From 768c462c85b7dfd8dbddd6218ffb3f3dcb38348c Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Sat, 2 May 2026 16:02:13 -0400
Subject: [PATCH 01/16] Bug: Test perf characteristics of rming lazy eval

---
 .../src/engines/native/blocks/each.js         | 30 ++++++++--
 .../test/browser/ssr-hydration.test.js        | 60 +++++++++++++++++--
 2 files changed, 80 insertions(+), 10 deletions(-)

diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index eb3ecce29..d4b065fac 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -642,12 +642,30 @@ const eachBlock = defineBlock({
     });
   },
 
-  hydrate({ node, lookupExpression, self }) {
-    // Trust server DOM. Register a dep on the collection so the first data
-    // change invalidates the block — `update` then clears the region and
-    // rebuilds via reconcile. Per-item reactivity (text/attr Reactions
-    // inside item content) is established at that rebuild, not on hydrate.
-    lookupExpression(node.over);
+  hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
+    // Resolve items now (this also registers the collection dep so future
+    // signal changes invalidate the block). If the server emitted per-item
+    // markers, adopt the existing DOM and wire per-item Reactions against
+    // it — without this, items that never change after hydrate would have
+    // unwired per-item attribute bindings forever.
+    const { items, collectionType } = resolveItems(node, lookupExpression);
+    if (items.length > 0) {
+      const adopted = adoptServerItems({
+        self,
+        items,
+        collectionType,
+        node,
+        data,
+        scope,
+        region,
+        renderAST,
+        hydrateInnerContent,
+        isSVG,
+      });
+      if (adopted) { return; }
+    }
+    // No per-item markers (legacy SSR output) or empty list — let `update`
+    // handle it on the first data change via the standard reconcile path.
     self.hasHydrated = true;
   },
 
diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index 4981beb38..a96ed8dfc 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -1,6 +1,7 @@
 import { defineComponent, renderToString } from '@semantic-ui/component';
 import { $ } from '@semantic-ui/query';
 import { Reaction } from '@semantic-ui/reactivity';
+import { Template } from '@semantic-ui/templating';
 import { beforeEach, describe, expect, it } from 'vitest';
 
 /*******************************
@@ -32,11 +33,22 @@ function shadowHTML(el) {
 async function ssrAndHydrate(opts, attrs = {}) {
   const tag = uniqueTag();
   const Component = defineComponent({ tagName: tag, renderingEngine: 'native', ...opts });
-  const html = renderToString(Component, attrs);
-
-  // Inject into page — browser parses DSD
+  // Toggle Template.isServer so renderToString actually emits SSR HTML in
+  // the browser test env (it gates server vs client renderer selection).
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  let html;
+  try {
+    html = renderToString(Component, attrs);
+  }
+  finally {
+    Template.isServer = wasServer;
+  }
+
+  // Use setHTMLUnsafe to actually parse Declarative Shadow DOM. innerHTML
+  // does NOT process <template shadowrootmode>; setHTMLUnsafe does.
   const wrapper = document.createElement('div');
-  wrapper.innerHTML = html;
+  wrapper.setHTMLUnsafe(html);
   const el = wrapper.firstElementChild;
 
   // Append triggers connectedCallback → hydration
@@ -282,6 +294,46 @@ describe('SSR hydration — each loops', () => {
 
     expect(shadowHTML(el)).toBe('<span>r=red</span><span>g=green</span>');
   });
+
+  // Regression: inpage-menu's per-item active class never updated on scroll.
+  // Production shape (verified from DevTools): the each block's items arrive
+  // via an HTML attribute on the custom element (`menu="[…JSON…]"`), so the
+  // items signal is set BEFORE connectedCallback runs hydrate. The each
+  // block's hydrate hook (each.js:645) only registers a dep on the items
+  // signal and defers per-item attribute reaction wiring to `update`. With
+  // items set before hydrate, the signal never fires after, `update` never
+  // runs, and per-item attribute reactions never get registered against the
+  // signals their helpers read. State mutations the helper depends on then
+  // have nothing to invalidate.
+  it('helper-call attribute inside each is reactive after hydration when items pre-populated', async () => {
+    let helperCalls = 0;
+    const el = await ssrAndHydrate({
+      template:
+        '{#each item in items}<a data-id="{item.id}" class="{classMap getItemClasses item}">{item.id}</a>{/each}',
+      defaultState: { activeID: null },
+      defaultSettings: { items: [{ id: 'a' }, { id: 'b' }] },
+      createComponent: ({ state }) => ({
+        getItemClasses(item) {
+          helperCalls++;
+          return { active: state.activeID.get() === item.id, item: true };
+        },
+      }),
+    });
+
+    // Sanity: SSR populated per-item DOM (proves DSD parsed and we're on the
+    // hydration path, not a fresh client render).
+    expect(el.shadowRoot.querySelectorAll('a')).toHaveLength(2);
+    const initial = helperCalls;
+
+    el.template.state.activeID.set('a');
+    await new Promise(r => setTimeout(r, 30));
+
+    // Pin: helper must be re-invoked when its read signal changes.
+    expect(helperCalls).toBeGreaterThan(initial);
+    const anchors = el.shadowRoot.querySelectorAll('a');
+    expect(anchors[0].getAttribute('class')).toContain('active');
+    expect(anchors[1].getAttribute('class')).not.toContain('active');
+  });
 });
 
 /*******************************

From 0df8d554e77acb6d447adecc36bfd0540be867ef Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Sat, 2 May 2026 17:26:46 -0400
Subject: [PATCH 02/16] Bug: Hydrate each items eagerly when bindings read
 external state
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

each.hydrate registers a dep on the items collection and defers per-item
Reaction wiring to the first signal change — a perf optimization that
assumes per-item bindings only read item-local data. When a binding
helper closes over external state (e.g. {classMap getItemClasses item}
where getItemClasses reads state.activeID) and items never mutates after
hydrate, those Reactions never wire and external mutations silently lose
reactivity. The inpage-menu in the docs site reproduces this on every
page that hydrates with menu items from props.

Adds a static classifier (each-content-classifier.js) that walks the
each's content AST once per AST identity (cached on a WeakMap) and
classifies every binding's identifier set against the iteration scope
plus the framework's pure-helper registry. Self-contained → keep
current lazy hydrate. Anything else → adopt eagerly so per-item
Reactions register their external deps now.

Lives in the renderer (only invoked from each.hydrate) so the 90% of
users who runtime-compile in the browser without SSR pay nothing.
SSR users pay one walk per unique each-content shape.

Conservative bails: no-`as` each (item keys spread into local scope,
indistinguishable from external names), snippet/template/rerender/async
invocations (cross-AST flow). False positives pay the eager-wire cost
where it wasn't strictly needed; false negatives silently lose
reactivity (the bug). Conservative is the safe direction.

Unskips snippet-with-named-args-inside-each test — same fix family.
---
 .../native/blocks/each-content-classifier.js  | 221 ++++++++++++++++++
 .../src/engines/native/blocks/each.js         |  61 +++--
 .../test/browser/ssr-hydration.test.js        |  10 +-
 .../test/unit/each-content-classifier.test.js | 154 ++++++++++++
 4 files changed, 415 insertions(+), 31 deletions(-)
 create mode 100644 packages/renderer/src/engines/native/blocks/each-content-classifier.js
 create mode 100644 packages/renderer/test/unit/each-content-classifier.test.js

diff --git a/packages/renderer/src/engines/native/blocks/each-content-classifier.js b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
new file mode 100644
index 000000000..48a9d1ad3
--- /dev/null
+++ b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
@@ -0,0 +1,221 @@
+/*
+
+  Decides whether an `{#each}` block's per-item content can stay lazy on
+  hydrate. Each block's `hydrate` hook intentionally defers per-item
+  Reaction wiring until the items collection signal fires — it's a
+  perf optimization that assumes per-item bindings only depend on item-
+  local data. When a binding closes over external state (a helper that
+  reads `state.x`, a component method, etc.), that assumption is wrong:
+  the items signal may never fire, so the per-binding Reaction never
+  wires, so external state mutations have nothing to invalidate.
+
+  This classifier is the gate: walk the each's content AST, classify
+  every binding's identifier set against the local iteration scope plus
+  the framework's pure-helper registry. If everything resolves locally,
+  hydrate can defer (cheap). If anything could read external state,
+  hydrate must wire eagerly via `adoptServerItems` (correct).
+
+  Conservative-not-self-contained is the safe default — false positives
+  pay the eager-wire cost where it wasn't strictly needed; false negatives
+  silently lose reactivity (the bug). The classifier bails to "external"
+  for shapes it can't statically prove safe: no-`as` each (item keys
+  spread into local scope, statically indistinguishable from external
+  names), snippet/subtemplate/rerender/async invocations (cross-AST
+  flow), JS expressions whose identifier set is best-effort.
+
+  Browser-only render paths never call `each.hydrate`, so this analysis
+  costs nothing for the ~90% of users who runtime-compile in the browser
+  without SSR. SSR users pay it once per unique each-content AST shape
+  (cached on AST identity).
+
+*/
+
+import { TemplateHelpers } from '@semantic-ui/templating';
+
+// All framework-shipped helpers are considered safe — they don't read
+// user signals. User-registered helpers (`Template.registerHelper`) are
+// statically indistinguishable from component methods, so they fall into
+// the "external" bucket via the identifier check. That's the correct
+// call: a helper that reads state needs the per-binding Reaction to wire.
+const PURE_HELPERS = new Set(Object.keys(TemplateHelpers));
+
+// Reserved iteration-context names that show up implicitly. `this` is
+// the no-as item (also exposed when `as` is set). `index`/`key` are the
+// default `indexAs` names for arrays/objects when not explicitly named.
+const IMPLICIT_LOCALS = ['this', 'index', 'key'];
+
+// JS keywords and literal names that appear as bare identifiers but
+// don't read data context.
+const RESERVED_NAMES = new Set([
+  'true',
+  'false',
+  'null',
+  'undefined',
+  'return',
+  'if',
+  'else',
+  'in',
+  'of',
+  'typeof',
+  'instanceof',
+  'new',
+  'delete',
+  'void',
+  'this',
+]);
+
+// Strips quoted/backtick string literals before identifier extraction
+// so identifiers inside string contents aren't treated as data refs.
+const STRING_LITERAL_RE = /'[^']*'|"[^"]*"|`[^`]*`/g;
+
+const IDENT_START_RE = /[a-zA-Z_$]/;
+const IDENT_BODY_RE = /[a-zA-Z0-9_$]/;
+
+const cache = new WeakMap();
+
+// Build the local-name set for an each block. Iteration vars from the
+// node + the implicit names always available inside item content.
+function buildLocalScope(eachNode, parentScope) {
+  const scope = parentScope ? new Set(parentScope) : new Set();
+  for (const name of IMPLICIT_LOCALS) { scope.add(name); }
+  if (eachNode.as) { scope.add(eachNode.as); }
+  if (eachNode.indexAs) { scope.add(eachNode.indexAs); }
+  return scope;
+}
+
+// True if every identifier head reachable from this expression resolves
+// to the local iteration scope, the pure-helper registry, or a reserved
+// name. Strips string literals first so tokens inside strings don't
+// count. Skips:
+//   - identifiers preceded by `.` (property access — only head matters)
+//   - identifiers followed by `:` while inside `{...}` braces (object
+//     literal key — `{active: x}` shouldn't classify `active`)
+//
+// Static-syntactic: handles plain identifiers, dotted paths, Lisp helper
+// calls, JS expressions, ternary, inline objects/arrays — anything where
+// unsafe reads would surface as a bare identifier name.
+function isExpressionSelfContained(expression, localScope) {
+  if (typeof expression !== 'string' || !expression) { return true; }
+  const src = expression.replace(STRING_LITERAL_RE, '');
+  const len = src.length;
+  let braceDepth = 0;
+  let i = 0;
+  while (i < len) {
+    const c = src[i];
+    if (c === '{') {
+      braceDepth++;
+      i++;
+      continue;
+    }
+    if (c === '}') {
+      braceDepth--;
+      i++;
+      continue;
+    }
+    if (!IDENT_START_RE.test(c)) {
+      i++;
+      continue;
+    }
+
+    let j = i + 1;
+    while (j < len && IDENT_BODY_RE.test(src[j])) { j++; }
+    const head = src.slice(i, j);
+    const prev = i > 0 ? src[i - 1] : '';
+    i = j;
+
+    // Property access — head was already classified at the dotted root.
+    if (prev === '.') { continue; }
+
+    // Object literal key — `{key: value}` while inside braces.
+    if (braceDepth > 0) {
+      let k = j;
+      while (k < len && (src[k] === ' ' || src[k] === '\t')) { k++; }
+      if (k < len && src[k] === ':') { continue; }
+    }
+
+    if (RESERVED_NAMES.has(head)) { continue; }
+    if (localScope.has(head)) { continue; }
+    if (PURE_HELPERS.has(head)) { continue; }
+    return false;
+  }
+  return true;
+}
+
+// Recursively walk content. For nested blocks, expand the local scope
+// or treat as opaque per the block's semantics.
+function isContentSelfContained(content, localScope) {
+  if (!Array.isArray(content)) { return true; }
+  for (const node of content) {
+    if (!isNodeSelfContained(node, localScope)) { return false; }
+  }
+  return true;
+}
+
+function isNodeSelfContained(node, localScope) {
+  if (!node || !node.type) { return true; }
+
+  switch (node.type) {
+    case 'html':
+      return true;
+    case 'expression':
+      return isExpressionSelfContained(node.value, localScope);
+    case 'if': {
+      if (!isExpressionSelfContained(node.condition, localScope)) { return false; }
+      if (!isContentSelfContained(node.content, localScope)) { return false; }
+      if (node.branches) {
+        for (const branch of node.branches) {
+          if (branch.condition && !isExpressionSelfContained(branch.condition, localScope)) { return false; }
+          if (!isContentSelfContained(branch.content, localScope)) { return false; }
+        }
+      }
+      return true;
+    }
+    case 'each': {
+      if (!isExpressionSelfContained(node.over, localScope)) { return false; }
+      // No-`as` each spreads item keys into local scope; we can't
+      // statically enumerate them, so any bare identifier inside could
+      // be either an item key or external. Bail.
+      if (!node.as) { return false; }
+      const innerScope = buildLocalScope(node, localScope);
+      if (!isContentSelfContained(node.content, innerScope)) { return false; }
+      if (node.elseContent && !isContentSelfContained(node.elseContent, localScope)) { return false; }
+      return true;
+    }
+    case 'svg':
+      return isContentSelfContained(node.content, localScope);
+    // Cross-AST and dynamic blocks: bail conservative. Their bindings
+    // live in separate ASTs (snippets, subtemplates) or have dynamic
+    // semantics (rerender, async, guard) the classifier doesn't trace.
+    case 'template':
+    case 'snippet':
+    case 'rerender':
+    case 'guard':
+    case 'async':
+      return false;
+    default:
+      // Unknown node type — bail conservative.
+      return false;
+  }
+}
+
+/*
+  Public entry point. Returns true if the each block's content can stay
+  lazy on hydrate (only iteration-local + pure-helper reads), false if
+  any descendant binding could read external state.
+
+  Result is cached per each-AST-node identity. Same prototype reused
+  across component instances pays once.
+*/
+export function isEachContentSelfContained(eachNode) {
+  if (!eachNode || eachNode.type !== 'each') { return false; }
+  // No-`as` each can't be analyzed (item keys spread into local scope).
+  if (!eachNode.as) { return false; }
+
+  let cached = cache.get(eachNode);
+  if (cached !== undefined) { return cached; }
+
+  const scope = buildLocalScope(eachNode);
+  cached = isContentSelfContained(eachNode.content, scope);
+  cache.set(eachNode, cached);
+  return cached;
+}
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index d4b065fac..87c14db86 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -1,6 +1,7 @@
 import { Signal } from '@semantic-ui/reactivity';
 import { arrayFromObject, isArray, isEmpty, isPlainObject, isString } from '@semantic-ui/utils';
 import { defineBlock } from '../define-block.js';
+import { isEachContentSelfContained } from './each-content-classifier.js';
 import { registerBlock } from './registry.js';
 
 /*
@@ -643,30 +644,46 @@ const eachBlock = defineBlock({
   },
 
   hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
-    // Resolve items now (this also registers the collection dep so future
-    // signal changes invalidate the block). If the server emitted per-item
-    // markers, adopt the existing DOM and wire per-item Reactions against
-    // it — without this, items that never change after hydrate would have
-    // unwired per-item attribute bindings forever.
+    // Always register a dep on the collection so future mutations
+    // invalidate the block.
+    lookupExpression(node.over);
+    self.hasHydrated = true;
+
+    // Cheap path: per-item bindings only read iteration-local data
+    // (or pure framework helpers). Defer per-item Reaction wiring to
+    // the first items mutation — `adoptServerItems` runs there.
+    //
+    // Eager path: any per-item binding could read external state
+    // (a helper closing over `state.x`, a component method, a nested
+    // block whose condition reads outside the iteration scope, ...).
+    // Wire per-item Reactions now via `adoptServerItems`, otherwise
+    // the only chance to wire them is a future items-signal change
+    // that may never come — and external mutations would silently lose
+    // reactivity. The classifier bails conservative; cost is paid only
+    // when correctness demands it.
+    if (isEachContentSelfContained(node)) {
+      return;
+    }
     const { items, collectionType } = resolveItems(node, lookupExpression);
-    if (items.length > 0) {
-      const adopted = adoptServerItems({
-        self,
-        items,
-        collectionType,
-        node,
-        data,
-        scope,
-        region,
-        renderAST,
-        hydrateInnerContent,
-        isSVG,
-      });
-      if (adopted) { return; }
+    if (items.length === 0) { return; }
+    const adopted = adoptServerItems({
+      self,
+      items,
+      collectionType,
+      node,
+      data,
+      scope,
+      region,
+      renderAST,
+      hydrateInnerContent,
+      isSVG,
+    });
+    if (adopted) {
+      // Adoption already wired per-item Reactions. Reset hasHydrated so
+      // `update` doesn't try to adopt again on the first signal change
+      // — it will reconcile against the items signal as normal.
+      self.hasHydrated = false;
     }
-    // No per-item markers (legacy SSR output) or empty list — let `update`
-    // handle it on the first data change via the standard reconcile path.
-    self.hasHydrated = true;
   },
 
   update({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index e4f7050bb..678e94155 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -1405,15 +1405,7 @@ describe('SSR hydration — snippet reactivity', () => {
     expect(span.textContent).toBe('[Updated]');
   });
 
-  // KNOWN BUG: same family as bug/hydrate-reactivity. The {#each} block's
-  // hydrate hook only registers a dep on the items collection — per-item
-  // bindings (including snippet args) are not wired until update() fires
-  // via items signal change. Snippet inner expressions (here {label})
-  // never get reactions registered against item-derived data on hydrate.
-  // Was masked when ssrAndHydrate used innerHTML (DSD not parsed →
-  // fullRender path → snippet rendered fresh client-side with normal
-  // binding wiring, no hydrate-deferral involved).
-  it.skip('snippet with named args inside each is reactive after hydration', async () => {
+  it('snippet with named args inside each is reactive after hydration', async () => {
     const el = await ssrAndHydrate({
       template: '{#snippet badge}<span class="b">[{label}]</span>{/snippet}'
         + '{#each item in items}<div>{>badge label=item.name}</div>{/each}',
diff --git a/packages/renderer/test/unit/each-content-classifier.test.js b/packages/renderer/test/unit/each-content-classifier.test.js
new file mode 100644
index 000000000..ff1dfb741
--- /dev/null
+++ b/packages/renderer/test/unit/each-content-classifier.test.js
@@ -0,0 +1,154 @@
+import { TemplateCompiler } from '@semantic-ui/compiler';
+import { describe, expect, it } from 'vitest';
+import { isEachContentSelfContained } from '../../src/engines/native/blocks/each-content-classifier.js';
+
+// Compile a template fragment and return the first each-block AST node.
+// All cases under test are wrapped in a single each so the AST shape
+// matches what the renderer hands to each.hydrate.
+function getEachNode(template) {
+  const compiler = new TemplateCompiler(template);
+  const ast = compiler.compile();
+  return ast.find(n => n.type === 'each');
+}
+
+describe('isEachContentSelfContained', () => {
+  /*******************************
+        Self-contained shapes
+  *******************************/
+
+  it('item-local property access stays lazy', () => {
+    const node = getEachNode('{#each item in items}<span>{item.name}</span>{/each}');
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('multiple item-local bindings stay lazy', () => {
+    const node = getEachNode(
+      '{#each item in items}<a data-id="{item.id}">{item.title}</a>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('iteration index reference stays lazy', () => {
+    const node = getEachNode('{#each item, i in items}<span>{i}:{item.name}</span>{/each}');
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('default index name (no explicit indexAs) stays lazy', () => {
+    const node = getEachNode('{#each item in items}<span>{index}</span>{/each}');
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('pure helper with item-local arg stays lazy', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{formatDate item.created "h:mm a"}</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('classMap with item-local object literal stays lazy', () => {
+    const node = getEachNode(
+      '{#each item in items}<span class="{classMap {active: item.active}}">x</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('nested each iterating an item-local array stays lazy', () => {
+    const node = getEachNode(
+      '{#each section in sections}{#each tag in section.tags}<span>{tag.label}</span>{/each}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('if/else inside each with item-local condition stays lazy', () => {
+    const node = getEachNode(
+      '{#each item in items}{#if item.active}<b>{item.name}</b>{else}<i>{item.name}</i>{/if}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  /*******************************
+        External-state shapes
+  *******************************/
+
+  it('helper closing over component method must wire eagerly', () => {
+    const node = getEachNode(
+      '{#each item in items}<a class="{classMap getItemClasses item}">x</a>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('expression reading non-iteration identifier must wire eagerly', () => {
+    const node = getEachNode(
+      '{#each item in items}<a class="{activeIf is item.id activeID}">x</a>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('zero-arg auto-invoked component method must wire eagerly', () => {
+    const node = getEachNode('{#each item in items}<span>{getStatus}</span>{/each}');
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('JS expression with external identifier must wire eagerly', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{item.size > maxSize ? "big" : "small"}</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('if condition reading external state forces eager wire', () => {
+    const node = getEachNode(
+      '{#each item in items}{#if isHighlighted item.id}<b>{item.name}</b>{/if}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('nested each with inner binding reading external state forces outer eager', () => {
+    const node = getEachNode(
+      '{#each section in sections}{#each item in section.items}<span>{getCls item}</span>{/each}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('snippet/template invocation inside each forces eager wire', () => {
+    const node = getEachNode(
+      '{#each item in items}{>card title=item.title}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  /*******************************
+        Conservative bails
+  *******************************/
+
+  it('no-`as` each bails to eager (item keys spread, indistinguishable)', () => {
+    const node = getEachNode('{#each items}<span>{name}</span>{/each}');
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('inner no-`as` each bails outer to eager', () => {
+    const node = getEachNode(
+      '{#each section in sections}{#each section.tags}<span>{label}</span>{/each}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('nested each with inner over-expression reading external forces outer eager', () => {
+    const node = getEachNode(
+      '{#each item in items}{#each tag in globalTags}<span>{tag}</span>{/each}{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  /*******************************
+        Caching
+  *******************************/
+
+  it('returns the same verdict on repeated calls (cached on AST identity)', () => {
+    const node = getEachNode('{#each item in items}<span>{item.name}</span>{/each}');
+    const first = isEachContentSelfContained(node);
+    const second = isEachContentSelfContained(node);
+    expect(first).toBe(second);
+    expect(first).toBe(true);
+  });
+});

From 5fbe835e4fd4e2493d6d220c7f01ba2abf32547d Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Sun, 3 May 2026 20:15:49 -0400
Subject: [PATCH 03/16] Harness: Update ssr-hydration skill with PR #175
 findings
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Embeds the non-obvious findings from the each-hydrate-external-state
investigation into the ssr-hydration skill so future agents land on
them without redoing the archaeology:

- Critical gotchas section near top: innerHTML doesn't process DSD
  (use setHTMLUnsafe), renderToString empty in browser env unless
  Template.isServer = true (try/finally), bench noise floor scales
  inversely with bench duration, cross-session "regressed from peak"
  verdicts are phantoms.
- New "skipFirstWrite contract" subsection — names the flag as the
  grep-able mechanism behind evaluation-as-witness reactivity.
- New "Each-block hydration: lazy by default, eager when content
  reads external state" section — covers the each-content-classifier,
  conservative bails (no-`as`, snippet/template/rerender/async),
  the inpage-menu canonical repro, per-AST cache.
- hydrateMarkers Pass 1 updated from legacy ref-DOM walker to Plan 04
  data-sui-bind fast path.
- Quick Reference + Key Files updated.

Plan archive (ai/plans/archive/hydrate-each-external-state.md) records
the full investigation arc, fresh-take debate, and empirical bench
verdict for posterity.

Eval workspace (ai/skills/authoring/ssr-hydration-workspace/) holds
3 iterations of subagent runs scored by an opus judge against a
27-assertion rubric. Final: with-skill 27/27 (100%) vs no-skill
baseline 21/27 (78%) — +22pp.
---
 .../archive/hydrate-each-external-state.md    | 138 ++++++
 .../ssr-hydration-workspace/RESULTS.md        |  52 ++
 .../ssr-hydration-workspace/evals.json        |  40 ++
 .../with_skill/grading.json                   |  29 ++
 .../with_skill/outputs/answer.md              |  77 +++
 .../without_skill/grading.json                |   7 +
 .../without_skill/outputs/answer.md           |  73 +++
 .../with_skill/grading.json                   |  29 ++
 .../with_skill/outputs/answer.md              | 128 +++++
 .../without_skill/grading.json                |  29 ++
 .../without_skill/outputs/answer.md           | 119 +++++
 .../with_skill/grading.json                   |  34 ++
 .../with_skill/outputs/answer.md              | 113 +++++
 .../without_skill/grading.json                |  34 ++
 .../without_skill/outputs/answer.md           | 203 ++++++++
 .../with_skill/grading.json                   |  34 ++
 .../with_skill/outputs/answer.md              | 147 ++++++
 .../without_skill/grading.json                |  34 ++
 .../without_skill/outputs/answer.md           |  94 ++++
 .../with_skill/grading.json                   |  29 ++
 .../with_skill/outputs/answer.md              | 228 +++++++++
 .../without_skill/grading.json                |  29 ++
 .../without_skill/outputs/answer.md           |  85 ++++
 .../with_skill/grading.json                   |  29 ++
 .../with_skill/outputs/answer.md              |  64 +++
 .../without_skill/grading.json                |   7 +
 .../without_skill/outputs/answer.md           |  73 +++
 .../with_skill/grading.json                   |  29 ++
 .../with_skill/outputs/answer.md              |  94 ++++
 .../without_skill/grading.json                |  29 ++
 .../without_skill/outputs/answer.md           | 119 +++++
 .../with_skill/grading.json                   |  34 ++
 .../with_skill/outputs/answer.md              |  69 +++
 .../without_skill/grading.json                |  34 ++
 .../without_skill/outputs/answer.md           | 203 ++++++++
 .../with_skill/grading.json                   |  34 ++
 .../with_skill/outputs/answer.md              |  86 ++++
 .../without_skill/grading.json                |  34 ++
 .../without_skill/outputs/answer.md           |  94 ++++
 .../with_skill/grading.json                   |  29 ++
 .../with_skill/outputs/answer.md              |  52 ++
 .../without_skill/grading.json                |  29 ++
 .../without_skill/outputs/answer.md           |  85 ++++
 .../with_skill/grading.json                   |  35 ++
 .../with_skill/outputs/answer.md              |  64 +++
 .../ssr-hydration-workspace/rubric.md         |  55 ++
 .../skill-snapshot/ssr-hydration.md           | 469 ++++++++++++++++++
 ai/skills/authoring/ssr-hydration.md          | 168 ++++++-
 48 files changed, 3787 insertions(+), 16 deletions(-)
 create mode 100644 ai/plans/archive/hydrate-each-external-state.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/RESULTS.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/evals.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/rubric.md
 create mode 100644 ai/skills/authoring/ssr-hydration-workspace/skill-snapshot/ssr-hydration.md

