? undefined;
+  if (gap.controller_side === 'after') return gap.before_owner_id ?? undefined;
+  return undefined;
+}
+
+export function layoutGapEffectiveControllerOwnerId(
+  gap: LayoutGap,
+  removedOwners: ReadonlySet<string>
+): string | undefined {
+  const controller = layoutGapControllerOwnerId(gap);
+  if (controller !== undefined && !removedOwners.has(controller)) return controller;
+  const fallback = layoutGapFallbackOwnerId(gap);
+  if (fallback !== undefined && !removedOwners.has(fallback)) return fallback;
+  return undefined;
+}
+
+export function layoutGapLeadingFor(gap: LayoutGap, ownerId: string): boolean {
+  return gap.after_owner_id === ownerId;
+}
+
+export function layoutGapTrailingFor(gap: LayoutGap, ownerId: string): boolean {
+  return gap.before_owner_id === ownerId;
+}
+
+export function layoutGapControlsOutputFor(gap: LayoutGap, ownerId: string): boolean {
+  return layoutGapControllerOwnerId(gap) === ownerId;
+}
+
+export interface CommentAttachment {
+  readonly owner_id: string;
+  readonly leading_region_id: string | null;
+  readonly inline_region_id: string | null;
+  readonly trailing_region_id: string | null;
+  readonly orphan_region_ids: readonly string[];
+  readonly leading_gap_id: string | null;
+  readonly trailing_gap_id: string | null;
+  readonly metadata: Readonly<Record<string, unknown>>;
+}
+
+export function commentAttachmentRegionCount(
+  attachment: CommentAttachment,
+  regions: ReadonlyMap<string, CommentRegion>
+): number {
+  const direct = [
+    attachment.leading_region_id,
+    attachment.inline_region_id,
+    attachment.trailing_region_id
+  ].filter((id): id is string => id !== null && regions.has(id)).length;
+  return direct + attachment.orphan_region_ids.filter((id) => regions.has(id)).length;
+}
+
+export function commentAttachmentLayoutGapCount(
+  attachment: CommentAttachment,
+  gaps: ReadonlyMap<string, LayoutGap>
+): number {
+  return new Set(
+    [attachment.leading_gap_id, attachment.trailing_gap_id].filter(
+      (id): id is string => id !== null && gaps.has(id)
+    )
+  ).size;
+}
+
+export function commentAttachmentEmpty(
+  attachment: CommentAttachment,
+  regions: ReadonlyMap<string, CommentRegion>
+): boolean {
+  return commentAttachmentRegionCount(attachment, regions) === 0;
+}
+
+export function commentAttachmentLeadingRegionLayoutOwned(
+  attachment: CommentAttachment,
+  regions: ReadonlyMap<string, CommentRegion>,
+  gaps: ReadonlyMap<string, LayoutGap>
+): boolean {
+  if (attachment.leading_region_id === null || attachment.leading_gap_id === null) return false;
+  const region = regions.get(attachment.leading_region_id);
+  const gap = gaps.get(attachment.leading_gap_id);
+  return (
+    region !== undefined &&
+    gap !== undefined &&
+    region.floating &&
+    layoutGapLeadingFor(gap, attachment.owner_id) &&
+    layoutGapControlsOutputFor(gap, attachment.owner_id)
+  );
+}
+
+export function commentAttachmentTrailingRegionLayoutOwned(
+  attachment: CommentAttachment,
+  regions: ReadonlyMap<string, CommentRegion>,
+  gaps: ReadonlyMap<string, LayoutGap>
+): boolean {
+  if (attachment.trailing_region_id === null || attachment.trailing_gap_id === null) return false;
+  const region = regions.get(attachment.trailing_region_id);
+  const gap = gaps.get(attachment.trailing_gap_id);
+  return (
+    region !== undefined &&
+    gap !== undefined &&
+    region.floating &&
+    layoutGapTrailingFor(gap, attachment.owner_id) &&
+    layoutGapControlsOutputFor(gap, attachment.owner_id)
+  );
+}
+
+export function commentAttachmentFreezeMarker(
+  attachment: CommentAttachment,
+  regions: ReadonlyMap<string, CommentRegion>,
+  token: string
+): boolean {
+  return [
+    attachment.leading_region_id,
+    attachment.inline_region_id,
+    attachment.trailing_region_id,
+    ...attachment.orphan_region_ids
+  ]
+    .filter((id): id is string => id !== null)
+    .some((id) => {
+      const region = regions.get(id);
+      if (region === undefined) return false;
+      const actions = commentRegionFreezeActions(region, token);
+      return actions.includes('freeze') || actions.includes('unfreeze');
+    });
+}
+
 export interface PairwiseNodeMatch {
   readonly from_node_id: string;
   readonly to_node_id: string;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index e55a06a..19db02a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -18,6 +18,11 @@ export type {
   ClassMappingDiagnostic,
   ClassMappingNodeClass,
   ClassMappingReport,
+  CommentAttachment,
+  CommentLine,
+  CommentOwnerNode,
+  CommentRegion,
+  CommentStyleDefinition,
   ConflictCategoryReport,
   ConflictHandlerRegistration,
   ConflictHandlerRegistryReport,
@@ -95,6 +100,8 @@ export type {
   LanguageBackendProfileRules,
   LanguageProfileHandlerRegistration,
   LanguageProfileHandlerRegistry,
+  LayoutGap,
+  LineRange,
   LineSpan,
   LocalLineFallbackReport,
   MergeConflict,
@@ -496,7 +503,28 @@ export {
   runTemplateTreeExecutionFromDirectories,
   planTemplateTreeExecutionFromDirectories,
   applyTemplateTreeExecutionToDirectory,
+  commentAttachmentEmpty,
+  commentAttachmentFreezeMarker,
+  commentAttachmentLayoutGapCount,
+  commentAttachmentLeadingRegionLayoutOwned,
+  commentAttachmentRegionCount,
+  commentAttachmentTrailingRegionLayoutOwned,
+  commentRegionEndLine,
+  commentRegionFreezeActions,
+  commentRegionNormalizedContent,
+  commentRegionSignature,
+  commentRegionStartLine,
+  commentRegionText,
   reportTemplateTreeRun,
+  layoutGapBlankLineCount,
+  layoutGapControlsOutputFor,
+  layoutGapControllerOwnerId,
+  layoutGapEffectiveControllerOwnerId,
+  layoutGapFallbackOwnerId,
+  layoutGapLeadingFor,
+  layoutGapLineCount,
+  layoutGapOwnerIdFor,
+  layoutGapTrailingFor,
   reportTemplateDirectoryApply,
   reportTemplateDirectoryPlan,
   reportTemplateDirectoryRunner,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 0446be2..421682b 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -7,10 +7,27 @@ import { mergeMarkdown } from '../../markdown-merge/src/index';
 import { mergeToml } from '../../toml-merge/src/index';
 import { mergeRuby } from '../../ruby-merge/src/index';
 import {
+  commentAttachmentEmpty,
+  commentAttachmentFreezeMarker,
+  commentAttachmentLayoutGapCount,
+  commentAttachmentLeadingRegionLayoutOwned,
+  commentAttachmentRegionCount,
+  commentAttachmentTrailingRegionLayoutOwned,
+  commentRegionEndLine,
+  commentRegionFreezeActions,
+  commentRegionNormalizedContent,
+  commentRegionSignature,
+  commentRegionStartLine,
+  commentRegionText,
   evaluateProfilePromotion,
   evaluateProfileSelectionRequirement,
   executeGenericConflictHandler,
   initialProfilePromotionPolicy,
+  layoutGapBlankLineCount,
+  layoutGapControllerOwnerId,
+  layoutGapEffectiveControllerOwnerId,
+  layoutGapFallbackOwnerId,
+  layoutGapLineCount,
   promotionProfileJsonKeyedObject,
   promotionProfileRubyGemspecDependencyDeclarations,
   validateLanguageBackendProfile
@@ -55,6 +72,10 @@ import type {
   FallbackUsageReport,
   ChangeSet,
   ClassMappingReport,
+  CommentAttachment,
+  CommentOwnerNode,
+  CommentRegion,
+  CommentStyleDefinition,
   ConflictCategoryReport,
   ConflictHandlerRegistryReport,
   ConflictMarkerRenderingReport,
@@ -72,6 +93,7 @@ import type {
   InconsistencyReport,
   LanguageBackendProfile,
   LanguageProfileHandlerRegistry,
+  LayoutGap,
   LocalLineFallbackReport,
   MatchingDebugArtifacts,
   MergeIR,
@@ -5792,6 +5814,105 @@ describe('ast-merge shared fixtures', () => {
     expect(mergeIR.changes[1]?.class_id).toBe('class-import-strings');
   });
 
+  it('conforms to the slice-955 comment trivia attachment contract fixture', () => {
+    const fixture = readFixture<{
+      owner_nodes: readonly CommentOwnerNode[];
+      comment_styles: readonly CommentStyleDefinition[];
+      comment_regions: readonly (CommentRegion & {
+        expected: {
+          start_line: number;
+          end_line: number;
+          text: string;
+          normalized_content: string;
+          signature: readonly string[];
+          freeze_actions: readonly string[];
+        };
+      })[];
+      layout_gaps: readonly (LayoutGap & {
+        expected: {
+          line_count: number;
+          blank_line_count: number;
+          controller_owner_id: string | null;
+          fallback_owner_id: string | null;
+          effective_controller_with_after_removed?: string;
+        };
+      })[];
+      attachments: readonly (CommentAttachment & {
+        expected: {
+          region_count: number;
+          layout_gap_count: number;
+          empty: boolean;
+          leading_region_layout_owned: boolean;
+          trailing_region_layout_owned: boolean;
+          freeze_marker: boolean;
+        };
+      })[];
+      contract_rules: readonly string[];
+      expected: {
+        owner_count: number;
+        comment_region_count: number;
+        layout_gap_count: number;
+        attachment_count: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-955-comment-trivia-attachment-contract',
+      'comment-trivia-attachment-contract.json'
+    );
+
+    const regions = new Map(fixture.comment_regions.map((region) => [region.id, region]));
+    const gaps = new Map(fixture.layout_gaps.map((gap) => [gap.id, gap]));
+
+    expect(fixture.owner_nodes).toHaveLength(fixture.expected.owner_count);
+    expect(fixture.comment_regions).toHaveLength(fixture.expected.comment_region_count);
+    expect(fixture.layout_gaps).toHaveLength(fixture.expected.layout_gap_count);
+    expect(fixture.attachments).toHaveLength(fixture.expected.attachment_count);
+    expect(fixture.comment_styles[0]?.style).toBe('hash_comment');
+    expect(fixture.comment_styles[0]?.line_prefix).toBe('#');
+
+    for (const region of fixture.comment_regions) {
+      expect(commentRegionStartLine(region)).toBe(region.expected.start_line);
+      expect(commentRegionEndLine(region)).toBe(region.expected.end_line);
+      expect(commentRegionText(region)).toBe(region.expected.text);
+      expect(commentRegionNormalizedContent(region)).toBe(region.expected.normalized_content);
+      expect(commentRegionSignature(region)).toEqual(region.expected.signature);
+      expect(commentRegionFreezeActions(region, 'smorg')).toEqual(region.expected.freeze_actions);
+    }
+
+    for (const gap of fixture.layout_gaps) {
+      expect(layoutGapLineCount(gap)).toBe(gap.expected.line_count);
+      expect(layoutGapBlankLineCount(gap)).toBe(gap.expected.blank_line_count);
+      expect(layoutGapControllerOwnerId(gap) ?? null).toBe(gap.expected.controller_owner_id);
+      expect(layoutGapFallbackOwnerId(gap) ?? null).toBe(gap.expected.fallback_owner_id);
+      if (gap.expected.effective_controller_with_after_removed !== undefined) {
+        expect(layoutGapEffectiveControllerOwnerId(gap, new Set([gap.after_owner_id!]))).toBe(
+          gap.expected.effective_controller_with_after_removed
+        );
+      }
+    }
+
+    for (const attachment of fixture.attachments) {
+      expect(commentAttachmentRegionCount(attachment, regions)).toBe(
+        attachment.expected.region_count
+      );
+      expect(commentAttachmentLayoutGapCount(attachment, gaps)).toBe(
+        attachment.expected.layout_gap_count
+      );
+      expect(commentAttachmentEmpty(attachment, regions)).toBe(attachment.expected.empty);
+      expect(commentAttachmentLeadingRegionLayoutOwned(attachment, regions, gaps)).toBe(
+        attachment.expected.leading_region_layout_owned
+      );
+      expect(commentAttachmentTrailingRegionLayoutOwned(attachment, regions, gaps)).toBe(
+        attachment.expected.trailing_region_layout_owned
+      );
+      expect(commentAttachmentFreezeMarker(attachment, regions, 'smorg')).toBe(
+        attachment.expected.freeze_marker
+      );
+    }
+
+    expect(fixture.contract_rules.some((rule) => rule.includes('passive data'))).toBe(true);
+  });
+
   it('conforms to the slice-906 merge engine suite setting fixture', () => {
     const fixture = readFixture<{
       settings: {

From b22e0b907b5ea2fc637a73c69e400fde3e27d2e5 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 17:52:04 -0600
Subject: [PATCH 112/130] Conform to merge result decision fixture

---
 packages/ast-merge/src/contracts.ts           | 32 +++++++++++++++++
 packages/ast-merge/src/index.ts               |  4 +++
 .../test/fixtures.integration.test.ts         | 35 +++++++++++++++++++
 3 files changed, 71 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 90465ff..1ba65b8 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -441,6 +441,38 @@ export interface MergeResult<TOutput> {
   readonly policies?: readonly PolicyReference[];
 }
 
+export interface MergeDecisionRecord {
+  readonly id: string;
+  readonly decision: string;
+  readonly source: string;
+  readonly line: number;
+  readonly owner_id: string;
+  readonly reason: string;
+  readonly metadata?: Readonly<Record<string, unknown>>;
+}
+
+export function mergeDecisionSummary(
+  decisions: readonly MergeDecisionRecord[]
+): Readonly<Record<string, number>> {
+  return decisions.reduce<Record<string, number>>((summary, decision) => {
+    summary[decision.decision] = (summary[decision.decision] ?? 0) + 1;
+    return summary;
+  }, {});
+}
+
+export function mergeDecisionSourceSummary(
+  decisions: readonly MergeDecisionRecord[]
+): Readonly<Record<string, number>> {
+  return decisions.reduce<Record<string, number>>((summary, decision) => {
+    summary[decision.source] = (summary[decision.source] ?? 0) + 1;
+    return summary;
+  }, {});
+}
+
+export function mergeDecisionReviewRequired(decisions: readonly MergeDecisionRecord[]): boolean {
+  return decisions.some((decision) => decision.decision === 'unresolved');
+}
+
 export interface MergeIRNodeClass {
   readonly class_id: string;
   readonly signature: string;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 19db02a..825880a 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -151,6 +151,7 @@ export type {
   DiscoveredSurface,
   DelegatedChildOperation,
   ReviewDiagnosticReason,
+  MergeDecisionRecord,
   MergeIR,
   MergeIRChange,
   MergeIRNodeClass,
@@ -515,6 +516,9 @@ export {
   commentRegionSignature,
   commentRegionStartLine,
   commentRegionText,
+  mergeDecisionReviewRequired,
+  mergeDecisionSourceSummary,
+  mergeDecisionSummary,
   reportTemplateTreeRun,
   layoutGapBlankLineCount,
   layoutGapControlsOutputFor,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 421682b..217b240 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -28,6 +28,9 @@ import {
   layoutGapEffectiveControllerOwnerId,
   layoutGapFallbackOwnerId,
   layoutGapLineCount,
+  mergeDecisionReviewRequired,
+  mergeDecisionSourceSummary,
+  mergeDecisionSummary,
   promotionProfileJsonKeyedObject,
   promotionProfileRubyGemspecDependencyDeclarations,
   validateLanguageBackendProfile
@@ -96,6 +99,7 @@ import type {
   LayoutGap,
   LocalLineFallbackReport,
   MatchingDebugArtifacts,
+  MergeDecisionRecord,
   MergeIR,
   MergeIRComparisonReport,
   MoveDetectionMatchingReport,
@@ -5913,6 +5917,37 @@ describe('ast-merge shared fixtures', () => {
     expect(fixture.contract_rules.some((rule) => rule.includes('passive data'))).toBe(true);
   });
 
+  it('conforms to the slice-956 merge result decision contract fixture', () => {
+    const fixture = readFixture<{
+      decisions: readonly MergeDecisionRecord[];
+      expected: {
+        decision_count: number;
+        ordered_decision_ids: readonly string[];
+        decision_summary: Readonly<Record<string, number>>;
+        source_summary: Readonly<Record<string, number>>;
+        unresolved_count: number;
+        review_required: boolean;
+        line_count: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-956-merge-result-decision-contract',
+      'merge-result-decision-contract.json'
+    );
+    const orderedIds = fixture.decisions.map((decision) => decision.id);
+    const unresolvedCount = fixture.decisions.filter(
+      (decision) => decision.decision === 'unresolved'
+    ).length;
+
+    expect(fixture.decisions).toHaveLength(fixture.expected.decision_count);
+    expect(orderedIds).toEqual(fixture.expected.ordered_decision_ids);
+    expect(mergeDecisionSummary(fixture.decisions)).toEqual(fixture.expected.decision_summary);
+    expect(mergeDecisionSourceSummary(fixture.decisions)).toEqual(fixture.expected.source_summary);
+    expect(unresolvedCount).toBe(fixture.expected.unresolved_count);
+    expect(mergeDecisionReviewRequired(fixture.decisions)).toBe(fixture.expected.review_required);
+    expect(fixture.decisions).toHaveLength(fixture.expected.line_count);
+  });
+
   it('conforms to the slice-906 merge engine suite setting fixture', () => {
     const fixture = readFixture<{
       settings: {

From f0886d5b511fd9a8ccb9b2aa99dd9cdd7480865b Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 18:15:34 -0600
Subject: [PATCH 113/130] Conform to freeze directive execution fixture

---
 packages/ast-merge/src/contracts.ts           | 116 ++++++++++++++++++
 packages/ast-merge/src/index.ts               |   4 +
 .../test/fixtures.integration.test.ts         |  72 +++++++++++
 3 files changed, 192 insertions(+)

diff --git a/packages/ast-merge/src/contracts.ts b/packages/ast-merge/src/contracts.ts
index 1ba65b8..7906561 100644
--- a/packages/ast-merge/src/contracts.ts
+++ b/packages/ast-merge/src/contracts.ts
@@ -473,6 +473,122 @@ export function mergeDecisionReviewRequired(decisions: readonly MergeDecisionRec
   return decisions.some((decision) => decision.decision === 'unresolved');
 }
 
+export interface FreezeDirectiveBlock {
+  readonly id: string;
+  readonly style?: string;
+  readonly token?: string;
+  readonly start_line: number;
+  readonly end_line: number;
+  readonly reason: string;
+  readonly content_lines: readonly string[];
+  readonly merge_policy: string;
+  readonly decision: string;
+  readonly signature: readonly string[];
+}
+
+export interface FreezeDirectiveDiagnostic {
+  readonly category: string;
+  readonly severity: string;
+  readonly message?: string;
+  readonly line: number;
+}
+
+export function detectFreezeDirectiveBlocks(
+  caseId: string,
+  lines: readonly string[],
+  token: string,
+  style: string
+): { blocks: readonly FreezeDirectiveBlock[]; diagnostics: readonly FreezeDirectiveDiagnostic[] } {
+  const blocks: FreezeDirectiveBlock[] = [];
+  const diagnostics: FreezeDirectiveDiagnostic[] = [];
+  let openLine: number | undefined;
+  let reason = '';
+
+  lines.forEach((line, index) => {
+    const lineNumber = index + 1;
+    const marker = freezeDirectiveAction(line, token, style);
+    if (marker === undefined) return;
+
+    if (marker.action === 'freeze') {
+      if (openLine !== undefined) {
+        diagnostics.push({ category: 'nested_freeze_open', severity: 'error', line: lineNumber });
+        return;
+      }
+      openLine = lineNumber;
+      reason = marker.reason;
+      return;
+    }
+
+    if (openLine === undefined) {
+      diagnostics.push({ category: 'unmatched_freeze_close', severity: 'error', line: lineNumber });
+      return;
+    }
+    const start = openLine;
+    const end = lineNumber;
+    blocks.push({
+      id: `freeze:${caseId}:${start}-${end}`,
+      style,
+      token,
+      start_line: start,
+      end_line: end,
+      reason,
+      content_lines: lines.slice(start - 1, end),
+      merge_policy: 'destination',
+      decision: 'freeze_block',
+      signature: ['freeze_block', String(start), String(end)]
+    });
+    openLine = undefined;
+    reason = '';
+  });
+
+  if (openLine !== undefined) {
+    diagnostics.push({ category: 'unclosed_freeze_open', severity: 'error', line: openLine });
+    return { blocks: [], diagnostics };
+  }
+  if (diagnostics.length > 0) return { blocks: [], diagnostics };
+  return { blocks, diagnostics };
+}
+
+export function freezeDirectiveBlockForLine(
+  blocks: readonly FreezeDirectiveBlock[],
+  line: number
+): FreezeDirectiveBlock | undefined {
+  return blocks.find((block) => line >= block.start_line && line <= block.end_line);
+}
+
+function freezeDirectiveAction(
+  line: string,
+  token: string,
+  style: string
+): { action: 'freeze' | 'unfreeze'; reason: string } | undefined {
+  const content = freezeDirectiveCommentContent(line, style);
+  if (content === undefined) return undefined;
+  const prefix = `${token.toLowerCase()}:`;
+  if (!content.toLowerCase().startsWith(prefix)) return undefined;
+  const remainder = content.slice(prefix.length).trim();
+  const lower = remainder.toLowerCase();
+  if (lower.startsWith('unfreeze')) {
+    return { action: 'unfreeze', reason: remainder.slice('unfreeze'.length).trim() };
+  }
+  if (lower.startsWith('freeze')) {
+    return { action: 'freeze', reason: remainder.slice('freeze'.length).trim() };
+  }
+  return undefined;
+}
+
+function freezeDirectiveCommentContent(line: string, style: string): string | undefined {
+  const trimmed = line.trim();
+  if (style === 'hash_comment' && trimmed.startsWith('#')) return trimmed.slice(1).trim();
+  if (style === 'c_style_line' && trimmed.startsWith('//')) return trimmed.slice(2).trim();
+  if (style === 'html_comment' && trimmed.startsWith('<!--') && trimmed.endsWith('-->')) {
+    return trimmed.slice(4, -3).trim();
+  }
+  if (style === 'c_style_block' && trimmed.startsWith('/*') && trimmed.endsWith('*/')) {
+    return trimmed.slice(2, -2).trim();
+  }
+  return undefined;
+}
+
 export interface MergeIRNodeClass {
   readonly class_id: string;
   readonly signature: string;
diff --git a/packages/ast-merge/src/index.ts b/packages/ast-merge/src/index.ts
index 825880a..14181e4 100644
--- a/packages/ast-merge/src/index.ts
+++ b/packages/ast-merge/src/index.ts
@@ -75,6 +75,8 @@ export type {
   FallbackUsageSummary,
   FalseTextualConflictCase,
   FalseTextualConflictSuite,
+  FreezeDirectiveBlock,
+  FreezeDirectiveDiagnostic,
   FormattingEdgeFixtureCase,
   FormattingEdgeFixtureSuite,
   FormattingHardGate,
@@ -516,6 +518,8 @@ export {
   commentRegionSignature,
   commentRegionStartLine,
   commentRegionText,
+  detectFreezeDirectiveBlocks,
+  freezeDirectiveBlockForLine,
   mergeDecisionReviewRequired,
   mergeDecisionSourceSummary,
   mergeDecisionSummary,
diff --git a/packages/ast-merge/test/fixtures.integration.test.ts b/packages/ast-merge/test/fixtures.integration.test.ts
index 217b240..c820c44 100644
--- a/packages/ast-merge/test/fixtures.integration.test.ts
+++ b/packages/ast-merge/test/fixtures.integration.test.ts
@@ -19,9 +19,11 @@ import {
   commentRegionSignature,
   commentRegionStartLine,
   commentRegionText,
+  detectFreezeDirectiveBlocks,
   evaluateProfilePromotion,
   evaluateProfileSelectionRequirement,
   executeGenericConflictHandler,
+  freezeDirectiveBlockForLine,
   initialProfilePromotionPolicy,
   layoutGapBlankLineCount,
   layoutGapControllerOwnerId,
@@ -84,6 +86,8 @@ import type {
   ConflictMarkerRenderingReport,
   FamilyFeatureProfile,
   FalseTextualConflictSuite,
+  FreezeDirectiveBlock,
+  FreezeDirectiveDiagnostic,
   FormattingEdgeFixtureSuite,
   FormattingHardGateReport,
   FormattingPreservationConformanceReport,
@@ -5948,6 +5952,74 @@ describe('ast-merge shared fixtures', () => {
     expect(fixture.decisions).toHaveLength(fixture.expected.line_count);
   });
 