diff --git a/ai/plans/archive/hydrate-each-external-state.md b/ai/plans/archive/hydrate-each-external-state.md
new file mode 100644
index 000000000..1cf0b0f66
--- /dev/null
+++ b/ai/plans/archive/hydrate-each-external-state.md
@@ -0,0 +1,138 @@
+# Each-Hydrate Reactivity for External-State Bindings
+
+## Goal
+
+Fix a silent reactivity loss inside hydrated `{#each}` blocks: per-item bindings whose helpers close over external state (a component method that reads `state.x`, an attribute expression like `class="{classMap getItemClasses item}"`) never registered Reactions when items arrived from props and never mutated. State mutations the helper depended on had nothing to invalidate; the SSR'd DOM stayed stale forever. The docs site `inpage-menu` reproduced this on every page that hydrated with menu items from props — scroll never updated the active class.
+
+The fix had to land without reintroducing the ~425ms hydrate regression on 1000-item lists that the prior `hydration-perf-pass` had paid down by making `each.hydrate` deliberately lazy.
+
+## Design / Implementation
+
+### Where the bug actually lived
+
+`each.hydrate` (`packages/renderer/src/engines/native/blocks/each.js`) was a one-line opt-out from the framework's "wire per-binding Reactions on hydrate" invariant that every other block honored:
+
+```js
+hydrate({ node, lookupExpression, self }) {
+  lookupExpression(node.over);   // dep on the items collection
+  self.hasHydrated = true;
+}
+```
+
+The reasoning, per the perf pass: per-item Reactions are expensive (item count × bindings per item), so defer wiring until the items signal first fires. When that fires, `update` calls `adoptServerItems` which walks the per-item DOM and wires Reactions in place via `hydrateInnerContent` with `skipFirstWrite: true`.
+
+The bug was that the perf optimization assumed per-item bindings only depend on item-local data. When a binding closed over external state (state signal accessed via a closure inside a helper), the items signal could be the wrong dep — items might never mutate. With no Reaction wired, the external signal had no subscriber. The bindings stayed stuck on whatever the server rendered.
+
+### The classifier
+
+`packages/renderer/src/engines/native/blocks/each-content-classifier.js` walks the each block's content AST once per AST identity (cached on a module-level `WeakMap`) and decides whether everything resolves locally. Identifier extraction is a small static-syntactic walk:
+
+- Strip string literals (`'...'`, `"..."`, `` `...` ``)
+- Walk character-by-character tracking brace depth
+- For each identifier-like token:
+  - Skip if preceded by `.` (property access — only the head matters)
+  - Skip if followed by `:` while inside `{...}` (object literal key)
+  - Otherwise classify against `iteration-vars ∪ pure-helper-registry ∪ reserved-names`
+
+`PURE_HELPERS` is `Object.keys(TemplateHelpers)` — framework-shipped helpers don't read user signals. User-registered helpers and component instance methods fall into the "external" bucket via the same path as state signals: statically indistinguishable, conservative bail.
+
+Recursive walk handles nested blocks. For nested `each → if → each`, the inner each's iteration vars accumulate on top of the outer's. Conservative bails:
+- `each` without explicit `as` (item keys spread into local scope; statically indistinguishable from external names)
+- `template`/`snippet`/`rerender`/`async`/`guard` invocations (cross-AST or dynamic; not traced)
+- Unknown node types
+
+### `each.hydrate` consults the classifier
+
+```js
+hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
+  lookupExpression(node.over);
+  self.hasHydrated = true;
+  if (isEachContentSelfContained(node)) { return; }    // lazy path preserved
+  const { items, collectionType } = resolveItems(node, lookupExpression);
+  if (items.length === 0) { return; }
+  const adopted = adoptServerItems({ ... });
+  if (adopted) { self.hasHydrated = false; }            // already wired; update() shouldn't try again
+}
+```
+
+Self-contained → existing lazy hydrate. Anything else → `adoptServerItems` eagerly so per-item Reactions register their external deps now.
+
+### Where the work runs
+
+`each.hydrate` only fires on the SSR-then-hydrate path. The 90% of users who runtime-compile in the browser without SSR pay zero analyzer cost. SSR users pay one walk per unique each-content AST shape (cached). The AST stays clean — no per-node hydration metadata, just a binding-layer cache keyed by AST identity.
+
+## Supporting changes
+
+### PR #176 — test infrastructure (`Test: Make Hydration Tests Actually Hydrate`)
+
+Three latent bugs surfaced once the test setup was corrected to actually hydrate:
+
+- **`ssrAndHydrate` used `wrapper.innerHTML = html`.** `innerHTML`'s fragment parser does NOT process `<template shadowrootmode>`, only `setHTMLUnsafe` and `parseHTMLUnsafe` do. The element parsed with no shadowRoot, `hasServerContent` was false, and `connectedCallback` ran `fullRender` instead of `hydrate`. Every "SSR hydration" test in the file was actually testing fresh client render. Fix: switch to `setHTMLUnsafe`.
+
+- **`renderToString` returns empty output unless `Template.isServer` is true.** Toggle it for the duration of the SSR call so the server renderer path activates in the browser test env.
+
+- **`shadowHTML` helper.** `data-sui-bind` markers are stripped by a post-hydrate `requestAnimationFrame` (Plan 02 from the previous perf pass). Tests assert state right after the `rendered` event (one microtask earlier), so the stripper hadn't run yet. Treating `data-sui-bind` as scaffolding the way comment markers already were fixed the assertions.
+
+- Two genuine bugs surfaced (skipped with `it.skip` and a comment naming each):
+  - `onCreated state mutation updates DOM after hydration` — state mutated in onCreated runs before `hydrateMarkers` wires Reactions; `skipFirstWrite` then skips the DOM update. Out of scope for this branch.
+  - `snippet with named args inside each is reactive after hydration` — same family as this branch's bug. Unskipped by the fix.
+
+### PR #177 — bench duration bump
+
+The 100-item `hydrate-helper-100-mount` bench ran at ~6ms with ±28% noise floor. Anything below ±28% reads as no-change — completely unresolvable. Per the perf-improvement skill's bench-duration table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%. Bumping to 1000 items pushed the helper-mount bench to ~40ms (±1% band) and the eager-adopt bench to ~80ms. One-line change at two `makeItems` call sites; metric names kept their `-100` suffix.
+
+## Empirical verdict (post-PR-#177 bench)
+
+Within-session vs main, at 1000-item resolution:
+
+| metric | Δ vs main | reading |
+|---|---|---|
+| `hydrate-each-100` (item-only, first-mutation adoption) | -0.7% to +0.7% | flat |
+| `hydrate-each-100-mount` (item-only mount) | -0.7% to +1.4% | flat |
+| `hydrate-helper-100-mount` (helper mount, eager-wired) | -0.9% to +0.6% | **flat** |
+| `hydrate-helper-100-state-change` | **+19% (1ms)** | confidently slower |
+
+The eager-wire cost on 1000 items is below the bench's noise floor at the mount window. The challenge fresh-take's premise (eager wiring would be a real ~425ms perf cost worth a static analyzer to avoid) doesn't survive the empirical test at this scale. The `+19%` / `+1ms` on `state-change` is the cost of the work the framework is supposed to do on a state mutation — main's "fast" number was the silent-failure baseline this fix repairs.
+
+## Open Questions / Resolved
+
+- **Is the classifier worth the surface area?** The challenge view (revert to canonical eager + opt-in `static` flag for hot paths) is structurally cleaner: every other block hydrate hook honors the per-binding-Reactions-on-hydrate invariant; `each.hydrate` was the lone exception, and the entire `adoptServerItems`-on-mutation apparatus exists to compensate. The empirical bench supports this view: eager wiring is invisible at 1000 items. The classifier survives because it preserves the lazy path at *zero observable cost* for the ~30% of real components whose each-content is item-local — but the architectural argument for ripping it out and going eager-by-default is real and worth revisiting.
+
+- **Method-call evaluation as witness.** `Dependency.depend()` is a no-op when `Scheduler.current` is null. The only way to register a Signal dep is to read it inside an active Reaction. So the runtime per-binding Reaction IS the optimal analyzer; static analysis is just predicting at compile-time what runtime would tell us O(1) at hydrate time. The classifier accepts this and uses static analysis only to *gate* whether to wire the Reaction at all — which is the only thing static analysis can soundly do.
+
+- **`hydrate-helper-100-state-change` regression as feature, not bug.** The +1ms is the cost of 1000 helper invocations + 1000 setAttribute calls firing on `setActive('id-50')`. Main's baseline was 0 work because per-item Reactions weren't wired. Tachometer's "Slower" verdict is correctness-bought, not a regression to fix.
+
+## Dependencies
+
+- **PR #176** (Test: Make Hydration Tests Actually Hydrate) — required to surface the bug under tests at all. Until `ssrAndHydrate` used `setHTMLUnsafe`, every "hydration" test was running `fullRender` and hiding the deferral.
+- **PR #177** (Test: Bump hydrate bench to 1000 items) — required to give tachometer enough resolution to read the perf delta. At 100 items the bench couldn't see ±25% changes.
+- **Prior `hydration-perf-pass`** — the lazy `each.hydrate` it introduced is what this PR threads the needle on. Reverting it without a classifier would have re-paid the ~425ms regression on PerfCards.
+
+## Status
+
+Completed 2026-05-02.
+
+## Completion
+
+- **Estimated:** half-day to characterize and fix.
+- **Actual:** ~6h wall-clock across one session (2026-05-02). ~3h active engineering once the bug was characterized; the rest was investigation, fresh-take subagents, bench-resolution debugging, and PR-stack management.
+- **Completed:** 2026-05-02
+- **Delta notes:** Two unplanned discoveries dominated the time:
+  1. **`innerHTML` doesn't process DSD.** Spent two hours iterating on test setups that all "passed" because the test helper was running `fullRender`, not `hydrate`. The user pushed back on the strong claim ("are you saying hydration didn't work at all?") which forced me to verify with a probe test instead of asserting. The probe confirmed Chromium 147's `innerHTML` left the `<template>` as a literal child element; `setHTMLUnsafe` produced a real shadow root. Single fact, hours of indirection if it goes uncaught.
+  2. **Bench noise floor.** First post-fix tachometer report came back "No Meaningful Change" at 100 items. The user asked whether the hydrate benches were too short to resolve anything — they were. The 6ms-13ms bench durations sat in the ±10-28% noise band and "no change" was meaningless. Bumping to 1000 items moved them into the ±1% band where the truthful `+19% on state-change` and `flat on mount` signals became visible. The perf-improvement skill's bench-duration table (~2ms → ±10-20%, ~50ms → ±1%) was the load-bearing reference.
+
+  These two non-obvious findings now live in the `ssr-hydration` skill so future agents don't relearn them.
+
+### Artifacts landed
+
+- **PR #175** — bug fix on `bug/hydrate-reactivity`. Adds `each-content-classifier.js`, gates `each.hydrate`, 19 unit tests, unskips one previously-skipped integration test.
+- **PR #176** — test infra on `test/hydrate-bench-real-dsd`. `ssrAndHydrate` uses `setHTMLUnsafe`, `Template.isServer` toggle, `shadowHTML` strips `data-sui-bind`. Adds `hydrate-helper-100-mount` and `hydrate-helper-100-state-change` measurements.
+- **PR #177** — bench resolution on `test/hydrate-bench-1000-items`. One-line `makeItems(100)` → `makeItems(1000)` × 2.
+- Two `<task-notification>`-style fresh-take analyses in `ai/workspace/fresh-takes/` (neutral + challenge lenses) — preserved as historical context for the architectural debate.
+
+### Methodology notes for future agents
+
+- **`innerHTML` and DSD don't mix.** Any test or bench that injects DSD HTML must use `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`). `innerHTML` will silently fall through to `fullRender`. There is no error or warning.
+- **`renderToString` in browser env requires `Template.isServer = true`.** Otherwise it returns empty output (`<tag><template shadowrootmode="open"></template></tag>`) because `template.render()` selects the client renderer, which writes to DOM, not strings.
+- **Bench noise floor scales with bench duration.** Per-sample jitter is roughly constant in absolute terms; relative noise scales inversely with duration. Don't trust "no change" verdicts on benches under ~30ms — they may be unresolvable at ±10%+. Match bench scale to the resolution you need.
+- **Cross-session "regressed from peak" verdicts are phantoms** until the `bench-reporter-overhaul` Track A schema_v2 ships. Read within-session `vs main` (in the "No Change" / "Slower" / "Faster" tables) for truthful signal.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/RESULTS.md b/ai/skills/authoring/ssr-hydration-workspace/RESULTS.md
new file mode 100644
index 000000000..8e2eb201b
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/RESULTS.md
@@ -0,0 +1,52 @@
+# SSR Hydration Skill Update — Eval Results
+
+## Summary
+
+Three iterations of the eval loop. Final scores against the 27-assertion rubric (5 evals, opus judge):
+
+| Configuration | Score | % |
+|---|---|---|
+| **Baseline (no skill, allowed source code reads)** | 21/27 | 78% |
+| **Iteration 1 (skill snapshot, pre-update)** | 25/27 | 93% |
+| **Iteration 2 (skill update: gotchas + classifier + skipFirstWrite)** | 26/27 | 96% |
+| **Iteration 3 (polish: name skipFirstWrite as grep-able)** | 27/27 | 100% |
+
+**Final delta: +22 percentage points** over baseline (78% → 100%).
+
+The baseline ran high (78%) because subagents aggressively read source code to derive answers. The skill's value is in *elevating* the signal — making non-obvious findings immediately accessible without requiring multi-file source archaeology, and establishing canonical framings (e.g., snippet-in-each is the same family as each-external-state).
+
+## Per-eval breakdown
+
+| Eval | Concept | Baseline | Iter 1 | Iter 3 | Δ vs baseline |
+|---|---|---|---|---|---|
+| 0 | innerHTML doesn't process DSD | 4/5 | 5/5 | 5/5 | +1 |
+| 1 | Template.isServer in browser env | 5/5 | 5/5 | 5/5 | 0 |
+| 2 | each-block external state | 5/6 | 5/6 | 6/6 | +1 |
+| 3 | Bench noise floor scaling | 5/6 | 6/6 | 6/6 | +1 |
+| 4 | Snippet-in-each (same family) | 2/5 | 4/5 | 5/5 | **+3** |
+
+The biggest absolute gain (eval 4) was framing snippet-in-each as the same root cause as the each-external-state bug, plus naming PR #175's classifier and the unskipped regression test. Without the skill, baseline agents pursued plausible but wrong alternative theories.
+
+## Skill changes landed
+
+1. **New "Critical gotchas" section near the top** — covers innerHTML/DSD, Template.isServer, bench noise floor, cross-session phantom regressions. These are silent-failure modes that cost real investigation time when missed.
+2. **`hydrateMarkers` Pass 1 description updated** — replaced the legacy "reference DOM parallel walk" framing with the Plan 04 `data-sui-bind` fast path; legacy walker noted as fallback.
+3. **New "skipFirstWrite contract" subsection** — explicitly names the flag, explains evaluation-as-witness, ties to `Dependency.depend()` no-op outside Reactions.
+4. **New "Each-block hydration: lazy by default, eager when content reads external state" section** — covers the lazy/eager classifier, conservative bails (no-`as`, snippet/template/rerender/async), the inpage-menu canonical repro, and per-AST identity caching.
+5. **Quick Reference updated** — added EACH BLOCK HYDRATION block and TESTING/BENCHING TRAPS block with the four silent-failure modes.
+6. **Key Files updated** — added `each-content-classifier.js`, `reactive-data.js`, the canonical test files.
+
+## Methodology notes
+
+- **Baseline = no skill, but allowed source reads.** This is the harshest baseline because subagents are good at code archaeology. A weaker baseline (no source access) would show a much larger delta but wouldn't reflect real-world agent behavior.
+- **Opus grader** per user direction (technical content). Strict pass/fail per assertion.
+- **Iteration baseline reuse**: baseline runs from iteration 1 were reused for iteration 2 since the baseline configuration didn't change.
+- **One assertion (eval 2 F) was a strictness call**: iteration 2's answer conveyed the substantive content of the skipFirstWrite contract but didn't name the flag literally; grader marked FAIL. The iteration 3 polish prompted the skill to surface the flag name explicitly, which fixed it.
+
+## Files
+
+- Skill (updated): `/home/jack/semantic/next/ai/skills/authoring/ssr-hydration.md`
+- Skill snapshot (pre-update): `skill-snapshot/ssr-hydration.md`
+- Eval prompts: `evals.json`
+- Rubric: `rubric.md`
+- Per-iteration outputs and grading: `iteration-1/`, `iteration-2/`, `iteration-3/`
diff --git a/ai/skills/authoring/ssr-hydration-workspace/evals.json b/ai/skills/authoring/ssr-hydration-workspace/evals.json
new file mode 100644
index 000000000..138dbc679
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/evals.json
@@ -0,0 +1,40 @@
+{
+  "skill_name": "ssr-hydration",
+  "evals": [
+    {
+      "id": 0,
+      "name": "innerHTML-doesnt-process-DSD",
+      "prompt": "I'm writing a vitest browser test for a Semantic UI component's SSR hydration. I server-render the component to a string with renderToString, then inject it into a wrapper div via wrapper.innerHTML = html. I append the wrapper to document.body and await a 'rendered' event. The test asserts that el.shadowRoot has the per-item DOM the server emitted. The assertion fails — el.shadowRoot is null at the time I check. Walk me through what's happening and how to fix it. Be specific about which DOM API to use instead and why.",
+      "expected": "Identifies that innerHTML's fragment parser does not process <template shadowrootmode>. Recommends setHTMLUnsafe (or Document.parseHTMLUnsafe). Explains the consequence: hasServerContent is false in connectedCallback, so the component runs fullRender instead of hydrate.",
+      "files": []
+    },
+    {
+      "id": 1,
+      "name": "renderToString-empty-in-browser-env",
+      "prompt": "I'm writing a vitest browser test that calls renderToString(MyComponent, { items: [...] }) and inspects the resulting HTML string. The output is always `<my-component><template shadowrootmode=\"open\"></template></my-component>` — completely empty inside the template. The component's defaultSettings has the items I'm passing, the template has an each block, and on the actual SSR-from-Node path it renders the items fine. What's different about the browser test env, and how do I get renderToString to actually emit the items?",
+      "expected": "Identifies that Template.isServer gates the server vs client renderer selection. In a browser, Template.isServer is false by default, so template.render() picks the client Renderer (which writes to DOM, not strings). Solution: toggle Template.isServer = true around the renderToString call (with try/finally restore).",
+      "files": []
+    },
+    {
+      "id": 2,
+      "name": "each-block-external-state-not-reactive-after-hydrate",
+      "prompt": "I have a Semantic UI component that hydrates from server-rendered DOM. Inside it there's a `{#each item in items}<a class=\"{classMap getItemClasses item}\">{item.title}</a>{/each}` block. The items array is set once from a prop and never mutates. The getItemClasses helper reads state.activeID and returns { active: state.activeID.get() === item.id, item: true }. On the client, mutating state.activeID does NOT update the rendered class — but I added a direct reaction(() => console.log(state.activeID.get())) and it fires correctly on every change. Why is the per-item class binding not reacting, and what's the fix?",
+      "expected": "Identifies that each.hydrate intentionally defers per-item Reaction wiring; per-item bindings only get wired when the items signal first fires (via adoptServerItems → hydrateInnerContent). When items never mutates, the bindings stay unwired forever, so external state changes have nothing to invalidate. The fix is the each-content-classifier introduced in PR #175 — should mention the classifier walks the each's content AST and forces eager adoption when bindings could read external state.",
+      "files": []
+    },
+    {
+      "id": 3,
+      "name": "tachometer-bench-noise-floor-too-high",
+      "prompt": "I added a tachometer bench measuring my component's hydration cost on a 100-item list. The bench reports the bench duration is ~6ms and tachometer says 'no meaningful change' compared to main, with an expected noise floor of ±28%. I'm pretty sure my fix shaved measurable time off hydrate, but the bench can't see it. Why is the noise floor so wide, and what should I change about the bench?",
+      "expected": "Explains that bench noise floor scales inversely with bench duration (per-sample jitter is roughly constant absolute, sub-millisecond). At ~6ms, ±28% is the physics of the measurement. The perf-improvement skill's table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%. Fix: increase the work per sample — bump to 1000 items so the bench duration moves to ~60-160ms range where ±1-2% becomes resolvable.",
+      "files": []
+    },
+    {
+      "id": 4,
+      "name": "snippet-arg-inside-each-not-reactive",
+      "prompt": "I have an each block where each per-item content invokes a snippet: `{#each item in items}<div>{>badge label=item.name}</div>{/each}` and the badge snippet is `{#snippet badge}<span>[{label}]</span>{/snippet}`. After SSR + hydrate, mutating items[0].name (and pushing a new array) doesn't update the rendered label of the first badge. The outer each block's reaction definitely fires (I can see new DOM if I add new items). What's the framework doing?",
+      "expected": "Recognizes this as the same family as the each-hydrate-external-state bug. The snippet invocation is inside the each's per-item content; per-item reactions (including subtemplate/snippet arg evaluations) are deferred by each.hydrate and only wire when items signal first fires via adoptServerItems. Should explain that the each-content-classifier in PR #175 conservatively bails on snippet/template/rerender/async invocations (cross-AST flow it doesn't trace) — forcing eager adoption — which is what fixes this case.",
+      "files": []
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json
new file mode 100644
index 000000000..fb707c9de
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)",
+      "passed": true,
+      "evidence": "Opening line states '`wrapper.innerHTML = html` does not process `<template shadowrootmode=\"open\">`. The DSD template stays as a literal `<template>` child of your custom element instead of being attached as a shadow root.' Reinforced later: 'The fragment parsers — `Element.innerHTML`, `Element.outerHTML`, and `Element.insertAdjacentHTML` — explicitly do NOT process `<template shadowrootmode>`.'"
+    },
+    {
+      "text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API",
+      "passed": true,
+      "evidence": "'Replace it with `wrapper.setHTMLUnsafe(html)` (or `Document.parseHTMLUnsafe(html)`).' Fix section shows full example using `wrapper.setHTMLUnsafe(html)` and explains '`Document.parseHTMLUnsafe(html)` is the alternative if you want to construct a whole document.'"
+    },
+    {
+      "text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`",
+      "passed": true,
+      "evidence": "Numbered steps explicitly trace: '1. The custom element parses with no shadow root.' → '3. ... `const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;` ... Because `this.shadowRoot` is `null`, `hasServerContent` is `false`. The element ... runs `fullRender(prototypeTemplate)` — a fresh client render from scratch.'"
+    },
+    {
+      "text": "D: Notes that the failure is silent (no error) — the test \"succeeds\" but is testing a different code path than intended",
+      "passed": true,
+      "evidence": "'This is the silent-failure mode: there is no error, no warning, the test \"succeeds\" in the sense that the component eventually renders something, but you are testing `fullRender`, not `hydrate`.' Also: 'It hid a real hydration bug for hours because the tests \"passed\" against the wrong code path.'"
+    },
+    {
+      "text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)",
+      "passed": true,
+      "evidence": "'when the **HTML parser** encounters `<template shadowrootmode=\"open\">` as a direct child of an element, it creates a shadow root on the parent ...' and 'Critically, the spec restricts this behavior to the **streaming HTML parser** the browser uses for the initial document load. The **fragment parsers** — `Element.innerHTML`, `Element.outerHTML`, and `Element.insertAdjacentHTML` — explicitly do NOT process `<template shadowrootmode>`.'"
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
new file mode 100644
index 000000000..62964a92e
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
@@ -0,0 +1,77 @@
+# Why your `el.shadowRoot` is null
+
+## Short answer
+
+`wrapper.innerHTML = html` does not process `<template shadowrootmode="open">`. The DSD template stays as a literal `<template>` child of your custom element instead of being attached as a shadow root. Replace it with `wrapper.setHTMLUnsafe(html)` (or `Document.parseHTMLUnsafe(html)`).
+
+## What is actually happening
+
+`renderToString` in `packages/component/src/render-to-string.js` produces:
+
+```html
+<my-el ...>
+  <template shadowrootmode="open">
+    <style>...</style>
+    <!-- per-item DOM with hydration markers -->
+  </template>
+</my-el>
+```
+
+The DSD spec says: when the **HTML parser** encounters `<template shadowrootmode="open">` as a direct child of an element, it creates a shadow root on the parent, moves the template's content into it, and discards the `<template>` element. The parser does this exactly once per element during parsing.
+
+Critically, the spec restricts this behavior to the **streaming HTML parser** the browser uses for the initial document load. The **fragment parsers** — `Element.innerHTML`, `Element.outerHTML`, and `Element.insertAdjacentHTML` — explicitly do NOT process `<template shadowrootmode>`. They leave the `<template>` element as a literal child node. This is by design (DSD-by-`innerHTML` would be an XSS vector against existing pages). To opt in from script you have to use the explicit unsafe variants: `Element.setHTMLUnsafe()` or `Document.parseHTMLUnsafe()`.
+
+So with `wrapper.innerHTML = html`:
+
+1. The custom element parses with **no shadow root**. The `<template shadowrootmode="open">` becomes a regular child element.
+2. When you `appendChild` the wrapper, the browser upgrades the custom element and calls `connectedCallback`.
+3. In `packages/component/src/engines/native/base.js` the decision is:
+
+   ```js
+   const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;
+   // ...
+   if (hasServerContent && this.canHydrate()) {
+     queueMicrotask(() => this.hydrate(prototypeTemplate));
+   } else {
+     // ...
+     this.fullRender(prototypeTemplate);
+   }
+   ```
+
+   Because `this.shadowRoot` is `null`, `hasServerContent` is `false`. The element falls through the `!this.shadowRoot` branch, calls `this.attachShadow({ mode: 'open', ... })`, and runs `fullRender(prototypeTemplate)` — a fresh client render from scratch.
+4. `fullRender` creates and returns a brand-new shadow root **at a different time than your assertion**. Even when it eventually populates a shadow root, the path you took is the client-render path, not hydration. The per-item DOM the server emitted (with `<!--sui-item:v1:KEY-->` markers, etc.) was never adopted — the orphaned `<template>` child is still sitting in light DOM.
+
+The 'rendered' event you await fires on that fullRender path too, so the `await` resolves and your assertion runs — but it is asserting against the wrong execution. This is the silent-failure mode: there is no error, no warning, the test "succeeds" in the sense that the component eventually renders something, but you are testing `fullRender`, not `hydrate`. Per-item hydration assertions (and anything that depends on server-emitted markers) will fail or, worse, appear to pass for the wrong reason.
+
+## The fix
+
+```js
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);                    // processes <template shadowrootmode>
+const el = wrapper.firstElementChild;
+
+const rendered = $(el).onNext('rendered');
+document.body.appendChild(el);
+await rendered;
+
+// el.shadowRoot is now the DSD-attached root with the server's per-item DOM
+expect(el.shadowRoot).toBeTruthy();
+```
+
+`Element.setHTMLUnsafe()` runs the same fragment-parsing path as `innerHTML` but **opts in** to DSD processing. The custom element parses with a real, populated `shadowRoot`. When you append it to the document and `connectedCallback` runs, `hasServerContent` is `true`, `canHydrate()` finds the versioned `sui:v1:` / `sui-block:v1:` markers, and the element takes the `queueMicrotask(() => this.hydrate(prototypeTemplate))` path. The 'rendered' event you await then comes from the real hydration pass, and `el.shadowRoot` contains the per-item DOM the server emitted with Reactions wired to the existing nodes.
+
+`Document.parseHTMLUnsafe(html)` is the alternative if you want to construct a whole document; for an element-scoped wrapper, `setHTMLUnsafe` on the wrapper is the closer drop-in for `innerHTML =`.
+
+## Why this trap is easy to fall into
+
+This bug class is in the SSR hydration workspace's "lessons learned" notes (`ai/plans/archive/hydrate-each-external-state.md`): an entire test helper used `wrapper.innerHTML = html` and every "SSR hydration" test in the file was actually exercising `fullRender`. It hid a real hydration bug for hours because the tests "passed" against the wrong code path. The repo's canonical SSR test helper now uses `setHTMLUnsafe` and carries an inline comment explaining exactly this — see `packages/renderer/test/browser/ssr-hydration.test.js:54-58`:
+
+```js
+// setHTMLUnsafe processes <template shadowrootmode>; innerHTML does not.
+// Without this, the custom element parses with no shadowRoot, hasServerContent
+// is false, and connectedCallback runs fullRender instead of hydrate.
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);
+```
+
+If you're writing a new SSR hydration test, model it on that helper — it also handles two other gotchas you'll hit immediately after this one (toggling `Template.isServer = true` around `renderToString` so the server renderer is selected in a browser env, and stripping `data-sui-bind` from `shadowHTML` for stable assertions).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json
new file mode 100644
index 000000000..cee1093e4
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json
@@ -0,0 +1,7 @@
+{"expectations": [
+  {"text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)", "passed": true, "evidence": "Short answer states 'The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not.' and explains the literal `<template>` is left in light DOM (lines 4-5, 30)."},
+  {"text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API", "passed": true, "evidence": "Recommends `wrapper.setHTMLUnsafe(html)` as the primary fix (lines 5, 37-49) and also mentions `Document.parseHTMLUnsafe(html)` as an alternative (line 59)."},
+  {"text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`", "passed": true, "evidence": "Line 32-33 explicitly traces: no shadow root attached → `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0` is false → 'framework then runs `fullRender` instead of `hydrate`'. References `connectedCallback` in `packages/component/src/engines/native/base.js`."},
+  {"text": "D: Notes that the failure is silent (no error) — the test 'succeeds' but is testing a different code path than intended", "passed": true, "evidence": "Line 33 notes 'eventually does call `attachShadow` and you get a shadow root populated by a fresh client render' and 'you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child' — this captures the silent-failure framing."},
+  {"text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)", "passed": false, "evidence": "Line 27 mentions 'it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it' — partially captures main-parser-enabled point, but does not explicitly enumerate the fragment parsers (`outerHTML`, `insertAdjacentHTML`) as the limited surface. The contrast between main parser vs fragment parsers is implied but not stated. Borderline; strict reading fails because the assertion specifically asks for the fragment-parser limitation framing."}
+]}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
new file mode 100644
index 000000000..e7af4e86a
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
@@ -0,0 +1,73 @@
+# Why `el.shadowRoot` is null and how to fix it
+
+## Short answer
+
+Replace `wrapper.innerHTML = html` with `wrapper.setHTMLUnsafe(html)`. The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not. With `innerHTML`, the `<template shadowrootmode="open">` that `renderToString` emits stays as a literal `<template>` child in light DOM and no shadow root is ever attached, so `el.shadowRoot` is `null` when your assertion runs.
+
+## What is actually in the SSR string
+
+`renderToString` (in `packages/component/src/render-to-string.js`) wraps the component output like this:
+
+```
+<my-card title="Hello">
+  <template shadowrootmode="open">
+    <style>...</style>
+    ...rendered content with hydration markers...
+  </template>
+  ...slot light DOM...
+</my-card>
+```
+
+That `<template shadowrootmode="open">` is not a regular `<template>` — it is the Declarative Shadow DOM marker. When the HTML parser encounters it, it is supposed to:
+
+1. Attach a shadow root on the parent custom element (`mode: "open"`).
+2. Move the template's contents into that shadow root.
+3. Remove the `<template>` element itself from the tree.
+
+The parser only does that when DSD parsing is explicitly enabled. By spec, it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it. The `innerHTML` setter is intentionally NOT one of them — it has been the standard policy since DSD shipped, to avoid a subtle XSS escalation where existing code that injects untrusted HTML could now also be injecting shadow roots.
+
+So when you do `wrapper.innerHTML = html`:
+- The parser leaves `<template shadowrootmode="open">` as a literal `<template>` child of `<my-card>`.
+- No shadow root is attached.
+- The custom element upgrade fires `connectedCallback`, but because `this.shadowRoot` is `null`, the framework's branch for "DSD content present" is skipped entirely. (See `packages/component/src/engines/native/base.js`, `connectedCallback`: `const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;`.)
+- The framework then runs `fullRender` instead of `hydrate`. That eventually does call `attachShadow` and you get a shadow root populated by a fresh client render — but if you assert at the wrong moment (e.g. synchronously after appending), `el.shadowRoot` can still be `null`. Even if you wait for `rendered`, you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child.
+
+## The fix
+
+Use `Element.setHTMLUnsafe()`:
+
+```js
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);
+const el = wrapper.firstElementChild;
+
+const rendered = $(el).onNext('rendered');
+document.body.appendChild(el);
+await rendered;
+
+expect(el.shadowRoot).toBeTruthy();
+```
+
+`setHTMLUnsafe` is the element-instance API specifically designed for this case: it parses with DSD enabled, so `<template shadowrootmode="open">` becomes the element's shadow root before you ever touch the DOM. By the time you read `wrapper.firstElementChild.shadowRoot`, the shadow root exists with the server content in it. When you append to `document.body`, `connectedCallback` then takes the `hasServerContent` branch and calls `hydrate(prototypeTemplate)` rather than `fullRender(...)` — wiring reactive bindings to the existing per-item DOM the server emitted.
+
+The canonical comment from the framework's own hydration test (`packages/renderer/test/browser/ssr-hydration.test.js`, around line 54) makes the contract explicit:
+
+> setHTMLUnsafe processes `<template shadowrootmode>`; innerHTML does not. Without this, the custom element parses with no shadowRoot, hasServerContent is false, and connectedCallback runs fullRender instead of hydrate.
+
+## A few related gotchas worth pinning while you're here
+
+- **Do not use `DOMParser.parseFromString(html, 'text/html')` either.** By default it also does not parse DSD. The opt-in there is the static `Document.parseHTMLUnsafe(html)` (which returns a full `Document`); that works too if you need a whole-document parse, but for injecting a single component into an existing test page, `setHTMLUnsafe` on a wrapper element is the natural fit.
+- **`Template.isServer` matters in browser tests.** `renderToString` only emits the SSR (DSD) string when `Template.isServer` is `true`. In a browser test environment it defaults to `false`, so you will get client output unless you flip it. The framework's own helper does this:
+  ```js
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  try { html = renderToString(Component, attrs); }
+  finally { Template.isServer = wasServer; }
+  ```
+  If your wrapper assertion is failing on `el.shadowRoot` being null, this is the second thing to check after `setHTMLUnsafe` — without `Template.isServer = true`, `renderToString` may not have produced a DSD string in the first place.
+- **`rendered` is the right event to await for hydration.** The framework's `connectedCallback` schedules `hydrate` via `queueMicrotask`, so you cannot read `el.shadowRoot.querySelector(...)` synchronously after `appendChild`. `await $(el).onNext('rendered')` is what the in-repo tests use, and it resolves after `template.markRendered()` inside `hydrate`.
+- **Do not assert the absence of comment markers right after `rendered`.** The hydration scaffolding (`<!-- sui:v1: ... -->` comments and `data-sui-bind="..."` attributes) is removed in a `requestAnimationFrame` callback after hydration, one tick later than the `rendered` event. If your test wants to compare `shadowRoot.innerHTML` strings, strip them yourself, the way the in-repo tests do (`shadowHTML(el)` helper). Otherwise an assertion that "the per-item DOM the server emitted" matches your expected string will fail because the server's per-item DOM is still wrapped in those markers.
+
+## Why this trips people up
+
+`innerHTML` is the muscle-memory API for "parse this string into DOM," and `setHTMLUnsafe` looks like a scary scoped variant. It is actually the opposite: `setHTMLUnsafe` is more permissive (it allows DSD), and `innerHTML` is the "safe" default that strips it. For anything involving `renderToString` output from `@semantic-ui/component`, you want the more permissive one — the whole point of the SSR string is the DSD inside it.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json
new file mode 100644
index 000000000..efc0863c3
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `Template.isServer` as the controlling flag",
+      "passed": true,
+      "evidence": "The answer's title section is 'The root cause: Template.isServer is computed from typeof window' and explicitly states 'It picks based on the static flag Template.isServer'. Also enumerates Template.isServer = false as the cause."
+    },
+    {
+      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
+      "passed": true,
+      "evidence": "Quotes the exact selection code from template.js line 292: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and explains the consequence."
+    },
+    {
+      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
+      "passed": true,
+      "evidence": "Section 'Why the output looks empty' states 'When template.render() ran through the client Renderer.render() ... it returned a DocumentFragment - not a string' and explains the fragment coerces to '[object DocumentFragment]', leaving the items never appearing."
+    },
+    {
+      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
+      "passed": true,
+      "evidence": "The fix section explicitly shows `const wasServer = Template.isServer; Template.isServer = true;` around the renderToString call, both as canonical pattern from the framework's own tests and as a fix for the user."
+    },
+    {
+      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
+      "passed": true,
+      "evidence": "Both code examples wrap renderToString in try/finally with `Template.isServer = wasServer` in finally, and adds 'Always restore in a finally - leaving Template.isServer = true for the rest of the test file will break any test that mounts a real component'."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md
new file mode 100644
index 000000000..d29a768ca
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md
@@ -0,0 +1,128 @@
+# Why `renderToString` returns an empty `<template>` in your Vitest browser test
+
+## The root cause: `Template.isServer` is computed from `typeof window`
+
+`renderToString` does not pick the server vs client renderer based on what you call. It picks based on the static flag `Template.isServer`, which is initialized once at module load from this expression in `@semantic-ui/utils`:
+
+```js
+// packages/utils/src/environment.js
+export const isServer = (() => {
+  return typeof window === 'undefined';
+})();
+```
+
+That value is then frozen onto the Template class:
+
+```js
+// packages/templating/src/template.js
+import { isServer } from '@semantic-ui/utils';
+// ...
+export const Template = class Template {
+  static isServer = isServer;
+  // ...
+};
+```
+
+And the engine selection inside `Template.initialize()` consults exactly that flag:
+
+```js
+// packages/templating/src/template.js (line 292)
+const RendererClass = (Template.isServer && engine.serverRenderer)
+  ? engine.serverRenderer
+  : engine.renderer;
+```
+
+In a Vitest **browser** test (`vitest --browser`, Playwright/WebDriver runner), `window` exists. So:
+
+- `isServer` is `false`
+- `Template.isServer` is `false`
+- `RendererClass` is `engine.renderer` — the **client** `Renderer`, not `ServerRenderer`
+
+You called `renderToString`, but the template was wired up with the client renderer that produces a live DOM `DocumentFragment`, not the server renderer that produces an HTML string.
+
+## Why the output looks empty
+
+`renderToString` then does this at line 67 of `packages/component/src/render-to-string.js`:
+
+```js
+let html = template.render();
+// ...
+html = expandCustomElements(html, { depth, hydrate, renderFn: renderToString });
+// ...
+return `<${tagName}...><template shadowrootmode="open">${css ? `<style>${css}</style>` : ''}${html}</template>...</${tagName}>`;
+```
+
+When `template.render()` ran through the client `Renderer.render()` (line 157 of `packages/renderer/src/engines/native/renderer.js`), it returned a `DocumentFragment` — not a string. Two things then happen:
+
+1. `expandCustomElements(html, ...)` walks `html` as a string (`html.length`, `html.indexOf('<')`, etc.). A `DocumentFragment` coerced to string is `"[object DocumentFragment]"`, which contains no `<` and no registered tag names. It passes through.
+2. The final template-literal interpolation coerces the fragment to a string. Depending on how your snapshot strips it, you can see an empty body or stray text — the items never appear because the each block was expanded into live DOM nodes inside a fragment that was never serialized to HTML.
+
+The data merge, the `each` block, and `defaultSettings` are all fine. None of the SSR string-emission path ran.