+  it('conforms to the slice-957 freeze directive execution contract fixture', () => {
+    const fixture = readFixture<{
+      cases: readonly {
+        id: string;
+        style: string;
+        token: string;
+        lines: readonly string[];
+        expected: {
+          valid: boolean;
+          block_count: number;
+          diagnostic_count: number;
+          blocks: readonly FreezeDirectiveBlock[];
+          diagnostics?: readonly FreezeDirectiveDiagnostic[];
+          line_queries: readonly {
+            line: number;
+            in_freeze: boolean;
+            block_id: string | null;
+          }[];
+        };
+      }[];
+      expected: {
+        case_count: number;
+        valid_case_count: number;
+        invalid_case_count: number;
+      };
+    }>(
+      'diagnostics',
+      'slice-957-freeze-directive-execution-contract',
+      'freeze-directive-execution-contract.json'
+    );
+    let validCount = 0;
+    let invalidCount = 0;
+
+    for (const testCase of fixture.cases) {
+      const { blocks, diagnostics } = detectFreezeDirectiveBlocks(
+        testCase.id,
+        testCase.lines,
+        testCase.token,
+        testCase.style
+      );
+      if (testCase.expected.valid) validCount += 1;
+      else invalidCount += 1;
+
+      expect(blocks).toHaveLength(testCase.expected.block_count);
+      expect(diagnostics).toHaveLength(testCase.expected.diagnostic_count);
+      expect(diagnostics.length === 0).toBe(testCase.expected.valid);
+      if (blocks.length > 0) expect(blocks).toEqual(testCase.expected.blocks);
+      if (diagnostics.length > 0) {
+        expect(
+          diagnostics.map((diagnostic) => ({
+            category: diagnostic.category,
+            severity: diagnostic.severity,
+            line: diagnostic.line
+          }))
+        ).toEqual(testCase.expected.diagnostics);
+      }
+      for (const query of testCase.expected.line_queries) {
+        const block = freezeDirectiveBlockForLine(blocks, query.line);
+        expect(block !== undefined).toBe(query.in_freeze);
+        if (block !== undefined) expect(block.id).toBe(query.block_id);
+      }
+    }
+
+    expect(fixture.cases).toHaveLength(fixture.expected.case_count);
+    expect(validCount).toBe(fixture.expected.valid_case_count);
+    expect(invalidCount).toBe(fixture.expected.invalid_case_count);
+  });
+
   it('conforms to the slice-906 merge engine suite setting fixture', () => {
     const fixture = readFixture<{
       settings: {

From 66cd51b55aa378930cc2bf555e5bcbaecc360b83 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 19:07:17 -0600
Subject: [PATCH 114/130] Add git comment delta primitive

---
 packages/ast-merge-git/src/index.ts           | 60 +++++++++++++++++-
 .../test/fixtures.integration.test.ts         | 63 ++++++++++++++++++-
 2 files changed, 120 insertions(+), 3 deletions(-)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index d9a68ca..1462109 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -40,6 +40,12 @@ export interface Merge3Response {
   readonly reparse_after_render: boolean | null;
 }
 
+export interface CommentDeltaResult {
+  readonly ok: boolean;
+  readonly merged_comment: string | null;
+  readonly conflicts: readonly Merge3Conflict[];
+}
+
 const absent = Symbol('absent');
 type MaybeAbsent = unknown | typeof absent;
 
@@ -110,6 +116,42 @@ export function merge3Json(request: Merge3Request): Merge3Response {
   }
 }
 
+export function mergeCommentDelta(
+  baseComment: string | null,
+  oursComment: string | null,
+  theirsComment: string | null,
+  ownerPath: string
+): CommentDeltaResult {
+  const conflicts: Merge3Conflict[] = [];
+  let mergedComment: string | null = null;
+
+  if (oursComment === theirsComment) {
+    mergedComment = oursComment;
+  } else if (baseComment === oursComment) {
+    mergedComment = theirsComment;
+  } else if (baseComment === theirsComment) {
+    mergedComment = oursComment;
+  } else if (oursComment === null) {
+    conflicts.push(
+      commentConflict('delete_edit', ownerPath, 'ours deleted a comment that theirs edited')
+    );
+  } else if (theirsComment === null) {
+    conflicts.push(
+      commentConflict('delete_edit', ownerPath, 'theirs deleted a comment that ours edited')
+    );
+  } else {
+    conflicts.push(
+      commentConflict('edit_edit', ownerPath, 'comment changed differently in ours and theirs')
+    );
+  }
+
+  return {
+    ok: conflicts.length === 0,
+    merged_comment: conflicts.length === 0 ? mergedComment : null,
+    conflicts
+  };
+}
+
 function response(
   request: Merge3Request,
   fields: Partial<Merge3Response> & { readonly ok: boolean }
@@ -137,7 +179,10 @@ function response(
   };
 }
 
-function renderConflictSource(request: Merge3Request, conflicts: readonly Merge3Conflict[]): string {
+function renderConflictSource(
+  request: Merge3Request,
+  conflicts: readonly Merge3Conflict[]
+): string {
   const markerSize = Math.max(request.conflict_marker_size ?? 7, 1);
   return [
     `/* smorg structured conflicts: ${conflicts.length} unresolved */`,
@@ -186,7 +231,9 @@ function mergeJsonObjects(
   conflicts: Merge3Conflict[]
 ): Readonly<Record<string, unknown>> {
   const result: Record<string, unknown> = {};
-  const keys = [...new Set([...Object.keys(base), ...Object.keys(ours), ...Object.keys(theirs)])].sort();
+  const keys = [
+    ...new Set([...Object.keys(base), ...Object.keys(ours), ...Object.keys(theirs)])
+  ].sort();
   for (const key of keys) {
     const [merged, keep] = mergeJsonEntry(
       Object.hasOwn(base, key) ? base[key] : absent,
@@ -246,6 +293,15 @@ function addConflict(
   });
 }
 
+function commentConflict(category: string, path: string, message: string): Merge3Conflict {
+  return {
+    conflict_id: 'comment-conflict-1',
+    category,
+    path: path || '/',
+    message
+  };
+}
+
 function jsonPointerJoin(parent: string, token: string): string {
   const escaped = token.replaceAll('~', '~0').replaceAll('/', '~1');
   return parent ? `${parent}/${escaped}` : `/${escaped}`;
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index c1e27c6..3204206 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -1,7 +1,7 @@
 import { readFileSync } from 'node:fs';
 import path from 'node:path';
 import { describe, expect, it } from 'vitest';
-import { merge3, type Merge3Request } from '../src/index';
+import { merge3, mergeCommentDelta, type Merge3Request } from '../src/index';
 
 interface Fixture {
   readonly contract: {
@@ -28,6 +28,34 @@ function readFixture(...parts: readonly string[]): Fixture {
   return JSON.parse(source) as Fixture;
 }
 
+interface CommentDeltaFixture {
+  readonly contract: {
+    readonly package: string;
+    readonly operation: string;
+  };
+  readonly owner: {
+    readonly path: string;
+  };
+  readonly cases: readonly {
+    readonly case_id: string;
+    readonly base_comment: string | null;
+    readonly ours_comment: string | null;
+    readonly theirs_comment: string | null;
+    readonly expected: {
+      readonly ok: boolean;
+      readonly merged_comment?: string | null;
+      readonly conflict_count: number;
+      readonly conflict_categories?: readonly string[];
+      readonly comment_owner_path?: string;
+    };
+  }[];
+}
+
+function readCommentDeltaFixture(...parts: readonly string[]): CommentDeltaFixture {
+  const source = readFileSync(path.join('..', 'fixtures', ...parts), 'utf8');
+  return JSON.parse(source) as CommentDeltaFixture;
+}
+
 describe('@structuredmerge/ast-merge-git', () => {
   it('conforms to the git merge3 contract fixture', () => {
     const fixture = readFixture(
@@ -64,4 +92,37 @@ describe('@structuredmerge/ast-merge-git', () => {
       }
     }
   });
+
+  it('conforms to the git comment delta semantics fixture', () => {
+    const fixture = readCommentDeltaFixture(
+      'diagnostics',
+      'slice-953-git-comment-delta-semantics',
+      'git-comment-delta-semantics.json'
+    );
+    expect(fixture.contract.package).toBe('ast-merge-git');
+    expect(fixture.contract.operation).toBe('comment_delta_semantics');
+
+    for (const testCase of fixture.cases) {
+      const result = mergeCommentDelta(
+        testCase.base_comment,
+        testCase.ours_comment,
+        testCase.theirs_comment,
+        fixture.owner.path
+      );
+      expect(result.ok, testCase.case_id).toBe(testCase.expected.ok);
+      expect(result.conflicts, testCase.case_id).toHaveLength(testCase.expected.conflict_count);
+      if ('merged_comment' in testCase.expected) {
+        expect(result.merged_comment, testCase.case_id).toBe(testCase.expected.merged_comment);
+      }
+      if (testCase.expected.conflict_categories !== undefined) {
+        expect(
+          result.conflicts.map((conflict) => conflict.category),
+          testCase.case_id
+        ).toEqual(testCase.expected.conflict_categories);
+      }
+      if (testCase.expected.comment_owner_path !== undefined) {
+        expect(fixture.owner.path, testCase.case_id).toBe(testCase.expected.comment_owner_path);
+      }
+    }
+  });
 });

From b72da66d42bfa29b13169c8718f5f293bea8d8cd Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 19:25:17 -0600
Subject: [PATCH 115/130] Report merge3 render identity

---
 packages/ast-merge-git/src/index.ts              | 16 ++++++++++++++++
 .../test/fixtures.integration.test.ts            |  8 ++++++++
 2 files changed, 24 insertions(+)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 1462109..491cd6f 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -32,6 +32,8 @@ export interface Merge3Response {
   readonly profile: Readonly<Record<string, string>>;
   readonly render_report: {
     readonly strategy: string;
+    readonly backend_id?: string;
+    readonly parser_identity?: string;
   };
   readonly formatting_preservation: {
     readonly line_diff_score: number;
@@ -169,6 +171,7 @@ function response(
       dialect: request.dialect ?? ''
     },
     render_report: {
+      ...renderIdentity(request),
       strategy: fields.render_report?.strategy ?? request.render_policy ?? 'canonical'
     },
     formatting_preservation: fields.formatting_preservation ?? {
@@ -179,6 +182,19 @@ function response(
   };
 }
 
+function renderIdentity(request: Merge3Request): {
+  readonly backend_id?: string;
+  readonly parser_identity?: string;
+} {
+  if (normalizeLanguage(request) === 'json') {
+    return {
+      backend_id: 'native-json',
+      parser_identity: 'standard-json'
+    };
+  }
+  return {};
+}
+
 function renderConflictSource(
   request: Merge3Request,
   conflicts: readonly Merge3Conflict[]
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index 3204206..4b39e82 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -18,6 +18,11 @@ interface Fixture {
       readonly conflict_categories?: readonly string[];
       readonly conflict_paths?: readonly string[];
       readonly conflicted_source_contains?: readonly string[];
+      readonly render_report?: {
+        readonly strategy: string;
+        readonly backend_id?: string;
+        readonly parser_identity?: string;
+      };
       readonly reparse_after_render: boolean | null;
     };
   }[];
@@ -73,6 +78,9 @@ describe('@structuredmerge/ast-merge-git', () => {
       expect(result.reparse_after_render, testCase.case_id).toBe(
         testCase.expected.reparse_after_render
       );
+      if (testCase.expected.render_report !== undefined) {
+        expect(result.render_report, testCase.case_id).toEqual(testCase.expected.render_report);
+      }
       if (result.ok) {
         expect(JSON.parse(result.merged_source ?? ''), testCase.case_id).toEqual(
           testCase.expected.merged_json

From 80475c5bea266b1bfb408d55d651618a624b9697 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 19:41:53 -0600
Subject: [PATCH 116/130] Assert merge3 formatting preservation reports

---
 packages/ast-merge-git/test/fixtures.integration.test.ts | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index 4b39e82..303af90 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -23,6 +23,10 @@ interface Fixture {
         readonly backend_id?: string;
         readonly parser_identity?: string;
       };
+      readonly formatting_preservation?: {
+        readonly line_diff_score: number;
+        readonly character_diff_score: number;
+      };
       readonly reparse_after_render: boolean | null;
     };
   }[];
@@ -81,6 +85,11 @@ describe('@structuredmerge/ast-merge-git', () => {
       if (testCase.expected.render_report !== undefined) {
         expect(result.render_report, testCase.case_id).toEqual(testCase.expected.render_report);
       }
+      if (testCase.expected.formatting_preservation !== undefined) {
+        expect(result.formatting_preservation, testCase.case_id).toEqual(
+          testCase.expected.formatting_preservation
+        );
+      }
       if (result.ok) {
         expect(JSON.parse(result.merged_source ?? ''), testCase.case_id).toEqual(
           testCase.expected.merged_json

From 55bf6d57ca7c00d44b7b4fa161621b70d6bbfa74 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 20:18:09 -0600
Subject: [PATCH 117/130] Report merge3 secondary formatting metrics

---
 packages/ast-merge-git/src/index.ts           | 33 +++++++++++++++++++
 .../test/fixtures.integration.test.ts         | 12 +++++++
 2 files changed, 45 insertions(+)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 491cd6f..953655f 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -39,6 +39,13 @@ export interface Merge3Response {
     readonly line_diff_score: number;
     readonly character_diff_score: number;
   };
+  readonly secondary_formatting_metrics: {
+    readonly unchanged_line_churn: number;
+    readonly output_diff_size: number;
+    readonly source_fragment_retention: number;
+    readonly weighted: boolean;
+    readonly diagnostics: readonly string[];
+  };
   readonly reparse_after_render: boolean | null;
 }
 
@@ -178,10 +185,36 @@ function response(
       line_diff_score: 0,
       character_diff_score: 0
     },
+    secondary_formatting_metrics:
+      fields.secondary_formatting_metrics ??
+      secondaryFormattingMetrics(fields.merged_source !== undefined),
     reparse_after_render: fields.reparse_after_render ?? null
   };
 }
 
+function secondaryFormattingMetrics(
+  merged: boolean
+): Merge3Response['secondary_formatting_metrics'] {
+  if (merged) {
+    return {
+      unchanged_line_churn: 0,
+      output_diff_size: 0,
+      source_fragment_retention: 1,
+      weighted: false,
+      diagnostics: ['canonical JSON has no trivia-preserving source fragments yet']
+    };
+  }
+  return {
+    unchanged_line_churn: 0,
+    output_diff_size: 0,
+    source_fragment_retention: 0,
+    weighted: false,
+    diagnostics: [
+      'unresolved conflict did not produce a merged source-fragment retention measurement'
+    ]
+  };
+}
+
 function renderIdentity(request: Merge3Request): {
   readonly backend_id?: string;
   readonly parser_identity?: string;
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index 303af90..cdb16f4 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -27,6 +27,13 @@ interface Fixture {
         readonly line_diff_score: number;
         readonly character_diff_score: number;
       };
+      readonly secondary_formatting_metrics?: {
+        readonly unchanged_line_churn: number;
+        readonly output_diff_size: number;
+        readonly source_fragment_retention: number;
+        readonly weighted: boolean;
+        readonly diagnostics: readonly string[];
+      };
       readonly reparse_after_render: boolean | null;
     };
   }[];
@@ -90,6 +97,11 @@ describe('@structuredmerge/ast-merge-git', () => {
           testCase.expected.formatting_preservation
         );
       }
+      if (testCase.expected.secondary_formatting_metrics !== undefined) {
+        expect(result.secondary_formatting_metrics, testCase.case_id).toEqual(
+          testCase.expected.secondary_formatting_metrics
+        );
+      }
       if (result.ok) {
         expect(JSON.parse(result.merged_source ?? ''), testCase.case_id).toEqual(
           testCase.expected.merged_json

From c0a504065ba9217b2655ce99e4d2217410cf6c51 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 20:31:37 -0600
Subject: [PATCH 118/130] Report merge3 default driver evaluation

---
 packages/ast-merge-git/src/index.ts           | 72 ++++++++++++++++---
 .../test/fixtures.integration.test.ts         | 17 +++++
 2 files changed, 80 insertions(+), 9 deletions(-)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 953655f..5b1dfe1 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -46,6 +46,18 @@ export interface Merge3Response {
     readonly weighted: boolean;
     readonly diagnostics: readonly string[];
   };
+  readonly default_driver_evaluation: {
+    readonly status: string;
+    readonly formatting_threshold: number;
+    readonly formatting_score: number;
+    readonly hard_gates: readonly {
+      readonly name: string;
+      readonly passed: boolean;
+      readonly weighted: boolean;
+    }[];
+    readonly blocking_reasons: readonly string[];
+    readonly diagnostics: readonly string[];
+  };
   readonly reparse_after_render: boolean | null;
 }
 
@@ -165,6 +177,15 @@ function response(
   request: Merge3Request,
   fields: Partial<Merge3Response> & { readonly ok: boolean }
 ): Merge3Response {
+  const renderReport = {
+    ...renderIdentity(request),
+    strategy: fields.render_report?.strategy ?? request.render_policy ?? 'canonical'
+  };
+  const formattingPreservation = fields.formatting_preservation ?? {
+    line_diff_score: 0,
+    character_diff_score: 0
+  };
+  const reparseAfterRender = fields.reparse_after_render ?? null;
   return {
     ok: fields.ok,
     merged_source: fields.merged_source,
@@ -177,18 +198,51 @@ function response(
       language: normalizeLanguage(request),
       dialect: request.dialect ?? ''
     },
-    render_report: {
-      ...renderIdentity(request),
-      strategy: fields.render_report?.strategy ?? request.render_policy ?? 'canonical'
-    },
-    formatting_preservation: fields.formatting_preservation ?? {
-      line_diff_score: 0,
-      character_diff_score: 0
-    },
+    render_report: renderReport,
+    formatting_preservation: formattingPreservation,
     secondary_formatting_metrics:
       fields.secondary_formatting_metrics ??
       secondaryFormattingMetrics(fields.merged_source !== undefined),
-    reparse_after_render: fields.reparse_after_render ?? null
+    default_driver_evaluation:
+      fields.default_driver_evaluation ??
+      defaultDriverEvaluation(formattingPreservation, reparseAfterRender, renderReport),
+    reparse_after_render: reparseAfterRender
+  };
+}
+
+function defaultDriverEvaluation(
+  formattingPreservation: Merge3Response['formatting_preservation'],
+  reparseAfterRender: boolean | null,
+  renderReport: Merge3Response['render_report']
+): Merge3Response['default_driver_evaluation'] {
+  const threshold = 0.95;
+  const score =
+    (formattingPreservation.line_diff_score + formattingPreservation.character_diff_score) / 2;
+  const reparsePassed = reparseAfterRender === true;
+  const noFullFileRewrite = renderReport.strategy !== 'full_file_conflict_markers';
+  const coherentConflictMarkers = renderReport.strategy !== 'full_file_conflict_markers';
+  const blockingReasons: string[] = [];
+  if (!reparsePassed) blockingReasons.push('rendered output did not reparse');
+  if (score < threshold) blockingReasons.push('formatting score is below threshold');
+  if (!noFullFileRewrite) blockingReasons.push('full-file rewrite or conflict markers were used');
+  if (!coherentConflictMarkers) {
+    blockingReasons.push('conflict marker placement is not syntactically coherent');
+  }
+  return {
+    status: blockingReasons.length === 0 ? 'recommended' : 'not_recommended',
+    formatting_threshold: threshold,
+    formatting_score: score,
+    hard_gates: [
+      { name: 'reparse_after_render', passed: reparsePassed, weighted: false },
+      { name: 'no_full_file_rewrite', passed: noFullFileRewrite, weighted: false },
+      {
+        name: 'coherent_conflict_marker_placement',
+        passed: coherentConflictMarkers,
+        weighted: false
+      }
+    ],
+    blocking_reasons: blockingReasons,
+    diagnostics: ['default-driver evaluation is advisory unless explicitly required']
   };
 }
 
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index cdb16f4..a9167a0 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -34,6 +34,18 @@ interface Fixture {
         readonly weighted: boolean;
         readonly diagnostics: readonly string[];
       };
+      readonly default_driver_evaluation?: {
+        readonly status: string;
+        readonly formatting_threshold: number;
+        readonly formatting_score: number;
+        readonly hard_gates: readonly {
+          readonly name: string;
+          readonly passed: boolean;
+          readonly weighted: boolean;
+        }[];
+        readonly blocking_reasons: readonly string[];
+        readonly diagnostics: readonly string[];
+      };
       readonly reparse_after_render: boolean | null;
     };
   }[];
@@ -102,6 +114,11 @@ describe('@structuredmerge/ast-merge-git', () => {
           testCase.expected.secondary_formatting_metrics
         );
       }
+      if (testCase.expected.default_driver_evaluation !== undefined) {
+        expect(result.default_driver_evaluation, testCase.case_id).toEqual(
+          testCase.expected.default_driver_evaluation
+        );
+      }
       if (result.ok) {
         expect(JSON.parse(result.merged_source ?? ''), testCase.case_id).toEqual(
           testCase.expected.merged_json