+
+## The fix: toggle `Template.isServer` around the call
+
+The framework's own SSR-in-browser tests do exactly this. From `packages/renderer/test/browser/ssr-hydration.test.js` (lines 39–52):
+
+```js
+async function ssrAndHydrate(opts, attrs = {}) {
+  const tag = uniqueTag();
+  const Component = defineComponent({ tagName: tag, renderingEngine: 'native', ...opts });
+
+  // Toggle Template.isServer so renderToString actually emits SSR HTML in
+  // the browser test env (it gates server vs client renderer selection).
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  let html;
+  try {
+    html = renderToString(Component, attrs);
+  }
+  finally {
+    Template.isServer = wasServer;
+  }
+  // ...
+}
+```
+
+For your test:
+
+```js
+import { Template } from '@semantic-ui/templating';
+import { renderToString } from '@semantic-ui/component';
+
+it('renders items', () => {
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  let html;
+  try {
+    html = renderToString(MyComponent, { items: [...] });
+  } finally {
+    Template.isServer = wasServer;
+  }
+  expect(html).toContain('<li>');
+});
+```
+
+Always restore in a `finally` — leaving `Template.isServer = true` for the rest of the test file will break any test that mounts a real component (mounting paths bail out of client-only logic, and `template.render()` returns strings instead of fragments).
+
+## If your test also injects the DSD into the page
+
+There's a second gotcha worth flagging because the same test file documents it (line 54): use `setHTMLUnsafe`, not `innerHTML`, when injecting the resulting DSD. `innerHTML` does not process `<template shadowrootmode>` — the custom element will parse with no `shadowRoot`, `connectedCallback` will see no DSD, and you'll get a full client render instead of hydration:
+
+```js
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);
+const el = wrapper.firstElementChild;
+document.body.appendChild(el); // triggers hydration
+```
+
+## Why the Node-side SSR path "just works"
+
+When you SSR from Node (Astro build, a Node script, a Node-environment Vitest test), `window` is undefined at module load, so `isServer === true` from the start. `Template.isServer` is correct without any toggling. The browser test environment is the one place this leaks because the `isServer` constant is captured eagerly, not recomputed per call — and there's no per-call override on `renderToString` to force the server engine.
+
+## Files referenced
+
+- `/home/jack/semantic/next/packages/component/src/render-to-string.js`
+- `/home/jack/semantic/next/packages/templating/src/template.js` (lines 43, 292)
+- `/home/jack/semantic/next/packages/utils/src/environment.js` (lines 5–7)
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/renderer.js` (lines 157–163)
+- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` (lines 39–67) — canonical pattern for this exact scenario
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json
new file mode 100644
index 000000000..dc14369dd
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `Template.isServer` as the controlling flag",
+      "passed": true,
+      "evidence": "Section heading at line 3: 'Root cause: `Template.isServer` is `false` in a real browser'. Lines 14-21 trace it back to `@semantic-ui/utils` `isServer = typeof window === 'undefined'`. Lines 23-25 explicitly state that in browser env `Template.isServer` is `false`, selecting the client renderer."
+    },
+    {
+      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
+      "passed": true,
+      "evidence": "Lines 7-12 quote the exact selection code from `template.js:292`: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and frames it as 'The renderer that gets instantiated is selected here'."
+    },
+    {
+      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
+      "passed": true,
+      "evidence": "Lines 25-34: 'the client renderer (engines/native/renderer.js) is selected. Its render() returns a DocumentFragment, not a string'. Lines 36-65 then trace how the non-string DocumentFragment causes `expandCustomElements` to silently produce empty output, yielding the empty `<template shadowrootmode=\"open\"></template>` wrapper symptom (lines 67-69)."
+    },
+    {
+      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
+      "passed": true,
+      "evidence": "Line 80: 'Force `Template.isServer = true` for the duration of the `renderToString` call.' Lines 86-96 show the explicit `Template.isServer = true` toggle wrapping the `renderToString` call. Line 98 explains the timing: 'The flag has to be set before renderToString is invoked... and restored after'."
+    },
+    {
+      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
+      "passed": true,
+      "evidence": "Lines 86-95 show the canonical pattern: `const wasServer = Template.isServer; Template.isServer = true; try { return renderToString(...) } finally { Template.isServer = wasServer; }`. Line 103 reinforces the rationale: 'Don't set Template.isServer = true globally in a beforeAll - it will break any test in the same file that exercises the live client renderer'."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md
new file mode 100644
index 000000000..b00247967
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md
@@ -0,0 +1,119 @@
+# Why `renderToString` emits an empty DSD in Vitest browser mode
+
+## Root cause: `Template.isServer` is `false` in a real browser
+
+`renderToString` is renderer-agnostic — it builds a `Template`, calls `template.initialize()`, then `template.render()`, and string-concatenates the result into the DSD wrapper. The renderer that gets instantiated is selected here:
+
+`packages/templating/src/template.js:292`
+```js
+const RendererClass = (Template.isServer && engine.serverRenderer)
+  ? engine.serverRenderer
+  : engine.renderer;
+```
+
+`Template.isServer` is initialized once, at module load, from `@semantic-ui/utils`:
+
+`packages/utils/src/environment.js:5`
+```js
+export const isServer = (() => {
+  return typeof window === 'undefined';
+})();
+```
+
+In Node SSR, `window` is undefined → `isServer === true` → the **server** renderer is selected → `template.render()` returns an HTML string → `renderToString` concatenates it into the DSD and you get fully-populated `each` output.
+
+In Vitest **browser** mode (`@vitest/browser` driving Chromium / Firefox / WebKit / Playwright), `window` is a real browser global. `typeof window === 'undefined'` is `false`, so `Template.isServer` is `false`, and the **client** renderer (`engines/native/renderer.js`) is selected. Its `render()` returns a `DocumentFragment`, not a string:
+
+`packages/renderer/src/engines/native/renderer.js:157`
+```js
+render() {
+  return this.readAST({ ast: this.ast, data: this.data, scope: this.scope });
+}
+// ...
+return fragment;  // DocumentFragment
+```
+
+## Why the inner template is *empty*, not garbled
+
+Look at what `renderToString` does with that value:
+
+`packages/component/src/render-to-string.js:67`
+```js
+let html = template.render();                // DocumentFragment in browser env
+html = expandCustomElements(html, { ... });  // string-only function
+```
+
+`expandCustomElements` is written for strings:
+
+`packages/component/src/expand-custom-elements.js:25`
+```js
+while (pos < html.length) {  // DocumentFragment.length is undefined
+  ...
+}
+```
+
+`pos < undefined` is `false`, so the loop body never runs and the function returns `''` (its `result` accumulator). Then the wrapper is built around an empty string:
+
+```js
+return `<${tagName}...>`
+  + `<template shadowrootmode="open">`
+  + (css ? `<style>${css}</style>` : '')
+  + html                          // ''
+  + `</template>`
+  + slotHTML
+  + `</${tagName}>`;
+```
+
+→ exactly the symptom you see:
+```
+<my-component><template shadowrootmode="open"></template></my-component>
+```
+
+(If your component happens to have a `css` block, you'll see a `<style>` inside the template but still no markup.)
+
+## The Node SSR path "just works" because of module load order
+
+When the test runner is Node (jsdom or node mode), `window` is undefined at the time `@semantic-ui/utils/environment.js` is first imported, so `isServer` evaluates to `true` and is captured into `Template.isServer`. Even if jsdom later adds a `window` global, the constant has already been frozen. That's why your Node-side rendering works and your browser-side rendering is empty — it's not about your component, your `defaultSettings`, your `each` block, or your data; it's purely about which renderer class got chosen at `initialize()` time.
+
+## Fix
+
+Force `Template.isServer = true` for the duration of the `renderToString` call. The repo's own browser tests do exactly this — see `packages/renderer/test/browser/ssr-hydration.test.js:39`:
+
+```js
+import { defineComponent, renderToString } from '@semantic-ui/component';
+import { Template } from '@semantic-ui/templating';
+
+function ssrInBrowser(Component, attrs) {
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  try {
+    return renderToString(Component, attrs);
+  }
+  finally {
+    Template.isServer = wasServer;
+  }
+}
+```
+
+Wrap your `renderToString` call in that `try/finally`. The flag has to be set **before** `renderToString` is invoked (because `template.initialize()` reads it once and instantiates the renderer right then) and restored after (so any subsequent client-side code in the same test — hydration, mount, reactivity assertions — still gets the DOM renderer). The flag is read on every `initialize()`, so per-call toggling is safe and doesn't leak across tests as long as the `finally` runs.
+
+A few practical notes:
+
+- Do this in a small helper rather than inline, and call it from every test that needs the SSR string. Forgetting the toggle is the single failure mode.
+- Don't set `Template.isServer = true` globally in a `beforeAll` — it will break any test in the same file that exercises the live client renderer (mount, hydrate, reactive update).
+- If you also want to verify hydration end-to-end (inject the DSD, let the browser parse `<template shadowrootmode="open">`, then upgrade the custom element), use `wrapper.setHTMLUnsafe(html)` instead of `innerHTML`. Plain `innerHTML` does not process declarative shadow DOM, so the element parses with no shadow root and `connectedCallback` falls back to a full client render — making your test a non-hydration test by accident. The browser test in `ssr-hydration.test.js:58` shows the pattern.
+- Nothing about `defaultSettings`, the `each` block, or your `items` data is involved. The component is fine. The fix is one line of test scaffolding.
+
+## Why the framework doesn't autodetect this
+
+`renderToString` could in principle override the engine selection itself (it already passes `renderingEngine: 'native'` to `proto.clone()`), but it currently delegates the server-vs-client decision to `Template.isServer`, which is a process-wide flag derived from `typeof window`. In the canonical use case — calling `renderToString` from a Node/Bun/Workers SSR path — that's correct and zero-config. The browser test environment is the edge case where the flag's heuristic is wrong, and the framework's own test suite handles it with the same toggle pattern shown above. Treat it as a known wart of running SSR code in a browser-mode test runner, not a bug in your component.
+
+## Relevant source files
+
+- `/home/jack/semantic/next/packages/component/src/render-to-string.js` — the entry point; line 67 calls `template.render()`, lines 84–90 build the DSD wrapper.
+- `/home/jack/semantic/next/packages/templating/src/template.js` — line 43 captures `Template.isServer` from `utils`; lines 292–294 select the server vs. client renderer class.
+- `/home/jack/semantic/next/packages/utils/src/environment.js` — line 5 defines `isServer = typeof window === 'undefined'`.
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/renderer.js` — line 157 `render()` returns a `DocumentFragment`.
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/server.js` — the alternative ServerRenderer that returns a string.
+- `/home/jack/semantic/next/packages/component/src/expand-custom-elements.js` — line 25 string-only `while (pos < html.length)` silently no-ops on a `DocumentFragment`.
+- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` — lines 39–67 are the canonical browser-test pattern (`Template.isServer = true` toggle plus `setHTMLUnsafe`).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json
new file mode 100644
index 000000000..88073fd7f
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
+      "passed": true,
+      "evidence": "Answer describes the lazy/eager paths in each.hydrate explicitly (lines 12-14) and frames the lazy path as 'a deliberate optimization' (line 105): 'if every per-item binding reads only iteration-local data, the items signal firing is the *only* thing that can ever invalidate them, so deferring wiring until that fire is safe and saves work.'"
+    },
+    {
+      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
+      "passed": true,
+      "evidence": "Lines 12-14: 'Lazy — only register a dependency on the items collection itself. Per-item bindings get no Reactions until the items signal fires for the first time, at which point `adoptServerItems` walks `<!--sui-item:v1:KEY-->` markers, reuses each item's server DOM, and wires per-item Reactions inside.'"
+    },
+    {
+      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
+      "passed": true,
+      "evidence": "Line 5: 'Your `items` Signal never mutates, so the each-block's lazy hydration optimization is *staying* lazy'. Line 54: 'Your items don't mutate, so `adoptServerItems` never runs, and the binding never gets a Reaction watching `state.activeID`.'"
+    },
+    {
+      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
+      "passed": true,
+      "evidence": "Line 5: 'The class binding has nothing watching `state.activeID` to invalidate.' Line 54: 'the binding never gets a Reaction watching `state.activeID`. That matches your symptoms exactly.' The whole 'Where your case lands' section traces `getItemClasses` through the classifier."
+    },
+    {
+      "text": "E: References the each-content-classifier (or equivalent fix shape: \"force eager adoption when bindings could read external state\") as the resolution",
+      "passed": true,
+      "evidence": "Answer extensively discusses `each-content-classifier.js` and `isEachContentSelfContained` (lines 16-33). Fix #3 (line 91) is explicit: 'Force eager wiring by adding any binding the classifier flags as external.' Files section also points to the classifier source path."
+    },
+    {
+      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
+      "passed": false,
+      "evidence": "No mention of `skipFirstWrite` anywhere in the answer (grep confirms zero occurrences). The answer discusses Reactions being 'wired' but never explains the skipFirstWrite mechanism — that the Reaction evaluates the binding once at hydrate time to register external deps without rewriting DOM. This mechanistic detail is missing."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md
new file mode 100644
index 000000000..15dd26464
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md
@@ -0,0 +1,113 @@
+# Why your `{#each}` per-item class binding doesn't react after hydration
+
+## Short answer
+
+Your `items` Signal never mutates, so the each-block's "lazy" hydration optimization is *staying* lazy — and on the lazy path no per-item Reactions are wired. The class binding has nothing watching `state.activeID` to invalidate. Your standalone `reaction(() => state.activeID.get())` works because you wired it directly; the each block never wired the equivalent for `getItemClasses`.
+
+The fix in 90% of cases: rewrite the helper as an inline expression that the static classifier can see reads external state, or push the active state into the items themselves. The "load-bearing" fix: the classifier in `each-content-classifier.js` should be flagging this as not-self-contained, so if it isn't, that's a classifier bug worth filing — see "If the classifier should have caught this" below.
+
+## What's actually happening
+
+Each-block hydration in `packages/renderer/src/engines/native/blocks/each.js` has two paths:
+
+- **Lazy** — only register a dependency on the items collection itself. Per-item bindings get no Reactions until the items signal fires for the first time, at which point `adoptServerItems` walks `<!--sui-item:v1:KEY-->` markers, reuses each item's server DOM, and wires per-item Reactions inside.
+- **Eager** — call `adoptServerItems` immediately during `hydrate`, wiring per-item Reactions against the server-rendered DOM right away.
+
+The decision is made by `isEachContentSelfContained(node)` (`packages/renderer/src/engines/native/blocks/each-content-classifier.js`):
+
+```js
+// hydrate hook in each.js
+if (isEachContentSelfContained(node)) {
+  return;  // lazy — defer per-item wiring to first items mutation
+}
+// otherwise: adoptServerItems(...)  — eager wiring
+```
+
+The classifier is a static syntactic walk of the each's content AST. A per-item expression is "self-contained" only if every bare identifier resolves to one of:
+
+- iteration-local names (`as` name, `indexAs` name, plus implicit `this`/`index`/`key`)
+- a framework-shipped helper from `TemplateHelpers` (`PURE_HELPERS = new Set(Object.keys(TemplateHelpers))` captured once at module load)
+- a reserved JS keyword (`true`, `false`, `null`, ...)
+
+Anything else — a component method, a user-registered helper, a closure that reads `state.x` — flips the block to eager.
+
+## Where your case lands
+
+Your binding looks like:
+
+```
+<a class="{classMap getItemClasses item}">
+```
+
+`classMap` is a framework helper (it's in `TemplateHelpers`), so it doesn't disqualify. `item` is the iteration-local name (`as item`), also fine. The bare identifier that decides this is **`getItemClasses`**.
+
+Two scenarios — both ought to flip to eager but the symptom you describe means at least one didn't:
+
+**Scenario A — `getItemClasses` is a component method exposed via `createComponent`'s return value.** The classifier doesn't trace data context, so `getItemClasses` resolves as "not in local scope, not in `PURE_HELPERS`, not reserved" → returns `false` → eager path runs. This *should* work. If it isn't, the issue is somewhere else (see Scenario B and the "If the classifier should have caught this" check).
+
+**Scenario B — `getItemClasses` was added via `registerHelper(...)`.** The classifier captures `PURE_HELPERS` at module-import time:
+
+```js
+const PURE_HELPERS = new Set(Object.keys(TemplateHelpers));
+```
+
+If the helper was registered *before* `each-content-classifier.js` loaded, it lands in the snapshot and the classifier mistakes it for a pure helper → returns `true` → lazy path → never wires per-item Reactions on hydrate. Your items don't mutate, so `adoptServerItems` never runs, and the binding never gets a Reaction watching `state.activeID`. That matches your symptoms exactly.
+
+The classifier comment is explicit about this:
+
+> User-registered helpers (`Template.registerHelper`) are statically indistinguishable from component methods, so they fall into the "external" bucket via the identifier check. That's the correct call: a helper that reads state needs the per-binding Reaction to wire.
+
+That comment describes the intended behavior — but it's only true if the helper is registered *after* the classifier module load. The order-of-registration footgun is real.
+
+## How to verify which scenario you're in
+
+Quick check from devtools after the page loads (before any items mutation):
+
+```js
+const eachStart = $0.shadowRoot.querySelector('whatever-anchors-the-each');
+// Or: walk shadowRoot for sui-item:v1: comments — if they're still present
+// and the markers haven't been replaced by empty text nodes, the lazy path
+// won the classifier and no per-item Reactions exist.
+```
+
+If the `<!--sui-item:v1:KEY-->` comment markers are still present in the DOM after first paint, you're on the lazy path. After eager-path adoption (or any reconcile) those markers are replaced by empty text-node startMarkers.
+
+You can also test it directly: mutate `state.items` once (e.g. `state.items.push(state.items.shift())` or just `state.items.set([...state.items.get()])`). If the active class suddenly starts updating after that, you've confirmed the lazy path was the culprit — the items mutation triggered `adoptServerItems`, which wired the per-item Reactions.
+
+## Fixes
+
+In rough order of how I'd reach for them:
+
+**1. Move `active` into the items themselves.** The cleanest. Build a derived items list (or update `items[i].active` on `activeID` change) and template against `item.active` directly. Now the binding only reads iteration-local data, the lazy path is correct, and reactivity flows through the item signal as designed.
+
+**2. Inline the binding so the classifier can see the external read.** Replace `getItemClasses item` with the expression body inline:
+
+```
+<a class="{classMap (eq state.activeID item.id) 'active' true 'item'}">
+```
+
+Now the classifier sees `state` as a bare identifier in local scope check → not local, not pure → returns `false` → eager wiring → reactive. (Confirm the spelling of `eq` in your helpers — `isEqual` may be the framework name.)
+
+**3. Force eager wiring by adding any binding the classifier flags as external.** If you want to keep the helper, add anything else inside the each that statically reads a non-local name — even a no-op. The classifier returns `false` on the first not-self-contained node it finds, and the whole block flips to eager.
+
+**4. Defer registration so the classifier sees the helper as external.** Avoid relying on this — it's order-of-imports magic — but if you must keep `getItemClasses` registered as a helper *and* keep the binding shape, ensure the helper is registered after `@semantic-ui/renderer`'s each-content-classifier module loads. The cleanest version of this is "don't register state-reading helpers"; treat `registerHelper` as for pure functions only, per its design intent.
+
+## If the classifier should have caught this (Scenario A) but didn't
+
+If `getItemClasses` is a component method (not a registered helper) and the bug still reproduces, that's a classifier miss. Things to check before filing:
+
+- Is `getItemClasses` named exactly the same as a `TemplateHelpers` key? (Look at `packages/templating/src/template-helpers.js` — `classMap`, `classIf`, `eq`, `is`, `isNot`, `join`, etc.) A name collision would let the classifier mistake your method for a pure helper.
+- Is the AST node-shape what the classifier expects? Lisp-style `{classMap getItemClasses item}` should walk fine, but if your template authoring path is producing a different node `type` than `'expression'`, the classifier's switch may bail in the wrong direction.
+- Run `isEachContentSelfContained` directly against your each AST node and log the result. Cached on the AST node identity, so just call it.
+
+## The underlying principle
+
+Hydration trusts the server DOM and wires Reactions to it — it doesn't re-evaluate. Per-item Reactions are the wires that connect future state changes to the existing per-item DOM. The lazy path is a deliberate optimization: if every per-item binding reads only iteration-local data, the items signal firing is the *only* thing that can ever invalidate them, so deferring wiring until that fire is safe and saves work.
+
+When a binding actually reads external state, that assumption breaks: the items signal may never fire, the wires never go in, and external mutations have nothing to invalidate. Your case is the canonical example. The classifier is the gate — if it lets the wrong shape through to the lazy path, the binding goes dark exactly the way you're describing.
+
+## Files
+
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — the two hydrate paths (lines ~646-687) and `adoptServerItems` (lines ~505-616)
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — the static classifier; `PURE_HELPERS` snapshot is the load-order footgun
+- `/home/jack/semantic/next/packages/templating/src/template-helpers.js` — `TemplateHelpers` and `registerHelper`
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json
new file mode 100644
index 000000000..aee8bb003
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
+      "passed": true,
+      "evidence": "Section 'What the each block does on hydrate' explicitly frames it as 'a deliberate optimization at hydrate time' and dedicates a paragraph (lines 55-59) to the rationale: 'the common case... the per-item binding reads only iteration-local data, the server-rendered DOM is already correct, and there is nothing to react to at hydrate time. Wiring N Reactions for N items at hydrate just to have them never fire is wasted work on first paint. Defer them and pay only on the first real change.'"
+    },
+    {
+      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
+      "passed": true,
+      "evidence": "Lines 35-53 quote the relevant `each.hydrate` code with `lookupExpression(node.over)` registering the items-collection dep, and explicitly state: 'Wiring inner Reactions is deferred to a function called `adoptServerItems`, which runs the first time `update` fires (i.e. the first time the items signal changes after hydrate).'"
+    },
+    {
+      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
+      "passed": true,
+      "evidence": "Lines 97-99: 'The killer detail: the items signal's only chance to wake the per-item bindings is to itself fire. Your items are set once from a prop. They never mutate. So the deferred wire-up never happens.' Also reinforced in lines 84-89 walking the post-hydrate timeline."
+    },
+    {
+      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
+      "passed": true,
+      "evidence": "Lines 75-91 directly link the bug: '`state.activeID` is *external* to the iteration scope. The per-item attribute binding's Reaction is the thing that needs to subscribe to it... Nothing in the each block is subscribed to `state.activeID`. The block does not invalidate.... Class string stays at whatever the server rendered.'"
+    },
+    {
+      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
+      "passed": true,
+      "evidence": "Section 'The framework fix (commit 0df8d554e)' (lines 102-135) names the file `packages/renderer/src/engines/native/blocks/each-content-classifier.js`, describes the classifier walking the each's content AST to answer 'could any binding inside this each read external state?', and concludes 'The classifier returns false → `each.hydrate` calls `adoptServerItems` *now* instead of deferring.'"
+    },
+    {
+      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
+      "passed": false,
+      "evidence": "The answer says per-item Reactions 'subscribe to `state.activeID` on their first run' (line 134) and that adoptServerItems 'walks the existing DOM (matched up to server item markers by key) and creates per-item Reactions on the already-rendered nodes', which captures the spirit of evaluation-as-subscription. However, the specific `skipFirstWrite: true` mechanism is never named, nor is the explicit notion that the Reaction trusts the SSR'd DOM and skips its first write so as not to clobber the server output. The rubric calls for the named flag/mechanism."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md
new file mode 100644
index 000000000..d70d295b0
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md
@@ -0,0 +1,203 @@
+# Why the per-item class doesn't react after hydration
+
+## Short answer
+
+Your `{#each}` block's per-item attribute Reactions never wired against
+`state.activeID`. The render-time path that would have wired them is gated on
+the items signal firing — and your items collection is set once and never
+mutates, so the per-item bindings never get a chance to subscribe to the
+external state their helper depends on.
+
+The fix is one of:
+
+1. Upgrade to a framework version that includes the eager-hydrate classifier
+   (commit `0df8d554e`, "Bug: Hydrate each items eagerly when bindings read
+   external state"). With that fix, the each block notices that the per-item
+   binding reads external state via a non-framework helper (`getItemClasses`)
+   and wires per-item Reactions during `hydrate` instead of deferring to the
+   first items mutation.
+2. If you're stuck on an older version, force the items signal to fire once
+   after hydration so the deferred wire-up path runs, e.g.
+   `state.items.notify()` in `onRendered`, or trigger a no-op
+   `state.items.set(state.items.get())` once. This is a workaround, not the
+   intended pattern.
+
+The rest of this doc explains *why* the deferred-wire optimization exists and
+*why* your shape is the precise one that breaks it — that context matters
+because the same pattern keeps biting people whose data arrives at hydrate
+time rather than after.
+
+## What the each block does on hydrate
+
+The native engine's each block (`packages/renderer/src/engines/native/blocks/each.js`)
+makes a deliberate optimization at hydrate time. From `each.hydrate`:
+
+```js
+hydrate({ node, lookupExpression, ... }) {
+  // Always register a dep on the collection so future mutations invalidate.
+  lookupExpression(node.over);
+  self.hasHydrated = true;
+
+  // ... possibly bail and DEFER per-item wiring ...
+}
+```
+
+Two things happen on hydrate:
+
+1. The block registers a dependency on the *items collection* signal so a
+   future mutation to the items array will rerun the block.
+2. It does **not** wire per-item Reactions for inner content. Per-item DOM
+   already exists (the server emitted it, bracketed by `<!--sui-item:v1:KEY-->`
+   markers). Wiring inner Reactions is deferred to a function called
+   `adoptServerItems`, which runs the first time `update` fires (i.e. the
+   first time the items signal changes after hydrate).
+
+The reason for the defer: the common case is `{#each item in items}<span>{item.name}</span>{/each}`
+— the per-item binding reads only iteration-local data, the server-rendered
+DOM is already correct, and there is nothing to react to at hydrate time. Wiring
+N Reactions for N items at hydrate just to have them never fire is wasted work
+on first paint. Defer them and pay only on the first real change.
+
+This optimization is unsafe whenever a per-item binding reads anything outside
+the iteration scope.
+
+## Why your case breaks
+
+Your binding looks like this:
+
+```hbs
+{#each item in items}
+  <a class="{classMap getItemClasses item}">{item.title}</a>
+{/each}
+```
+
+Where `getItemClasses` is a method that calls `state.activeID.get()`.
+
+`state.activeID` is *external* to the iteration scope. The per-item attribute
+binding's Reaction is the thing that needs to subscribe to it, because that
+Reaction is what writes the `class` attribute back to the DOM when activeID
+changes.
+
+But on the deferred path, that per-item Reaction is never created. Walk
+through what happens after hydrate:
+
+- Hydrate runs. The block registers a dep on `items` and bails (deferring per-
+  item wiring).
+- You mutate `state.activeID`.
+- Nothing in the each block is subscribed to `state.activeID`. The block does
+  not invalidate. `update` does not run. `adoptServerItems` does not run. No
+  per-item Reaction was ever wired against `state.activeID`.
+- Class string stays at whatever the server rendered.
+
+Your sanity check (`reaction(() => console.log(state.activeID.get()))`) works
+because *that* reaction subscribed at creation time. The Reactions inside the
+each block — the ones that would write the class attribute — were never
+created.
+
+The killer detail: the items signal's only chance to wake the per-item
+bindings is to itself fire. Your items are set once from a prop. They never
+mutate. So the deferred wire-up never happens.
+
+## The framework fix (commit 0df8d554e)
+
+The fix is a static classifier
+(`packages/renderer/src/engines/native/blocks/each-content-classifier.js`)
+that runs once per unique each-content AST shape (cached on AST identity, so
+it's effectively free per component instance). It walks the each's content
+AST and answers one question: "could any binding inside this each read
+external state?"
+
+The classifier knows about:
+
+- Iteration-local names (`item`, `index`, `key`, `this`, plus whatever the
+  user named in `as` / `,index` / `,key`)
+- The framework's pure helpers (`classMap`, `classIf`, `formatDate`,
+  `concat`, ... — everything in `TemplateHelpers`)
+- JS reserved names (`true`, `false`, `null`, `typeof`, ...)
+
+For each expression, every bare identifier head must resolve to one of those
+sets. If anything else appears (a component method, a user-registered helper,
+a state name closed over by an inline expression), the classifier returns
+"not self-contained."
+
+For your expression `{classMap getItemClasses item}`, the tokens are:
+
+- `classMap` — pure helper, OK
+- `getItemClasses` — not in the iteration scope, not in the pure-helper
+  registry → classifier returns false (external reads possible)
+- `item` — iteration-local, OK
+
+The classifier returns false → `each.hydrate` calls `adoptServerItems` *now*
+instead of deferring. `adoptServerItems` walks the existing DOM (matched up
+to server item markers by key) and creates per-item Reactions on the
+already-rendered nodes. Those Reactions subscribe to `state.activeID` on
+their first run, and from that point on, mutations propagate.
+
+There is a regression test pinning exactly your shape:
+`packages/renderer/test/browser/ssr-hydration.test.js:315` — "helper-call
+attribute inside each is reactive after hydration when items pre-populated".
+Its docstring is a transcription of this entire failure mode — it was
+discovered in production from a docs-site `inpage-menu` that wouldn't update
+its active-section indicator on scroll.
+
+## Things that won't fix it (so you can rule them out)
+
+- Replacing `classMap` with `classIf` or string concat — same shape,
+  `getItemClasses` (or whatever non-framework function you call) is still the
+  external-state read.
+- Using `state.activeID.peek()` instead of `.get()` — peek explicitly opts
+  out of dependency tracking. You'd lose reactivity *to* activeID, not gain
+  it.
+- Wrapping the helper call in a parent reactive context (e.g. the component's
+  `onRendered`) — that doesn't propagate down into the per-item Reactions
+  because the per-item Reactions are what need to exist in the first place.
+- Switching the items prop from a plain array to a Signal — the items signal
+  *is* already a Signal under the hood. The issue is not the items channel,
+  it's that the per-item bindings haven't been wired yet.
+
+## Things that will fix it
+
+- **Preferred:** upgrade to the framework version with the classifier fix.
+  No code change required on your side; the classifier inspects your AST
+  and sees `getItemClasses` is not a framework helper, switches to the
+  eager path, and your binding starts reacting.
+- **Workaround on older versions:** force the items signal to fire once
+  after hydrate so the deferred wire-up runs:
+  ```js
+  onRendered() {
+    state.items.notify();   // wakes the each block's items dep,
+                            // which runs update, which calls
+                            // adoptServerItems, which wires per-item
+                            // Reactions on the existing DOM
+  }
+  ```
+  This is not the intended API — the canonical fix is the classifier — but
+  it works mechanically because it triggers the same `adoptServerItems` path
+  that the classifier triggers eagerly.
+- **Workaround that sidesteps the each entirely:** lift the
+  state-dependent class to an attribute on the per-item *element* that uses
+  `data-active="{is item.id state.activeID}"` and style off `[data-active]` in
+  CSS, *if* you don't actually need a class. This works because the
+  attribute binding still goes through the same Reaction path — but on
+  versions without the fix it has the same problem. Don't do this; upgrade.
+
+## What to actually look at first
+
+Before assuming this is the bug, confirm:
+
+1. The component is hydrating, not full-rendering on the client. If
+   `el.shadowRoot` is missing on connect, hydration didn't run and you're
+   on the fresh-render path, which always wires Reactions. Check that your
+   server output includes `<template shadowrootmode="open">` and that
+   nothing strips it before the browser parses it.
+2. The classifier's caching is on AST identity (`WeakMap<ASTNode, boolean>`).
+   If you have two components that share an AST shape but only one of them
+   has an external-state helper, the one classified first wins for both —
+   but in practice each `defineComponent` call produces its own AST, so this
+   is unlikely to be your issue.
+3. If you registered `getItemClasses` via `Template.registerHelper` *before*
+   the classifier module first loaded, the classifier will see it as a pure
+   helper (because `PURE_HELPERS = new Set(Object.keys(TemplateHelpers))`
+   captures the registry once at module init). Define it as a component
+   method or inline `createComponent` field instead — that's how the
+   regression test fixture writes it, and it's the canonical pattern.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json
new file mode 100644
index 000000000..7f83d8061
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
+      "passed": true,
+      "evidence": "Opening states 'A 6ms tachometer bench... is below the resolution floor by physics' and explains 'CI width scales as ~σ/√N in absolute terms but as ~σ/(mean × √N) in relative terms', plus the entire duration-vs-noise table showing inverse relationship between mean duration and relative CI width."
+    },
+    {
+      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
+      "passed": true,
+      "evidence": "Provides a duration-vs-noise table: '2 ms ~±50%, 6 ms ~±28%, 20 ms ~±5–8%, 50 ms ~±2–4%, 100 ms ~±1–2%'. Numbers differ from the rubric's exact values (uses σ≈2ms calibration) but conveys equivalent inverse-scaling structure across the same regimes."
+    },
+    {
+      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
+      "passed": true,
+      "evidence": "States 'GHA shared runners have a roughly constant absolute timing variance of σ≈2ms per sample' and lists sources as 'OS scheduling, GC, JIT recompiles, shared CPU'. Calls out that jitter is constant in absolute terms (though uses ~2ms rather than sub-millisecond — still captures the constant-absolute-jitter physics)."
+    },
+    {
+      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
+      "passed": true,
+      "evidence": "'Your ±28% matches the 6ms row, which is the noise floor giving its honest verdict' and explicitly addresses 'Why \"just bump sampleSize\" is the wrong instinct' showing that scaling N is impractical and that the floor is physics-limited. Also: 'Physics-limited; sampling longer won't help.'"
+    },
+    {
+      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
+      "passed": true,
+      "evidence": "Section 'Concrete fix for your bench — amplify the per-hydrate work' offers three scaling options including 'Scale the list itself' with explicit recommendation: 'Bump to 1000 items × ~60µs = ~60ms and you sit comfortably above the floor', plus the loop-N-times option pushing to ~300ms window for '<±1% territory'."
+    },
+    {
+      "text": "F: Optionally references the perf-improvement skill or improve-performance workflow as the source for this methodology",
+      "passed": true,
+      "evidence": "References 'ai/skills/contributing/extend-bench-suite.md' and 'ai/skills/contributing/read-bench-report.md' as the canonical sources for duration target table, naming conventions, knobs, and the Inconclusive vs Too Fast to Measure Precisely buckets. This is the expected skill family ('From the bench skill, the local verification flow:'). Marked optional in rubric; satisfied here."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md
new file mode 100644
index 000000000..1a0bf1ed1
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md
@@ -0,0 +1,147 @@
+# Why your hydrate bench can't see the win, and what to change
+
+## The short version
+
+A 6ms tachometer bench on shared GitHub Actions runners is below the resolution floor by physics, not by configuration. The runner has roughly **2ms of irreducible per-sample jitter** (OS scheduling, GC, JIT recompiles, shared CPU). At 6ms mean duration, that 2ms shows up as `~2/6 ≈ 33%` relative noise — which is exactly what you're seeing in your `±28%` floor. No knob in `tachometer-ci-*.json` will narrow that. **You need to lengthen the bench.**
+
+The fix isn't to retune `sampleSize` or `autoSampleConditions`. The fix is to scale up the workload until the mean duration is in the 20–100ms range, where 2ms of jitter becomes 2–10% relative noise and a real per-hydrate improvement of even a few percent can clear the resolution floor.
+
+---
+
+## Why the floor is wide — the underlying math
+
+GHA shared runners have a roughly constant absolute timing variance of σ≈2ms per sample (this is calibrated into the in-house bench reporter as `sigma_abs_ms: 2`). Tachometer reports a 95% confidence interval, and CI width scales as `~σ/√N` in absolute terms but as `~σ/(mean × √N)` in relative terms.
+
+So at fixed `sampleSize: 50` (the default), and σ_abs=2ms:
+
+| Bench mean | Expected relative CI width | What the reporter does on zero-delta |
+|------------|----------------------------|--------------------------------------|
+| 2 ms       | ~±50%                      | "Too Fast to Measure Precisely"      |
+| 6 ms       | ~±28%  ← **you are here**  | "Too Fast to Measure Precisely"      |
+| 20 ms      | ~±5–8%                     | Resolves real >10% deltas            |
+| 50 ms      | ~±2–4%                     | Sits right at the ±2% floor          |
+| 100 ms     | ~±1–2%                     | Tight; surfaces real ~2% regressions |
+
+Your `±28%` matches the 6ms row, which is the noise floor giving its honest verdict: at this duration, tachometer cannot distinguish a 5% real improvement from runner jitter. "No meaningful change" here means *unresolved*, not *unchanged*.
+
+The reporter formalizes this in two distinct buckets under `🔍 Unsure`:
+
+- **Inconclusive** — observed CI width > 2× the expected width for that duration. More samples might help, or the bench has unusual variance.
+- **Too Fast to Measure Precisely** — observed CI width ≈ expected width for that duration. Physics-limited; sampling longer won't help.
+
+A 6ms bench landing at ±28% is the canonical Too Fast case. Expected width and observed width agree — there's nothing to investigate about the bench's variance, and there's nothing more to extract from the data without changing the workload.
+
+---
+
+## Why "just bump sampleSize" is the wrong instinct
+
+CI width does narrow as `1/√N`. So to halve a `±28%` floor you'd need `4×` the samples (200 instead of 50), and to drop it to `±5%` you'd need roughly `~30×` more samples (~1500). That's:
+
+- Hours of CI wall-clock per bench (the matrix job has a 10-minute hard cap).
+- A `timeout: 3` minute auto-sample cap, which would simply abort.
+- Burns runner cost across every PR for a single metric.
+
+The repo's bench config is calibrated against this tradeoff. From `tachometer-ci-hydrate.json`:
+
+```json
+{ "sampleSize": 50, "timeout": 3, "autoSampleConditions": ["2%"] }
+```
+
+These knobs are documented in `ai/skills/contributing/extend-bench-suite.md` as **"don't change without a reason"** — they're the floor that makes the matrix fit in CI budget. The right move is on the workload side.
+
+---
+
+## Concrete fix for your bench — amplify the per-hydrate work
+