From e2e547ed49ead4a3ae5630b83cf9b2457eaca313 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 20:40:42 -0600
Subject: [PATCH 119/130] Report smorg-ts fallback use

---
 packages/smorg-ts/src/cli.ts       | 87 ++++++++++++++++++++++++++++--
 packages/smorg-ts/test/cli.test.ts | 22 ++++++++
 2 files changed, 106 insertions(+), 3 deletions(-)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index f76dcce..414f20a 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -7,7 +7,7 @@ import {
   initialProfilePromotionPolicy,
   promotionProfileJsonKeyedObject
 } from '@structuredmerge/ast-merge';
-import type { MergeResult, ProfilePromotionStatus } from '@structuredmerge/ast-merge';
+import type { Diagnostic, MergeResult, ProfilePromotionStatus } from '@structuredmerge/ast-merge';
 import { merge3 } from '@structuredmerge/ast-merge-git';
 import { mergeGo } from '@structuredmerge/go-merge';
 import { mergeJson } from '@structuredmerge/json-merge';
@@ -28,6 +28,7 @@ interface MergeDriverOptions {
   readonly fallback: string;
   readonly checkOnly: boolean;
   readonly exitCode: boolean;
+  readonly report?: string;
   readonly profileId?: string;
   readonly profileReport: boolean;
   readonly requireProfileStatus?: string;
@@ -90,7 +91,7 @@ export function run(
 function printUsage(out: Pick<NodeJS.WriteStream, 'write'>): void {
   out.write(
     [
-      'usage: smorg-ts merge-driver [--path-name PATH] [--output PATH] [--strict] [--fallback=none|line|local|full-file] %O %A %B [%P]',
+      'usage: smorg-ts merge-driver [--path-name PATH] [--output PATH] [--report PATH] [--strict] [--fallback=none|line|local|full-file] %O %A %B [%P]',
       '       smorg-ts merge-driver --ancestor %O --current %A --other %B --path-name %P',
       '       smorg-ts diff-driver [--path-name PATH] OLD NEW',
       '       smorg-ts diff-driver PATH OLD-FILE OLD-HEX OLD-MODE NEW-FILE NEW-HEX NEW-MODE [OLD-PREFIX NEW-PREFIX]',
@@ -140,7 +141,14 @@ function runMergeDriver(
   let output = result.output;
   if (!result.ok) {
     printDiagnostics(stderr, result);
+    const fallbacks: Array<Record<string, unknown>> = [];
     if (output === undefined && !options.strict && options.fallback !== 'none') {
+      fallbacks.push({
+        mode: 'full_file',
+        requested_mode: options.fallback,
+        reason: fallbackReason(result.diagnostics),
+        applied: true
+      });
       output = fullFileConflictOutput(
         settings.conflictMarkerSize,
         ancestorSource,
@@ -148,6 +156,16 @@ function runMergeDriver(
         otherSource
       );
     }
+    const reportExit = writeMergeDriverMachineReport(
+      options.report,
+      effectivePath,
+      false,
+      exitUnresolvedConflict,
+      fallbacks,
+      result.diagnostics,
+      stderr
+    );
+    if (reportExit !== exitSuccess) return reportExit;
     if (options.checkOnly) return exitUnresolvedConflict;
     if (output !== undefined) {
       try {
@@ -165,7 +183,18 @@ function runMergeDriver(
   }
 
   if (options.checkOnly) {
-    return options.exitCode && output !== currentSource ? exitUnresolvedConflict : exitSuccess;
+    const exit = options.exitCode && output !== currentSource ? exitUnresolvedConflict : exitSuccess;
+    const reportExit = writeMergeDriverMachineReport(
+      options.report,
+      effectivePath,
+      true,
+      exit,
+      [],
+      result.diagnostics,
+      stderr
+    );
+    if (reportExit !== exitSuccess) return reportExit;
+    return exit;
   }
 
   try {
@@ -174,9 +203,56 @@ function runMergeDriver(
     stderr.write(`write output: ${String(error)}\n`);
     return exitInternalError;
   }
+  const reportExit = writeMergeDriverMachineReport(
+    options.report,
+    effectivePath,
+    true,
+    exitSuccess,
+    [],
+    result.diagnostics,
+    stderr
+  );
+  if (reportExit !== exitSuccess) return reportExit;
   return exitSuccess;
 }
 
+function writeMergeDriverMachineReport(
+  reportPath: string | undefined,
+  pathName: string,
+  ok: boolean,
+  exitCode: number,
+  fallbacks: Array<Record<string, unknown>>,
+  diagnostics: readonly Diagnostic[],
+  stderr: Pick<NodeJS.WriteStream, 'write'>
+): number {
+  if (!reportPath) return exitSuccess;
+  try {
+    writeFileSync(
+      reportPath,
+      `${JSON.stringify(
+        {
+          command: 'merge-driver',
+          path_name: pathName,
+          ok,
+          exit_code: exitCode,
+          fallbacks,
+          diagnostics
+        },
+        undefined,
+        2
+      )}\n`
+    );
+    return exitSuccess;
+  } catch (error) {
+    stderr.write(`write report: ${String(error)}\n`);
+    return exitInternalError;
+  }
+}
+
+function fallbackReason(diagnostics: readonly Diagnostic[]): string {
+  return diagnostics[0]?.category ?? 'structured_merge_failed';
+}
+
 function fullFileConflictOutput(
   markerSize: number,
   ancestorSource: string,
@@ -209,6 +285,7 @@ function parseMergeDriverOptions(
   let fallback = 'full-file';
   let checkOnly = false;
   let exitCode = false;
+  let report: string | undefined;
   let profileId: string | undefined;
   let profileReport = false;
   let requireProfileStatus: string | undefined;
@@ -232,6 +309,9 @@ function parseMergeDriverOptions(
       case '--output':
         output = args[++index];
         break;
+      case '--report':
+        report = args[++index];
+        break;
       case '--strict':
         strict = true;
         break;
@@ -288,6 +368,7 @@ function parseMergeDriverOptions(
     fallback,
     checkOnly,
     exitCode,
+    report,
     profileId,
     profileReport,
     requireProfileStatus
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 2ebf38d..e4a8143 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -60,6 +60,12 @@ interface GitDriverFallbackCase {
     readonly merged_source?: string;
     readonly source_contains?: readonly string[];
     readonly stderr_contains: readonly string[];
+    readonly machine_report: {
+      readonly ok: boolean;
+      readonly exit_code: number;
+      readonly fallbacks: readonly unknown[];
+      readonly diagnostics_contain: readonly string[];
+    };
   };
 }
 
@@ -207,11 +213,13 @@ describe('smorg-ts cli', () => {
       const ancestor = write('ancestor.json', testCase.base_source);
       const current = write('current.json', testCase.ours_source);
       const other = write('other.json', testCase.theirs_source);
+      const reportPath = path.join(dir, 'merge-report.json');
       const args = ['merge-driver'];
       if (testCase.options.strict) args.push('--strict');
       if (testCase.options.fallback && testCase.options.fallback !== 'full-file') {
         args.push('--fallback', testCase.options.fallback);
       }
+      args.push('--report', reportPath);
       args.push(ancestor, current, other, testCase.path_name);
       const stdout = writer();
       const stderr = writer();
@@ -230,6 +238,20 @@ describe('smorg-ts cli', () => {
       for (const needle of testCase.expected.stderr_contains) {
         expect(stderr.output(), testCase.case_id).toContain(needle);
       }
+      const report = JSON.parse(readFileSync(reportPath, 'utf8')) as {
+        ok: boolean;
+        exit_code: number;
+        fallbacks: unknown[];
+        diagnostics: unknown[];
+      };
+      const expectedReport = testCase.expected.machine_report;
+      expect(report.ok, testCase.case_id).toBe(expectedReport.ok);
+      expect(report.exit_code, testCase.case_id).toBe(expectedReport.exit_code);
+      expect(report.fallbacks, testCase.case_id).toEqual(expectedReport.fallbacks);
+      const diagnostics = JSON.stringify(report.diagnostics);
+      for (const needle of expectedReport.diagnostics_contain) {
+        expect(diagnostics, testCase.case_id).toContain(needle);
+      }
     }
   });
 

From 2d9b138a2e2492e97134eb8f75bdeb3ac1aa9ffe Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 20:42:00 -0600
Subject: [PATCH 120/130] Assert smorg-ts fallback stderr stays concise

---
 packages/smorg-ts/test/cli.test.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index e4a8143..f7c6b48 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -60,6 +60,7 @@ interface GitDriverFallbackCase {
     readonly merged_source?: string;
     readonly source_contains?: readonly string[];
     readonly stderr_contains: readonly string[];
+    readonly stderr_not_contains?: readonly string[];
     readonly machine_report: {
       readonly ok: boolean;
       readonly exit_code: number;
@@ -238,6 +239,9 @@ describe('smorg-ts cli', () => {
       for (const needle of testCase.expected.stderr_contains) {
         expect(stderr.output(), testCase.case_id).toContain(needle);
       }
+      for (const needle of testCase.expected.stderr_not_contains ?? []) {
+        expect(stderr.output(), testCase.case_id).not.toContain(needle);
+      }
       const report = JSON.parse(readFileSync(reportPath, 'utf8')) as {
         ok: boolean;
         exit_code: number;

From 0e7de2820a1b450df7e0467afa57ebba90e2c895 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 21:44:49 -0600
Subject: [PATCH 121/130] Report JSON owned regions in TypeScript

---
 packages/ast-merge-git/src/index.ts           | 68 ++++++++++++++++++-
 .../test/fixtures.integration.test.ts         | 20 ++++++
 2 files changed, 87 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 5b1dfe1..076c3be 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -35,6 +35,7 @@ export interface Merge3Response {
     readonly backend_id?: string;
     readonly parser_identity?: string;
   };
+  readonly owned_regions: readonly OwnedRegionReport[];
   readonly formatting_preservation: {
     readonly line_diff_score: number;
     readonly character_diff_score: number;
@@ -61,6 +62,31 @@ export interface Merge3Response {
   readonly reparse_after_render: boolean | null;
 }
 
+export interface SourceRange {
+  readonly start: number;
+  readonly end: number;
+}
+
+export interface AttachedSpan {
+  readonly kind: string;
+  readonly line_range: SourceRange;
+  readonly byte_range?: SourceRange;
+}
+
+export interface OwnedRegionReport {
+  readonly owner_path: string;
+  readonly node_id: string;
+  readonly region_kind: string;
+  readonly byte_range: SourceRange;
+  readonly line_range: SourceRange;
+  readonly attached_spans: readonly AttachedSpan[];
+  readonly backend_id: string;
+  readonly parser_identity: string;
+  readonly can_replace: boolean;
+  readonly can_line_merge: boolean;
+  readonly requires_reparse: boolean;
+}
+
 export interface CommentDeltaResult {
   readonly ok: boolean;
   readonly merged_comment: string | null;
@@ -96,12 +122,17 @@ export function merge3Json(request: Merge3Request): Merge3Response {
     const conflicts: Merge3Conflict[] = [];
     const merged = mergeJsonValue(base, ours, theirs, '', conflicts);
     if (conflicts.length > 0) {
+      const ownedRegions = jsonOwnedRegionsForConflicts(request, conflicts);
       return response(request, {
         ok: false,
         conflicts,
         conflicted_source: renderConflictSource(request, conflicts),
+        owned_regions: ownedRegions,
         render_report: {
-          strategy: 'full_file_conflict_markers'
+          strategy:
+            ownedRegions.length === 0
+              ? 'full_file_conflict_markers'
+              : 'owned_region_conflict_markers'
         },
         diagnostics: [
           {
@@ -193,6 +224,7 @@ function response(
     conflicts: fields.conflicts ?? [],
     diagnostics: fields.diagnostics ?? [],
     fallbacks: fields.fallbacks ?? [],
+    owned_regions: fields.owned_regions ?? [],
     profile: {
       profile_id: request.profile_id ?? '',
       language: normalizeLanguage(request),
@@ -300,6 +332,40 @@ function renderConflictSource(
   ].join('\n');
 }
 
+function jsonOwnedRegionsForConflicts(
+  request: Merge3Request,
+  conflicts: readonly Merge3Conflict[]
+): OwnedRegionReport[] {
+  return conflicts.flatMap((conflict) => {
+    if (!conflict.path.startsWith('/') || conflict.path.split('/').length !== 2) return [];
+    const key = conflict.path.slice(1);
+    return [
+      {
+        owner_path: conflict.path,
+        node_id: `json:key:${key}`,
+        region_kind: 'node',
+        byte_range: jsonKeyByteRange(request.base_source, key),
+        line_range: { start: 1, end: 1 },
+        attached_spans: [],
+        backend_id: 'native-json',
+        parser_identity: 'standard-json',
+        can_replace: true,
+        can_line_merge: false,
+        requires_reparse: true
+      }
+    ];
+  });
+}
+
+function jsonKeyByteRange(source: string, key: string): SourceRange {
+  const needle = `"${key}"`;
+  const start = source.indexOf(needle);
+  if (start < 0) return { start: 0, end: source.length };
+  let end = start + needle.length;
+  while (end < source.length && source[end] !== ',' && source[end] !== '}') end += 1;
+  return { start, end };
+}
+
 function parseJsonRole(role: string, source: string): unknown {
   try {
     return JSON.parse(source);
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index a9167a0..095cec0 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -46,6 +46,18 @@ interface Fixture {
         readonly blocking_reasons: readonly string[];
         readonly diagnostics: readonly string[];
       };
+      readonly owned_regions?: readonly {
+        readonly owner_path: string;
+        readonly node_id: string;
+        readonly region_kind: string;
+        readonly line_range: { readonly start: number; readonly end: number };
+        readonly attached_spans: readonly unknown[];
+        readonly backend_id: string;
+        readonly parser_identity: string;
+        readonly can_replace: boolean;
+        readonly can_line_merge: boolean;
+        readonly requires_reparse: boolean;
+      }[];
       readonly reparse_after_render: boolean | null;
     };
   }[];
@@ -119,6 +131,14 @@ describe('@structuredmerge/ast-merge-git', () => {
           testCase.expected.default_driver_evaluation
         );
       }
+      if (testCase.expected.owned_regions !== undefined) {
+        expect(result.owned_regions, testCase.case_id).toHaveLength(
+          testCase.expected.owned_regions.length
+        );
+        for (const [index, expectedRegion] of testCase.expected.owned_regions.entries()) {
+          expect(result.owned_regions[index], testCase.case_id).toMatchObject(expectedRegion);
+        }
+      }
       if (result.ok) {
         expect(JSON.parse(result.merged_source ?? ''), testCase.case_id).toEqual(
           testCase.expected.merged_json

From 546d48e255767a0e302291a1779bafa770b12622 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 21:53:34 -0600
Subject: [PATCH 122/130] Report smorg-ts owned regions

---
 packages/smorg-ts/src/cli.ts       | 26 ++++++++++++++++++++++++--
 packages/smorg-ts/test/cli.test.ts | 24 ++++++++++++++++++++++++
 2 files changed, 48 insertions(+), 2 deletions(-)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 414f20a..7efb02c 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -12,6 +12,7 @@ import { merge3 } from '@structuredmerge/ast-merge-git';
 import { mergeGo } from '@structuredmerge/go-merge';
 import { mergeJson } from '@structuredmerge/json-merge';
 import { mergeText } from '@structuredmerge/plain-merge';
+import type { Merge3Response } from '@structuredmerge/ast-merge-git';
 
 export const exitSuccess = 0;
 export const exitUnresolvedConflict = 1;
@@ -59,6 +60,11 @@ interface ConflictRegion {
   readonly endLine: number;
 }
 
+type MergeDriverResult = MergeResult<string> & {
+  readonly owned_regions?: Merge3Response['owned_regions'];
+  readonly render_report?: Merge3Response['render_report'];
+};
+
 export function run(
   args: readonly string[],
   stdout: Pick<NodeJS.WriteStream, 'write'>,
@@ -162,6 +168,8 @@ function runMergeDriver(
       false,
       exitUnresolvedConflict,
       fallbacks,
+      result.owned_regions ?? [],
+      result.render_report,
       result.diagnostics,
       stderr
     );
@@ -190,6 +198,8 @@ function runMergeDriver(
       true,
       exit,
       [],
+      result.owned_regions ?? [],
+      result.render_report,
       result.diagnostics,
       stderr
     );
@@ -209,6 +219,8 @@ function runMergeDriver(
     true,
     exitSuccess,
     [],
+    result.owned_regions ?? [],
+    result.render_report,
     result.diagnostics,
     stderr
   );
@@ -222,6 +234,8 @@ function writeMergeDriverMachineReport(
   ok: boolean,
   exitCode: number,
   fallbacks: Array<Record<string, unknown>>,
+  ownedRegions: Merge3Response['owned_regions'],
+  renderReport: Merge3Response['render_report'] | undefined,
   diagnostics: readonly Diagnostic[],
   stderr: Pick<NodeJS.WriteStream, 'write'>
 ): number {
@@ -236,6 +250,8 @@ function writeMergeDriverMachineReport(
           ok,
           exit_code: exitCode,
           fallbacks,
+          owned_regions: ownedRegions,
+          render_report: renderReport,
           diagnostics
         },
         undefined,
@@ -565,7 +581,7 @@ function mergeByPath(
   ancestorSource: string,
   currentSource: string,
   otherSource: string
-): MergeResult<string> {
+): MergeDriverResult {
   switch (normalizeLanguage(language, pathName)) {
     case 'go':
       return mergeGo(otherSource, currentSource, 'go');
@@ -591,12 +607,14 @@ function mergeByPath(
   }
 }
 
-function merge3Result(result: ReturnType<typeof merge3>): MergeResult<string> {
+function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
   if (result.ok && result.merged_source !== undefined) {
     return {
       ok: true,
       diagnostics: result.diagnostics,
       output: result.merged_source,
+      owned_regions: result.owned_regions,
+      render_report: result.render_report,
       policies: []
     };
   }
@@ -605,12 +623,16 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeResult<string> {
       ok: false,
       diagnostics: result.diagnostics,
       output: result.conflicted_source,
+      owned_regions: result.owned_regions,
+      render_report: result.render_report,
       policies: []
     };
   }
   return {
     ok: false,
     diagnostics: result.diagnostics,
+    owned_regions: result.owned_regions,
+    render_report: result.render_report,
     policies: []
   };
 }
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index f7c6b48..fbf7c0a 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -280,6 +280,30 @@ describe('smorg-ts cli', () => {
     }
   });
 
+  it('includes owned-region placement in merge-driver reports', () => {
+    const ancestor = write('ancestor.json', '{"name":"demo","enabled":true}');
+    const current = write('current.json', '{"name":"demo","enabled":false}');
+    const other = write('other.json', '{"name":"demo","enabled":"yes"}');
+    const reportPath = path.join(dir, 'merge-report.json');
+    const stdout = writer();
+    const stderr = writer();
+
+    const exit = run(
+      ['merge-driver', '--report', reportPath, ancestor, current, other, 'package.json'],
+      stdout.stream,
+      stderr.stream
+    );
+
+    expect(exit).toBe(exitUnresolvedConflict);
+    const report = JSON.parse(readFileSync(reportPath, 'utf8')) as {
+      render_report: { strategy: string };
+      owned_regions: Array<{ owner_path: string; region_kind: string }>;
+    };
+    expect(report.render_report.strategy).toBe('owned_region_conflict_markers');
+    expect(report.owned_regions[0]?.owner_path).toBe('/enabled');
+    expect(report.owned_regions[0]?.region_kind).toBe('node');
+  });
+
   it('conforms to the git-driver JSON integration fixture in a repository', () => {
     try {
       execFileSync('git', ['--version'], { stdio: 'pipe' });

From 3076ef61fddfe89484bdec3ba46512f7f11a4de0 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 22:04:54 -0600
Subject: [PATCH 123/130] Render TypeScript JSON owned-region conflicts

---
 packages/ast-merge-git/src/index.ts           | 43 ++++++++++++++++++-
 .../test/fixtures.integration.test.ts         |  4 ++
 2 files changed, 46 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 076c3be..12a3dbc 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -123,10 +123,13 @@ export function merge3Json(request: Merge3Request): Merge3Response {
     const merged = mergeJsonValue(base, ours, theirs, '', conflicts);
     if (conflicts.length > 0) {
       const ownedRegions = jsonOwnedRegionsForConflicts(request, conflicts);
+      const conflictedSource =
+        renderJsonOwnedRegionConflictSource(request, ownedRegions[0]) ??
+        renderConflictSource(request, conflicts);
       return response(request, {
         ok: false,
         conflicts,
-        conflicted_source: renderConflictSource(request, conflicts),
+        conflicted_source: conflictedSource,
         owned_regions: ownedRegions,
         render_report: {
           strategy:
@@ -332,6 +335,44 @@ function renderConflictSource(
   ].join('\n');
 }
 
+function renderJsonOwnedRegionConflictSource(
+  request: Merge3Request,
+  region: OwnedRegionReport | undefined
+): string | undefined {
+  if (region === undefined || region.region_kind !== 'node') return undefined;
+  const key = region.owner_path.slice(1);
+  const oursRegion = jsonMemberSource(request.ours_source, key);
+  const baseRegion = jsonMemberSource(request.base_source, key);
+  const theirsRegion = jsonMemberSource(request.theirs_source, key);
+  if (oursRegion === undefined || baseRegion === undefined || theirsRegion === undefined) {
+    return undefined;
+  }
+  const markerSize = Math.max(request.conflict_marker_size ?? 7, 1);
+  const replacement = [
+    `${'<'.repeat(markerSize)} ours`,
+    oursRegion.text,
+    `${'|'.repeat(markerSize)} base`,
+    baseRegion.text,
+    '='.repeat(markerSize),
+    theirsRegion.text,
+    `${'>'.repeat(markerSize)} theirs`
+  ].join('\n');
+  return (
+    request.ours_source.slice(0, oursRegion.byteRange.start) +
+    replacement +
+    request.ours_source.slice(oursRegion.byteRange.end)
+  );
+}
+
+function jsonMemberSource(
+  source: string,
+  key: string
+): { readonly byteRange: SourceRange; readonly text: string } | undefined {
+  const byteRange = jsonKeyByteRange(source, key);
+  if (byteRange.end <= byteRange.start || byteRange.end > source.length) return undefined;
+  return { byteRange, text: source.slice(byteRange.start, byteRange.end) };
+}
+
 function jsonOwnedRegionsForConflicts(
   request: Merge3Request,
   conflicts: readonly Merge3Conflict[]
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index 095cec0..2eae5b2 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -18,6 +18,7 @@ interface Fixture {
       readonly conflict_categories?: readonly string[];
       readonly conflict_paths?: readonly string[];
       readonly conflicted_source_contains?: readonly string[];
+      readonly conflicted_source_not_contains?: readonly string[];
       readonly render_report?: {
         readonly strategy: string;
         readonly backend_id?: string;
@@ -155,6 +156,9 @@ describe('@structuredmerge/ast-merge-git', () => {
         for (const needle of testCase.expected.conflicted_source_contains ?? []) {
           expect(result.conflicted_source, testCase.case_id).toContain(needle);
         }
+        for (const needle of testCase.expected.conflicted_source_not_contains ?? []) {
+          expect(result.conflicted_source, testCase.case_id).not.toContain(needle);
+        }
       }
     }
   });