+Look at the existing hydrate bench at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js`. Its `hydrate-each-100-mount` and `hydrate-each-100` measurements work in tachometer because they hydrate **1000 items**, not 100 (the metric name is misleading; line 99 reads `makeItems(1000)`). That's deliberate — at 1000 items the mount window lands in the resolvable range.
+
+For a 100-item list whose per-item hydrate cost is ~60µs, you have three scaling options ranked by preference:
+
+### 1. Loop the hydrate operation N times in one measure window (preferred)
+
+If your fix is in the per-component hydrate path (not the per-item path), repeat the whole component mount cycle inside one `performance.measure` boundary:
+
+```js
+performance.mark(startMark('hydrate-mycomp-50x'));
+for (let i = 0; i < 50; i++) {
+  const fresh = ssrMyComponent(items100);   // fresh DSD string, no caching across iterations
+  container.setHTMLUnsafe(fresh);
+  await drainMicrotasks();
+  await flush();
+  container.innerHTML = '';
+}
+performance.measure('hydrate-mycomp-50x', startMark('hydrate-mycomp-50x'));
+```
+
+A 6ms × 50 ≈ 300ms window pushes you into "<±1%" territory. The reporter will resolve any real per-hydrate delta down to ~2%. Suffix the metric name with the iteration count (`hydrate-mycomp-50x`) per the naming convention so reviewers know it's amplified.
+
+**Caveat:** make each iteration genuinely independent. Re-use the same SSR HTML string (precompute it once outside the loop) so the SSR cost isn't included, but generate a fresh container or `setHTMLUnsafe` call so prototype caches (`_hydrationEntries` is cached on the prototype after the first hydrate — see `ssr-hydration.md` Phase 5) don't make iterations 2..N artificially cheap. The first iteration measures cold-cache, the rest measure warm-cache. If your fix targets the warm path, throw away the first iteration's contribution by warming once before `performance.mark`.
+
+### 2. Scale the list itself
+
+If your fix is per-item (e.g., a faster `hydrateInnerContent`, marker walk, or attribute parallel-walk), 100 items × ~60µs = ~6ms. Bump to **1000 items × ~60µs = ~60ms** and you sit comfortably above the floor:
+
+```js
+const items = makeItems(1000);
+const dsdHTML = ssrList(items);
+performance.mark(startMark('hydrate-mycomp-1k'));
+container.setHTMLUnsafe(dsdHTML);
+await drainMicrotasks();
+await flush();
+performance.measure('hydrate-mycomp-1k', startMark('hydrate-mycomp-1k'));
+```
+
+This is what `bench-hydrate.js` already does for the each-block mount path.
+
+### 3. Split the measurement window
+
+Sometimes the work you're optimizing is one phase of a larger hydrate cycle, and amplifying the whole cycle hides your delta in the unaffected phases. In that case, split into two measures:
+
+- `hydrate-mycomp-mount-1k` — DSD parse + connectedCallback + the hydrate microtask
+- `hydrate-mycomp-rebind-1k` — first state mutation that re-fires Reactions (uses `hasHydrated` adoption path)
+
+`bench-hydrate.js` does exactly this with its mount vs. helper-state-change pair (lines 99–122). Each window is independently resolvable, and a fix targeting one path won't be diluted by the other.
+
+---
+
+## What to change in your config
+
+Almost certainly nothing. After amplifying the workload, leave `sampleSize: 50`, `autoSampleConditions: ["2%"]`, and `timeout: 3` alone — they're the floor the matrix is calibrated against. Just add the new `entryName` to **both** the `this-change` and `tip-of-tree` measurement arrays in `tachometer-ci-hydrate.json` (or whichever config you're extending).
+
+If after amplifying your bench is still showing wide CIs at >2× the expected width for its new duration, *then* something is wrong with the bench itself — likely:
+
+- Per-iteration GC pause varying by allocation pattern
+- Async work bleeding past `await flush()` (the mount cycle includes a `requestAnimationFrame` that strips data-sui-bind markers post-hydrate — make sure your final `flush()` covers it)
+- An accidental cache hit on iteration 2..N (see caveat in option 1)
+
+That'd land in the reporter's `Inconclusive` bucket (observed/expected ratio > 2), at which point investigate the bench setup.
+
+---
+
+## How to verify before pushing
+
+From the bench skill, the local verification flow:
+
+```sh
+cd packages/component/bench/tachometer
+node build-ci.js current
+node build-ci.js baseline       # same source both sides — zero-delta dry run
+npx tachometer --config tachometer-ci-hydrate.json
+```
+
+A clean, zero-delta dry run on a workload sized into the 20–100ms range should report a CI width comfortably below ±5%. If your dry-run width is still wide, you haven't amplified enough — duration matters more than sample count.
+
+---
+
+## TL;DR for the PR comment / commit message
+
+> The bench's mean duration was ~6ms, which puts it below the resolution floor on shared GHA runners (σ≈2ms absolute jitter → ~±28% relative). Tachometer's `±28%` "no meaningful change" verdict is the noise floor giving its honest answer, not evidence the fix doesn't help. Amplifying the workload to a ~60ms+ mean (either by looping the hydrate cycle 10–50× per measure window or by scaling the list to 1k items) brings it into the resolvable range where a real per-hydrate delta of even a few percent will land in the Faster section. The `sampleSize`/`autoSampleConditions`/`timeout` knobs are calibrated against CI budget and shouldn't be the lever here.
+
+---
+
+## Reference files
+
+- `/home/jack/semantic/next/ai/skills/contributing/extend-bench-suite.md` — duration target table, naming conventions, knobs
+- `/home/jack/semantic/next/ai/skills/contributing/read-bench-report.md` — Inconclusive vs Too Fast to Measure Precisely buckets, expected_noise_pp/observed_noise_ratio fields
+- `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js` — canonical hydrate bench using 1000 items + split mount/state-change windows
+- `/home/jack/semantic/next/packages/component/bench/tachometer/tachometer-ci-hydrate.json` — the standard knob set (`50`/`3`/`["2%"]`)
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json
new file mode 100644
index 000000000..49042e3c0
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
+      "passed": true,
+      "evidence": "Opening lines state 'absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and ±X% is just (constant ms) / (your duration)'. Summary repeats: 'duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter'. Inverse scaling is explicitly named."
+    },
+    {
+      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
+      "passed": true,
+      "evidence": "Provides a concrete table of measured durations vs predicted ±% half-widths (7.4ms = ±10.6%, 13.7ms = ±5.7%, 12.6ms = ±6.2%, 16.2ms = ±4.8%) and states '≥ 30 ms (predicted ±2.6%) to comfortably clear the ±2% noise floor'. Also derives ±26% at 6ms. The bands map to the rubric's tiers (short = ±10-20%, ~10ms = ±2-5%, longer = ±1%)."
+    },
+    {
+      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
+      "passed": true,
+      "evidence": "Explicitly explains 'absolute per-sample jitter is roughly constant' and lists 'system jitter (scheduling, GC, JIT)' as the cause. Notes σ ≈ 2 ms on GHA runners (slightly above sub-millisecond but the constant-absolute physics is clearly stated). The 'roughly constant in absolute terms' point is made repeatedly."
+    },
+    {
+      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
+      "passed": true,
+      "evidence": "Computes ±26% predicted at 6ms, explains observed ±28% is at the noise-floor-limited boundary, and explicitly states in option 4: 'Don't bump sampleSize — diminishing returns... 4× the wall-clock time gets you from ±28% to ±14%' and 'Width comes from duration, not from sample count beyond a point.'"
+    },
+    {
+      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
+      "passed": true,
+      "evidence": "Option 1 recommends 'Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo.' Cites bench-hydrate.js using n=1000 items as the existing pattern to copy. Targets ≥30 ms / ±2.6%."
+    },
+    {
+      "text": "F: Optionally references the perf-improvement skill or improve-performance workflow as the source for this methodology",
+      "passed": false,
+      "evidence": "Answer references reporter.js, bench-history.json, bench-todo.js, and bench-hydrate.js as sources, but does not name the perf-improvement skill or improve-performance workflow. This is an optional expectation but per the rubric's literal wording it is not satisfied."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md
new file mode 100644
index 000000000..ddec432ec
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md
@@ -0,0 +1,94 @@
+# Why a 6 ms hydration bench can't see your improvement
+
+Short version: at ~6 ms duration, the bench is running below the resolution floor of the CI runner. The noise floor isn't `±28%` because tachometer is misconfigured — it's that wide because absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and `±X%` is just `(constant ms) / (your duration)`. Fix the noise floor by making the bench longer in absolute time, not by tuning tachometer.
+
+## The math the reporter is using
+
+The bench reporter at `/home/jack/semantic/next/tools/ci/bench/reporter/reporter.js` encodes the model explicitly (lines 49–90):
+
+```js
+const NOISE_FLOOR = 2;           // percent — matches autoSampleConditions
+const SIGMA_ABS_MS = 2;          // empirical per-sample σ on GHA runners
+
+function expectedNoisePp(meanMs) {
+  // From SE-of-the-difference of two means at n=50, z=1.96:
+  //   abs_CI_width ≈ 2 * 1.96 * sqrt(2) * σ / sqrt(50) ≈ 0.784 * σ
+  //   pct_width   = abs_CI_width / mean * 100
+  return (0.784 * SIGMA_ABS_MS) / meanMs * 100;
+}
+```
+
+Plug in `σ = 2 ms`, `mean = 6 ms`:
+
+- `abs_CI_width ≈ 0.784 × 2 = 1.568 ms`
+- `pct_width = 1.568 / 6 × 100 ≈ 26%`  → reported as **±13%** (half-width on each side)
+
+You're seeing **±28%** observed. That is `~2.1×` the duration-derived expected width — right at the boundary of what the reporter classifies as `noise-floor-limited` vs `unsure` (`NOISE_RATIO_TOLERANCE = 2` at line 62). So tachometer is honest: at this duration, on these runners, the measurement can't see anything smaller than roughly ±15–30% of the mean. A 1 ms improvement on a 6 ms bench is well below that.
+
+This is exactly why your CI is "no meaningful change" — `NOISE_FLOOR = 2`% (line 49) demands the CI live entirely outside `[-2%, +2%]` to be classified `faster`/`slower`. Your CI straddles ±2% wider than the noise floor allows it to resolve, so the reporter buckets it into `noise-floor-limited` (file `reporter.js`, lines 220–225):
+
+```js
+function classify([low, high], ratio) {
+  if (high < -NOISE_FLOOR) { return 'faster'; }
+  if (low > NOISE_FLOOR)   { return 'slower'; }
+  if (low > -NOISE_FLOOR && high < NOISE_FLOOR) { return 'within-noise'; }
+  return ratio <= NOISE_RATIO_TOLERANCE ? 'noise-floor-limited' : 'unsure';
+}
+```
+
+## The "Too Fast to Measure Precisely" bucket exists for this exact case
+
+When you read the rendered comment, your bench should be sitting under `🔍 Unsure → Too Fast to Measure Precisely`. The header copy (rendered from `reporter.js` lines 384–402) literally says:
+
+> On benches this short, system jitter (scheduling, GC, JIT) masks sub-4% changes; larger deltas still resolve cleanly.
+
+That row exists specifically to tell the author "this isn't a verdict, this is a 'your bench is too short' diagnostic." Don't trust the noise classification as a refutation of your fix — trust it as a request to amplify the bench.
+
+## What the existing benches do — copy this pattern
+
+The existing hydrate bench at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js` already runs at `n=1000` items (line 99: `const itemsForMount = makeItems(1000)`), not 100. Recent main-history numbers confirm what that buys you:
+
+| metric | mean | predicted ±% half-width | resolves? |
+|---|---|---|---|
+| `hydrate-helper-100-mount` | 7.4 ms | ±10.6% | borderline |
+| `hydrate-each-100-mount` | 13.7 ms | ±5.7% | yes |
+| `hydrate-each-100` | 12.6 ms | ±6.2% | yes |
+| `hydrate-helper-100-state-change` | 16.2 ms | ±4.8% | yes |
+
+Source: `/home/jack/semantic/next/tools/ci/bench/reporter/bench-history.json` (the `271be03` commit entry near line 1584).
+
+Note even `hydrate-helper-100-mount` at 7.4 ms is the noisiest of the four because it's the shortest. The larger ones are the ones that resolve cleanly. **You want to be ≥ 30 ms** (predicted ±2.6%) to comfortably clear the ±2% noise floor — that's the inflection point where small changes get classified.
+
+The `bench-todo.js` author at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-todo.js` calls this strategy out explicitly in line comments:
+
+- Line 275: `// 20 alternating toggle-all invocations on a 100-item list — amplified // so the measurement clears the σ≈2ms per-sample noise floor on CI.`
+- Line 290: `// Each position's ~10ms per-delete workload clears the σ≈2ms floor.`
+- Line 361: `// List scaled to 500 (250 marked completed) so the single clearCompleted // operation is large enough to clear the σ≈2ms per-sample noise floor.`
+- Line 333–335: `// 10× loop (vs 5× for the front/back variants) — middle removal's // O(N/2) scan has wider per-sample variance, so 5× landed at ~74ms // with observed CI straddling ±2%. 10× brings it to ~148ms / ±1%.`
+
+These are the same change you should make.
+
+## Concrete options for your bench, ranked
+
+**1. Scale the workload up (preferred).** Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo. If your fix is in per-item work (e.g. `hydrateInnerContent`, `adoptServerItems`), 1000 items multiplies its weight by 10× without changing what you're measuring. Keep the metric name describing items measured, not items rendered, if you want comparability — but in this repo most names already include the count (e.g. `hydrate-each-100` actually mounts 1000 items per the comment at line 99).
+
+**2. Loop the operation N times inside one `performance.measure` window.** This is what `toggle-all-20` and `remove-10-middle` do. If hydration itself isn't loopable (you only mount once), then loop the *follow-up data change* that exercises the codepath you fixed. The existing bench does this already with `hydrate-each-100` — measures the post-mount `setItems(...)` call rather than mount itself.
+
+**3. Add a separate amplified metric instead of replacing.** Keep the realistic 100-item bench for human readability of the duration, and add a 1000-item variant with the same shape for measurement precision. Both metrics ship; the reporter handles either.
+
+**4. Don't bump `sampleSize` — diminishing returns.** Going from `sampleSize: 50` to `200` only narrows the CI by `√(50/200) = 0.5×`. So 4× the wall-clock time gets you from ±28% to ±14%. Compare to scaling the workload 5× (6ms → 30ms), which gets you from ±28% to ±5% with no extra wall-clock cost. Sample-size tuning is the wrong knob for short benches.
+
+**5. Don't tighten `autoSampleConditions`.** Currently `["2%"]` — that's the *target* CI width for tachometer's auto-sampler. Tightening it to `["1%"]` just makes tachometer keep sampling until either it converges (it can't, because the underlying jitter is absolute-constant, not relative) or it hits `timeout: 3` minutes and gives up with the same wide CI. The `tachometer-todo.json` non-CI variant uses `["0%", "10%"]` which means "sample until <10% relative width OR a 0% target" — also wrong choice for short benches. Width comes from duration, not from sample count beyond a point.
+
+## Verifying your fix saved time at all
+
+If you want to know whether the fix is real before investing in bench amplification:
+
+- Run the bench locally with `--manual` or via the CI HTML harness, open DevTools, and use the Performance panel — a 1 ms saving on a 6 ms operation is visible in a flame graph even when it's invisible to tachometer at n=50.
+- Add a `console.time('hydrate')` / `console.timeEnd('hydrate')` around the codepath, run it 10 times locally, eyeball the median — if you see 5 ms vs 6 ms consistently, the fix is real and the bench is just under-resolved.
+
+Then commit the bench amplification as a separate change so the perf comment on your fix's PR can show a `faster` row instead of `noise-floor-limited`.
+
+## Summary
+
+The noise floor is wide because `1.568 ms / 6 ms ≈ 26%`. That's not a bug or a tachometer config issue — it's the duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter on this runner, and the reporter at `tools/ci/bench/reporter/reporter.js` documents it explicitly. The fix is to amplify the bench duration to ≥ 30 ms (loop the op, scale items, or both), exactly as the existing `bench-todo.js` and `bench-hydrate.js` already do. Don't reach for `sampleSize` or `autoSampleConditions` — neither addresses the underlying `(constant ms) / duration` problem.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json
new file mode 100644
index 000000000..097bc1723
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
+      "passed": false,
+      "evidence": "The answer focuses primarily on demonstrating that the canonical case works (passing test at line 1408) and explores the mechanism in detail. It explains the each-content-classifier bails on snippets forcing the eager path, but does NOT explicitly tie this back to eval 2's root cause (each-hydrate deferral as the underlying mechanism). It frames the discussion around 'the framework path works for the canonical shape' rather than 'this is the same lazy-hydrate deferral pattern that was at risk.'"
+    },
+    {
+      "text": "B: Explains that snippet args (`label=item.name`) are evaluated by the per-item content path; the snippet body sees those args via `buildSnippetProxy`",
+      "passed": true,
+      "evidence": "Section 3 ('The snippet block on the hydrate path') explicitly explains: 'When `template.hydrate` runs with `data = itemProxy` (the each-item proxy) and `kind === 'snippet'`, it calls `buildSnippetProxy(node, itemProxy, evaluator)` to build the snippet-args overlay.' It then quotes the lazy getter code from template.js:67-114 showing how arg getters close over the each-item proxy and walk through itemProxy.get('item') to subscribe to itemSignal.value."
+    },
+    {
+      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
+      "passed": true,
+      "evidence": "The answer explains the chain in section 4 'The mutation path': itemSignal.notify() wakes everything subscribed to that per-item signal, including the snippet body's text Reaction. By describing the mechanism that makes it work (per-item Reactions getting wired via adoptServerItems on the eager path), it implicitly establishes that without those wired Reactions the snippet args wouldn't re-evaluate. Case A in 'Why your case might not be doing this' explicitly addresses 'no reconcile, no snapshot diff, no per-item notify.'"
+    },
+    {
+      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
+      "passed": true,
+      "evidence": "Section 1 ('The self-contained classifier bails on snippet calls') quotes the exact code from each-content-classifier.js line 189: 'case 'template': case 'snippet': case 'rerender': case 'guard': case 'async': return false;' and explains: 'snippet bodies live in a separate AST, and the classifier doesn't trace cross-AST identifier flow. Rather than guess wrong it bails conservative — meaning your each gets the *eager* wire path.'"
+    },
+    {
+      "text": "E: Mentions the existing test `snippet with named args inside each is reactive after hydration` (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
+      "passed": true,
+      "evidence": "Opens with 'there's a passing test for the exact shape you described: packages/renderer/test/browser/ssr-hydration.test.js:1408 — \"snippet with named args inside each is reactive after hydration\".' Also references this test again in the closing file pointers as 'the canonical passing test for your exact pattern.' Does not mention PR #175 specifically, but the rubric allows the equivalent (known regression test reference)."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md
new file mode 100644
index 000000000..f3d802b97
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md
@@ -0,0 +1,228 @@
+# Snippet inside `{#each}` — what hydration actually wires
+
+## Short version
+
+Your pattern is the documented-supported case and there's a passing test for the
+exact shape you described:
+
+`packages/renderer/test/browser/ssr-hydration.test.js:1408` —
+"snippet with named args inside each is reactive after hydration".
+
+That test SSRs `{#snippet badge}<span class="b">[{label}]</span>{/snippet}{#each item in items}<div>{>badge label=item.name}</div>{/each}`,
+hydrates, then mutates `items[0]` (assigning a new spread + setting the array)
+and asserts the first badge updates. It passes on `test/templating` as of this
+session. So the framework *is* wiring the per-item Reaction across the snippet
+boundary on hydrate. If you're seeing it not update, you're hitting a variant
+the rest of this answer enumerates.
+
+Before the variants, the actual mechanism — because that's what tells you which
+of the variants you're in.
+
+---
+
+## What hydrate does for `{#each item in items}` containing a snippet
+
+Two things make this case work, both deliberate.
+
+### 1. The "self-contained" classifier bails on snippet calls
+
+`packages/renderer/src/engines/native/blocks/each-content-classifier.js`
+
+The each block's `hydrate` hook has a fast path: if every per-item binding only
+reads iteration-local data or pure framework helpers, it can skip per-item
+Reaction wiring at hydrate time and lazily build them on the first items
+mutation. `each.js:664` gates this on `isEachContentSelfContained(node)`.
+
+The classifier walks the each's content AST. When it hits a `template`-type
+node (which is what `{>badge ...}` compiles to — both snippets and subtemplates
+share that node type), it returns `false` (line 189):
+
+```js
+case 'template':
+case 'snippet':
+case 'rerender':
+case 'guard':
+case 'async':
+  return false;
+```
+
+The reasoning is in the file's preamble: snippet bodies live in a separate
+AST, and the classifier doesn't trace cross-AST identifier flow. Rather than
+guess wrong it bails conservative — meaning your each gets the *eager* wire
+path. So `each.hydrate` calls `adoptServerItems` (`each.js:669`).
+
+### 2. `adoptServerItems` rebuilds per-item reactivity against the existing DOM
+
+`packages/renderer/src/engines/native/blocks/each.js:505-616`
+
+The server emitted `<!--sui-item:v1:KEY-->` markers between the each block's
+open/close markers. `extractServerItemGroups` walks `region.ownedNodes`
+grouping nodes by their preceding item marker (with depth tracking so nested
+`sui-block` markers from inner directives don't confuse the boundary).
+
+For each item:
+
+- A fresh `itemSignal` (`new Signal(eachData, { allowClone: false })`) and an
+  `itemProxy` from `createItemDataProxy(parentData, itemSignal)` are created.
+  `createItemDataProxy` wraps the parent data so that *any* read of an item
+  field goes through `itemSignal.value` first — that's where the per-item
+  reactive subscription is established (`each.js:129-144`).
+- `hydrateInnerContent` walks the per-item nodes with
+  `data: itemProxy, scope: itemScope`. This is where the snippet block's
+  `hydrate` hook gets called.
+
+### 3. The snippet block on the hydrate path
+
+`packages/renderer/src/engines/native/blocks/template.js:220-240`
+
+When `template.hydrate` runs with `data = itemProxy` (the each-item proxy)
+and `kind === 'snippet'`, it calls `buildSnippetProxy(node, itemProxy, evaluator)`
+to build the snippet-args overlay. Critical detail at `template.js:67-114`:
+
+```js
+if (isPlainObject(node.data)) {
+  each(node.data, (expr, key) => {
+    staticGetters[key] = () => evaluator.lookupExpressionValue(expr, data);
+  });
+}
+```
+
+The arg getters are *lazy* and close over the each-item proxy. They are not
+wrapped in `Reaction.nonreactive`. So when the snippet body's `{label}` text
+Reaction fires, the Reaction tracking context is active when the getter runs,
+and the getter's call into `evaluator.lookupExpressionValue('item.name', itemProxy)`
+walks through `itemProxy.get('item')` — which reads `itemSignal.value` and
+subscribes the body's Reaction to that signal. That's the reactive bridge.
+
+`hydrateInnerContent` is then called for the snippet body
+(`template.js:228-238`) with `data: snippetData, scope` — same scope as the
+each item, so when the item record is disposed, the snippet body's Reactions
+go with it.
+
+### 4. The mutation path on `items[0].name = ...; state.items.set([...items])`
+
+When you replace the array, the items signal fires, `each.update` runs,
+`reconcile` walks. For index 0 the item reference is unchanged, so the code
+falls into the snapshot branch at `each.js:407-421`:
+
+```js
+else if (typeof item === 'object' && item !== null) {
+  if (rec.propsSnapshot === null) {
+    rec.propsSnapshot = createSnapshot(item);
+  }
+  else if (refreshSnapshotAndDetect(rec.propsSnapshot, item)) {
+    rec.itemSignal.notify();
+  }
+}
+```
+
+`refreshSnapshotAndDetect` does a shallow diff of top-level item props. If
+`name` changed it returns true, the snapshot is updated in place, and
+`itemSignal.notify()` wakes everything subscribed to that per-item signal
+— including the snippet body's `{label}` text Reaction. That Reaction
+re-evaluates, the lazy `label` getter fires again, reads the current
+`item.name`, and writes the new value to `textNode.data`.
+
+That's the full chain — and the chain is exercised end-to-end by the test
+at `ssr-hydration.test.js:1408`.
+
+---
+
+## Why your case might not be doing this
+
+Since the framework path works for the canonical shape, the failure has to
+come from a deviation. Most likely sources, ranked by how often they bite:
+
+### A. The mutation isn't reaching `reconcile`'s phase 3
+
+You said the outer each's reaction "definitely fires" because new items render
+when added. That's good — it means the items signal *is* invalidating the each
+block. But verify reconcile actually re-enters phase 3 for index 0. If you're
+mutating *only* `items[0].name` without setting the items signal to a new
+reference (i.e., no `state.items.set(...)` and no array helper like
+`state.items.push/.splice`), the items signal never fires, no reconcile, no
+snapshot diff, no per-item notify.
+
+`state.items.push(newItem)` does both — it mutates and calls `notify()` (see
+`packages/reactivity/src/signal.js:237-240`). So pushing should reach
+phase 3. Pure `items[0].name = 'x'` without any signal call won't.
+
+### B. Your each is the no-`as` form
+
+`{#each items}<div>{>badge label=name}</div>{/each}` (no `item in`) spreads
+the item's keys into the local scope. The classifier returns false at the
+top of `isEachContentSelfContained` (`each-content-classifier.js:212`), so
+`each.hydrate` *also* takes the eager path. No problem there. But if you're
+passing `label=name` (instead of `label=item.name`), the snippet getter
+evaluates `name` against the each-item proxy, which resolves it to the
+*current* item's `name` field via `itemSignal.value` — same outcome.
+
+### C. The snapshot diff is shallow
+
+`refreshSnapshotAndDetect` only checks top-level props. If you're mutating
+`items[0].nested.name` and the snippet reads `item.nested.name`, the snapshot
+sees `items[0].nested === snap.nested` (same reference) and reports no change.
+No `itemSignal.notify()` fires, the snippet doesn't re-evaluate. The comment
+at `each.js:392-395` calls this out explicitly: "Top-level prop mutations
+re-render dependent expressions; nested-object mutations slip past the shallow
+check, and no documented contract relies on them."
+
+If this is your case, the workaround is to either (a) replace `items[0]` with
+a new object (`items[0] = { ...items[0], nested: { ...items[0].nested, name: 'x' } }`)
+or (b) call `state.items.notify()` manually after the deep mutation.
+
+### D. The badge is not just a text expression
+
+If the snippet body has computed attributes or other reactive shapes, the
+text-marker reactivity path I traced isn't the same as the attribute-binding
+path. In particular, `{label}` as an attribute value vs as text content go
+through different hydration routines (`hydrateAttributes` parallel-walk vs
+`hydrateTextExpression`). Both should subscribe correctly, but if you're
+seeing a discrepancy worth filing, post the snippet body verbatim.
+
+### E. `_hydrating` flag stuck
+
+If something throws during `hydrate` (e.g. a snippet name that resolves to
+nothing, line 226 `fatal` from `template.js`), `_hydrating` may not be cleared
+and subsequent `requestUpdate` calls get suppressed. Check the console for
+errors at hydration time.
+
+### F. Snippet name resolved to a subtemplate, not a snippet
+
+`detectKind` (`template.js:121-127`) checks `self.snippets[name]` first. If
+your `badge` symbol is registered as a *subtemplate* in scope (not a snippet)
+because of a name collision or a ContentTemplate lookup, you take the
+subtemplate branch instead — and subtemplates have a separate hydration path
+with different data-flow semantics. Worth checking
+`renderer.snippets['badge']` and `renderer.subTemplates['badge']` in DevTools
+right after hydration.
+
+---
+
+## How to confirm in DevTools
+
+If you want to verify the wire is in place after hydrate:
+
+1. Set a breakpoint in `template.js` at line 227 (`buildSnippetProxy` call)
+   inside the snippet branch of `hydrate`. Confirm it fires once per item
+   with `data` being an each-item proxy (test:
+   `isItemContext(data)` — exported from `each.js`).
+2. Set a breakpoint in `each.js:418` (`rec.itemSignal.notify()`) and trigger
+   your mutation. Confirm it fires for index 0.
+3. Set a breakpoint in `reactive-data.js:219` (the textNode reaction body).
+   Confirm it re-fires after step 2 and `value` is the new name.
+
+If step 2 doesn't fire, the snapshot diff isn't seeing the change (case C, or
+the mutation path doesn't reach reconcile — case A). If step 2 fires but
+step 3 doesn't, the snippet body's Reaction never subscribed to that
+itemSignal — would be a real framework bug, file it with a repro.
+
+---
+
+## File pointers
+
+- `packages/renderer/src/engines/native/blocks/each.js` — reconcile, `adoptServerItems`, snapshot diff
+- `packages/renderer/src/engines/native/blocks/each-content-classifier.js` — bails on snippets, forces eager wire
+- `packages/renderer/src/engines/native/blocks/template.js` — snippet branch, `buildSnippetProxy` lazy-getter pattern
+- `packages/renderer/src/engines/native/reactive-data.js:163` — `hydrateTextExpression` (firstRun subscription)
+- `packages/renderer/test/browser/ssr-hydration.test.js:1408` — the canonical passing test for your exact pattern
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json
new file mode 100644
index 000000000..ac9a6b11d
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
+      "passed": false,
+      "evidence": "The answer correctly identifies that the bug is not snippet-specific ('this isn't snippet-specific — any expression inside the each body that reads item.<prop> would hit the same bug'), but it diagnoses a fundamentally different root cause: a propsSnapshot === null edge case in adoptServerItems, not the each-hydrate deferral of per-item Reaction wiring. The answer asserts the snippet wiring is correct and per-item Reactions are properly wired against itemSignal during adoption — directly contradicting the deferral-as-root-cause framing of eval 2. Misses the connection to the same root cause."
+    },
+    {
+      "text": "B: Explains that snippet args (label=item.name) are evaluated by the per-item content path; the snippet body sees those args via buildSnippetProxy",
+      "passed": true,
+      "evidence": "Answer explicitly explains: 'Snippet args (label=item.name) become lazy getters captured by buildSnippetProxy (packages/renderer/src/engines/native/blocks/template.js:67-114). The snippet body's {label} reactive text-node Reaction reads snippetData.label, which calls the captured getter () => evaluator.lookupExpressionValue(item.name, itemProxy)...'. Identifies buildSnippetProxy and the per-item arg evaluation path."
+    },
+    {
+      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
+      "passed": false,
+      "evidence": "The answer takes the opposite position: 'So the text-node Reaction inside the snippet body does end up depending on the per-item itemSignal. The wiring is fine.' It claims the Reactions ARE wired and the bug is downstream (propsSnapshot/notify gating). Does not identify unwired per-item Reactions as the cause."
+    },
+    {
+      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
+      "passed": false,
+      "evidence": "The answer references each-content-classifier ('confirms eager hydration is forced when an each contains a template (snippet) node, so adoptServerItems is what runs during hydrate (line 189-194)') but positions this as confirming the path that exposes the bug, not as the fix. The proposed fix is to populate propsSnapshot in adoptServerItems — a completely different remediation than 'force eager adoption via classifier bail-out.'"
+    },
+    {
+      "text": "E: Mentions the existing test 'snippet with named args inside each is reactive after hydration' (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
+      "passed": true,
+      "evidence": "Answer references 'the existing snippet with named args inside each test' at packages/renderer/test/browser/ssr-hydration.test.js:1408-1433, noting it 'uses a new object ref and therefore doesn't catch this.' Identifies the existing scenario test even if framing it as a near-miss rather than the regression test PR #175 unskipped."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md
new file mode 100644
index 000000000..75b56128b
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md
@@ -0,0 +1,85 @@
+# What's happening
+
+The framework's snippet wiring is correct here — the bug you're hitting is a stale-snapshot edge case in `each`'s post-hydration reconcile path, not a snippet-arg reactivity hole. Specifically: the **first** post-hydration in-place mutation of an item slips through silently. The second mutation onwards updates the DOM normally.
+
+## The intended path
+
+For your template:
+
+```
+{#each item in items}<div>{>badge label=item.name}</div>{/each}
+```
+
+Reactivity flows like this:
+
+1. **Each block** wraps each item in a `Signal` (`itemSignal`) holding `{ item, index }`. A `Proxy` (`createItemDataProxy` in `packages/renderer/src/engines/native/blocks/each.js:129-144`) sits over the parent data and routes `data.item` lookups through `itemSignal.value`, which registers an `itemSignal` dep on whoever's reading.
+2. **Snippet args** (`label=item.name`) become **lazy getters** captured by `buildSnippetProxy` (`packages/renderer/src/engines/native/blocks/template.js:67-114`). The snippet body's `{label}` reactive text-node Reaction reads `snippetData.label`, which calls the captured getter `() => evaluator.lookupExpressionValue('item.name', itemProxy)`, which goes through the each's item-proxy and registers `itemSignal` as a dep on the text node's Reaction.
+
+So the text-node Reaction inside the snippet body **does** end up depending on the per-item `itemSignal`. The wiring is fine. The problem is whether `itemSignal.notify()` actually fires when you mutate in place.
+
+## The bug — `propsSnapshot` is `null` after adoption
+
+When you replace `state.items` with `state.items.set([...items])`, the items signal fires and `each.update` runs. For records whose `item` reference and index are unchanged (your case — same object, just a mutated `.name`), the equality gate inside `Signal.set` short-circuits because the wrapper `{ item, index }` looks identical by `===` (same item ref). To get around that, `each` keeps a `propsSnapshot` of each item's top-level props and shallow-compares on every reconcile to decide whether to call `itemSignal.notify()` manually:
+
+```js
+// packages/renderer/src/engines/native/blocks/each.js:396-422 (Phase 3)
+if (rec.item !== item || rec.index !== i) {
+  rec.itemSignal.set(getEachData(...));
+  ...
+  rec.propsSnapshot = createSnapshot(item);
+}
+else if (typeof item === 'object' && item !== null) {
+  if (rec.propsSnapshot === null) {
+    // "Fresh record (first reconcile after createRecord). Bindings
+    //  were wired synchronously against the signal's value; there's
+    //  no stale subscriber to wake."
+    rec.propsSnapshot = createSnapshot(item);
+  }
+  else if (refreshSnapshotAndDetect(rec.propsSnapshot, item)) {
+    rec.itemSignal.notify();
+  }
+}
+```
+
+That `propsSnapshot === null` branch assumes "no notify needed because we just wired the bindings against the current item value." That assumption is true for records produced by `createRecord` inside the same `reconcile` call (CSR, or post-hydration replacements), but it is **wrong** for records produced by `adoptServerItems` during hydration, because:
+
+- Adoption wires Reactions at hydrate time against the item's hydration-time `.name` (`'Apple'`).
+- The records are pushed with `propsSnapshot: null` (`packages/renderer/src/engines/native/blocks/each.js:583`).
+- Some unspecified time later, your code mutates `items[0].name = 'Cherry'` and pushes a new array.
+- `update` runs `reconcile`. Phase 3 sees `rec.item === items[0]` (still the same ref), index unchanged, and `propsSnapshot === null` — so it takes the "fresh record" branch, snapshots `{ name: 'Cherry' }` for next time, and **does not call `notify()`**.
+- The badge stays showing `[Apple]`.
+
+If you mutate again (`items[0].name = 'Date'`), `refreshSnapshotAndDetect` compares against the now-populated snapshot (`'Cherry' !== 'Date'`), fires `notify()`, and the DOM updates to `[Date]` — skipping the `'Cherry'` value entirely.
+
+## Why the "outer reaction definitely fires" observation is consistent
+
+Your test for "outer reaction fires" probably involves changing the array length (push, splice, swap). Those go through the `rec.item !== item || rec.index !== i` branch — `itemSignal.set(...)` runs unconditionally with a fresh wrapper object, equality gate passes (different wrapper ref), subscribers wake. That's why adding/removing/reordering items works fine after hydrate, but mutating an existing item's prop in place doesn't.
+
+It's also worth noting that this isn't snippet-specific — any expression inside the each body that reads `item.<prop>` would hit the same bug after hydration on the first in-place mutation. The snippet is just along for the ride. But the snippet structure does suppress one of the workarounds: with bare `{item.name}` directly in the each body, the same lookup path applies and the same bug should reproduce. A test using new object refs (`items[0] = { ...items[0], name: 'Crimson' }`) like the one at `packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` passes precisely because it dodges the equality gate by changing the item ref.
+
+## Workarounds (no source change)
+
+- Replace the item reference instead of mutating in place: `state.items.set(items.map((it, i) => i === 0 ? { ...it, name: 'Cherry' } : it))`. New ref → first branch of phase 3 → `itemSignal.set(...)` → DOM updates.
+- Toggle the value back-and-forth — the first mutation populates `propsSnapshot`, the second triggers `notify()`. Not really a workaround, just an explanation of why your second mutation works.
+- Use `state.items.notify()` after the in-place mutation to force the items signal to fire a second time — but this only buys you the same "phase 3 with populated snapshot" pass, so it would also need to happen after the first lost mutation, not as a fix for it.
+
+## The fix on the framework side
+
+`adoptServerItems` should populate `propsSnapshot` at adoption time, the same way Phase 3 does at the end of a normal reconcile. Either:
+
+```js
+// packages/renderer/src/engines/native/blocks/each.js:574-584
+newRecords.push({
+  ...,
+  propsSnapshot: createSnapshot(item),  // not null
+});
+```
+
+…or, equivalently, change the "fresh record" branch in Phase 3 to detect adoption explicitly. The first option is cleaner and matches the invariant the comment in Phase 3 already claims ("bindings were wired against the signal's value at the moment we set the snapshot").
+
+## Files to look at
+
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `adoptServerItems` (line 505), `reconcile` Phase 3 (line 396-422), `createSnapshot` / `refreshSnapshotAndDetect` (lines 86-122), `createItemDataProxy` (line 129).
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/template.js` — `buildSnippetProxy` lazy getters (line 67), snippet hydrate branch (line 224).
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — confirms eager hydration is forced when an each contains a `template` (snippet) node, so `adoptServerItems` is what runs during hydrate (line 189-194).
+- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` — the existing "snippet with named args inside each" test that uses a new object ref and therefore doesn't catch this.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json
new file mode 100644
index 000000000..ceece3c83
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)",
+      "passed": true,
+      "evidence": "Step 2: 'when you write `wrapper.innerHTML = renderToString(...)`, the `<template shadowrootmode=\"open\">…</template>` stays as a literal `<template>` child of your custom element. It is not unwrapped. The element has no shadow root.' Also explicitly named in step 1: fragment parsers including `innerHTML` do not process DSD."
+    },
+    {
+      "text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API",
+      "passed": true,
+      "evidence": "The Fix section: 'Use **`setHTMLUnsafe`** (or `Document.parseHTMLUnsafe` for a document-scoped variant)' with a code example showing `wrapper.setHTMLUnsafe(html)`."
+    },
+    {
+      "text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`",
+      "passed": true,
+      "evidence": "Steps 3-5 lay out the full chain: constructor sees `this.shadowRoot` is null, `_hydrating` stays false; connectedCallback evaluates `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0` to false; component falls through to `this.fullRender(prototypeTemplate)` instead of hydrate."
+    },
+    {
+      "text": "D: Notes that the failure is silent (no error) — the test \"succeeds\" but is testing a different code path than intended",
+      "passed": true,
+      "evidence": "Opening line: 'There is no error — the element is in the page, the `rendered` event fires, but it fired for the wrong reason. You are not testing hydration; you are testing a fresh client render that happens to start from a server-rendered string.' Reinforced in the closing section: 'There is no error and no warning. Tests pass for the wrong reason.'"
+    },
+    {
+      "text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)",
+      "passed": true,
+      "evidence": "Step 1: 'The browser's **main HTML parser** processes `<template shadowrootmode=\"open\">` natively — that's why an SSR'd page works in production. But the **fragment parsers** (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) **do not**. The DSD spec deliberately opts those out because injecting attacker-controlled HTML into an existing shadow root is an XSS escalation vector.'"
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
new file mode 100644
index 000000000..7ddc321a8
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
@@ -0,0 +1,64 @@
+# Why `el.shadowRoot` is `null` in your hydration test
+
+## What's happening
+
+`wrapper.innerHTML = html` is silently throwing away the Declarative Shadow DOM. There is no error — the element is in the page, the `rendered` event fires, but it fired for the wrong reason. You are not testing hydration; you are testing a fresh client render that happens to start from a server-rendered string.
+
+The chain of events:
+
+1. The browser's **main HTML parser** processes `<template shadowrootmode="open">` natively — that's why an SSR'd page works in production. But the **fragment parsers** (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) **do not**. The DSD spec deliberately opts those out because injecting attacker-controlled HTML into an existing shadow root is an XSS escalation vector.
+2. So when you write `wrapper.innerHTML = renderToString(...)`, the `<template shadowrootmode="open">…</template>` stays as a literal `<template>` child of your custom element. It is not unwrapped. The element has no shadow root.
+3. The browser appends the element, the upgrade runs, and the constructor checks `if (this.shadowRoot)` to decide whether to set `_hydrating = true`. It's `null`, so the flag stays false.
+4. `connectedCallback` then evaluates `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0`. With a null `shadowRoot`, that's `false`.
+5. The component falls through to `this.fullRender(prototypeTemplate)` — the standard client path. `fullRender` calls `attachShadow({ mode: 'open' })` itself, builds the template from scratch, and emits the `rendered` event you're awaiting.
+6. Now `el.shadowRoot` is finally non-null, but the time-of-check vs. time-of-await ordering you wrote treats it as null, OR the assertion runs against a freshly-rendered shadow root that — depending on what your component does in `createComponent` — may not match what the server emitted (e.g. server-only branches, marker-derived per-item DOM, etc.).
+
+That last point is the real bite for your test: even if you'd later see a non-null `shadowRoot`, **you'd be asserting against a client render, not against the server's per-item DOM**. The test would pass or fail for entirely the wrong reason.
+
+## The fix
+
+Use **`setHTMLUnsafe`** (or `Document.parseHTMLUnsafe` for a document-scoped variant). Both go through HTML parser entry points that the spec explicitly enables for DSD processing:
+
+```js
+// Element-scoped — what you want for a wrapper div
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);
+const el = wrapper.firstElementChild;
+
+document.body.appendChild(el);
+await $(el).onNext('rendered');
+
+// Now el.shadowRoot is the DSD-parsed root, hasServerContent is true,
+// and connectedCallback takes the hydrate() path.
+```
+
+The "Unsafe" suffix is misleading in this context — it does not mean "unsafe in a test"; it means "this method bypasses the XSS-escalation guard that the regular fragment parsers enforce." For SSR test fixtures where you control the input string, it's exactly the right tool.
+
+This is the only DOM API change you need. Everything downstream — `el.shadowRoot` being non-null at constructor time, `_hydrating` flag set, `canHydrate()` finding the `sui:v1:` markers, `requestAnimationFrame(() => hydrate(...))` deferring one frame, the `rendered` event firing after the hydration wiring completes — all of that follows automatically once the parser actually creates the shadow root from the `<template shadowrootmode>`.
+
+## One related gotcha to check while you're in there
+
+If your test runs in a Vitest browser environment, also confirm that `renderToString` is producing real SSR output and not an empty DSD wrapper. `Template.isServer` is set once at module load from `typeof window === 'undefined'`. In the browser test env, `window` exists, so `Template.isServer === false`, and the renderer-selection inside `Template.initialize()` picks the client `Renderer` — which returns a `DocumentFragment` that the `renderToString` template literal coerces to `'[object DocumentFragment]'` (or empty after `expandCustomElements` no-ops on it). The DSD wrapper is emitted but the inside is empty.
+
+Wrap the call in a `try/finally` toggle:
+
+```js
+const wasServer = Template.isServer;
+Template.isServer = true;
+let html;
+try {
+  html = renderToString(Component, attrs);
+} finally {
+  Template.isServer = wasServer;
+}
+```
+
+The `finally` matters — leaving `Template.isServer = true` after the call would break any subsequent client-side mount in the same test run, because the renderer selection only happens once per `template.initialize()`.
+
+## Canonical reference
+
+The helper you should mirror is `ssrAndHydrate` in `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` (lines 39-67). It does exactly the two things above — `Template.isServer` toggle around `renderToString`, then `wrapper.setHTMLUnsafe(html)` instead of `innerHTML` — and is the pattern every SSR-hydration browser test in the repo is built on. If you can use it directly rather than rolling your own, do.
+
+## Why this matters beyond your single test
+
+This is one of the canonical silent-failure modes for SSR work in this framework. There is no error and no warning. Tests pass for the wrong reason; benches measure `fullRender` instead of `hydrate` and report wrong numbers. If you're authoring more SSR tests or perf benchmarks, treat `setHTMLUnsafe` + `Template.isServer` toggle as a single non-negotiable pair — they are the entry conditions for the hydration code path even existing.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json
new file mode 100644
index 000000000..cee1093e4
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json
@@ -0,0 +1,7 @@
+{"expectations": [
+  {"text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)", "passed": true, "evidence": "Short answer states 'The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not.' and explains the literal `<template>` is left in light DOM (lines 4-5, 30)."},
+  {"text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API", "passed": true, "evidence": "Recommends `wrapper.setHTMLUnsafe(html)` as the primary fix (lines 5, 37-49) and also mentions `Document.parseHTMLUnsafe(html)` as an alternative (line 59)."},
+  {"text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`", "passed": true, "evidence": "Line 32-33 explicitly traces: no shadow root attached → `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0` is false → 'framework then runs `fullRender` instead of `hydrate`'. References `connectedCallback` in `packages/component/src/engines/native/base.js`."},
+  {"text": "D: Notes that the failure is silent (no error) — the test 'succeeds' but is testing a different code path than intended", "passed": true, "evidence": "Line 33 notes 'eventually does call `attachShadow` and you get a shadow root populated by a fresh client render' and 'you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child' — this captures the silent-failure framing."},
+  {"text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)", "passed": false, "evidence": "Line 27 mentions 'it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it' — partially captures main-parser-enabled point, but does not explicitly enumerate the fragment parsers (`outerHTML`, `insertAdjacentHTML`) as the limited surface. The contrast between main parser vs fragment parsers is implied but not stated. Borderline; strict reading fails because the assertion specifically asks for the fragment-parser limitation framing."}
+]}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
new file mode 100644
index 000000000..e7af4e86a
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
@@ -0,0 +1,73 @@
+# Why `el.shadowRoot` is null and how to fix it
+
+## Short answer
+
+Replace `wrapper.innerHTML = html` with `wrapper.setHTMLUnsafe(html)`. The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not. With `innerHTML`, the `<template shadowrootmode="open">` that `renderToString` emits stays as a literal `<template>` child in light DOM and no shadow root is ever attached, so `el.shadowRoot` is `null` when your assertion runs.
+
+## What is actually in the SSR string
+
+`renderToString` (in `packages/component/src/render-to-string.js`) wraps the component output like this:
+
+```
+<my-card title="Hello">
+  <template shadowrootmode="open">
+    <style>...</style>
+    ...rendered content with hydration markers...
+  </template>
+  ...slot light DOM...
+</my-card>
+```
+
+That `<template shadowrootmode="open">` is not a regular `<template>` — it is the Declarative Shadow DOM marker. When the HTML parser encounters it, it is supposed to:
+
+1. Attach a shadow root on the parent custom element (`mode: "open"`).
+2. Move the template's contents into that shadow root.
+3. Remove the `<template>` element itself from the tree.
+
+The parser only does that when DSD parsing is explicitly enabled. By spec, it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it. The `innerHTML` setter is intentionally NOT one of them — it has been the standard policy since DSD shipped, to avoid a subtle XSS escalation where existing code that injects untrusted HTML could now also be injecting shadow roots.
+
+So when you do `wrapper.innerHTML = html`:
+- The parser leaves `<template shadowrootmode="open">` as a literal `<template>` child of `<my-card>`.
+- No shadow root is attached.
+- The custom element upgrade fires `connectedCallback`, but because `this.shadowRoot` is `null`, the framework's branch for "DSD content present" is skipped entirely. (See `packages/component/src/engines/native/base.js`, `connectedCallback`: `const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;`.)
+- The framework then runs `fullRender` instead of `hydrate`. That eventually does call `attachShadow` and you get a shadow root populated by a fresh client render — but if you assert at the wrong moment (e.g. synchronously after appending), `el.shadowRoot` can still be `null`. Even if you wait for `rendered`, you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child.
+
+## The fix
+
+Use `Element.setHTMLUnsafe()`:
+
+```js
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);
+const el = wrapper.firstElementChild;
+
+const rendered = $(el).onNext('rendered');
+document.body.appendChild(el);
+await rendered;
+
+expect(el.shadowRoot).toBeTruthy();
+```
+
+`setHTMLUnsafe` is the element-instance API specifically designed for this case: it parses with DSD enabled, so `<template shadowrootmode="open">` becomes the element's shadow root before you ever touch the DOM. By the time you read `wrapper.firstElementChild.shadowRoot`, the shadow root exists with the server content in it. When you append to `document.body`, `connectedCallback` then takes the `hasServerContent` branch and calls `hydrate(prototypeTemplate)` rather than `fullRender(...)` — wiring reactive bindings to the existing per-item DOM the server emitted.
+
+The canonical comment from the framework's own hydration test (`packages/renderer/test/browser/ssr-hydration.test.js`, around line 54) makes the contract explicit:
+
+> setHTMLUnsafe processes `<template shadowrootmode>`; innerHTML does not. Without this, the custom element parses with no shadowRoot, hasServerContent is false, and connectedCallback runs fullRender instead of hydrate.
+
+## A few related gotchas worth pinning while you're here
+
+- **Do not use `DOMParser.parseFromString(html, 'text/html')` either.** By default it also does not parse DSD. The opt-in there is the static `Document.parseHTMLUnsafe(html)` (which returns a full `Document`); that works too if you need a whole-document parse, but for injecting a single component into an existing test page, `setHTMLUnsafe` on a wrapper element is the natural fit.
+- **`Template.isServer` matters in browser tests.** `renderToString` only emits the SSR (DSD) string when `Template.isServer` is `true`. In a browser test environment it defaults to `false`, so you will get client output unless you flip it. The framework's own helper does this:
+  ```js
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  try { html = renderToString(Component, attrs); }
+  finally { Template.isServer = wasServer; }
+  ```
+  If your wrapper assertion is failing on `el.shadowRoot` being null, this is the second thing to check after `setHTMLUnsafe` — without `Template.isServer = true`, `renderToString` may not have produced a DSD string in the first place.
+- **`rendered` is the right event to await for hydration.** The framework's `connectedCallback` schedules `hydrate` via `queueMicrotask`, so you cannot read `el.shadowRoot.querySelector(...)` synchronously after `appendChild`. `await $(el).onNext('rendered')` is what the in-repo tests use, and it resolves after `template.markRendered()` inside `hydrate`.
+- **Do not assert the absence of comment markers right after `rendered`.** The hydration scaffolding (`<!-- sui:v1: ... -->` comments and `data-sui-bind="..."` attributes) is removed in a `requestAnimationFrame` callback after hydration, one tick later than the `rendered` event. If your test wants to compare `shadowRoot.innerHTML` strings, strip them yourself, the way the in-repo tests do (`shadowHTML(el)` helper). Otherwise an assertion that "the per-item DOM the server emitted" matches your expected string will fail because the server's per-item DOM is still wrapped in those markers.
+
+## Why this trips people up
+
+`innerHTML` is the muscle-memory API for "parse this string into DOM," and `setHTMLUnsafe` looks like a scary scoped variant. It is actually the opposite: `setHTMLUnsafe` is more permissive (it allows DSD), and `innerHTML` is the "safe" default that strips it. For anything involving `renderToString` output from `@semantic-ui/component`, you want the more permissive one — the whole point of the SSR string is the DSD inside it.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json
new file mode 100644
index 000000000..1ee09ce37
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `Template.isServer` as the controlling flag",
+      "passed": true,
+      "evidence": "Opens with 'Template.isServer is set once at module load from typeof window === undefined' and reiterates throughout: 'in the browser env, renderToString ends up using the client Renderer'. Summary explicitly names Template.isServer as root cause."
+    },
+    {
+      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
+      "passed": true,
+      "evidence": "Quotes the exact selection code from packages/templating/src/template.js:292: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and explains the consequence."
+    },
+    {
+      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
+      "passed": true,
+      "evidence": "States 'the client Renderer, which returns a DocumentFragment from render() rather than an HTML string. That fragment gets coerced into the surrounding template literal as [object DocumentFragment], then the string-only expandCustomElements no-ops on it, and the DSD wrapper is emitted with nothing inside the <template shadowrootmode=\"open\">'."
+    },
+    {
+      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
+      "passed": true,
+      "evidence": "Fix section prescribes 'Toggle Template.isServer = true around the call' with a code example setting `Template.isServer = true` before renderToString."
+    },
+    {
+      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
+      "passed": true,
+      "evidence": "Code example uses try/finally with `wasServer = Template.isServer` saved up front and `Template.isServer = wasServer` in the finally. Explicitly explains: 'The try/finally is load-bearing. If you leave Template.isServer = true after the call, any subsequent client-side hydration or mount in the same test breaks'."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md
new file mode 100644
index 000000000..f994c34a6
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md
@@ -0,0 +1,94 @@
+# Why `renderToString` is empty in your browser test
+
+You've hit a known silent-failure mode. Your component, settings, and template are all fine — the problem is that `renderToString` is picking the **client renderer** instead of the server one, because of how engine selection is gated.
+
+## What's happening
+
+`Template.isServer` is set **once at module load** from `typeof window === 'undefined'` (in `@semantic-ui/utils`). In a vitest browser test, `window` exists, so `Template.isServer === false` for the entire run.
+
+Inside `Template.initialize()` the engine selection looks like this (`packages/templating/src/template.js:292`):
+
+```js
+const RendererClass = (Template.isServer && engine.serverRenderer)
+  ? engine.serverRenderer
+  : engine.renderer;
+```
+
+So in the browser env, `renderToString` ends up using the **client `Renderer`**, which returns a `DocumentFragment` from `render()` rather than an HTML string. That fragment gets coerced into the surrounding template literal as `'[object DocumentFragment]'`, then the string-only `expandCustomElements` no-ops on it, and the DSD wrapper is emitted with nothing inside the `<template shadowrootmode="open">`.
+
+That matches your symptom exactly:
+
+```
+<my-component><template shadowrootmode="open"></template></my-component>
+```
+
+It's not your `each` block, not `defaultSettings`, not the data shape — it's the renderer selection. On Node the same code works because `window` is undefined and `Template.isServer` is `true`.
+
+## The fix
+
+Toggle `Template.isServer = true` around the call, with a `try/finally` so it gets restored:
+
+```js
+import { Template } from '@semantic-ui/templating';
+import { renderToString } from '@semantic-ui/component';
+
+const wasServer = Template.isServer;
+Template.isServer = true;
+let html;
+try {
+  html = renderToString(MyComponent, { items: [...] });
+} finally {
+  Template.isServer = wasServer;
+}
+```
+
+The `try/finally` is load-bearing. If you leave `Template.isServer = true` after the call, any subsequent client-side hydration or mount in the same test breaks, because renderer selection happens once per `template.initialize()` and you've now flipped every component into the server engine.
+
+## If you also plan to inject the HTML and let it hydrate
+
+Don't use `innerHTML` — it does **not** process Declarative Shadow DOM. The fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) are opted out of DSD by spec for XSS reasons. Use `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`):
+
+```js
+const wrapper = document.createElement('div');
+wrapper.setHTMLUnsafe(html);   // shadow root attaches; innerHTML would not
+const el = wrapper.firstElementChild;
+document.body.appendChild(el); // triggers connectedCallback → hydrate
+```
+
+With `innerHTML` your test will silently appear to work but actually exercise `fullRender` (client-only) instead of `hydrate`, because `el.shadowRoot` is `null` when `connectedCallback` fires and `hasServerContent` is false.
+
+## Canonical helper to copy
+
+`packages/renderer/test/browser/ssr-hydration.test.js` has the canonical `ssrAndHydrate` helper that does both pieces correctly. Worth pattern-matching against rather than rolling your own:
+
+```js
+async function ssrAndHydrate(opts, attrs = {}) {
+  const tag = uniqueTag();
+  const Component = defineComponent({ tagName: tag, renderingEngine: 'native', ...opts });
+
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  let html;
+  try {
+    html = renderToString(Component, attrs);
+  } finally {
+    Template.isServer = wasServer;
+  }
+
+  const wrapper = document.createElement('div');
+  wrapper.setHTMLUnsafe(html);
+  const el = wrapper.firstElementChild;
+
+  const rendered = $(el).onNext('rendered');
+  document.body.appendChild(el);
+  await rendered;
+  return el;
+}
+```
+
+## Summary
+
+- **Root cause:** `Template.isServer` is computed once at module load from `typeof window`. In a browser test it's `false`, so `renderToString` selects the client `Renderer` (returns a `DocumentFragment`) instead of the `ServerRenderer` (returns a string). The DSD wrapper string is emitted but nothing fills the inside.
+- **Fix:** Set `Template.isServer = true` with `try/finally` around your `renderToString` call.
+- **If injecting + hydrating:** also use `setHTMLUnsafe`, never `innerHTML`. `innerHTML` skips DSD processing and your test will silently measure the wrong code path.
+- **Reference:** `packages/renderer/test/browser/ssr-hydration.test.js` (`ssrAndHydrate`).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json
new file mode 100644
index 000000000..dc14369dd
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `Template.isServer` as the controlling flag",
+      "passed": true,
+      "evidence": "Section heading at line 3: 'Root cause: `Template.isServer` is `false` in a real browser'. Lines 14-21 trace it back to `@semantic-ui/utils` `isServer = typeof window === 'undefined'`. Lines 23-25 explicitly state that in browser env `Template.isServer` is `false`, selecting the client renderer."
+    },
+    {
+      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
+      "passed": true,
+      "evidence": "Lines 7-12 quote the exact selection code from `template.js:292`: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and frames it as 'The renderer that gets instantiated is selected here'."
+    },
+    {
+      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
+      "passed": true,
+      "evidence": "Lines 25-34: 'the client renderer (engines/native/renderer.js) is selected. Its render() returns a DocumentFragment, not a string'. Lines 36-65 then trace how the non-string DocumentFragment causes `expandCustomElements` to silently produce empty output, yielding the empty `<template shadowrootmode=\"open\"></template>` wrapper symptom (lines 67-69)."
+    },
+    {
+      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
+      "passed": true,
+      "evidence": "Line 80: 'Force `Template.isServer = true` for the duration of the `renderToString` call.' Lines 86-96 show the explicit `Template.isServer = true` toggle wrapping the `renderToString` call. Line 98 explains the timing: 'The flag has to be set before renderToString is invoked... and restored after'."
+    },
+    {
+      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
+      "passed": true,
+      "evidence": "Lines 86-95 show the canonical pattern: `const wasServer = Template.isServer; Template.isServer = true; try { return renderToString(...) } finally { Template.isServer = wasServer; }`. Line 103 reinforces the rationale: 'Don't set Template.isServer = true globally in a beforeAll - it will break any test in the same file that exercises the live client renderer'."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md
new file mode 100644
index 000000000..b00247967
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md
@@ -0,0 +1,119 @@
+# Why `renderToString` emits an empty DSD in Vitest browser mode
+
+## Root cause: `Template.isServer` is `false` in a real browser
+
+`renderToString` is renderer-agnostic — it builds a `Template`, calls `template.initialize()`, then `template.render()`, and string-concatenates the result into the DSD wrapper. The renderer that gets instantiated is selected here:
+
+`packages/templating/src/template.js:292`
+```js
+const RendererClass = (Template.isServer && engine.serverRenderer)
+  ? engine.serverRenderer
+  : engine.renderer;
+```
+
+`Template.isServer` is initialized once, at module load, from `@semantic-ui/utils`:
+
+`packages/utils/src/environment.js:5`
+```js
+export const isServer = (() => {
+  return typeof window === 'undefined';
+})();
+```
+
+In Node SSR, `window` is undefined → `isServer === true` → the **server** renderer is selected → `template.render()` returns an HTML string → `renderToString` concatenates it into the DSD and you get fully-populated `each` output.
+
+In Vitest **browser** mode (`@vitest/browser` driving Chromium / Firefox / WebKit / Playwright), `window` is a real browser global. `typeof window === 'undefined'` is `false`, so `Template.isServer` is `false`, and the **client** renderer (`engines/native/renderer.js`) is selected. Its `render()` returns a `DocumentFragment`, not a string:
+
+`packages/renderer/src/engines/native/renderer.js:157`
+```js
+render() {
+  return this.readAST({ ast: this.ast, data: this.data, scope: this.scope });
+}
+// ...
+return fragment;  // DocumentFragment
+```
+
+## Why the inner template is *empty*, not garbled
+
+Look at what `renderToString` does with that value:
+
+`packages/component/src/render-to-string.js:67`
+```js
+let html = template.render();                // DocumentFragment in browser env
+html = expandCustomElements(html, { ... });  // string-only function
+```
+
+`expandCustomElements` is written for strings:
+
+`packages/component/src/expand-custom-elements.js:25`
+```js
+while (pos < html.length) {  // DocumentFragment.length is undefined
+  ...
+}
+```
+
+`pos < undefined` is `false`, so the loop body never runs and the function returns `''` (its `result` accumulator). Then the wrapper is built around an empty string:
+
+```js
+return `<${tagName}...>`
+  + `<template shadowrootmode="open">`
+  + (css ? `<style>${css}</style>` : '')
+  + html                          // ''
+  + `</template>`
+  + slotHTML
+  + `</${tagName}>`;
+```
+
+→ exactly the symptom you see:
+```
+<my-component><template shadowrootmode="open"></template></my-component>
+```
+
+(If your component happens to have a `css` block, you'll see a `<style>` inside the template but still no markup.)
+
+## The Node SSR path "just works" because of module load order
+
+When the test runner is Node (jsdom or node mode), `window` is undefined at the time `@semantic-ui/utils/environment.js` is first imported, so `isServer` evaluates to `true` and is captured into `Template.isServer`. Even if jsdom later adds a `window` global, the constant has already been frozen. That's why your Node-side rendering works and your browser-side rendering is empty — it's not about your component, your `defaultSettings`, your `each` block, or your data; it's purely about which renderer class got chosen at `initialize()` time.
+
+## Fix
+
+Force `Template.isServer = true` for the duration of the `renderToString` call. The repo's own browser tests do exactly this — see `packages/renderer/test/browser/ssr-hydration.test.js:39`:
+
+```js
+import { defineComponent, renderToString } from '@semantic-ui/component';
+import { Template } from '@semantic-ui/templating';
+
+function ssrInBrowser(Component, attrs) {
+  const wasServer = Template.isServer;
+  Template.isServer = true;
+  try {
+    return renderToString(Component, attrs);
+  }
+  finally {
+    Template.isServer = wasServer;
+  }
+}
+```
+
+Wrap your `renderToString` call in that `try/finally`. The flag has to be set **before** `renderToString` is invoked (because `template.initialize()` reads it once and instantiates the renderer right then) and restored after (so any subsequent client-side code in the same test — hydration, mount, reactivity assertions — still gets the DOM renderer). The flag is read on every `initialize()`, so per-call toggling is safe and doesn't leak across tests as long as the `finally` runs.
+
+A few practical notes:
+
+- Do this in a small helper rather than inline, and call it from every test that needs the SSR string. Forgetting the toggle is the single failure mode.
+- Don't set `Template.isServer = true` globally in a `beforeAll` — it will break any test in the same file that exercises the live client renderer (mount, hydrate, reactive update).
+- If you also want to verify hydration end-to-end (inject the DSD, let the browser parse `<template shadowrootmode="open">`, then upgrade the custom element), use `wrapper.setHTMLUnsafe(html)` instead of `innerHTML`. Plain `innerHTML` does not process declarative shadow DOM, so the element parses with no shadow root and `connectedCallback` falls back to a full client render — making your test a non-hydration test by accident. The browser test in `ssr-hydration.test.js:58` shows the pattern.
+- Nothing about `defaultSettings`, the `each` block, or your `items` data is involved. The component is fine. The fix is one line of test scaffolding.
+
+## Why the framework doesn't autodetect this
+
+`renderToString` could in principle override the engine selection itself (it already passes `renderingEngine: 'native'` to `proto.clone()`), but it currently delegates the server-vs-client decision to `Template.isServer`, which is a process-wide flag derived from `typeof window`. In the canonical use case — calling `renderToString` from a Node/Bun/Workers SSR path — that's correct and zero-config. The browser test environment is the edge case where the flag's heuristic is wrong, and the framework's own test suite handles it with the same toggle pattern shown above. Treat it as a known wart of running SSR code in a browser-mode test runner, not a bug in your component.
+
+## Relevant source files
+
+- `/home/jack/semantic/next/packages/component/src/render-to-string.js` — the entry point; line 67 calls `template.render()`, lines 84–90 build the DSD wrapper.
+- `/home/jack/semantic/next/packages/templating/src/template.js` — line 43 captures `Template.isServer` from `utils`; lines 292–294 select the server vs. client renderer class.
+- `/home/jack/semantic/next/packages/utils/src/environment.js` — line 5 defines `isServer = typeof window === 'undefined'`.
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/renderer.js` — line 157 `render()` returns a `DocumentFragment`.
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/server.js` — the alternative ServerRenderer that returns a string.
+- `/home/jack/semantic/next/packages/component/src/expand-custom-elements.js` — line 25 string-only `while (pos < html.length)` silently no-ops on a `DocumentFragment`.
+- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` — lines 39–67 are the canonical browser-test pattern (`Template.isServer = true` toggle plus `setHTMLUnsafe`).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json
new file mode 100644
index 000000000..3d3676b77
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
+      "passed": true,
+      "evidence": "Answer states: 'each.hydrate is the only block hydrate hook in the framework that does not unconditionally wire per-item Reactions. It is a deliberate perf optimization' and explains the perf cost (~425ms for 1000 items)."
+    },
+    {
+      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
+      "passed": true,
+      "evidence": "Answer step 2-4 explicitly chains: 'It registers a dependency on the items collection signal (via lookupExpression(node.over))... It does not wire per-item Reactions... The lazy path defers wiring until the items signal first fires, then wires in place via adoptServerItems.'"
+    },
+    {
+      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
+      "passed": true,
+      "evidence": "Steps 3-4: 'Because items is set once from a prop and never mutates, the items signal never fires. Because the items signal never fires, each.update never runs, adoptServerItems never runs, and the per-item Reactions for {classMap getItemClasses item} are never wired.'"
+    },
+    {
+      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
+      "passed": true,
+      "evidence": "Diagnosis section explicitly traces `getItemClasses(item) reads state.activeID.get()` as the external signal, and step 5 states 'When you mutate state.activeID, there is no Reaction subscribed to it on the per-item bindings — so nothing invalidates and nothing re-renders the class.'"
+    },
+    {
+      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
+      "passed": true,
+      "evidence": "Fix section names 'packages/renderer/src/engines/native/blocks/each-content-classifier.js' as the static analyzer that 'walks the each block's content AST and decides whether every binding's identifier head resolves to iteration-vars ∪ pure-helper-registry ∪ reserved-names. each.hydrate consults it: self-contained → keep the lazy path; anything that could read external state → eager adoptServerItems'."
+    },
+    {
+      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
+      "passed": false,
+      "evidence": "Answer captures the spirit ('per-binding Reactions evaluating their expressions at wire time — which is exactly what didn't happen' and 'There is no \"register without running.\" Dependency.depend() is a no-op when Scheduler.current is null. The only way to register a dep on a signal is to read it inside a wired Reaction's compute callback') but does NOT explicitly mention the `skipFirstWrite: true` flag or that the Reactions trust the SSR'd DOM rather than re-rendering on first wire."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md
new file mode 100644
index 000000000..c7f2718ce
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md
@@ -0,0 +1,69 @@
+# Why the per-item class binding doesn't react
+
+## Diagnosis
+
+This is the canonical "each-block lazy hydrate, content reads external state" bug. It is the exact shape of the docs-site `inpage-menu` regression that PR #175 was written to address.
+
+### What's happening
+
+`each.hydrate` is the only block hydrate hook in the framework that does **not** unconditionally wire per-item Reactions. It is a deliberate perf optimization: per-item Reactions cost `item count × bindings per item` to wire, so on a 1000-item list eagerly wiring on hydrate added ~425ms in a previous experiment. The lazy path defers wiring until the items signal first fires, then wires in place via `adoptServerItems`.
+
+The deferral is correct **only when** every per-item binding depends on item-local data (the iteration variable, `index`/`key`, framework helpers like `classMap`, `activeIf`, `is`). Your binding violates that assumption:
+
+```
+{classMap getItemClasses item}
+   |
+   +-- getItemClasses(item) reads state.activeID.get()
+                                        ^^^^^^^^^^^^^^
+                                        external signal
+```
+
+### The silent-failure chain
+
+1. SSR renders the `<a>` elements with the correct `active` class for the initial `state.activeID`. The DOM looks fine.
+2. On hydrate, `each.hydrate` runs:
+   - It registers a dependency on the `items` collection signal (via `lookupExpression(node.over)`).
+   - It does **not** wire per-item Reactions. Instead it sets `self.hasHydrated = true` and returns. `adoptServerItems` is **not** called.
+3. Because `items` is set once from a prop and never mutates, the items signal never fires.
+4. Because the items signal never fires, `each.update` never runs, `adoptServerItems` never runs, and the per-item Reactions for `{classMap getItemClasses item}` are never wired.
+5. When you mutate `state.activeID`, there is no Reaction subscribed to it on the per-item bindings — so nothing invalidates and nothing re-renders the class.
+
+Your sanity-check `reaction(() => console.log(state.activeID.get()))` works because *that* Reaction is wired explicitly and registers its own dependency on `state.activeID` on first run. The framework's per-expression reactivity guarantee comes from per-binding Reactions evaluating their expressions at wire time — which is exactly what didn't happen for the items inside the `{#each}`.
+
+This is load-bearing: there is no "register without running." `Dependency.depend()` is a no-op when `Scheduler.current` is null. The only way to register a dep on a signal is to read it inside a wired Reaction's compute callback. No wired Reaction on the per-item binding means no dep on `state.activeID`, which means no reactivity. Hydration markers being clean and the SSR'd class being correct is a red herring — it just means the server-side render of the initial state was right.
+
+## Fix
+
+PR #175 introduced a static analyzer at `packages/renderer/src/engines/native/blocks/each-content-classifier.js` that walks the each block's content AST and decides whether every binding's identifier head resolves to `iteration-vars ∪ pure-helper-registry ∪ reserved-names`. `each.hydrate` consults it: self-contained → keep the lazy path; anything that could read external state → eager `adoptServerItems` so per-item Reactions register their external deps now.
+
+If the framework version you're on includes that classifier, **the fix is upstream** — `getItemClasses` reads `state.activeID`, the helper isn't in the framework's pure-helper registry (`TemplateHelpers`), the classifier returns false, and `each.hydrate` will eagerly wire. Verify by checking whether `packages/renderer/src/engines/native/blocks/each-content-classifier.js` exists in your install, and whether `each.js`'s `hydrate` function calls `isEachContentSelfContained(node)`. If both are present, the bug is something else (e.g., your each block uses no-`as` syntax — the classifier conservatively bails, but you'd then *not* see this bug because conservative bails go eager).
+
+If you're on a version *before* the classifier shipped (or if for some reason `getItemClasses` is not visible to the analyzer — e.g., it's registered as a user helper via `Template.registerHelper` and the classifier's identifier check sees it as external — which is the *correct* call in that case), the workarounds available to you in user-land are:
+
+1. **Inline the active check at the call site.** Move the binding into syntax the classifier can trace, or — pre-classifier — into syntax that doesn't hide the external read inside a helper:
+
+   ```
+   {#each item in items}
+     <a class="{classMap (object active=(eq state.activeID item.id)) item=true}">
+       {item.title}
+     </a>
+   {/each}
+   ```
+
+   This still reads external state, so on a pre-classifier version it still bugs out — but on a classifier version it's properly classified as external, and the helper registry recognizes `classMap` and `eq` as pure.
+
+2. **Make the items signal fire whenever `state.activeID` changes.** Re-assigning `state.items.set(state.items.get())` after each `state.activeID` mutation forces `each.update` to run, which calls `adoptServerItems`, which wires the per-item Reactions and registers their deps on `state.activeID` going forward. This is a one-time wire — you only need to nudge once after hydrate. Ugly but mechanically correct.
+
+3. **Force a re-mount of the each block** by wrapping it in a `{#rerender}` keyed on a version counter you bump on each `activeID` change. Throws away the per-item DOM and re-renders client-side — works but defeats hydration.
+
+The first option is the right user-land fix on a classifier-aware version; option 2 is the diagnostic that proves the diagnosis (if mutating items once unsticks the reactivity, you've confirmed the lazy-hydrate gate is the culprit). Option 3 is a hammer.
+
+## Why this is silent
+
+There is no error, no warning, no DevTools breadcrumb. The SSR'd DOM is correct, the hydration markers are clean, the items array is intact, the `state.activeID` signal mutates and any *direct* reaction to it fires. Only the per-item bindings are missing their subscriptions. The lazy-hydrate optimization trades correctness for the assumption that per-item bindings are item-local — and external-state reads inside per-item bindings violate that assumption invisibly.
+
+## Key files
+
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `each.hydrate`, the deferral gate, and `adoptServerItems`
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — `isEachContentSelfContained`, the static analyzer that decides lazy vs eager
+- `/home/jack/semantic/next/packages/renderer/test/unit/each-content-classifier.test.js` — coverage for item-local, external-read, and conservative-bail cases
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json
new file mode 100644
index 000000000..aee8bb003
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
+      "passed": true,
+      "evidence": "Section 'What the each block does on hydrate' explicitly frames it as 'a deliberate optimization at hydrate time' and dedicates a paragraph (lines 55-59) to the rationale: 'the common case... the per-item binding reads only iteration-local data, the server-rendered DOM is already correct, and there is nothing to react to at hydrate time. Wiring N Reactions for N items at hydrate just to have them never fire is wasted work on first paint. Defer them and pay only on the first real change.'"
+    },
+    {
+      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
+      "passed": true,
+      "evidence": "Lines 35-53 quote the relevant `each.hydrate` code with `lookupExpression(node.over)` registering the items-collection dep, and explicitly state: 'Wiring inner Reactions is deferred to a function called `adoptServerItems`, which runs the first time `update` fires (i.e. the first time the items signal changes after hydrate).'"
+    },
+    {
+      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
+      "passed": true,
+      "evidence": "Lines 97-99: 'The killer detail: the items signal's only chance to wake the per-item bindings is to itself fire. Your items are set once from a prop. They never mutate. So the deferred wire-up never happens.' Also reinforced in lines 84-89 walking the post-hydrate timeline."
+    },
+    {
+      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
+      "passed": true,
+      "evidence": "Lines 75-91 directly link the bug: '`state.activeID` is *external* to the iteration scope. The per-item attribute binding's Reaction is the thing that needs to subscribe to it... Nothing in the each block is subscribed to `state.activeID`. The block does not invalidate.... Class string stays at whatever the server rendered.'"
+    },
+    {
+      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
+      "passed": true,
+      "evidence": "Section 'The framework fix (commit 0df8d554e)' (lines 102-135) names the file `packages/renderer/src/engines/native/blocks/each-content-classifier.js`, describes the classifier walking the each's content AST to answer 'could any binding inside this each read external state?', and concludes 'The classifier returns false → `each.hydrate` calls `adoptServerItems` *now* instead of deferring.'"
+    },
+    {
+      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
+      "passed": false,
+      "evidence": "The answer says per-item Reactions 'subscribe to `state.activeID` on their first run' (line 134) and that adoptServerItems 'walks the existing DOM (matched up to server item markers by key) and creates per-item Reactions on the already-rendered nodes', which captures the spirit of evaluation-as-subscription. However, the specific `skipFirstWrite: true` mechanism is never named, nor is the explicit notion that the Reaction trusts the SSR'd DOM and skips its first write so as not to clobber the server output. The rubric calls for the named flag/mechanism."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md
new file mode 100644
index 000000000..d70d295b0
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md
@@ -0,0 +1,203 @@
+# Why the per-item class doesn't react after hydration
+
+## Short answer
+
+Your `{#each}` block's per-item attribute Reactions never wired against
+`state.activeID`. The render-time path that would have wired them is gated on
+the items signal firing — and your items collection is set once and never
+mutates, so the per-item bindings never get a chance to subscribe to the
+external state their helper depends on.
+
+The fix is one of:
+
+1. Upgrade to a framework version that includes the eager-hydrate classifier
+   (commit `0df8d554e`, "Bug: Hydrate each items eagerly when bindings read
+   external state"). With that fix, the each block notices that the per-item
+   binding reads external state via a non-framework helper (`getItemClasses`)
+   and wires per-item Reactions during `hydrate` instead of deferring to the
+   first items mutation.
+2. If you're stuck on an older version, force the items signal to fire once
+   after hydration so the deferred wire-up path runs, e.g.
+   `state.items.notify()` in `onRendered`, or trigger a no-op
+   `state.items.set(state.items.get())` once. This is a workaround, not the
+   intended pattern.
+
+The rest of this doc explains *why* the deferred-wire optimization exists and
+*why* your shape is the precise one that breaks it — that context matters
+because the same pattern keeps biting people whose data arrives at hydrate
+time rather than after.
+
+## What the each block does on hydrate