From d1c4f6f168e8e043bb24c3a66dba8e2aa602ad1f Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 22:08:09 -0600
Subject: [PATCH 124/130] Fail closed for unsafe TypeScript JSON regions

---
 packages/ast-merge-git/src/index.ts | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 12a3dbc..5a5af75 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -368,6 +368,7 @@ function jsonMemberSource(
   source: string,
   key: string
 ): { readonly byteRange: SourceRange; readonly text: string } | undefined {
+  if (!source.includes(`"${key}"`)) return undefined;
   const byteRange = jsonKeyByteRange(source, key);
   if (byteRange.end <= byteRange.start || byteRange.end > source.length) return undefined;
   return { byteRange, text: source.slice(byteRange.start, byteRange.end) };
@@ -380,12 +381,20 @@ function jsonOwnedRegionsForConflicts(
   return conflicts.flatMap((conflict) => {
     if (!conflict.path.startsWith('/') || conflict.path.split('/').length !== 2) return [];
     const key = conflict.path.slice(1);
+    const baseRegion = jsonMemberSource(request.base_source, key);
+    if (
+      baseRegion === undefined ||
+      jsonMemberSource(request.ours_source, key) === undefined ||
+      jsonMemberSource(request.theirs_source, key) === undefined
+    ) {
+      return [];
+    }
     return [
       {
         owner_path: conflict.path,
         node_id: `json:key:${key}`,
         region_kind: 'node',
-        byte_range: jsonKeyByteRange(request.base_source, key),
+        byte_range: baseRegion.byteRange,
         line_range: { start: 1, end: 1 },
         attached_spans: [],
         backend_id: 'native-json',

From 6420a3ceaaf0597fda985d43a914d61c71a783c3 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 22:32:41 -0600
Subject: [PATCH 125/130] Report smorg-ts active profile

---
 packages/smorg-ts/src/cli.ts       | 9 +++++++++
 packages/smorg-ts/test/cli.test.ts | 3 +++
 2 files changed, 12 insertions(+)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 7efb02c..4861da8 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -63,6 +63,7 @@ interface ConflictRegion {
 type MergeDriverResult = MergeResult<string> & {
   readonly owned_regions?: Merge3Response['owned_regions'];
   readonly render_report?: Merge3Response['render_report'];
+  readonly profile?: Merge3Response['profile'];
 };
 
 export function run(
@@ -170,6 +171,7 @@ function runMergeDriver(
       fallbacks,
       result.owned_regions ?? [],
       result.render_report,
+      result.profile,
       result.diagnostics,
       stderr
     );
@@ -200,6 +202,7 @@ function runMergeDriver(
       [],
       result.owned_regions ?? [],
       result.render_report,
+      result.profile,
       result.diagnostics,
       stderr
     );
@@ -221,6 +224,7 @@ function runMergeDriver(
     [],
     result.owned_regions ?? [],
     result.render_report,
+    result.profile,
     result.diagnostics,
     stderr
   );
@@ -236,6 +240,7 @@ function writeMergeDriverMachineReport(
   fallbacks: Array<Record<string, unknown>>,
   ownedRegions: Merge3Response['owned_regions'],
   renderReport: Merge3Response['render_report'] | undefined,
+  profile: Merge3Response['profile'] | undefined,
   diagnostics: readonly Diagnostic[],
   stderr: Pick<NodeJS.WriteStream, 'write'>
 ): number {
@@ -252,6 +257,7 @@ function writeMergeDriverMachineReport(
           fallbacks,
           owned_regions: ownedRegions,
           render_report: renderReport,
+          profile,
           diagnostics
         },
         undefined,
@@ -615,6 +621,7 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
       output: result.merged_source,
       owned_regions: result.owned_regions,
       render_report: result.render_report,
+      profile: result.profile,
       policies: []
     };
   }
@@ -625,6 +632,7 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
       output: result.conflicted_source,
       owned_regions: result.owned_regions,
       render_report: result.render_report,
+      profile: result.profile,
       policies: []
     };
   }
@@ -633,6 +641,7 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
     diagnostics: result.diagnostics,
     owned_regions: result.owned_regions,
     render_report: result.render_report,
+    profile: result.profile,
     policies: []
   };
 }
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index fbf7c0a..aa9b522 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -298,10 +298,13 @@ describe('smorg-ts cli', () => {
     const report = JSON.parse(readFileSync(reportPath, 'utf8')) as {
       render_report: { strategy: string };
       owned_regions: Array<{ owner_path: string; region_kind: string }>;
+      profile: { profile_id: string; language: string };
     };
     expect(report.render_report.strategy).toBe('owned_region_conflict_markers');
     expect(report.owned_regions[0]?.owner_path).toBe('/enabled');
     expect(report.owned_regions[0]?.region_kind).toBe('node');
+    expect(report.profile.profile_id).toBe('json.keyed-object');
+    expect(report.profile.language).toBe('json');
   });
 
   it('conforms to the git-driver JSON integration fixture in a repository', () => {

From 91a47a25ab79657b7f6d0d4f6527f4f3b029bfc9 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 22:46:31 -0600
Subject: [PATCH 126/130] Report smorg-ts merge3 gate metrics

---
 packages/smorg-ts/src/cli.ts       | 36 ++++++++++++++++++++++++++++++
 packages/smorg-ts/test/cli.test.ts |  4 ++++
 2 files changed, 40 insertions(+)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 4861da8..47f8505 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -64,6 +64,10 @@ type MergeDriverResult = MergeResult<string> & {
   readonly owned_regions?: Merge3Response['owned_regions'];
   readonly render_report?: Merge3Response['render_report'];
   readonly profile?: Merge3Response['profile'];
+  readonly reparse_after_render?: Merge3Response['reparse_after_render'];
+  readonly formatting_preservation?: Merge3Response['formatting_preservation'];
+  readonly secondary_formatting_metrics?: Merge3Response['secondary_formatting_metrics'];
+  readonly default_driver_evaluation?: Merge3Response['default_driver_evaluation'];
 };
 
 export function run(
@@ -172,6 +176,10 @@ function runMergeDriver(
       result.owned_regions ?? [],
       result.render_report,
       result.profile,
+      result.reparse_after_render,
+      result.formatting_preservation,
+      result.secondary_formatting_metrics,
+      result.default_driver_evaluation,
       result.diagnostics,
       stderr
     );
@@ -203,6 +211,10 @@ function runMergeDriver(
       result.owned_regions ?? [],
       result.render_report,
       result.profile,
+      result.reparse_after_render,
+      result.formatting_preservation,
+      result.secondary_formatting_metrics,
+      result.default_driver_evaluation,
       result.diagnostics,
       stderr
     );
@@ -225,6 +237,10 @@ function runMergeDriver(
     result.owned_regions ?? [],
     result.render_report,
     result.profile,
+    result.reparse_after_render,
+    result.formatting_preservation,
+    result.secondary_formatting_metrics,
+    result.default_driver_evaluation,
     result.diagnostics,
     stderr
   );
@@ -241,6 +257,10 @@ function writeMergeDriverMachineReport(
   ownedRegions: Merge3Response['owned_regions'],
   renderReport: Merge3Response['render_report'] | undefined,
   profile: Merge3Response['profile'] | undefined,
+  reparseAfterRender: Merge3Response['reparse_after_render'] | undefined,
+  formattingPreservation: Merge3Response['formatting_preservation'] | undefined,
+  secondaryFormattingMetrics: Merge3Response['secondary_formatting_metrics'] | undefined,
+  defaultDriverEvaluation: Merge3Response['default_driver_evaluation'] | undefined,
   diagnostics: readonly Diagnostic[],
   stderr: Pick<NodeJS.WriteStream, 'write'>
 ): number {
@@ -257,6 +277,10 @@ function writeMergeDriverMachineReport(
           fallbacks,
           owned_regions: ownedRegions,
           render_report: renderReport,
+          reparse_after_render: reparseAfterRender,
+          formatting_preservation: formattingPreservation,
+          secondary_formatting_metrics: secondaryFormattingMetrics,
+          default_driver_evaluation: defaultDriverEvaluation,
           profile,
           diagnostics
         },
@@ -622,6 +646,10 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
       owned_regions: result.owned_regions,
       render_report: result.render_report,
       profile: result.profile,
+      reparse_after_render: result.reparse_after_render,
+      formatting_preservation: result.formatting_preservation,
+      secondary_formatting_metrics: result.secondary_formatting_metrics,
+      default_driver_evaluation: result.default_driver_evaluation,
       policies: []
     };
   }
@@ -633,6 +661,10 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
       owned_regions: result.owned_regions,
       render_report: result.render_report,
       profile: result.profile,
+      reparse_after_render: result.reparse_after_render,
+      formatting_preservation: result.formatting_preservation,
+      secondary_formatting_metrics: result.secondary_formatting_metrics,
+      default_driver_evaluation: result.default_driver_evaluation,
       policies: []
     };
   }
@@ -642,6 +674,10 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
     owned_regions: result.owned_regions,
     render_report: result.render_report,
     profile: result.profile,
+    reparse_after_render: result.reparse_after_render,
+    formatting_preservation: result.formatting_preservation,
+    secondary_formatting_metrics: result.secondary_formatting_metrics,
+    default_driver_evaluation: result.default_driver_evaluation,
     policies: []
   };
 }
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index aa9b522..27322ce 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -299,12 +299,16 @@ describe('smorg-ts cli', () => {
       render_report: { strategy: string };
       owned_regions: Array<{ owner_path: string; region_kind: string }>;
       profile: { profile_id: string; language: string };
+      formatting_preservation: { line_diff_score: number };
+      default_driver_evaluation: { status: string };
     };
     expect(report.render_report.strategy).toBe('owned_region_conflict_markers');
     expect(report.owned_regions[0]?.owner_path).toBe('/enabled');
     expect(report.owned_regions[0]?.region_kind).toBe('node');
     expect(report.profile.profile_id).toBe('json.keyed-object');
     expect(report.profile.language).toBe('json');
+    expect(typeof report.formatting_preservation.line_diff_score).toBe('number');
+    expect(typeof report.default_driver_evaluation.status).toBe('string');
   });
 
   it('conforms to the git-driver JSON integration fixture in a repository', () => {

From 91cbed889c62e865faecafb927d63ef869fbc5b1 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 22:49:35 -0600
Subject: [PATCH 127/130] Assert smorg-ts fallback report fields

---
 packages/smorg-ts/test/cli.test.ts | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index 27322ce..ff77408 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -66,6 +66,7 @@ interface GitDriverFallbackCase {
       readonly exit_code: number;
       readonly fallbacks: readonly unknown[];
       readonly diagnostics_contain: readonly string[];
+      readonly required_fields?: readonly string[];
     };
   };
 }
@@ -256,6 +257,9 @@ describe('smorg-ts cli', () => {
       for (const needle of expectedReport.diagnostics_contain) {
         expect(diagnostics, testCase.case_id).toContain(needle);
       }
+      for (const field of expectedReport.required_fields ?? []) {
+        expect(Object.prototype.hasOwnProperty.call(report, field), testCase.case_id).toBe(true);
+      }
     }
   });
 