+
+The native engine's each block (`packages/renderer/src/engines/native/blocks/each.js`)
+makes a deliberate optimization at hydrate time. From `each.hydrate`:
+
+```js
+hydrate({ node, lookupExpression, ... }) {
+  // Always register a dep on the collection so future mutations invalidate.
+  lookupExpression(node.over);
+  self.hasHydrated = true;
+
+  // ... possibly bail and DEFER per-item wiring ...
+}
+```
+
+Two things happen on hydrate:
+
+1. The block registers a dependency on the *items collection* signal so a
+   future mutation to the items array will rerun the block.
+2. It does **not** wire per-item Reactions for inner content. Per-item DOM
+   already exists (the server emitted it, bracketed by `<!--sui-item:v1:KEY-->`
+   markers). Wiring inner Reactions is deferred to a function called
+   `adoptServerItems`, which runs the first time `update` fires (i.e. the
+   first time the items signal changes after hydrate).
+
+The reason for the defer: the common case is `{#each item in items}<span>{item.name}</span>{/each}`
+— the per-item binding reads only iteration-local data, the server-rendered
+DOM is already correct, and there is nothing to react to at hydrate time. Wiring
+N Reactions for N items at hydrate just to have them never fire is wasted work
+on first paint. Defer them and pay only on the first real change.
+
+This optimization is unsafe whenever a per-item binding reads anything outside
+the iteration scope.
+
+## Why your case breaks
+
+Your binding looks like this:
+
+```hbs
+{#each item in items}
+  <a class="{classMap getItemClasses item}">{item.title}</a>
+{/each}
+```
+
+Where `getItemClasses` is a method that calls `state.activeID.get()`.
+
+`state.activeID` is *external* to the iteration scope. The per-item attribute
+binding's Reaction is the thing that needs to subscribe to it, because that
+Reaction is what writes the `class` attribute back to the DOM when activeID
+changes.
+
+But on the deferred path, that per-item Reaction is never created. Walk
+through what happens after hydrate:
+
+- Hydrate runs. The block registers a dep on `items` and bails (deferring per-
+  item wiring).
+- You mutate `state.activeID`.
+- Nothing in the each block is subscribed to `state.activeID`. The block does
+  not invalidate. `update` does not run. `adoptServerItems` does not run. No
+  per-item Reaction was ever wired against `state.activeID`.
+- Class string stays at whatever the server rendered.
+
+Your sanity check (`reaction(() => console.log(state.activeID.get()))`) works
+because *that* reaction subscribed at creation time. The Reactions inside the
+each block — the ones that would write the class attribute — were never
+created.
+
+The killer detail: the items signal's only chance to wake the per-item
+bindings is to itself fire. Your items are set once from a prop. They never
+mutate. So the deferred wire-up never happens.
+
+## The framework fix (commit 0df8d554e)
+
+The fix is a static classifier
+(`packages/renderer/src/engines/native/blocks/each-content-classifier.js`)
+that runs once per unique each-content AST shape (cached on AST identity, so
+it's effectively free per component instance). It walks the each's content
+AST and answers one question: "could any binding inside this each read
+external state?"
+
+The classifier knows about:
+
+- Iteration-local names (`item`, `index`, `key`, `this`, plus whatever the
+  user named in `as` / `,index` / `,key`)
+- The framework's pure helpers (`classMap`, `classIf`, `formatDate`,
+  `concat`, ... — everything in `TemplateHelpers`)
+- JS reserved names (`true`, `false`, `null`, `typeof`, ...)
+
+For each expression, every bare identifier head must resolve to one of those
+sets. If anything else appears (a component method, a user-registered helper,
+a state name closed over by an inline expression), the classifier returns
+"not self-contained."
+
+For your expression `{classMap getItemClasses item}`, the tokens are:
+
+- `classMap` — pure helper, OK
+- `getItemClasses` — not in the iteration scope, not in the pure-helper
+  registry → classifier returns false (external reads possible)
+- `item` — iteration-local, OK
+
+The classifier returns false → `each.hydrate` calls `adoptServerItems` *now*
+instead of deferring. `adoptServerItems` walks the existing DOM (matched up
+to server item markers by key) and creates per-item Reactions on the
+already-rendered nodes. Those Reactions subscribe to `state.activeID` on
+their first run, and from that point on, mutations propagate.
+
+There is a regression test pinning exactly your shape:
+`packages/renderer/test/browser/ssr-hydration.test.js:315` — "helper-call
+attribute inside each is reactive after hydration when items pre-populated".
+Its docstring is a transcription of this entire failure mode — it was
+discovered in production from a docs-site `inpage-menu` that wouldn't update
+its active-section indicator on scroll.
+
+## Things that won't fix it (so you can rule them out)
+
+- Replacing `classMap` with `classIf` or string concat — same shape,
+  `getItemClasses` (or whatever non-framework function you call) is still the
+  external-state read.
+- Using `state.activeID.peek()` instead of `.get()` — peek explicitly opts
+  out of dependency tracking. You'd lose reactivity *to* activeID, not gain
+  it.
+- Wrapping the helper call in a parent reactive context (e.g. the component's
+  `onRendered`) — that doesn't propagate down into the per-item Reactions
+  because the per-item Reactions are what need to exist in the first place.
+- Switching the items prop from a plain array to a Signal — the items signal
+  *is* already a Signal under the hood. The issue is not the items channel,
+  it's that the per-item bindings haven't been wired yet.
+
+## Things that will fix it
+
+- **Preferred:** upgrade to the framework version with the classifier fix.
+  No code change required on your side; the classifier inspects your AST
+  and sees `getItemClasses` is not a framework helper, switches to the
+  eager path, and your binding starts reacting.
+- **Workaround on older versions:** force the items signal to fire once
+  after hydrate so the deferred wire-up runs:
+  ```js
+  onRendered() {
+    state.items.notify();   // wakes the each block's items dep,
+                            // which runs update, which calls
+                            // adoptServerItems, which wires per-item
+                            // Reactions on the existing DOM
+  }
+  ```
+  This is not the intended API — the canonical fix is the classifier — but
+  it works mechanically because it triggers the same `adoptServerItems` path
+  that the classifier triggers eagerly.
+- **Workaround that sidesteps the each entirely:** lift the
+  state-dependent class to an attribute on the per-item *element* that uses
+  `data-active="{is item.id state.activeID}"` and style off `[data-active]` in
+  CSS, *if* you don't actually need a class. This works because the
+  attribute binding still goes through the same Reaction path — but on
+  versions without the fix it has the same problem. Don't do this; upgrade.
+
+## What to actually look at first
+
+Before assuming this is the bug, confirm:
+
+1. The component is hydrating, not full-rendering on the client. If
+   `el.shadowRoot` is missing on connect, hydration didn't run and you're
+   on the fresh-render path, which always wires Reactions. Check that your
+   server output includes `<template shadowrootmode="open">` and that
+   nothing strips it before the browser parses it.
+2. The classifier's caching is on AST identity (`WeakMap<ASTNode, boolean>`).
+   If you have two components that share an AST shape but only one of them
+   has an external-state helper, the one classified first wins for both —
+   but in practice each `defineComponent` call produces its own AST, so this
+   is unlikely to be your issue.
+3. If you registered `getItemClasses` via `Template.registerHelper` *before*
+   the classifier module first loaded, the classifier will see it as a pure
+   helper (because `PURE_HELPERS = new Set(Object.keys(TemplateHelpers))`
+   captures the registry once at module init). Define it as a component
+   method or inline `createComponent` field instead — that's how the
+   regression test fixture writes it, and it's the canonical pattern.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json
new file mode 100644
index 000000000..6dd313e6a
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
+      "passed": true,
+      "evidence": "Stated explicitly: 'Relative noise is `absolute_jitter / bench_duration`, so it scales inversely with how long the bench takes' and 'The floor is a function of duration, not sample count.'"
+    },
+    {
+      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
+      "passed": true,
+      "evidence": "Reproduces the table verbatim under 'Why the floor is ±28%': '~2ms | ±10-20%', '~10ms | ±2-5%', '~50ms+ | ±1% or tighter' (with the ~6ms row added for context)."
+    },
+    {
+      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
+      "passed": true,
+      "evidence": "States: 'Per-sample timing jitter on a CI runner — OS scheduling, GC pauses, JIT recompilations — is roughly constant in absolute terms, typically σ≈1-2ms.' Note: the rubric says 'typically sub-millisecond' while the answer says σ≈1-2ms; the qualitative claim (constant absolute jitter, named sources) matches."
+    },
+    {
+      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
+      "passed": true,
+      "evidence": "States: 'At 6ms, ~2ms of absolute jitter is ~33% relative — exactly where your ±28% lives' and explicitly: 'Even pushing `sampleSize` to 200+ would only narrow the CI within the noise floor — it would not push *below* it. The floor is a function of duration, not sample count.'"
+    },
+    {
+      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
+      "passed": true,
+      "evidence": "Section 'What to change about the bench' recommends amplifying per-sample work; option 1: 'Bump item count (most reliable) ... 1000 items ... pushes it into the 50-100ms range where ±1% becomes resolvable.' Concrete next step: 'Bump items to 1000.'"
+    },
+    {
+      "text": "F: Optionally references the perf-improvement skill or `improve-performance` workflow as the source for this methodology",
+      "passed": true,
+      "evidence": "References section explicitly cites 'ai/skills/workflows/contributing/improve-performance.md — duration/noise table, tuning-knob semantics' and also 'ai/skills/contributing/read-bench-report.md'."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md
new file mode 100644
index 000000000..e535c0b6d
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md
@@ -0,0 +1,86 @@
+# Why your 6ms hydrate bench can't see the fix — and what to change
+
+## Short answer
+
+A ±28% noise floor on a 6ms bench means tachometer is correctly reporting that the measurement *cannot resolve* changes smaller than ~28%. This isn't a tachometer bug, a sample-size problem, or a config-tuning problem — it is the physical floor of what a 6ms wall-clock bench can detect on a CI runner. Your fix may be very real; the bench is simply too short to see it.
+
+The fix is **not** to crank `sampleSize` or tighten `autoSampleConditions`. The fix is to **amplify per-sample work** so the bench duration moves into a band where small relative changes survive the absolute jitter floor.
+
+---
+
+## Why the floor is ±28%
+
+Per-sample timing jitter on a CI runner — OS scheduling, GC pauses, JIT recompilations — is roughly **constant in absolute terms**, typically σ≈1-2ms. Relative noise is `absolute_jitter / bench_duration`, so it scales inversely with how long the bench takes:
+
+| Bench duration | Expected relative noise floor |
+|---|---|
+| ~2ms  | ±10-20% |
+| ~6ms  | ~±25-30% (your bench) |
+| ~10ms | ±2-5% |
+| ~50ms+ | ±1% or tighter |
+
+At 6ms, ~2ms of absolute jitter is ~33% relative — exactly where your ±28% lives. The reporter's `Expected Noise` column predicts this from duration, and your bench's CI width matches it. That's the diagnostic signal: **observed CI ≈ expected noise floor → bench is noise-floor-limited, not under-sampled.**
+
+Why this is not a sampling problem:
+- The 95% CI is built from sample variance. Tachometer's `autoSampleConditions` only controls the *resolution it chases* — it doesn't relax the CI itself. Asking for ±1% on a 6ms bench means tachometer keeps sampling until it hits `timeout`, then gives up "Unsure."
+- Sample-size scaling is √N. To halve a CI you need 4× samples, and per-config wall-clock time grows accordingly. Even pushing `sampleSize` to 200+ would only narrow the CI within the noise floor — it would not push *below* it. The floor is a function of duration, not sample count.
+
+---
+
+## What to change about the bench
+
+Increase per-sample work until duration is in the ±2-5% band (~10ms+), ideally toward ±1% (~50ms+). Three knobs, in order of preference:
+
+### 1. Bump item count (most reliable)
+
+The canonical hydrate bench at `packages/component/bench/tachometer/bench-hydrate.js` uses **1000 items**, not 100, despite the metric being named `hydrate-each-100`. The name is historical; the size was chosen to push the measure window past the noise floor. A 100-item list typically produces a 5-10ms hydrate; a 1000-item list pushes it into the 50-100ms range where ±1% becomes resolvable.
+
+If you copied the `-100` naming from another bench, leave the metric name alone — what matters is that the per-sample workload is large enough.
+
+### 2. Split mount vs. first-data-change into separate windows
+
+The canonical bench measures hydration in two distinct `performance.measure` windows:
+
+- `hydrate-each-100-mount` — DSD parse + `connectedCallback` + the hydrate microtask + the post-hydrate rAF. This catches regressions that move per-item wiring earlier (e.g. an eager `adoptServerItems` in `each.hydrate`).
+- `hydrate-each-100` — the first-data-change adoption pass after mount. This catches regressions in the AST→entries cache (`renderer.js buildStringCache`) — on a cache miss the path reverts to a full `buildHTMLStringPure` per item.
+
+If your fix targets only one of these phases, putting them in one combined measure dilutes the signal. Split them — and pick the window that contains your fix.
+
+### 3. Loop the operation N times inside one `performance.measure`
+
+If item count is fixed by what you're benching, loop the hydration cycle N times inside a single measure. A 100-item × 10-cycle measure gets you the same ~60ms duration as a 1000-item × 1-cycle one, with the same noise-floor benefit. The mount path needs `setHTMLUnsafe` each iteration (not `innerHTML` — that does *not* process DSD, see below) and a fresh container.
+
+---
+
+## Don't reach for these (they look like the fix, but aren't)
+
+- **Cranking `sampleSize` past 50** — narrows CI inside the floor, doesn't lower the floor. Wastes per-config timeout budget.
+- **Tightening `autoSampleConditions` to `["1%"]` or `["0%"]`** — tells tachometer to keep chasing resolution it physically can't reach. The run burns its `timeout` and emits Unsure verdicts. Set the threshold *above* the predicted noise floor, not below it.
+- **Re-running the bench expecting noise to "settle"** — it won't. The floor is inherent to the duration; subsequent runs will look the same.
+- **Trusting the cross-session "regressed from peak" column** — that comparison operates on absolute ms across runs on different runner conditions and produces phantom regressions on PRs that didn't change perf. Read the within-session `vs main` column. (The schema_v2 reporter overhaul addresses this.)
+
+---
+
+## Sanity check before you re-bench
+
+When `tachometer` says "no meaningful change," confirm the bench is actually exercising the hydrate path you changed. Two silent failure modes — both common, both produce a bench that "works" while measuring the wrong thing — are worth verifying before scaling up:
+
+1. **`innerHTML` doesn't process Declarative Shadow DOM.** Only `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) attaches the shadow root from `<template shadowrootmode="open">`. If your bench uses `innerHTML`, the custom element's `shadowRoot` is `null` when `connectedCallback` fires, `hasServerContent` is false, and the element falls through to `fullRender` instead of `hydrate`. Your bench measures fresh client render.
+
+2. **`renderToString` returns an empty body in browser test env unless `Template.isServer = true`.** That flag is set once at module load from `typeof window === 'undefined'`. In Chrome (which is where tachometer runs), it's `false`, the client `Renderer` is selected, and the DSD wrapper is emitted around an empty string. The canonical `bench-hydrate.js` sidesteps this by driving `ServerRenderer` directly off the cloned template's AST in the browser — note the lack of a top-level `renderToString` call. If you're calling `renderToString` from the bench, wrap it in a `try/finally` that toggles `Template.isServer`.
+
+If either of these is in play, your fix never had a chance to register because the bench was never running the hydrate code path. Verify the SSR'd HTML contains hydration markers (`<!--sui:v1:N-->` / `<!--sui-block:v1:N-->`) and that the post-DSD shadow root is non-empty before any JS runs.
+
+---
+
+## Concrete next step
+
+Bump items to 1000 (or loop the 100-item op 10×), re-run, and confirm the `Expected Noise` column drops into the ±1-3% range. Then your real fix should be visible — or the bench will tell you, with statistical confidence, that it isn't.
+
+## References
+
+- `packages/component/bench/tachometer/bench-hydrate.js` — canonical 1000-item dual-window pattern
+- `ai/skills/authoring/ssr-hydration.md` — Gotcha 3 (noise floor scaling) and Gotchas 1-2 (silent-failure traps)
+- `ai/skills/workflows/contributing/improve-performance.md` — duration/noise table, tuning-knob semantics
+- `ai/skills/contributing/read-bench-report.md` — how to read `Expected Noise` vs. observed CI width in the reporter
+- `tools/ci/bench/reporter/reporter.js` — the `Expected Noise` column emitter
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json
new file mode 100644
index 000000000..49042e3c0
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json
@@ -0,0 +1,34 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
+      "passed": true,
+      "evidence": "Opening lines state 'absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and ±X% is just (constant ms) / (your duration)'. Summary repeats: 'duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter'. Inverse scaling is explicitly named."
+    },
+    {
+      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
+      "passed": true,
+      "evidence": "Provides a concrete table of measured durations vs predicted ±% half-widths (7.4ms = ±10.6%, 13.7ms = ±5.7%, 12.6ms = ±6.2%, 16.2ms = ±4.8%) and states '≥ 30 ms (predicted ±2.6%) to comfortably clear the ±2% noise floor'. Also derives ±26% at 6ms. The bands map to the rubric's tiers (short = ±10-20%, ~10ms = ±2-5%, longer = ±1%)."
+    },
+    {
+      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
+      "passed": true,
+      "evidence": "Explicitly explains 'absolute per-sample jitter is roughly constant' and lists 'system jitter (scheduling, GC, JIT)' as the cause. Notes σ ≈ 2 ms on GHA runners (slightly above sub-millisecond but the constant-absolute physics is clearly stated). The 'roughly constant in absolute terms' point is made repeatedly."
+    },
+    {
+      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
+      "passed": true,
+      "evidence": "Computes ±26% predicted at 6ms, explains observed ±28% is at the noise-floor-limited boundary, and explicitly states in option 4: 'Don't bump sampleSize — diminishing returns... 4× the wall-clock time gets you from ±28% to ±14%' and 'Width comes from duration, not from sample count beyond a point.'"
+    },
+    {
+      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
+      "passed": true,
+      "evidence": "Option 1 recommends 'Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo.' Cites bench-hydrate.js using n=1000 items as the existing pattern to copy. Targets ≥30 ms / ±2.6%."
+    },
+    {
+      "text": "F: Optionally references the perf-improvement skill or improve-performance workflow as the source for this methodology",
+      "passed": false,
+      "evidence": "Answer references reporter.js, bench-history.json, bench-todo.js, and bench-hydrate.js as sources, but does not name the perf-improvement skill or improve-performance workflow. This is an optional expectation but per the rubric's literal wording it is not satisfied."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md
new file mode 100644
index 000000000..ddec432ec
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md
@@ -0,0 +1,94 @@
+# Why a 6 ms hydration bench can't see your improvement
+
+Short version: at ~6 ms duration, the bench is running below the resolution floor of the CI runner. The noise floor isn't `±28%` because tachometer is misconfigured — it's that wide because absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and `±X%` is just `(constant ms) / (your duration)`. Fix the noise floor by making the bench longer in absolute time, not by tuning tachometer.
+
+## The math the reporter is using
+
+The bench reporter at `/home/jack/semantic/next/tools/ci/bench/reporter/reporter.js` encodes the model explicitly (lines 49–90):
+
+```js
+const NOISE_FLOOR = 2;           // percent — matches autoSampleConditions
+const SIGMA_ABS_MS = 2;          // empirical per-sample σ on GHA runners
+
+function expectedNoisePp(meanMs) {
+  // From SE-of-the-difference of two means at n=50, z=1.96:
+  //   abs_CI_width ≈ 2 * 1.96 * sqrt(2) * σ / sqrt(50) ≈ 0.784 * σ
+  //   pct_width   = abs_CI_width / mean * 100
+  return (0.784 * SIGMA_ABS_MS) / meanMs * 100;
+}
+```
+
+Plug in `σ = 2 ms`, `mean = 6 ms`:
+
+- `abs_CI_width ≈ 0.784 × 2 = 1.568 ms`
+- `pct_width = 1.568 / 6 × 100 ≈ 26%`  → reported as **±13%** (half-width on each side)
+
+You're seeing **±28%** observed. That is `~2.1×` the duration-derived expected width — right at the boundary of what the reporter classifies as `noise-floor-limited` vs `unsure` (`NOISE_RATIO_TOLERANCE = 2` at line 62). So tachometer is honest: at this duration, on these runners, the measurement can't see anything smaller than roughly ±15–30% of the mean. A 1 ms improvement on a 6 ms bench is well below that.
+
+This is exactly why your CI is "no meaningful change" — `NOISE_FLOOR = 2`% (line 49) demands the CI live entirely outside `[-2%, +2%]` to be classified `faster`/`slower`. Your CI straddles ±2% wider than the noise floor allows it to resolve, so the reporter buckets it into `noise-floor-limited` (file `reporter.js`, lines 220–225):
+
+```js
+function classify([low, high], ratio) {
+  if (high < -NOISE_FLOOR) { return 'faster'; }
+  if (low > NOISE_FLOOR)   { return 'slower'; }
+  if (low > -NOISE_FLOOR && high < NOISE_FLOOR) { return 'within-noise'; }
+  return ratio <= NOISE_RATIO_TOLERANCE ? 'noise-floor-limited' : 'unsure';
+}
+```
+
+## The "Too Fast to Measure Precisely" bucket exists for this exact case
+
+When you read the rendered comment, your bench should be sitting under `🔍 Unsure → Too Fast to Measure Precisely`. The header copy (rendered from `reporter.js` lines 384–402) literally says:
+
+> On benches this short, system jitter (scheduling, GC, JIT) masks sub-4% changes; larger deltas still resolve cleanly.
+
+That row exists specifically to tell the author "this isn't a verdict, this is a 'your bench is too short' diagnostic." Don't trust the noise classification as a refutation of your fix — trust it as a request to amplify the bench.
+
+## What the existing benches do — copy this pattern
+
+The existing hydrate bench at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js` already runs at `n=1000` items (line 99: `const itemsForMount = makeItems(1000)`), not 100. Recent main-history numbers confirm what that buys you:
+
+| metric | mean | predicted ±% half-width | resolves? |
+|---|---|---|---|
+| `hydrate-helper-100-mount` | 7.4 ms | ±10.6% | borderline |
+| `hydrate-each-100-mount` | 13.7 ms | ±5.7% | yes |
+| `hydrate-each-100` | 12.6 ms | ±6.2% | yes |
+| `hydrate-helper-100-state-change` | 16.2 ms | ±4.8% | yes |
+
+Source: `/home/jack/semantic/next/tools/ci/bench/reporter/bench-history.json` (the `271be03` commit entry near line 1584).
+
+Note even `hydrate-helper-100-mount` at 7.4 ms is the noisiest of the four because it's the shortest. The larger ones are the ones that resolve cleanly. **You want to be ≥ 30 ms** (predicted ±2.6%) to comfortably clear the ±2% noise floor — that's the inflection point where small changes get classified.
+
+The `bench-todo.js` author at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-todo.js` calls this strategy out explicitly in line comments:
+
+- Line 275: `// 20 alternating toggle-all invocations on a 100-item list — amplified // so the measurement clears the σ≈2ms per-sample noise floor on CI.`
+- Line 290: `// Each position's ~10ms per-delete workload clears the σ≈2ms floor.`
+- Line 361: `// List scaled to 500 (250 marked completed) so the single clearCompleted // operation is large enough to clear the σ≈2ms per-sample noise floor.`
+- Line 333–335: `// 10× loop (vs 5× for the front/back variants) — middle removal's // O(N/2) scan has wider per-sample variance, so 5× landed at ~74ms // with observed CI straddling ±2%. 10× brings it to ~148ms / ±1%.`
+
+These are the same change you should make.
+
+## Concrete options for your bench, ranked
+
+**1. Scale the workload up (preferred).** Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo. If your fix is in per-item work (e.g. `hydrateInnerContent`, `adoptServerItems`), 1000 items multiplies its weight by 10× without changing what you're measuring. Keep the metric name describing items measured, not items rendered, if you want comparability — but in this repo most names already include the count (e.g. `hydrate-each-100` actually mounts 1000 items per the comment at line 99).
+
+**2. Loop the operation N times inside one `performance.measure` window.** This is what `toggle-all-20` and `remove-10-middle` do. If hydration itself isn't loopable (you only mount once), then loop the *follow-up data change* that exercises the codepath you fixed. The existing bench does this already with `hydrate-each-100` — measures the post-mount `setItems(...)` call rather than mount itself.
+
+**3. Add a separate amplified metric instead of replacing.** Keep the realistic 100-item bench for human readability of the duration, and add a 1000-item variant with the same shape for measurement precision. Both metrics ship; the reporter handles either.
+
+**4. Don't bump `sampleSize` — diminishing returns.** Going from `sampleSize: 50` to `200` only narrows the CI by `√(50/200) = 0.5×`. So 4× the wall-clock time gets you from ±28% to ±14%. Compare to scaling the workload 5× (6ms → 30ms), which gets you from ±28% to ±5% with no extra wall-clock cost. Sample-size tuning is the wrong knob for short benches.
+
+**5. Don't tighten `autoSampleConditions`.** Currently `["2%"]` — that's the *target* CI width for tachometer's auto-sampler. Tightening it to `["1%"]` just makes tachometer keep sampling until either it converges (it can't, because the underlying jitter is absolute-constant, not relative) or it hits `timeout: 3` minutes and gives up with the same wide CI. The `tachometer-todo.json` non-CI variant uses `["0%", "10%"]` which means "sample until <10% relative width OR a 0% target" — also wrong choice for short benches. Width comes from duration, not from sample count beyond a point.
+
+## Verifying your fix saved time at all
+
+If you want to know whether the fix is real before investing in bench amplification:
+
+- Run the bench locally with `--manual` or via the CI HTML harness, open DevTools, and use the Performance panel — a 1 ms saving on a 6 ms operation is visible in a flame graph even when it's invisible to tachometer at n=50.
+- Add a `console.time('hydrate')` / `console.timeEnd('hydrate')` around the codepath, run it 10 times locally, eyeball the median — if you see 5 ms vs 6 ms consistently, the fix is real and the bench is just under-resolved.
+
+Then commit the bench amplification as a separate change so the perf comment on your fix's PR can show a `faster` row instead of `noise-floor-limited`.
+
+## Summary
+
+The noise floor is wide because `1.568 ms / 6 ms ≈ 26%`. That's not a bug or a tachometer config issue — it's the duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter on this runner, and the reporter at `tools/ci/bench/reporter/reporter.js` documents it explicitly. The fix is to amplify the bench duration to ≥ 30 ms (loop the op, scale items, or both), exactly as the existing `bench-todo.js` and `bench-hydrate.js` already do. Don't reach for `sampleSize` or `autoSampleConditions` — neither addresses the underlying `(constant ms) / duration` problem.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json
new file mode 100644
index 000000000..3c6d9ad37
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
+      "passed": true,
+      "evidence": "Opens with 'This is the **lazy each-block hydration** trap' and frames it as a deferred per-item Reaction wiring problem rather than a snippet-specific bug. Step 5 explicitly distinguishes that pushing a new array fires the outer Reaction while mutating items[0] in place doesn't invalidate anything — directly mirroring the each.hydrate deferral framing."
+    },
+    {
+      "text": "B: Explains that snippet args (label=item.name) are evaluated by the per-item content path; the snippet body sees those args via buildSnippetProxy",
+      "passed": true,
+      "evidence": "Step 4: 'wraps the badge's snippet invocation hydrate hook... wrapped in Reactions whose compute function reads `label` through the snippet-arg proxy (`buildSnippetProxy` at `template.js:67`), which re-evaluates `item.name` against the item context's reactive data channel.' Names buildSnippetProxy and the snippet-arg threading explicitly."
+    },
+    {
+      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
+      "passed": true,
+      "evidence": "Step 4: 'Without that adoption pass, **none of those Reactions exist.** The text node containing `[first]` is just static text on the page; nothing is observing `item.name` to write to it.' Step 5 reinforces: 'writing `items[0].name = \"second\"`... doesn't invalidate anything observing that text node.'"
+    },
+    {
+      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
+      "passed": true,
+      "evidence": "'Why the snippet matters specifically' section: 'The classifier in `each-content-classifier.js` walks the per-item content AST and bails to \"external\" (forcing eager wiring) on cross-AST nodes — `template`, `snippet`, `rerender`, `guard`, `async` (lines 189-194 of that file).' Also notes 'snippet → bail to eager → adoption wires the snippet's interior bindings.'"
+    },
+    {
+      "text": "E: Mentions the existing test 'snippet with named args inside each is reactive after hydration' (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
+      "passed": true,
+      "evidence": "Multiple references to PR #175: 'Worth checking your branch is on PR #175 or later — the snippet-bail test was unskipped there.' And later: 'Branch predates PR #175 — `each.hydrate` doesn't consult the classifier at all and stays unconditionally lazy. The snippet-arg-in-each test was unskipped in that PR; before it, this exact case was a known silent-failure bug.'"
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md
new file mode 100644
index 000000000..d59a2c264
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md
@@ -0,0 +1,52 @@
+# Snippet-with-args inside `{#each}` after SSR + hydrate: stale label
+
+## Short answer
+
+This is the **lazy each-block hydration** trap. After SSR, `each.hydrate` registered a Reaction on `items` (the collection) but **never wired the per-item Reactions** that would track `item.name`. Pushing a new array fires the outer Reaction (you see new DOM), but mutating `items[0].name` has nothing to invalidate, because the binding inside the badge snippet (`{label}` resolving to `item.name`) was never wrapped in a Reaction.
+
+The classifier that's supposed to upgrade this case to eager wiring exists (`each-content-classifier.js`) and explicitly bails on snippet invocations — but only if it is reached and operating as documented. The symptoms you describe match exactly what happens when the bail does *not* fire (or fires but `adoptServerItems` returns false): per-item Reactions stay un-wired, external/snippet bindings lose reactivity. Worth checking your branch is on PR #175 or later — the snippet-bail test was unskipped there.
+
+## What the framework is actually doing, step by step
+
+1. **Server render.** `ServerRenderer` walks the AST. The each block emits its open/close markers and per-item `<!--sui-item:v1:KEY-->` markers. The snippet invocation `{>badge label=item.name}` is evaluated inline — `item.name` resolves to `"first"` and the badge's `<span>[{label}]</span>` is rendered with `label = "first"`. No JS runs in the SSR snippet path; it's pure string concatenation with markers wrapping the dynamic text node.
+
+2. **Browser parse.** DSD inflates. You see `<span>[first]</span>` for item 0 immediately.
+
+3. **Hydration of the each block.** `each.hydrate` (`packages/renderer/src/engines/native/blocks/each.js:646`) does two things:
+   - `lookupExpression(node.over)` — registers a dep on `items`. **This is the only Reaction wired for the block at this point.** That's why pushing a new array fires reactivity (the outer Reaction sees the items signal change), and that's why `update` runs and you see new DOM.
+   - Consults `isEachContentSelfContained(node)` (`each-content-classifier.js`). If true → `return` (stay lazy, no per-item Reactions). If false → call `adoptServerItems` immediately to walk the server's per-item DOM and wire per-item Reactions in place.
+
+4. **Per-item bindings wire only in the eager path.** `adoptServerItems` walks `<!--sui-item:v1:KEY-->` markers, builds the per-item data context with the item-context proxy, and calls `hydrateInnerContent` — which calls `hydrateMarkers` against the inner ASTthat triggers the badge's snippet invocation hydrate hook. That's where `<!--sui:v1:N-->` markers around the snippet's `{label}` text get wrapped in Reactions whose compute function reads `label` through the snippet-arg proxy (`buildSnippetProxy` at `template.js:67`), which re-evaluates `item.name` against the item context's reactive data channel.
+
+   Without that adoption pass, **none of those Reactions exist.** The text node containing `[first]` is just static text on the page; nothing is observing `item.name` to write to it.
+
+5. **Why pushing a new array still updates the DOM but mutating `items[0].name` doesn't.** The outer Reaction on `items` is wired (step 3a). Pushing a new array → items signal fires → `each.update` runs → reconcile builds DOM for new items (and that fresh-render path *does* wire per-item Reactions for the newly-created items via the normal render flow). But the existing item 0's DOM was adopted from SSR and **its per-item Reactions never wired**, so writing `items[0].name = "second"` (or even replacing items[0] with a new object that has the same key) doesn't invalidate anything observing that text node.
+
+## Why the snippet matters specifically
+
+The classifier in `each-content-classifier.js` walks the per-item content AST and bails to "external" (forcing eager wiring) on cross-AST nodes — `template`, `snippet`, `rerender`, `guard`, `async` (lines 189-194 of that file). The reason: the snippet's body lives in a *separate AST*, and the classifier doesn't recurse into it. Even if your snippet's body only reads its arg, the arg expression (`label=item.name`) is evaluated inside the per-item content path against the parent scope's data context, threaded through `buildSnippetProxy`'s lazy getters — and those getters are only re-invoked when the per-binding Reactions inside the snippet's text node fire. Those Reactions only exist if per-item adoption happened. So snippet → bail to eager → adoption wires the snippet's interior bindings.
+
+If your bug is reproducing this on a branch with the classifier in place, the most likely failure modes are:
+
+- The classifier ran but returned `true` (treated as self-contained). Walk the AST node it was given for this each — confirm the snippet invocation appears as a `node.type === 'snippet'` (or `'template'`) child. If it's classified as something else, the bail doesn't trigger.
+- The classifier returned `false` but `adoptServerItems` returned `false` (couldn't find matching `sui-item:v1:KEY` markers — key mismatch between server and client item IDs). Look at `getItemID` (`each.js:42`) — keys are stringified, server emits string keys; if your client items have e.g. numeric `id` and the SSR pass produced numeric-string keys, they should match, but a mismatch silently falls through to fresh render on `update`, not on `hydrate`. On `hydrate` failure there's no fallback render — the existing DOM stays as-is and Reactions don't wire.
+- Branch predates PR #175 — `each.hydrate` doesn't consult the classifier at all and stays unconditionally lazy. The snippet-arg-in-each test was unskipped in that PR; before it, this exact case was a known silent-failure bug.
+
+## What to check, in order
+
+1. `git log --oneline packages/renderer/src/engines/native/blocks/each-content-classifier.js` — confirm the file exists on your branch and PR #175 is in your history.
+2. In a debugger, set a breakpoint on `isEachContentSelfContained` and confirm it returns `false` for your each AST node. If true → the snippet child isn't being classified as `snippet`/`template` (parser issue, not a hydrate issue).
+3. If false, breakpoint on `adoptServerItems` inside `each.hydrate` and confirm it runs and returns `true`. If it returns `false`, check your server-emitted `<!--sui-item:v1:KEY-->` keys against the client item IDs (`getItemID` output) — mismatched keys is the silent-failure mode here.
+4. As a sanity check that the per-item Reactions are the missing piece: replace the snippet with inline content (`<span>[{item.name}]</span>`) and re-test. That should *also* fail under the same lazy assumption (well, no — inline content with explicit `as` and item-only reads is "self-contained" so it stays lazy and would have the same symptom — but the symptom would attribute to "lazy each, items signal never fires because we mutated items[0] in place" rather than "snippet bail didn't trigger"). To confirm it's specifically the snippet path: replace the inner content with `<span>{state.somethingExternal}</span>` — that should bail eager via the identifier check and your per-item Reactions should wire and update.
+
+## Fixing the immediate symptom (workarounds, in order of preference)
+
+1. **Notify the items signal after mutation.** `state.items.notify()` (or assign through a `.set` that triggers it) after `items[0].name = "second"`. This forces the outer Reaction to fire, which on the second invocation flows through `each.update`'s adoption path (which *does* try to wire per-item Reactions). This is the cheapest fix and works without any framework changes.
+2. **Replace the item, don't mutate it.** `state.items[0] = { ...items[0], name: "second" }` then `notify()`, or use the array helper `state.items.set(0, { ...items[0], name: "second" })`. Same idea — gives the items signal a top-level identity change to fire on.
+3. **If you can't change the mutation pattern**, the framework-level fix is what PR #175 already does: ensure your branch has the classifier and that it bails on snippet invocations. If it does and the bug still reproduces, that's a real bug — file with the AST shape and the SSR'd HTML and we can trace whether the classifier or the adoption pass is the failure point.
+
+## Key files
+
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `each.hydrate` at line 646; `adoptServerItems` at line 505
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — bail set; snippet/template at lines 189-194
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/template.js` — `buildSnippetProxy` at line 67; snippet hydrate path at line 220
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json
new file mode 100644
index 000000000..ac9a6b11d
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json
@@ -0,0 +1,29 @@
+{
+  "expectations": [
+    {
+      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
+      "passed": false,
+      "evidence": "The answer correctly identifies that the bug is not snippet-specific ('this isn't snippet-specific — any expression inside the each body that reads item.<prop> would hit the same bug'), but it diagnoses a fundamentally different root cause: a propsSnapshot === null edge case in adoptServerItems, not the each-hydrate deferral of per-item Reaction wiring. The answer asserts the snippet wiring is correct and per-item Reactions are properly wired against itemSignal during adoption — directly contradicting the deferral-as-root-cause framing of eval 2. Misses the connection to the same root cause."
+    },
+    {
+      "text": "B: Explains that snippet args (label=item.name) are evaluated by the per-item content path; the snippet body sees those args via buildSnippetProxy",
+      "passed": true,
+      "evidence": "Answer explicitly explains: 'Snippet args (label=item.name) become lazy getters captured by buildSnippetProxy (packages/renderer/src/engines/native/blocks/template.js:67-114). The snippet body's {label} reactive text-node Reaction reads snippetData.label, which calls the captured getter () => evaluator.lookupExpressionValue(item.name, itemProxy)...'. Identifies buildSnippetProxy and the per-item arg evaluation path."
+    },
+    {
+      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
+      "passed": false,
+      "evidence": "The answer takes the opposite position: 'So the text-node Reaction inside the snippet body does end up depending on the per-item itemSignal. The wiring is fine.' It claims the Reactions ARE wired and the bug is downstream (propsSnapshot/notify gating). Does not identify unwired per-item Reactions as the cause."
+    },
+    {
+      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
+      "passed": false,
+      "evidence": "The answer references each-content-classifier ('confirms eager hydration is forced when an each contains a template (snippet) node, so adoptServerItems is what runs during hydrate (line 189-194)') but positions this as confirming the path that exposes the bug, not as the fix. The proposed fix is to populate propsSnapshot in adoptServerItems — a completely different remediation than 'force eager adoption via classifier bail-out.'"
+    },
+    {
+      "text": "E: Mentions the existing test 'snippet with named args inside each is reactive after hydration' (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
+      "passed": true,
+      "evidence": "Answer references 'the existing snippet with named args inside each test' at packages/renderer/test/browser/ssr-hydration.test.js:1408-1433, noting it 'uses a new object ref and therefore doesn't catch this.' Identifies the existing scenario test even if framing it as a near-miss rather than the regression test PR #175 unskipped."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md
new file mode 100644
index 000000000..75b56128b
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md
@@ -0,0 +1,85 @@
+# What's happening
+
+The framework's snippet wiring is correct here — the bug you're hitting is a stale-snapshot edge case in `each`'s post-hydration reconcile path, not a snippet-arg reactivity hole. Specifically: the **first** post-hydration in-place mutation of an item slips through silently. The second mutation onwards updates the DOM normally.
+
+## The intended path
+
+For your template:
+
+```
+{#each item in items}<div>{>badge label=item.name}</div>{/each}
+```
+
+Reactivity flows like this:
+
+1. **Each block** wraps each item in a `Signal` (`itemSignal`) holding `{ item, index }`. A `Proxy` (`createItemDataProxy` in `packages/renderer/src/engines/native/blocks/each.js:129-144`) sits over the parent data and routes `data.item` lookups through `itemSignal.value`, which registers an `itemSignal` dep on whoever's reading.
+2. **Snippet args** (`label=item.name`) become **lazy getters** captured by `buildSnippetProxy` (`packages/renderer/src/engines/native/blocks/template.js:67-114`). The snippet body's `{label}` reactive text-node Reaction reads `snippetData.label`, which calls the captured getter `() => evaluator.lookupExpressionValue('item.name', itemProxy)`, which goes through the each's item-proxy and registers `itemSignal` as a dep on the text node's Reaction.
+
+So the text-node Reaction inside the snippet body **does** end up depending on the per-item `itemSignal`. The wiring is fine. The problem is whether `itemSignal.notify()` actually fires when you mutate in place.
+
+## The bug — `propsSnapshot` is `null` after adoption
+
+When you replace `state.items` with `state.items.set([...items])`, the items signal fires and `each.update` runs. For records whose `item` reference and index are unchanged (your case — same object, just a mutated `.name`), the equality gate inside `Signal.set` short-circuits because the wrapper `{ item, index }` looks identical by `===` (same item ref). To get around that, `each` keeps a `propsSnapshot` of each item's top-level props and shallow-compares on every reconcile to decide whether to call `itemSignal.notify()` manually:
+
+```js
+// packages/renderer/src/engines/native/blocks/each.js:396-422 (Phase 3)
+if (rec.item !== item || rec.index !== i) {
+  rec.itemSignal.set(getEachData(...));
+  ...
+  rec.propsSnapshot = createSnapshot(item);
+}
+else if (typeof item === 'object' && item !== null) {
+  if (rec.propsSnapshot === null) {
+    // "Fresh record (first reconcile after createRecord). Bindings
+    //  were wired synchronously against the signal's value; there's
+    //  no stale subscriber to wake."
+    rec.propsSnapshot = createSnapshot(item);
+  }
+  else if (refreshSnapshotAndDetect(rec.propsSnapshot, item)) {
+    rec.itemSignal.notify();
+  }
+}
+```
+
+That `propsSnapshot === null` branch assumes "no notify needed because we just wired the bindings against the current item value." That assumption is true for records produced by `createRecord` inside the same `reconcile` call (CSR, or post-hydration replacements), but it is **wrong** for records produced by `adoptServerItems` during hydration, because:
+
+- Adoption wires Reactions at hydrate time against the item's hydration-time `.name` (`'Apple'`).
+- The records are pushed with `propsSnapshot: null` (`packages/renderer/src/engines/native/blocks/each.js:583`).
+- Some unspecified time later, your code mutates `items[0].name = 'Cherry'` and pushes a new array.
+- `update` runs `reconcile`. Phase 3 sees `rec.item === items[0]` (still the same ref), index unchanged, and `propsSnapshot === null` — so it takes the "fresh record" branch, snapshots `{ name: 'Cherry' }` for next time, and **does not call `notify()`**.
+- The badge stays showing `[Apple]`.
+
+If you mutate again (`items[0].name = 'Date'`), `refreshSnapshotAndDetect` compares against the now-populated snapshot (`'Cherry' !== 'Date'`), fires `notify()`, and the DOM updates to `[Date]` — skipping the `'Cherry'` value entirely.
+
+## Why the "outer reaction definitely fires" observation is consistent
+
+Your test for "outer reaction fires" probably involves changing the array length (push, splice, swap). Those go through the `rec.item !== item || rec.index !== i` branch — `itemSignal.set(...)` runs unconditionally with a fresh wrapper object, equality gate passes (different wrapper ref), subscribers wake. That's why adding/removing/reordering items works fine after hydrate, but mutating an existing item's prop in place doesn't.
+
+It's also worth noting that this isn't snippet-specific — any expression inside the each body that reads `item.<prop>` would hit the same bug after hydration on the first in-place mutation. The snippet is just along for the ride. But the snippet structure does suppress one of the workarounds: with bare `{item.name}` directly in the each body, the same lookup path applies and the same bug should reproduce. A test using new object refs (`items[0] = { ...items[0], name: 'Crimson' }`) like the one at `packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` passes precisely because it dodges the equality gate by changing the item ref.
+
+## Workarounds (no source change)
+
+- Replace the item reference instead of mutating in place: `state.items.set(items.map((it, i) => i === 0 ? { ...it, name: 'Cherry' } : it))`. New ref → first branch of phase 3 → `itemSignal.set(...)` → DOM updates.
+- Toggle the value back-and-forth — the first mutation populates `propsSnapshot`, the second triggers `notify()`. Not really a workaround, just an explanation of why your second mutation works.
+- Use `state.items.notify()` after the in-place mutation to force the items signal to fire a second time — but this only buys you the same "phase 3 with populated snapshot" pass, so it would also need to happen after the first lost mutation, not as a fix for it.
+
+## The fix on the framework side
+
+`adoptServerItems` should populate `propsSnapshot` at adoption time, the same way Phase 3 does at the end of a normal reconcile. Either:
+
+```js
+// packages/renderer/src/engines/native/blocks/each.js:574-584
+newRecords.push({
+  ...,
+  propsSnapshot: createSnapshot(item),  // not null
+});
+```
+
+…or, equivalently, change the "fresh record" branch in Phase 3 to detect adoption explicitly. The first option is cleaner and matches the invariant the comment in Phase 3 already claims ("bindings were wired against the signal's value at the moment we set the snapshot").
+
+## Files to look at
+
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `adoptServerItems` (line 505), `reconcile` Phase 3 (line 396-422), `createSnapshot` / `refreshSnapshotAndDetect` (lines 86-122), `createItemDataProxy` (line 129).
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/template.js` — `buildSnippetProxy` lazy getters (line 67), snippet hydrate branch (line 224).
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — confirms eager hydration is forced when an each contains a `template` (snippet) node, so `adoptServerItems` is what runs during hydrate (line 189-194).
+- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` — the existing "snippet with named args inside each" test that uses a new object ref and therefore doesn't catch this.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json
new file mode 100644
index 000000000..e9af5648d
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json
@@ -0,0 +1,35 @@
+{
+  "expectations": [
+    {
+      "text": "A: Identifies each.hydrate deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
+      "passed": true,
+      "evidence": "Line 9: 'On the SSR-then-hydrate path, each.hydrate does not unconditionally wire per-item Reactions. Per-item wiring is expensive (item count x bindings per item — ~425ms on a 1000-item list in prior benches), so the framework defers it'. Explicitly framed as deliberate deferral for performance, not a bug."
+    },
+    {
+      "text": "B: Explains the chain: each.hydrate only registers a dep on node.over; per-item Reactions wire later via adoptServerItems when items signal fires",
+      "passed": true,
+      "evidence": "Line 9: 'when hydrate runs, it only registers a dependency on the items collection signal and waits for update to fire. update then calls adoptServerItems, which finally wires per-item Reactions onto the existing server-rendered nodes.' Says 'items collection signal' rather than node.over by name, but the chain is correctly described."
+    },
+    {
+      "text": "C: Recognizes that if items never mutates, update never runs, and per-item bindings stay unwired forever",
+      "passed": true,
+      "evidence": "Line 13: 'Because items is set once from a prop and never mutates, the items signal never fires after hydrate. update never runs. adoptServerItems never fires. The per-item Reactions for class=\"{classMap getItemClasses item}\" are never wired.' Verbatim match to expectation."
+    },
+    {
+      "text": "D: Connects the bug to getItemClasses reading state.activeID — the external signal has no Reaction to invalidate, so mutations are silently lost",
+      "submitted": true,
+      "passed": true,
+      "evidence": "Line 15: 'With no Reaction wired around getItemClasses(item), state.activeID.depend() is never called inside a tracked compute. Mutations to state.activeID have no subscriber on those bindings to invalidate. The class string in the DOM stays at whatever the server emitted.' Direct connection made."
+    },
+    {
+      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
+      "passed": true,
+      "evidence": "Section 'Why the classifier didn't catch it' (lines 22-31) discusses each-content-classifier.js / isEachContentSelfContained extensively. Fix 2 (line 47): 'Force the each block onto the eager hydrate path. The classifier is the public contract for this.' Both classifier reference and the equivalent fix shape are explicit."
+    },
+    {
+      "text": "F: Notes the per-binding Reactions use skipFirstWrite: true — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
+      "passed": true,
+      "evidence": "Line 17: 'The framework's per-expression reactivity guarantee depends on the per-binding Reaction running at least once with Scheduler.current set — that's the only way Dependency.depend() becomes a no-op-no-more. The lazy each path skips that step. There is no \"register without running\" — the evaluation IS the witness.' Captures the 'evaluation IS the registration' insight. skipFirstWrite is referenced explicitly in Key files section: 'reactive-data.js — skipFirstWrite contract; the load-bearing per-binding evaluation that registers signal deps'."
+    }
+  ]
+}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md
new file mode 100644
index 000000000..a3c03e4ad
--- /dev/null
+++ b/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md
@@ -0,0 +1,64 @@
+# Why the per-item class binding doesn't react
+
+## What's happening
+
+This is the canonical lazy-each-hydrate bug. The fact that your top-level `reaction(() => state.activeID.get())` fires correctly proves the signal itself is healthy — the loss of reactivity is local to the per-item bindings inside the `{#each}` block.
+
+The mechanism, from `packages/renderer/src/engines/native/blocks/each.js` and `each-content-classifier.js`:
+
+1. On the SSR-then-hydrate path, `each.hydrate` does **not** unconditionally wire per-item Reactions. Per-item wiring is expensive (item count × bindings per item — ~425ms on a 1000-item list in prior benches), so the framework defers it: when hydrate runs, it only registers a dependency on the `items` collection signal and waits for `update` to fire. `update` then calls `adoptServerItems`, which finally wires per-item Reactions onto the existing server-rendered nodes.
+
+2. That deferral assumes per-item bindings only read **item-local** data. Your `getItemClasses(item)` helper closes over `state.activeID` — external state. The deferral assumption is broken.
+
+3. Because `items` is set once from a prop and never mutates, the items signal never fires after hydrate. `update` never runs. `adoptServerItems` never fires. The per-item Reactions for `class="{classMap getItemClasses item}"` are **never wired**.
+
+4. With no Reaction wired around `getItemClasses(item)`, `state.activeID.depend()` is never called inside a tracked compute. Mutations to `state.activeID` have no subscriber on those bindings to invalidate. The class string in the DOM stays at whatever the server emitted.
+
+The reason your standalone `reaction(...)` works is that it wires its own tracked compute; the dependency is registered there. The framework's per-expression reactivity guarantee depends on the per-binding Reaction running at least once with `Scheduler.current` set — that's the only way `Dependency.depend()` becomes a no-op-no-more. The lazy each path skips that step. There is no "register without running" — the evaluation IS the witness.
+
+This is exactly the inpage-menu bug the skill calls out: items arrived as a prop, never changed, `getItemClasses(item)` reading `state.activeID` never updated the rendered class.
+
+## Why the classifier didn't catch it
+
+PR #175 added `each-content-classifier.js` (`isEachContentSelfContained`) to gate this. `each.hydrate` consults it; if anything in the block resolves outside the iteration scope ∪ framework helper registry, hydrate falls through to eager `adoptServerItems` and wires per-item Reactions immediately.
+
+In your case, the classifier walks `{classMap getItemClasses item}` and sees:
+- `classMap` — in `TemplateHelpers`, pure helper allowlist, fine.
+- `getItemClasses` — **not** in the registry. Not an iteration-local. Not a reserved name.
+
+Whether the classifier currently treats this as "external → eager-wire" depends on which version of the classifier is running. The classifier is conservative by design: any identifier head that doesn't resolve to iteration-vars or `TemplateHelpers` should bail to eager wiring. If `getItemClasses` was registered via `Template.registerHelper`, it is statically indistinguishable from a component method that reads state — and the classifier deliberately treats user-registered helpers as external (the correct call, per the comment in `each-content-classifier.js`).
+
+So one of two things is true: either the classifier is correctly bailing and something downstream is broken, or you're hitting a path the classifier doesn't trace into. The likely path-not-traced cases listed in the skill are: `{#each}` without explicit `as`, snippet/template/rerender/async/guard wrappers, or unknown identifiers — `getItemClasses` falls in the "unknown identifier" bucket which should force eager wiring.
+
+## How to fix it (in order of preference)
+
+**Fix 1 — Make the dependency item-local.** Best fix for clarity and perf. Move the `state.activeID` read out of the per-item helper and pass the comparison result down as item-local data, or compute it inside a `computed`/derived signal that the helper reads from a stable reference. Concretely, restructure so the helper takes `(item, activeID)` — but that still reads state at the call site. A cleaner shape: store `activeID` on the iteration via a derived `items` collection that includes per-item `isActive`, OR restructure the template to compute the active flag at the binding site:
+
+```svelte
+{#each item in items}
+  <a class="{classMap (object active=(eq item.id activeID) item=true)}">
+    {item.title}
+  </a>
+{/each}
+```
+
+This puts `activeID` directly in the per-item binding expression. `activeID` is a top-level identifier from the data context (resolved at the binding's compute). The binding still needs a per-item Reaction to register the dependency — which you'd get via fix 2.
+
+**Fix 2 — Force the each block onto the eager hydrate path.** The classifier is the public contract for this. If it's not currently bailing on your `getItemClasses` call, file a repro — but in the meantime, you can force eagerness by structuring the each block in a way the classifier can't prove self-contained. Simplest reliable triggers: use a snippet wrapper (`{>itemRow item=item}`), drop the explicit `as` (use `{#each items}` with `{this.title}`), or wrap the contents in an `{#async}`/`{#rerender}`. Each of these is on the conservative-bail list and forces eager `adoptServerItems`.
+
+This is a workaround, not a real fix — the classifier should be doing this for you.
+
+**Fix 3 — Mutate `items` once after hydrate.** If you can tolerate it, calling `state.items.set(state.items.get())` after hydrate fires the items signal, triggers `update` → `adoptServerItems` → per-item Reactions wire, and reactivity is restored. This is a hack and shouldn't ship — it adds a render pass and obscures the underlying issue — but it confirms the diagnosis if you want to verify before changing template structure.
+
+## Recommended next step
+
+Verify which path your component is actually taking. Add a `console.log` at the top of `each.hydrate` in `packages/renderer/src/engines/native/blocks/each.js` printing the result of `isEachContentSelfContained(node)`. If it returns `true` (lazy), the classifier missed your case — that's a classifier bug worth filing, because `getItemClasses` is a user-defined name that should not resolve to anything in the safe registry. If it returns `false` (eager), but reactivity still doesn't wire, the bug is downstream of the classifier and needs a different trace.
+
+My read is that the classifier should already be bailing here, so the most likely diagnosis is that `getItemClasses` is being treated as a known-safe helper somehow (e.g., registered through a path the classifier whitelists, or the helper name happens to match something in `TemplateHelpers`). Worth checking: `Object.keys(TemplateHelpers).includes('getItemClasses')` from a console at runtime. If true — rename. If false — file the repro.
+
+## Key files
+
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `each.hydrate` gate, `adoptServerItems`
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — `isEachContentSelfContained`, the lazy/eager gate
+- `/home/jack/semantic/next/packages/renderer/src/engines/native/reactive-data.js` — `skipFirstWrite` contract; the load-bearing per-binding evaluation that registers signal deps
+- `/home/jack/semantic/next/packages/renderer/test/unit/each-content-classifier.test.js` — classifier behavior tests (item-local, external, conservative-bail cases)
diff --git a/ai/skills/authoring/ssr-hydration-workspace/rubric.md b/ai/skills/authoring/ssr-hydration-workspace/rubric.md
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@@ -0,0 +1,55 @@
+# SSR Hydration Skill Eval Rubric
+
+Each eval prompt has 5-8 binary assertions (pass/fail). Skill is "significantly better than baseline" when its mean pass rate exceeds baseline by at least 30 percentage points across all evals, AND no eval regresses below baseline.
+
+## Eval 0: innerHTML-doesnt-process-DSD
+
+| # | Assertion |
+|---|---|
+| A | Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec) |
+| B | Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API |
+| C | Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate` |
+| D | Notes that the failure is silent (no error) — the test "succeeds" but is testing a different code path than intended |
+| E | Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) |
+
+## Eval 1: renderToString-empty-in-browser-env
+
+| # | Assertion |
+|---|---|
+| A | Identifies `Template.isServer` as the controlling flag |
+| B | Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer` |
+| C | Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty |
+| D | Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call |
+| E | Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected) |
+
+## Eval 2: each-block-external-state-not-reactive-after-hydrate
+
+| # | Assertion |
+|---|---|
+| A | Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design) |
+| B | Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires |
+| C | Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever |
+| D | Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost |
+| E | References the each-content-classifier (or equivalent fix shape: "force eager adoption when bindings could read external state") as the resolution |
+| F | Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps |
+
+## Eval 3: tachometer-bench-noise-floor-too-high
+
+| # | Assertion |
+|---|---|
+| A | Identifies that bench noise floor scales inversely with bench duration |
+| B | Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1% |
+| C | Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond |
+| D | Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it |
+| E | Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band |
+| F | Optionally references the perf-improvement skill or `improve-performance` workflow as the source for this methodology |
+
+## Eval 4: snippet-arg-inside-each-not-reactive
+
+| # | Assertion |
+|---|---|
+| A | Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug |
+| B | Explains that snippet args (`label=item.name`) are evaluated by the per-item content path; the snippet body sees those args via `buildSnippetProxy` |
+| C | Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place |
+| D | Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix |
+| E | Mentions the existing test `snippet with named args inside each is reactive after hydration` (PR #175 unskipped it) OR equivalent: this scenario is a known regression test |
diff --git a/ai/skills/authoring/ssr-hydration-workspace/skill-snapshot/ssr-hydration.md b/ai/skills/authoring/ssr-hydration-workspace/skill-snapshot/ssr-hydration.md
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@@ -0,0 +1,469 @@
+---
+title: SSR & Hydration Pipeline — Server Render to Live DOM
+description: How a component renders on the server, arrives as DSD in the browser, and hydrates into a reactive component. Covers renderToString, ServerRenderer, expandCustomElements, DSD parsing, the hydrate-or-render decision, and hydrateMarkers. Load before working on SSR, hydration, Astro integration, or server rendering bugs.
+keywords: [SSR, hydration, server rendering, declarative shadow DOM, DSD, renderToString, ServerRenderer, hydrateMarkers, expandCustomElements, markers]
+audience: authoring
+skill: ssr-hydration
+type: skill
+---
+
+# SSR & Hydration Pipeline — Server Render to Live DOM
+
+> **Skill:** `ssr-hydration`
+> **Purpose:** How a component renders on the server, arrives as Declarative Shadow DOM in the browser, and hydrates into a fully reactive component. Load this before working on SSR, hydration, Astro integration, or server rendering bugs.
+
+---
+
+## Why SSR Exists Here
+
+SSR in Semantic UI exists for **first paint performance** — the user sees styled, structured content before JavaScript loads. The server produces Declarative Shadow DOM (DSD) that the browser renders immediately. JavaScript then hydrates the existing DOM with reactive bindings.
+
+This is not server rendering for SEO or static generation. The goal is a fast visual that the client seamlessly takes over.
+
+---
+
+## The Full Lifecycle
+
+A server-rendered component passes through five phases from definition to interactivity:
+
+```
+1. SERVER: renderToString(ComponentClass, attrs)
+   |
+   +-- Clone prototype Template with data
+   +-- Template.initialize() -> createComponent() runs
+   +-- ServerRenderer.render() -> HTML string with hydration markers
+   +-- expandCustomElements() -> recursively render nested components
+   +-- Wrap in DSD: <tag><template shadowrootmode="open">...</template></tag>
+   |
+   v
+2. NETWORK: HTML string arrives in browser
+   |
+   v
+3. BROWSER PARSE: DSD parsing
+   |
+   +-- Browser encounters <template shadowrootmode="open">
+   +-- Automatically creates shadow root and moves content into it
+   +-- User sees styled content BEFORE any JavaScript loads
+   |
+   v
+4. JS LOADS: Custom element upgrade
+   |
+   +-- Browser calls constructor() -> detects existing shadowRoot -> sets _hydrating flag
+   +-- Browser calls connectedCallback() -> detects DSD content
+   +-- canHydrate() checks marker version
+   +-- requestAnimationFrame(() => hydrate()) — deferred so browser can paint first
+   |
+   v
+5. HYDRATION: hydrate(prototypeTemplate)
+   |
+   +-- Clone template, initialize (createComponent runs again, client-side)
+   +-- Build entries from AST (cached on prototype)
+   +-- hydrateMarkers() walks existing DOM, wires Reactions to server-rendered nodes
+   +-- Remove all hydration comment markers (clean DevTools)
+   +-- Component is now fully reactive — indistinguishable from client-rendered
+```
+
+---
+
+## Phase 1: Server Rendering
+
+### renderToString
+
+`packages/component/src/render-to-string.js`
+
+The entry point for SSR. Takes a component class (returned by `defineComponent` with a `tagName`) and an attributes object, returns a complete DSD HTML string.
+
+```js
+import { defineComponent, renderToString } from '@semantic-ui/component';
+
+const MyCard = defineComponent({ tagName: 'my-card', template, css, ... });
+const html = renderToString(MyCard, { title: 'Hello' });
+// -> <my-card title="Hello"><template shadowrootmode="open"><style>...</style>...</template></my-card>
+```
+
+The function performs these steps in order:
+
+**1. Normalize attributes** — Kebab-case HTML attribute names are converted to camelCase property names. `fromAttribute` converters from the component's property definitions are applied.
+
+**2. Resolve attribute aliases** — For spec-driven primitives, bare attributes like `primary` are resolved to their canonical form (`emphasis="primary"`) using `resolveAttributeAliases()` from `component-helpers.js` — the same shared helper the client uses.
+
+**3. Merge data context** — Spec defaults, component defaults, and normalized attributes are merged in that order (last wins):
+
+```js
+const data = { ...specDefaults, ...defaultSettings, ...normalizedAttrs };
+```
+
+**4. Clone and initialize** — The prototype template is cloned with the data context, forcing the native engine (ServerRenderer handles string output). `template.initialize()` runs `createComponent()` — the same function that runs on the client. The `isServer` param is `true`, so components can guard client-only logic.
+
+**5. Compute `{uiClasses}` classes** — After `initialize()`, because `createComponent` can modify settings that affect spec resolution (e.g., input's `configureSearch` sets `icon`).
+
+**6. Render** — `template.render()` delegates to `ServerRenderer.render()`, which walks the AST and produces an HTML string with hydration comment markers.
+
+**7. Expand nested custom elements** — `expandCustomElements()` scans the rendered HTML for custom element tags, looks them up in the component registry, and recursively calls `renderToString` to expand their shadow DOM as nested DSD.
+
+**8. Wrap in DSD** — The final output wraps the rendered HTML in a DSD template with the component's CSS:
+
+```html
+<my-card title="Hello">
+  <template shadowrootmode="open">
+    <style>/* component CSS */</style>
+    <!-- rendered HTML with hydration markers -->
+  </template>
+</my-card>
+```
+
+When `hydrate: false` is passed, the outer element gets an `ssr` attribute that prevents self-hydration — used for components that should remain static.
+
+### ServerRenderer
+
+`packages/renderer/src/engines/native/server.js`
+
+The server-side counterpart to the client `Renderer`. Same constructor interface, same `ExpressionEvaluator`, but produces HTML strings instead of DOM. No Reactions, no Signals, no DynamicRegion — pure string concatenation.
+
+```js
+render() {
+  let html = this.renderNodes(this.ast, this.data);
+  return html.replace(REMOVE_ATTR_REGEX, '');
+}
+```
+
+**Hydration markers** — The server embeds comment markers in the HTML so the client's hydration pass can locate dynamic positions:
+
+| Position | Server output | Client uses to... |
+|----------|--------------|-------------------|
+| Text expression | `<!--sui:v1:3-->Hello` | Find text node, wire Reaction |
+| Block open | `<!--sui-block:v1:5-->` | Find block boundary, wire directive |
+| Block close | `<!--/sui-block:v1:5:b1000-->` | Determine block extent and branch index |
+| Attribute expression | *(evaluated inline, no marker)* | Client builds reference DOM from AST |
+
+Block closing markers include metadata: `b1000` means the `if` main branch was taken, `b0` means the first `elseif`, `b-1` means no branch matched. The client uses this during hydration to understand what the server rendered without re-evaluating conditions.
+
+**Expression handling in attributes** — Unlike the client (which uses `__suiN__` markers), the server evaluates attribute expressions inline and emits their final values. Properties (`.prop=`) and events (`@click=`) are stripped via `REMOVE_ATTR` sentinel. Boolean attributes are removed when falsy.
+
+**Block directives** — Conditionals, each, async, rerender, and template nodes all emit the same open/close marker pattern. Inside the markers, the server renders the content that matched:
+
+```html
+<!--sui-block:v1:2-->
+  <span class="on">Visible</span>
+<!--/sui-block:v1:2:b1000-->
+```
+
+For `{#async}`, the server always renders `loadingContent` (never awaits the promise). The client's hydration wires the real async Reaction which fetches and replaces.
+
+### expandCustomElements
+
+`packages/component/src/expand-custom-elements.js`
+
+After the top-level component renders, its HTML may contain nested custom element tags (e.g., `<ui-icon icon="star">` inside a button template). This function:
+
+1. Scans the HTML string for tags containing a hyphen (custom element spec)
+2. Looks up each tag in the component registry
+3. Skips elements that already have a DSD (Astro pre-renders child components in some paths)
+4. Calls `renderToString` recursively with a depth counter (max 10)
+5. Applies `fromAttribute` converters to deserialize attribute strings into typed values
+
+This is string-level processing — no DOM parsing. It uses a hand-written parser (`findNextCustomElement`, `parseOpenTag`, `findClosingTag`) that handles nesting, self-closing tags, and quoted attributes.
+
+---
+
+## Phase 3: Browser DSD Parsing
+
+When the browser encounters `<template shadowrootmode="open">` during HTML parsing:
+
+1. It creates a shadow root on the parent element (mode: open)
+2. It moves the template's content into the shadow root
+3. It removes the `<template>` element itself
+
+This happens during HTML parsing, before any JavaScript loads. The user sees styled content immediately because:
+- The shadow root isolates styles (component CSS is in a `<style>` tag inside the DSD)
+- The content structure matches what the component would render on the client
+- No flash of unstyled content, no layout shift
+
+---
+
+## Phase 4: Custom Element Upgrade
+
+When the component's JavaScript loads and `customElements.define()` runs, the browser upgrades all matching elements.
+
+### Constructor
+
+```js
+constructor() {
+  super();
+  // If the element has a declarative shadow root, suppress requestUpdate
+  // until hydration completes — attribute parsing fires before
+  // connectedCallback and would schedule a render cascade
+  if (this.shadowRoot) {
+    this._hydrating = true;
+  }
+  // ... initialize settings, property store
+}
+```
+
+The `_hydrating` flag prevents attribute-triggered re-renders during the upgrade phase. Without this, `attributeChangedCallback` would fire for every server-rendered attribute and schedule renders before the template is ready.
+
+### connectedCallback — The Decision Point
+
+```js
+connectedCallback() {
+  if (this.template) return;           // already initialized
+  if (this.hasAttribute('ssr')) return; // marked as server-only, skip
+
+  const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;
+
+  if (!this.shadowRoot) {
+    this.attachShadow({ mode: 'open', delegatesFocus });
+  }
+
+  if (hasServerContent && this.canHydrate()) {
+    // DSD present and markers are compatible — defer hydration
+    requestAnimationFrame(() => this.hydrate(prototypeTemplate));
+  } else {
+    if (hasServerContent) {
+      this.shadowRoot.innerHTML = ''; // version mismatch — discard
+    }
+    this.fullRender(prototypeTemplate);
+  }
+}
+```
+
+Three paths:
+
+| Condition | Path | What happens |
+|-----------|------|-------------|
+| No existing shadow root | `fullRender()` | Standard client render — `attachShadow`, clone template, initialize, render, append |
+| DSD present + compatible markers | `hydrate()` | Wire Reactions to existing DOM, no re-render |
+| DSD present + incompatible markers | `fullRender()` | Discard server content, render from scratch |
+
+**`canHydrate()`** walks shadow root comments looking for versioned markers (`sui:v1:` or `sui-block:v1:`). If found, it checks the version matches `MARKER_VERSION`. No markers means static content — safe to hydrate (nothing to wire).
+
+**`requestAnimationFrame`** — Hydration is deferred one frame so the browser can paint the server-rendered content first. The user sees the visual immediately; interactivity arrives on the next frame.
+
+---
+
+## Phase 5: Hydration
+
+`WebComponentBase.hydrate()` in `packages/component/src/engines/native/base.js`
+
+Hydration wires reactive bindings to the existing server-rendered DOM. It does not re-render or validate the server's output — it trusts the DOM is correct and attaches the machinery for future reactivity.
+
+### The hydrate() Method
+
+```js
+hydrate(prototypeTemplate) {
+  // 1. Remove server <style> — CSS is handled via adoptedStyleSheets
+  this.shadowRoot.querySelector('style')?.remove();
+
+  // 2. Clone template with data context (same as fullRender)
+  this.template = prototypeTemplate.clone({ data: this.getData(), element: this, renderRoot });
+  this.template._isHydrating = true;
+  this.component = this.template.instance;
+
+  // 3. Build entries from AST (cached on prototype — depends only on AST, not data)
+  if (!prototypeTemplate._hydrationEntries) {
+    const { entries } = this.template.renderer.buildHTMLString(this.template.ast);
+    prototypeTemplate._hydrationEntries = entries;
+  }
+
+  // 4. Walk server DOM, wire Reactions to existing nodes
+  this.template.renderer.hydrateMarkers(
+    this.shadowRoot, entries, data, scope
+  );
+
+  // 5. Clean up
+  this.template._isHydrating = false;
+  this._hydrating = false;
+  this.removeMarkers();  // remove all comment markers for clean DevTools
+  setTimeout(() => this.template?.onRendered(), 0);
+}
+```
+
+### hydrateMarkers — The Core Algorithm
+
+`Renderer.hydrateMarkers()` in `packages/renderer/src/engines/native/renderer.js`
+
+Two passes over the server-rendered DOM:
+
+**Pass 1: Attribute bindings** — The server didn't embed attribute markers (it evaluated them inline), so hydration can't find markers in the DOM. Instead, it builds a **reference DOM** from the AST's `buildHTMLString` output (which contains `__suiN__` markers), then walks the reference DOM and real DOM in parallel:
+
+```
+Reference DOM: <div class="__sui0__ card" data-count="__sui1__">
+Real DOM:      <div class="dark card" data-count="3">
+```
+
+For each marker found in the reference element's attributes, the corresponding real element gets a Reaction wired. Block-owned elements (children inside `{#if}`, `{#each}`, etc.) are skipped because they're handled recursively by block hydration.
+
+**Pass 2: Comment markers** — A TreeWalker finds `<!--sui:v1:N-->` (text expressions) and `<!--sui-block:v1:N-->` (block directives) at the top level only. Block nesting is tracked via `blockDepth` — inner markers are skipped because block handlers process their own children recursively.
+
+For each marker:
+
+| Marker type | Hydration action |
+|-------------|-----------------|
+| Text expression | Wire a Reaction that sets `textNode.data` on change |
+| Conditional block | Collect owned DOM nodes between open/close markers, wire Reaction for future branch changes |
+| Each block | Collect per-item DOM nodes, create item Signals and Proxies for each, wire Reaction for list changes |
+| Template/snippet | Collect owned nodes, initialize subtemplate, recursively hydrate inner markers |
+| Async block | Wire the full async Reaction (loading → resolved → error), existing loading content gets replaced when promise resolves |
+| Rerender block | Collect owned nodes, wire the rerender/guard Reaction |
+
+### Key Hydration Behaviors
+
+**Trust-then-wire** — Hydration doesn't re-evaluate conditions to validate server output. It trusts the DOM and wires Reactions. If state truly diverges (e.g., `initialize()` changes a setting), the Reaction fires naturally on the next microtask and updates the DOM. See `ssr-principles` for the full rationale.
+
+**`_isHydrating` flag** — Set during hydration wiring. `createComponent` callbacks receive `isHydrating: true` so they can skip client-only setup that would conflict with the wiring pass. Template lifecycle events (`created`, `rendered`) are suppressed during hydration to avoid double-firing.
+
+**`_hydrating` flag on element** — Set during constructor if DSD is detected. Prevents `attributeChangedCallback` from triggering `adjustPropertyFromAttribute` and `requestUpdate` during the upgrade phase. Cleared after hydration completes.
+
+**Marker removal** — After hydration, `removeMarkers()` walks the shadow root and removes all `sui` comment nodes. This keeps DevTools clean and is possible because all Reactions are already wired to real DOM nodes (text nodes, elements), not to the markers themselves.
+
+**Hydration entries are cached** on the prototype template (`_hydrationEntries`). They depend only on AST structure, not data, so all instances of the same component share them.
+
+---
+
+## Concrete Trace: Counter Component
+
+Here is a concrete trace of a simple counter component through all phases:
+
+```js
+// Definition (shared between server and client)
+const Counter = defineComponent({
+  tagName: 'ui-counter',
+  template: '<div class="counter">Count: {count}</div>',
+  css: '.counter { padding: 8px; }',
+  defaultState: { count: 0 },
+  createComponent: ({ state, interval }) => ({
+    initialize: () => interval(() => state.count.increment(), 1000),
+  }),
+});
+```
+
+**Server:**
+```js
+const html = renderToString(Counter, {});
+```
+
+1. `renderToString` creates data context: `{ count: 0 }`
+2. `template.initialize()` calls `createComponent` — `interval()` is a no-op on server (`isServer: true`)
+3. `ServerRenderer.render()` walks AST, produces:
+   ```html
+   <div class="counter">Count: <!--sui:v1:0-->0</div>
+   ```
+4. No nested custom elements to expand
+5. Final output:
+   ```html
+   <ui-counter>
+     <template shadowrootmode="open">
+       <style>.counter { padding: 8px; }</style>
+       <div class="counter">Count: <!--sui:v1:0-->0</div>
+     </template>
+   </ui-counter>
+   ```
+
+**Browser parse:** Shadow root created with content. User sees "Count: 0" immediately.
+
+**JS loads:** `customElements.define('ui-counter', ...)` upgrades the element.
+- Constructor detects `this.shadowRoot` exists, sets `_hydrating = true`
+- `connectedCallback` detects DSD content, `canHydrate()` finds `sui:v1:` marker
+- Defers: `requestAnimationFrame(() => this.hydrate(prototypeTemplate))`
+
+**Hydration:**
+1. Remove `<style>` tag (CSS moves to `adoptedStyleSheets`)
+2. Clone template with `{ count: 0 }`, initialize — `createComponent` runs again, this time `interval()` is real, starts the timer
+3. Build entries from AST: `[{ id: 0, type: 'expression', node: { value: 'count' }, classification: { type: 'text' } }]`
+4. `hydrateMarkers` finds `<!--sui:v1:0-->`, wires a Reaction:
+   ```js
+   Reaction.create(() => {
+     const value = this.eval('count', data);  // reads count Signal -> dependency registered
+     textNode.data = value ?? '';              // sets "0" (no-op, already correct)
+   });
+   ```
+5. Remove marker comments, clear `_hydrating`
+
+**Live:** One second later, `state.count.increment()` fires. The count Signal updates to 1. The Reaction re-evaluates, sets `textNode.data = '1'`. The counter is ticking.
+
+---
+
+## Astro Integration
+
+Semantic UI components render in Astro via the standard `client:*` directives. The integration uses the `source` export condition in `package.json` so Astro's Vite build processes component source directly.
+
+```astro
+---
+import { Button, Icon } from '@semantic-ui/core';
+---
+<Button emphasis="primary" client:load>Click Me</Button>
+<Icon icon="star" client:load />
+```
+
+For SSR, Astro calls `renderToString` during the build/SSR pass. The `client:load` directive tells Astro to include the component's JavaScript and hydrate on page load.
+
+Components without `client:*` are rendered as server-only — they get the `ssr` attribute and are never hydrated. Their DSD is parsed and displayed, but no JavaScript is loaded for them.
+
+For `client:only` components, there is no server render. The component renders entirely on the client via `fullRender()`. `forwardAstroProps()` ensures Astro-provided attributes are available before `connectedCallback`.
+
+---
+
+## Quick Reference
+
+```
+SERVER RENDERING
+  renderToString(ComponentClass, attrs, { slots, depth, hydrate })
+  -> normalize attrs (kebab->camel, fromAttribute converters)
+  -> resolveAttributeAliases (spec fuzzing)
+  -> merge: specDefaults + defaultSettings + attrs
+  -> clone template, initialize (createComponent with isServer: true)
+  -> ServerRenderer.render() -> HTML string with markers
+  -> expandCustomElements() -> recursive DSD for nested components
+  -> wrap in <template shadowrootmode="open">
+
+HYDRATION MARKERS
+  <!--sui:v1:N-->         text expression (followed by evaluated value)
+  <!--sui-block:v1:N-->   block directive open
+  <!--/sui-block:v1:N:bX--> block directive close (X = branch index)
+  __suiN__                attribute marker (client buildHTMLString only, not in SSR output)
+
+HYDRATION DECISION
+  No shadow root              -> fullRender (standard client path)
+  DSD + canHydrate()          -> requestAnimationFrame -> hydrate()
+  DSD + version mismatch      -> discard server DOM -> fullRender
+  hasAttribute('ssr')         -> skip entirely (server-only component)
+
+HYDRATION WIRING
+  1. Remove server <style> (CSS -> adoptedStyleSheets)
+  2. Clone template, initialize (createComponent runs client-side)
+  3. Build entries from AST (cached on prototype)
+  4. hydrateMarkers: parallel walk for attributes, comment walk for text + blocks
+  5. Remove all comment markers
+  6. Fire onRendered
+```
+
+---
+
+## Key Files
+
+```
+packages/component/src/
+├── render-to-string.js           renderToString — SSR entry point
+├── expand-custom-elements.js     Recursive custom element expansion
+├── component-helpers.js          Shared: resolveAttributeAliases, getUIClasses
+├── engines/native/base.js        WebComponentBase — hydrate(), canHydrate(), fullRender()
+└── engines/native/factory.js     Creates web component class with observedAttributes
+
+packages/renderer/src/
+├── build-html-string.js          Shared HTML assembly + marker format constants
+├── expression-evaluator.js       Shared expression evaluation
+├── engines/native/server.js      ServerRenderer — AST -> HTML string
+└── engines/native/renderer.js    Renderer — hydrateMarkers(), hydrateAttributes()
+```
+
+---
+
+## Related Skills
+
+| Skill | Use when... |
+|-------|-------------|
+| **Render Pipeline** (`render-pipeline`) | How the client render pipeline works — AST, engines, expression evaluation |
+| **SSR & Hydration Principles** (`ssr-principles`) | The governing constraints — trust-then-wire, shared helpers, mismatch prevention |
+| **Native Renderer** (`native-renderer`) | Deep dive into native renderer internals (contributing audience) |
+| **Component Authoring** (`component-authoring`) | Using `defineComponent`, lifecycle hooks, and SSR-safe patterns |
+| **Mental Model** (`mental-model`) | Framework architecture and the Template-as-core-abstraction philosophy |
diff --git a/ai/skills/authoring/ssr-hydration.md b/ai/skills/authoring/ssr-hydration.md
index 38513e8a2..7a089436e 100644
--- a/ai/skills/authoring/ssr-hydration.md
+++ b/ai/skills/authoring/ssr-hydration.md
@@ -22,6 +22,78 @@ This is not server rendering for SEO or static generation. The goal is a fast vi
 