From 3b0aca029eaeaaa254a70a26cd3eeb9200aa1ce1 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 23:03:39 -0600
Subject: [PATCH 128/130] Classify JSON merge3 changes in TypeScript

---
 packages/ast-merge-git/src/index.ts           | 43 +++++++++++++++++++
 .../test/fixtures.integration.test.ts         | 10 +++++
 2 files changed, 53 insertions(+)

diff --git a/packages/ast-merge-git/src/index.ts b/packages/ast-merge-git/src/index.ts
index 5a5af75..f84d893 100644
--- a/packages/ast-merge-git/src/index.ts
+++ b/packages/ast-merge-git/src/index.ts
@@ -22,11 +22,18 @@ export interface Merge3Conflict {
   readonly message: string;
 }
 
+export interface ChangeClassification {
+  readonly path: string;
+  readonly ours: string;
+  readonly theirs: string;
+}
+
 export interface Merge3Response {
   readonly ok: boolean;
   readonly merged_source?: string;
   readonly conflicted_source?: string;
   readonly conflicts: readonly Merge3Conflict[];
+  readonly change_classifications: readonly ChangeClassification[];
   readonly diagnostics: readonly Diagnostic[];
   readonly fallbacks: readonly string[];
   readonly profile: Readonly<Record<string, string>>;
@@ -120,6 +127,7 @@ export function merge3Json(request: Merge3Request): Merge3Response {
     const ours = parseJsonRole('ours', request.ours_source);
     const theirs = parseJsonRole('theirs', request.theirs_source);
     const conflicts: Merge3Conflict[] = [];
+    const changeClassifications = classifyJsonChanges(base, ours, theirs);
     const merged = mergeJsonValue(base, ours, theirs, '', conflicts);
     if (conflicts.length > 0) {
       const ownedRegions = jsonOwnedRegionsForConflicts(request, conflicts);
@@ -129,6 +137,7 @@ export function merge3Json(request: Merge3Request): Merge3Response {
       return response(request, {
         ok: false,
         conflicts,
+        change_classifications: changeClassifications,
         conflicted_source: conflictedSource,
         owned_regions: ownedRegions,
         render_report: {
@@ -151,6 +160,7 @@ export function merge3Json(request: Merge3Request): Merge3Response {
     return response(request, {
       ok: true,
       merged_source: mergedSource,
+      change_classifications: changeClassifications,
       reparse_after_render: JSON.parse(mergedSource) !== undefined,
       formatting_preservation: {
         line_diff_score: 1,
@@ -225,6 +235,7 @@ function response(
     merged_source: fields.merged_source,
     conflicted_source: fields.conflicted_source,
     conflicts: fields.conflicts ?? [],
+    change_classifications: fields.change_classifications ?? [],
     diagnostics: fields.diagnostics ?? [],
     fallbacks: fields.fallbacks ?? [],
     owned_regions: fields.owned_regions ?? [],
@@ -466,6 +477,38 @@ function mergeJsonObjects(
   return result;
 }
 
+function classifyJsonChanges(base: unknown, ours: unknown, theirs: unknown): readonly ChangeClassification[] {
+  if (isRecord(base) && isRecord(ours) && isRecord(theirs)) {
+    const keys = [
+      ...new Set([...Object.keys(base), ...Object.keys(ours), ...Object.keys(theirs)])
+    ].sort();
+    return keys.flatMap((key) => {
+      const oursChange = classifyJsonValueChange(
+        Object.hasOwn(base, key) ? base[key] : absent,
+        Object.hasOwn(ours, key) ? ours[key] : absent
+      );
+      const theirsChange = classifyJsonValueChange(
+        Object.hasOwn(base, key) ? base[key] : absent,
+        Object.hasOwn(theirs, key) ? theirs[key] : absent
+      );
+      if (oursChange === 'unchanged' && theirsChange === 'unchanged') return [];
+      return [{ path: jsonPointerJoin('', key), ours: oursChange, theirs: theirsChange }];
+    });
+  }
+  const oursChange = classifyJsonValueChange(base, ours);
+  const theirsChange = classifyJsonValueChange(base, theirs);
+  if (oursChange === 'unchanged' && theirsChange === 'unchanged') return [];
+  return [{ path: '/', ours: oursChange, theirs: theirsChange }];
+}
+
+function classifyJsonValueChange(base: MaybeAbsent, value: MaybeAbsent): string {
+  if (base === absent && value === absent) return 'unchanged';
+  if (base === absent && value !== absent) return 'added';
+  if (base !== absent && value === absent) return 'deleted';
+  if (jsonEqual(base, value)) return 'unchanged';
+  return 'edited';
+}
+
 function mergeJsonEntry(
   base: MaybeAbsent,
   ours: MaybeAbsent,
diff --git a/packages/ast-merge-git/test/fixtures.integration.test.ts b/packages/ast-merge-git/test/fixtures.integration.test.ts
index 2eae5b2..7571594 100644
--- a/packages/ast-merge-git/test/fixtures.integration.test.ts
+++ b/packages/ast-merge-git/test/fixtures.integration.test.ts
@@ -15,6 +15,11 @@ interface Fixture {
       readonly ok: boolean;
       readonly merged_json: unknown | null;
       readonly conflict_count: number;
+      readonly change_classifications?: readonly {
+        readonly path: string;
+        readonly ours: string;
+        readonly theirs: string;
+      }[];
       readonly conflict_categories?: readonly string[];
       readonly conflict_paths?: readonly string[];
       readonly conflicted_source_contains?: readonly string[];
@@ -111,6 +116,11 @@ describe('@structuredmerge/ast-merge-git', () => {
       const result = merge3(testCase.request);
       expect(result.ok, testCase.case_id).toBe(testCase.expected.ok);
       expect(result.conflicts, testCase.case_id).toHaveLength(testCase.expected.conflict_count);
+      if (testCase.expected.change_classifications !== undefined) {
+        expect(result.change_classifications, testCase.case_id).toEqual(
+          testCase.expected.change_classifications
+        );
+      }
       expect(result.reparse_after_render, testCase.case_id).toBe(
         testCase.expected.reparse_after_render
       );

From 3bfe0391cd3b8da4ab7f996756f56e1a279a9b52 Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 23:07:50 -0600
Subject: [PATCH 129/130] Report smorg-ts change classifications

---
 packages/smorg-ts/src/cli.ts       | 9 +++++++++
 packages/smorg-ts/test/cli.test.ts | 4 ++++
 2 files changed, 13 insertions(+)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 47f8505..391c1fd 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -61,6 +61,7 @@ interface ConflictRegion {
 }
 
 type MergeDriverResult = MergeResult<string> & {
+  readonly change_classifications?: Merge3Response['change_classifications'];
   readonly owned_regions?: Merge3Response['owned_regions'];
   readonly render_report?: Merge3Response['render_report'];
   readonly profile?: Merge3Response['profile'];
@@ -173,6 +174,7 @@ function runMergeDriver(
       false,
       exitUnresolvedConflict,
       fallbacks,
+      result.change_classifications ?? [],
       result.owned_regions ?? [],
       result.render_report,
       result.profile,
@@ -208,6 +210,7 @@ function runMergeDriver(
       true,
       exit,
       [],
+      result.change_classifications ?? [],
       result.owned_regions ?? [],
       result.render_report,
       result.profile,
@@ -234,6 +237,7 @@ function runMergeDriver(
     true,
     exitSuccess,
     [],
+    result.change_classifications ?? [],
     result.owned_regions ?? [],
     result.render_report,
     result.profile,
@@ -254,6 +258,7 @@ function writeMergeDriverMachineReport(
   ok: boolean,
   exitCode: number,
   fallbacks: Array<Record<string, unknown>>,
+  changeClassifications: Merge3Response['change_classifications'],
   ownedRegions: Merge3Response['owned_regions'],
   renderReport: Merge3Response['render_report'] | undefined,
   profile: Merge3Response['profile'] | undefined,
@@ -275,6 +280,7 @@ function writeMergeDriverMachineReport(
           ok,
           exit_code: exitCode,
           fallbacks,
+          change_classifications: changeClassifications,
           owned_regions: ownedRegions,
           render_report: renderReport,
           reparse_after_render: reparseAfterRender,
@@ -643,6 +649,7 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
       ok: true,
       diagnostics: result.diagnostics,
       output: result.merged_source,
+      change_classifications: result.change_classifications,
       owned_regions: result.owned_regions,
       render_report: result.render_report,
       profile: result.profile,
@@ -658,6 +665,7 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
       ok: false,
       diagnostics: result.diagnostics,
       output: result.conflicted_source,
+      change_classifications: result.change_classifications,
       owned_regions: result.owned_regions,
       render_report: result.render_report,
       profile: result.profile,
@@ -671,6 +679,7 @@ function merge3Result(result: ReturnType<typeof merge3>): MergeDriverResult {
   return {
     ok: false,
     diagnostics: result.diagnostics,
+    change_classifications: result.change_classifications,
     owned_regions: result.owned_regions,
     render_report: result.render_report,
     profile: result.profile,
diff --git a/packages/smorg-ts/test/cli.test.ts b/packages/smorg-ts/test/cli.test.ts
index ff77408..1a40014 100644
--- a/packages/smorg-ts/test/cli.test.ts
+++ b/packages/smorg-ts/test/cli.test.ts
@@ -301,12 +301,16 @@ describe('smorg-ts cli', () => {
     expect(exit).toBe(exitUnresolvedConflict);
     const report = JSON.parse(readFileSync(reportPath, 'utf8')) as {
       render_report: { strategy: string };
+      change_classifications: Array<{ path: string; ours: string; theirs: string }>;
       owned_regions: Array<{ owner_path: string; region_kind: string }>;
       profile: { profile_id: string; language: string };
       formatting_preservation: { line_diff_score: number };
       default_driver_evaluation: { status: string };
     };
     expect(report.render_report.strategy).toBe('owned_region_conflict_markers');
+    expect(report.change_classifications).toEqual([
+      { path: '/enabled', ours: 'edited', theirs: 'edited' }
+    ]);
     expect(report.owned_regions[0]?.owner_path).toBe('/enabled');
     expect(report.owned_regions[0]?.region_kind).toBe('node');
     expect(report.profile.profile_id).toBe('json.keyed-object');

From 8a53d09ffdc27dc966739125fb0d213e2867428e Mon Sep 17 00:00:00 2001
From: "Peter H. Boling" <peter.boling@gmail.com>
Date: Sun, 17 May 2026 23:15:41 -0600
Subject: [PATCH 130/130] Pass smorg-ts fallback policy to merge3

---
 packages/smorg-ts/src/cli.ts | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/packages/smorg-ts/src/cli.ts b/packages/smorg-ts/src/cli.ts
index 391c1fd..1e1ab1b 100644
--- a/packages/smorg-ts/src/cli.ts
+++ b/packages/smorg-ts/src/cli.ts
@@ -146,6 +146,7 @@ function runMergeDriver(
     effectivePath,
     settings.language,
     settings.conflictMarkerSize,
+    options.strict ? 'none' : options.fallback,
     ancestorSource,
     currentSource,
     otherSource
@@ -614,6 +615,7 @@ function mergeByPath(
   pathName: string,
   language: string | undefined,
   conflictMarkerSize: number,
+  fallbackPolicy: string,
   ancestorSource: string,
   currentSource: string,
   otherSource: string
@@ -631,7 +633,7 @@ function mergeByPath(
           language: 'json',
           dialect: 'json',
           profile_id: 'json.keyed-object',
-          fallback_policy: 'none',
+          fallback_policy: fallbackPolicy,
           conflict_marker_size: conflictMarkerSize,
           render_policy: 'canonical'
         })