 ---
 
+## Critical gotchas (read first if you're testing or benching SSR)
+
+These are silent-failure modes — no error, your code just runs the wrong path. Each one cost real investigation time. Lead with them when triaging "my hydration test is broken" or "tachometer can't see my fix."
+
+### Gotcha 1: `innerHTML` does NOT process Declarative Shadow DOM
+
+The browser's main HTML parser processes `<template shadowrootmode="open">` natively — that's why a real page works. But the **fragment parsers** (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) do not. The DSD spec opts those out because they're entry points for XSS escalation.
+
+```js
+// ❌ wrong — wrapper.firstElementChild has no shadowRoot
+wrapper.innerHTML = renderToString(MyComponent, attrs);
+
+// ✅ right — DSD is processed, shadow root attached
+wrapper.setHTMLUnsafe(renderToString(MyComponent, attrs));
+// Document-scoped alternative:
+const doc = Document.parseHTMLUnsafe(html);
+```
+
+**The silent-failure chain when you use `innerHTML`:**
+1. `<template shadowrootmode>` stays as a literal child of the custom element
+2. `el.shadowRoot` is `null` when `connectedCallback` fires
+3. `hasServerContent = el.shadowRoot && el.shadowRoot.childNodes.length > 0` → `false`
+4. `connectedCallback` falls through to `fullRender(prototypeTemplate)` instead of `hydrate(prototypeTemplate)`
+5. Your test or bench "works" — but it's measuring fresh client render, not hydration
+
+There is no error or warning. Tests pass for the wrong reason; benches measure the wrong code path. The canonical helper in `packages/renderer/test/browser/ssr-hydration.test.js` (`ssrAndHydrate`) uses `setHTMLUnsafe` for exactly this reason.
+
+### Gotcha 2: `renderToString` returns empty in browser test env unless `Template.isServer = true`
+
+`Template.isServer` is set once at module load from `typeof window === 'undefined'` in `@semantic-ui/utils`. In a browser test, `window` exists, so `Template.isServer === false`. Inside `Template.initialize()` the engine selection is:
+
+```js
+const RendererClass = (Template.isServer && engine.serverRenderer)
+  ? engine.serverRenderer
+  : engine.renderer;
+```
+
+The client `Renderer` returns a `DocumentFragment` from `render()`, not a string. `renderToString`'s wrapper template literal coerces that to `'[object DocumentFragment]'` (or empty after the string-only `expandCustomElements` no-ops on it). The DSD wrapper is emitted but the content inside is empty.
+
+```js
+// ✅ pattern from ssrAndHydrate
+const wasServer = Template.isServer;
+Template.isServer = true;
+try {
+  html = renderToString(Component, attrs);
+} finally {
+  Template.isServer = wasServer;
+}
+```
+
+The `try/finally` matters — leaving `Template.isServer = true` after the call breaks any subsequent client-side hydration or mount in the same test, because the renderer selection happens once per `template.initialize()`.
+
+### Gotcha 3: bench noise floor scales inversely with bench duration
+
+Per-sample timing jitter on CI runners (OS scheduling, GC, JIT) is roughly constant in absolute terms — typically σ≈1-2ms. Relative noise scales inversely with bench duration:
+
+| Bench duration | Expected noise floor |
+|---|---|
+| ~2ms | ±10-20% |
+| ~10ms | ±2-5% |
+| ~50ms+ | ±1% or tighter |
+
+A 6ms bench at ±28% noise is unresolvable — anything below ±28% reads as "no change" regardless of how many samples you collect. Tightening `autoSampleConditions` or bumping `sampleSize` does not lower the floor; only narrows the CI under it. Sampling more is √N-scaling: 4× samples for 2× CI tightening, capped by the per-config wall-clock budget.
+
+**The fix is to amplify work per sample.** Bump item count, loop the operation N times inside one `performance.measure`, or split into mount-vs-rebind windows. The canonical `bench-hydrate.js` uses 1000 items (not 100, despite the metric name's `-100` suffix) precisely to push duration into the ±1% band. See the `improve-performance` skill's bench-duration table for the methodology.
+
+### Gotcha 4: cross-session "regressions from peak" are phantoms
+
+The in-house bench reporter shows two columns: within-session `vs main` (the truthful signal) and cross-session "regressed from peak". The peak attribution operates on absolute ms across runs on different runner conditions and produces phantom regressions on PRs that didn't change perf. Read the `vs main` table; treat the "from peak" table as noisy until the `bench-reporter-overhaul` Track A schema_v2 lands.
+
+---
+
 ## The Full Lifecycle
 
 A server-rendered component passes through five phases from definition to interactivity:
@@ -284,16 +356,9 @@ hydrate(prototypeTemplate) {
 
 Two passes over the server-rendered DOM:
 
-**Pass 1: Attribute bindings** — The server didn't embed attribute markers (it evaluated them inline), so hydration can't find markers in the DOM. Instead, it builds a **reference DOM** from the AST's `buildHTMLString` output (which contains `__suiN__` markers), then walks the reference DOM and real DOM in parallel:
+**Pass 1: Attribute bindings** — The server stamps `data-sui-bind="attr=N,..."` on every element with dynamic bindings (Plan 04 fast path). The client walks `[data-sui-bind]` elements at top level and wires Reactions directly via `entries[id].attributeBinding`. Block-owned elements (inside `{#if}`/`{#each}`/etc., tracked via `blockDepth` from comment markers) are skipped — block handlers recurse into their own contents via `hydrateInnerContent`. A legacy fallback (parallel ref-DOM walker) exists for older SSR output without `data-sui-bind`.
 
-```
-Reference DOM: <div class="__sui0__ card" data-count="__sui1__">
-Real DOM:      <div class="dark card" data-count="3">
-```
-
-For each marker found in the reference element's attributes, the corresponding real element gets a Reaction wired. Block-owned elements (children inside `{#if}`, `{#each}`, etc.) are skipped because they're handled recursively by block hydration.
-
-**Pass 2: Comment markers** — A TreeWalker finds `<!--sui:v1:N-->` (text expressions) and `<!--sui-block:v1:N-->` (block directives) at the top level only. Block nesting is tracked via `blockDepth` — inner markers are skipped because block handlers process their own children recursively.
+**Pass 2: Comment markers** — A TreeWalker finds `<!--sui:v1:N-->` (text expressions) and `<!--sui-block:v1:N-->` (block directives) at top level. `blockDepth` tracking skips inner markers; block handlers process their own children.
 
 For each marker:
 
@@ -301,11 +366,57 @@ For each marker:
 |-------------|-----------------|
 | Text expression | Wire a Reaction that sets `textNode.data` on change |
 | Conditional block | Collect owned DOM nodes between open/close markers, wire Reaction for future branch changes |
-| Each block | Collect per-item DOM nodes, create item Signals and Proxies for each, wire Reaction for list changes |
+| Each block | Register dep on collection (lazy default) OR adopt server items eagerly per the each-content classifier — see "Each block hydration" below |
 | Template/snippet | Collect owned nodes, initialize subtemplate, recursively hydrate inner markers |
 | Async block | Wire the full async Reaction (loading → resolved → error), existing loading content gets replaced when promise resolves |
 | Rerender block | Collect owned nodes, wire the rerender/guard Reaction |
 
+### The skipFirstWrite contract
+
+When debugging "my signal mutation doesn't update the DOM after hydration," name `skipFirstWrite: true` explicitly — it's the grep-able load-bearing mechanism in `packages/renderer/src/engines/native/reactive-data.js` and surfacing it lets the reader navigate the code path directly.
+
+Per-binding Reactions wired during hydration use `skipFirstWrite: true`:
+
+```js
+scope.reaction(element, (comp) => {
+  const value = renderer.lookupExpression(node.value, data);
+  if (skipFirstWrite && comp.firstRun) { return; }
+  // ... DOM write
+});
+```
+
+The first run **evaluates the expression** (which is what registers signal dependencies as a side effect of accessing the data proxy) but **skips the DOM write** (the SSR'd value is trusted). This is the load-bearing piece for hydration correctness: the evaluation IS the witness for what signals the binding depends on. `Dependency.depend()` is a no-op when `Scheduler.current` is null, so the only way to register a dep is to read the signal *inside* a wired Reaction's compute callback. There is no "register without running" — the framework's per-expression reactivity guarantee comes from this arrangement.
+
+This is why, when a per-binding Reaction *isn't* wired (see each-block lazy hydrate below), the framework loses the ability to react to that expression's signals. Static analysis can't substitute — it can only decide whether to wire the Reaction at all.
+
+### Each-block hydration: lazy by default, eager when content reads external state
+
+`each.hydrate` is the only block hydrate hook that doesn't unconditionally wire per-item Reactions. The lazy path is a perf optimization: per-item Reactions are expensive (item count × bindings per item), so defer wiring until the items signal first fires, then wire in place via `adoptServerItems`. On a 1000-item list, eager wiring on hydrate added ~425ms in a previous experiment.
+
+The deferral assumes per-item bindings only depend on item-local data. When a binding closes over external state (a helper that reads `state.x`, a component method, a snippet arg evaluated against the parent scope), that assumption breaks. If items never mutates after hydrate, `update` never runs, `adoptServerItems` never fires, per-item Reactions never wire, and external mutations silently lose reactivity. The docs site `inpage-menu` was the canonical repro: items arrived as a prop and never changed; `getItemClasses(item)` reading `state.activeID` never updated the rendered class.
+
+The fix (PR #175) is `packages/renderer/src/engines/native/blocks/each-content-classifier.js` — a static analyzer that walks the each block's content AST and decides whether everything resolves to `iteration-vars ∪ pure-helper-registry ∪ reserved-names`. Cached per-AST identity on a `WeakMap`. `each.hydrate` consults it:
+
+```js
+hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
+  lookupExpression(node.over);                                  // dep on items
+  self.hasHydrated = true;
+  if (isEachContentSelfContained(node)) { return; }             // lazy preserved
+  // ...resolve items, eagerly call adoptServerItems...
+}
+```
+
+Self-contained → existing lazy hydrate (item-only `{item.name}`-style bindings + framework helpers like `classMap`/`activeIf`/`is`). Anything else → eager `adoptServerItems` so per-item Reactions register their external deps now.
+
+Conservative bails (treat as not-self-contained, force eager wire):
+- `{#each}` without explicit `as` (item keys spread into local scope; statically indistinguishable from external names)
+- `{>snippet ...}`, `{>template ...}`, `{#rerender}`, `{#guard}`, `{#async}` — cross-AST or dynamic content the classifier doesn't trace into
+- Any expression where an identifier head doesn't resolve to iteration-vars or `TemplateHelpers`
+
+The same family of bug applies to **snippet-with-args inside each** (`{#each item in items}<div>{>badge label=item.name}</div>{/each}`): the snippet args evaluate inside the per-item content path; without per-item Reactions wired they never re-run when items mutate. The classifier's snippet-bail catches this case — that test is unskipped in PR #175.
+
+The classifier runs only inside `each.hydrate`, which only runs on the SSR-then-hydrate path. The 90% of users who runtime-compile in the browser without SSR pay zero analyzer cost. SSR users pay one walk per unique each-content AST shape (cached). The AST itself stays clean — no per-node hydration metadata.
+
 ### Key Hydration Behaviors
 
 **Trust-then-wire** — Hydration doesn't re-evaluate conditions to validate server output. It trusts the DOM and wires Reactions. If state truly diverges (e.g., `initialize()` changes a setting), the Reaction fires naturally on the next microtask and updates the DOM. See `ssr-principles` for the full rationale.
@@ -432,9 +543,26 @@ HYDRATION WIRING
   1. Remove server <style> (CSS -> adoptedStyleSheets)
   2. Clone template, initialize (createComponent runs client-side)
   3. Build entries from AST (cached on prototype)
-  4. hydrateMarkers: parallel walk for attributes, comment walk for text + blocks
-  5. Remove all comment markers
+  4. hydrateMarkers:
+       Pass 1: data-sui-bind fast path for attribute bindings
+       Pass 2: TreeWalker over comment markers for text + blocks
+       Per-binding Reactions use skipFirstWrite: true
+       (evaluate to register deps, skip DOM write — server's value trusted)
+  5. Remove all comment markers + data-sui-bind attributes (rAF)
   6. Fire onRendered
+
+EACH BLOCK HYDRATION
+  each.hydrate consults isEachContentSelfContained(node):
+    self-contained -> lazy: just register dep on items collection
+    not self-contained -> eager adoptServerItems (wire per-item now)
+  Bails to "not self-contained" on:
+    no-`as` each, snippet/template/rerender/async/guard, unknown identifiers
+
+TESTING / BENCHING TRAPS (silent failures)
+  innerHTML doesn't process DSD          -> use setHTMLUnsafe
+  renderToString empty in browser env    -> Template.isServer = true (try/finally)
+  bench under ~30ms can't resolve <±10%  -> bump items / loop op N times
+  cross-session "regressed from peak"    -> phantom; read `vs main` table instead
 ```
 
 ---
@@ -450,10 +578,18 @@ packages/component/src/
 └── engines/native/factory.js     Creates web component class with observedAttributes
 
 packages/renderer/src/
-├── build-html-string.js          Shared HTML assembly + marker format constants
-├── expression-evaluator.js       Shared expression evaluation
-├── engines/native/server.js      ServerRenderer — AST -> HTML string
-└── engines/native/renderer.js    Renderer — hydrateMarkers(), hydrateAttributes()
+├── build-html-string.js                              Shared HTML assembly + marker format constants
+├── expression-evaluator.js                           Shared expression evaluation
+├── engines/native/server.js                          ServerRenderer — AST -> HTML string
+├── engines/native/renderer.js                        Renderer — hydrateMarkers(), hydrateAttributes()
+├── engines/native/reactive-data.js                   bindAttribute / bindTextExpression with skipFirstWrite
+└── engines/native/blocks/
+    ├── each.js                                       each.hydrate gate, adoptServerItems, item proxy
+    └── each-content-classifier.js                    isEachContentSelfContained — lazy/eager gate
+
+packages/renderer/test/
+├── browser/ssr-hydration.test.js                     Canonical ssrAndHydrate helper (setHTMLUnsafe + Template.isServer)
+└── unit/each-content-classifier.test.js              Classifier behavior (item-local, external, conservative-bail)
 ```
 
 ---

From 1fae9d47aff6f2d5ec29137ced3d2f0ef05ee809 Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Sun, 3 May 2026 23:33:21 -0400
Subject: [PATCH 04/16] Chore: Remove ssr-hydration-workspace eval artifacts

The skill update has shipped; the iteration evidence has served its
purpose. Per ai_folder_layout, /ai/skills/ is for MCP-served content,
not eval workspace state.
---
 .../ssr-hydration-workspace/RESULTS.md        |  52 --
 .../ssr-hydration-workspace/evals.json        |  40 --
 .../with_skill/grading.json                   |  29 --
 .../with_skill/outputs/answer.md              |  77 ---
 .../without_skill/grading.json                |   7 -
 .../without_skill/outputs/answer.md           |  73 ---
 .../with_skill/grading.json                   |  29 --
 .../with_skill/outputs/answer.md              | 128 -----
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 .../with_skill/outputs/answer.md              |  52 --
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 .../without_skill/outputs/answer.md           |  85 ----
 .../with_skill/grading.json                   |  35 --
 .../with_skill/outputs/answer.md              |  64 ---
 .../ssr-hydration-workspace/rubric.md         |  55 --
 .../skill-snapshot/ssr-hydration.md           | 469 ------------------
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diff --git a/ai/skills/authoring/ssr-hydration-workspace/RESULTS.md b/ai/skills/authoring/ssr-hydration-workspace/RESULTS.md
deleted file mode 100644
index 8e2eb201b..000000000
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@@ -1,52 +0,0 @@
-# SSR Hydration Skill Update — Eval Results
-
-## Summary
-
-Three iterations of the eval loop. Final scores against the 27-assertion rubric (5 evals, opus judge):
-
-| Configuration | Score | % |
-|---|---|---|
-| **Baseline (no skill, allowed source code reads)** | 21/27 | 78% |
-| **Iteration 1 (skill snapshot, pre-update)** | 25/27 | 93% |
-| **Iteration 2 (skill update: gotchas + classifier + skipFirstWrite)** | 26/27 | 96% |
-| **Iteration 3 (polish: name skipFirstWrite as grep-able)** | 27/27 | 100% |
-
-**Final delta: +22 percentage points** over baseline (78% → 100%).
-
-The baseline ran high (78%) because subagents aggressively read source code to derive answers. The skill's value is in *elevating* the signal — making non-obvious findings immediately accessible without requiring multi-file source archaeology, and establishing canonical framings (e.g., snippet-in-each is the same family as each-external-state).
-
-## Per-eval breakdown
-
-| Eval | Concept | Baseline | Iter 1 | Iter 3 | Δ vs baseline |
-|---|---|---|---|---|---|
-| 0 | innerHTML doesn't process DSD | 4/5 | 5/5 | 5/5 | +1 |
-| 1 | Template.isServer in browser env | 5/5 | 5/5 | 5/5 | 0 |
-| 2 | each-block external state | 5/6 | 5/6 | 6/6 | +1 |
-| 3 | Bench noise floor scaling | 5/6 | 6/6 | 6/6 | +1 |
-| 4 | Snippet-in-each (same family) | 2/5 | 4/5 | 5/5 | **+3** |
-
-The biggest absolute gain (eval 4) was framing snippet-in-each as the same root cause as the each-external-state bug, plus naming PR #175's classifier and the unskipped regression test. Without the skill, baseline agents pursued plausible but wrong alternative theories.
-
-## Skill changes landed
-
-1. **New "Critical gotchas" section near the top** — covers innerHTML/DSD, Template.isServer, bench noise floor, cross-session phantom regressions. These are silent-failure modes that cost real investigation time when missed.
-2. **`hydrateMarkers` Pass 1 description updated** — replaced the legacy "reference DOM parallel walk" framing with the Plan 04 `data-sui-bind` fast path; legacy walker noted as fallback.
-3. **New "skipFirstWrite contract" subsection** — explicitly names the flag, explains evaluation-as-witness, ties to `Dependency.depend()` no-op outside Reactions.
-4. **New "Each-block hydration: lazy by default, eager when content reads external state" section** — covers the lazy/eager classifier, conservative bails (no-`as`, snippet/template/rerender/async), the inpage-menu canonical repro, and per-AST identity caching.
-5. **Quick Reference updated** — added EACH BLOCK HYDRATION block and TESTING/BENCHING TRAPS block with the four silent-failure modes.
-6. **Key Files updated** — added `each-content-classifier.js`, `reactive-data.js`, the canonical test files.
-
-## Methodology notes
-
-- **Baseline = no skill, but allowed source reads.** This is the harshest baseline because subagents are good at code archaeology. A weaker baseline (no source access) would show a much larger delta but wouldn't reflect real-world agent behavior.
-- **Opus grader** per user direction (technical content). Strict pass/fail per assertion.
-- **Iteration baseline reuse**: baseline runs from iteration 1 were reused for iteration 2 since the baseline configuration didn't change.
-- **One assertion (eval 2 F) was a strictness call**: iteration 2's answer conveyed the substantive content of the skipFirstWrite contract but didn't name the flag literally; grader marked FAIL. The iteration 3 polish prompted the skill to surface the flag name explicitly, which fixed it.
-
-## Files
-
-- Skill (updated): `/home/jack/semantic/next/ai/skills/authoring/ssr-hydration.md`
-- Skill snapshot (pre-update): `skill-snapshot/ssr-hydration.md`
-- Eval prompts: `evals.json`
-- Rubric: `rubric.md`
-- Per-iteration outputs and grading: `iteration-1/`, `iteration-2/`, `iteration-3/`
diff --git a/ai/skills/authoring/ssr-hydration-workspace/evals.json b/ai/skills/authoring/ssr-hydration-workspace/evals.json
deleted file mode 100644
index 138dbc679..000000000
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@@ -1,40 +0,0 @@
-{
-  "skill_name": "ssr-hydration",
-  "evals": [
-    {
-      "id": 0,
-      "name": "innerHTML-doesnt-process-DSD",
-      "prompt": "I'm writing a vitest browser test for a Semantic UI component's SSR hydration. I server-render the component to a string with renderToString, then inject it into a wrapper div via wrapper.innerHTML = html. I append the wrapper to document.body and await a 'rendered' event. The test asserts that el.shadowRoot has the per-item DOM the server emitted. The assertion fails — el.shadowRoot is null at the time I check. Walk me through what's happening and how to fix it. Be specific about which DOM API to use instead and why.",
-      "expected": "Identifies that innerHTML's fragment parser does not process <template shadowrootmode>. Recommends setHTMLUnsafe (or Document.parseHTMLUnsafe). Explains the consequence: hasServerContent is false in connectedCallback, so the component runs fullRender instead of hydrate.",
-      "files": []
-    },
-    {
-      "id": 1,
-      "name": "renderToString-empty-in-browser-env",
-      "prompt": "I'm writing a vitest browser test that calls renderToString(MyComponent, { items: [...] }) and inspects the resulting HTML string. The output is always `<my-component><template shadowrootmode=\"open\"></template></my-component>` — completely empty inside the template. The component's defaultSettings has the items I'm passing, the template has an each block, and on the actual SSR-from-Node path it renders the items fine. What's different about the browser test env, and how do I get renderToString to actually emit the items?",
-      "expected": "Identifies that Template.isServer gates the server vs client renderer selection. In a browser, Template.isServer is false by default, so template.render() picks the client Renderer (which writes to DOM, not strings). Solution: toggle Template.isServer = true around the renderToString call (with try/finally restore).",
-      "files": []
-    },
-    {
-      "id": 2,
-      "name": "each-block-external-state-not-reactive-after-hydrate",
-      "prompt": "I have a Semantic UI component that hydrates from server-rendered DOM. Inside it there's a `{#each item in items}<a class=\"{classMap getItemClasses item}\">{item.title}</a>{/each}` block. The items array is set once from a prop and never mutates. The getItemClasses helper reads state.activeID and returns { active: state.activeID.get() === item.id, item: true }. On the client, mutating state.activeID does NOT update the rendered class — but I added a direct reaction(() => console.log(state.activeID.get())) and it fires correctly on every change. Why is the per-item class binding not reacting, and what's the fix?",
-      "expected": "Identifies that each.hydrate intentionally defers per-item Reaction wiring; per-item bindings only get wired when the items signal first fires (via adoptServerItems → hydrateInnerContent). When items never mutates, the bindings stay unwired forever, so external state changes have nothing to invalidate. The fix is the each-content-classifier introduced in PR #175 — should mention the classifier walks the each's content AST and forces eager adoption when bindings could read external state.",
-      "files": []
-    },
-    {
-      "id": 3,
-      "name": "tachometer-bench-noise-floor-too-high",
-      "prompt": "I added a tachometer bench measuring my component's hydration cost on a 100-item list. The bench reports the bench duration is ~6ms and tachometer says 'no meaningful change' compared to main, with an expected noise floor of ±28%. I'm pretty sure my fix shaved measurable time off hydrate, but the bench can't see it. Why is the noise floor so wide, and what should I change about the bench?",
-      "expected": "Explains that bench noise floor scales inversely with bench duration (per-sample jitter is roughly constant absolute, sub-millisecond). At ~6ms, ±28% is the physics of the measurement. The perf-improvement skill's table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%. Fix: increase the work per sample — bump to 1000 items so the bench duration moves to ~60-160ms range where ±1-2% becomes resolvable.",
-      "files": []
-    },
-    {
-      "id": 4,
-      "name": "snippet-arg-inside-each-not-reactive",
-      "prompt": "I have an each block where each per-item content invokes a snippet: `{#each item in items}<div>{>badge label=item.name}</div>{/each}` and the badge snippet is `{#snippet badge}<span>[{label}]</span>{/snippet}`. After SSR + hydrate, mutating items[0].name (and pushing a new array) doesn't update the rendered label of the first badge. The outer each block's reaction definitely fires (I can see new DOM if I add new items). What's the framework doing?",
-      "expected": "Recognizes this as the same family as the each-hydrate-external-state bug. The snippet invocation is inside the each's per-item content; per-item reactions (including subtemplate/snippet arg evaluations) are deferred by each.hydrate and only wire when items signal first fires via adoptServerItems. Should explain that the each-content-classifier in PR #175 conservatively bails on snippet/template/rerender/async invocations (cross-AST flow it doesn't trace) — forcing eager adoption — which is what fixes this case.",
-      "files": []
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json
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--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/grading.json
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@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)",
-      "passed": true,
-      "evidence": "Opening line states '`wrapper.innerHTML = html` does not process `<template shadowrootmode=\"open\">`. The DSD template stays as a literal `<template>` child of your custom element instead of being attached as a shadow root.' Reinforced later: 'The fragment parsers — `Element.innerHTML`, `Element.outerHTML`, and `Element.insertAdjacentHTML` — explicitly do NOT process `<template shadowrootmode>`.'"
-    },
-    {
-      "text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API",
-      "passed": true,
-      "evidence": "'Replace it with `wrapper.setHTMLUnsafe(html)` (or `Document.parseHTMLUnsafe(html)`).' Fix section shows full example using `wrapper.setHTMLUnsafe(html)` and explains '`Document.parseHTMLUnsafe(html)` is the alternative if you want to construct a whole document.'"
-    },
-    {
-      "text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`",
-      "passed": true,
-      "evidence": "Numbered steps explicitly trace: '1. The custom element parses with no shadow root.' → '3. ... `const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;` ... Because `this.shadowRoot` is `null`, `hasServerContent` is `false`. The element ... runs `fullRender(prototypeTemplate)` — a fresh client render from scratch.'"
-    },
-    {
-      "text": "D: Notes that the failure is silent (no error) — the test \"succeeds\" but is testing a different code path than intended",
-      "passed": true,
-      "evidence": "'This is the silent-failure mode: there is no error, no warning, the test \"succeeds\" in the sense that the component eventually renders something, but you are testing `fullRender`, not `hydrate`.' Also: 'It hid a real hydration bug for hours because the tests \"passed\" against the wrong code path.'"
-    },
-    {
-      "text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)",
-      "passed": true,
-      "evidence": "'when the **HTML parser** encounters `<template shadowrootmode=\"open\">` as a direct child of an element, it creates a shadow root on the parent ...' and 'Critically, the spec restricts this behavior to the **streaming HTML parser** the browser uses for the initial document load. The **fragment parsers** — `Element.innerHTML`, `Element.outerHTML`, and `Element.insertAdjacentHTML` — explicitly do NOT process `<template shadowrootmode>`.'"
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
deleted file mode 100644
index 62964a92e..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,77 +0,0 @@
-# Why your `el.shadowRoot` is null
-
-## Short answer
-
-`wrapper.innerHTML = html` does not process `<template shadowrootmode="open">`. The DSD template stays as a literal `<template>` child of your custom element instead of being attached as a shadow root. Replace it with `wrapper.setHTMLUnsafe(html)` (or `Document.parseHTMLUnsafe(html)`).
-
-## What is actually happening
-
-`renderToString` in `packages/component/src/render-to-string.js` produces:
-
-```html
-<my-el ...>
-  <template shadowrootmode="open">
-    <style>...</style>
-    <!-- per-item DOM with hydration markers -->
-  </template>
-</my-el>
-```
-
-The DSD spec says: when the **HTML parser** encounters `<template shadowrootmode="open">` as a direct child of an element, it creates a shadow root on the parent, moves the template's content into it, and discards the `<template>` element. The parser does this exactly once per element during parsing.
-
-Critically, the spec restricts this behavior to the **streaming HTML parser** the browser uses for the initial document load. The **fragment parsers** — `Element.innerHTML`, `Element.outerHTML`, and `Element.insertAdjacentHTML` — explicitly do NOT process `<template shadowrootmode>`. They leave the `<template>` element as a literal child node. This is by design (DSD-by-`innerHTML` would be an XSS vector against existing pages). To opt in from script you have to use the explicit unsafe variants: `Element.setHTMLUnsafe()` or `Document.parseHTMLUnsafe()`.
-
-So with `wrapper.innerHTML = html`:
-
-1. The custom element parses with **no shadow root**. The `<template shadowrootmode="open">` becomes a regular child element.
-2. When you `appendChild` the wrapper, the browser upgrades the custom element and calls `connectedCallback`.
-3. In `packages/component/src/engines/native/base.js` the decision is:
-
-   ```js
-   const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;
-   // ...
-   if (hasServerContent && this.canHydrate()) {
-     queueMicrotask(() => this.hydrate(prototypeTemplate));
-   } else {
-     // ...
-     this.fullRender(prototypeTemplate);
-   }
-   ```
-
-   Because `this.shadowRoot` is `null`, `hasServerContent` is `false`. The element falls through the `!this.shadowRoot` branch, calls `this.attachShadow({ mode: 'open', ... })`, and runs `fullRender(prototypeTemplate)` — a fresh client render from scratch.
-4. `fullRender` creates and returns a brand-new shadow root **at a different time than your assertion**. Even when it eventually populates a shadow root, the path you took is the client-render path, not hydration. The per-item DOM the server emitted (with `<!--sui-item:v1:KEY-->` markers, etc.) was never adopted — the orphaned `<template>` child is still sitting in light DOM.
-
-The 'rendered' event you await fires on that fullRender path too, so the `await` resolves and your assertion runs — but it is asserting against the wrong execution. This is the silent-failure mode: there is no error, no warning, the test "succeeds" in the sense that the component eventually renders something, but you are testing `fullRender`, not `hydrate`. Per-item hydration assertions (and anything that depends on server-emitted markers) will fail or, worse, appear to pass for the wrong reason.
-
-## The fix
-
-```js
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);                    // processes <template shadowrootmode>
-const el = wrapper.firstElementChild;
-
-const rendered = $(el).onNext('rendered');
-document.body.appendChild(el);
-await rendered;
-
-// el.shadowRoot is now the DSD-attached root with the server's per-item DOM
-expect(el.shadowRoot).toBeTruthy();
-```
-
-`Element.setHTMLUnsafe()` runs the same fragment-parsing path as `innerHTML` but **opts in** to DSD processing. The custom element parses with a real, populated `shadowRoot`. When you append it to the document and `connectedCallback` runs, `hasServerContent` is `true`, `canHydrate()` finds the versioned `sui:v1:` / `sui-block:v1:` markers, and the element takes the `queueMicrotask(() => this.hydrate(prototypeTemplate))` path. The 'rendered' event you await then comes from the real hydration pass, and `el.shadowRoot` contains the per-item DOM the server emitted with Reactions wired to the existing nodes.
-
-`Document.parseHTMLUnsafe(html)` is the alternative if you want to construct a whole document; for an element-scoped wrapper, `setHTMLUnsafe` on the wrapper is the closer drop-in for `innerHTML =`.
-
-## Why this trap is easy to fall into
-
-This bug class is in the SSR hydration workspace's "lessons learned" notes (`ai/plans/archive/hydrate-each-external-state.md`): an entire test helper used `wrapper.innerHTML = html` and every "SSR hydration" test in the file was actually exercising `fullRender`. It hid a real hydration bug for hours because the tests "passed" against the wrong code path. The repo's canonical SSR test helper now uses `setHTMLUnsafe` and carries an inline comment explaining exactly this — see `packages/renderer/test/browser/ssr-hydration.test.js:54-58`:
-
-```js
-// setHTMLUnsafe processes <template shadowrootmode>; innerHTML does not.
-// Without this, the custom element parses with no shadowRoot, hasServerContent
-// is false, and connectedCallback runs fullRender instead of hydrate.
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);
-```
-
-If you're writing a new SSR hydration test, model it on that helper — it also handles two other gotchas you'll hit immediately after this one (toggling `Template.isServer = true` around `renderToString` so the server renderer is selected in a browser env, and stripping `data-sui-bind` from `shadowHTML` for stable assertions).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json
deleted file mode 100644
index cee1093e4..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/grading.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{"expectations": [
-  {"text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)", "passed": true, "evidence": "Short answer states 'The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not.' and explains the literal `<template>` is left in light DOM (lines 4-5, 30)."},
-  {"text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API", "passed": true, "evidence": "Recommends `wrapper.setHTMLUnsafe(html)` as the primary fix (lines 5, 37-49) and also mentions `Document.parseHTMLUnsafe(html)` as an alternative (line 59)."},
-  {"text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`", "passed": true, "evidence": "Line 32-33 explicitly traces: no shadow root attached → `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0` is false → 'framework then runs `fullRender` instead of `hydrate`'. References `connectedCallback` in `packages/component/src/engines/native/base.js`."},
-  {"text": "D: Notes that the failure is silent (no error) — the test 'succeeds' but is testing a different code path than intended", "passed": true, "evidence": "Line 33 notes 'eventually does call `attachShadow` and you get a shadow root populated by a fresh client render' and 'you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child' — this captures the silent-failure framing."},
-  {"text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)", "passed": false, "evidence": "Line 27 mentions 'it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it' — partially captures main-parser-enabled point, but does not explicitly enumerate the fragment parsers (`outerHTML`, `insertAdjacentHTML`) as the limited surface. The contrast between main parser vs fragment parsers is implied but not stated. Borderline; strict reading fails because the assertion specifically asks for the fragment-parser limitation framing."}
-]}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
deleted file mode 100644
index e7af4e86a..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,73 +0,0 @@
-# Why `el.shadowRoot` is null and how to fix it
-
-## Short answer
-
-Replace `wrapper.innerHTML = html` with `wrapper.setHTMLUnsafe(html)`. The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not. With `innerHTML`, the `<template shadowrootmode="open">` that `renderToString` emits stays as a literal `<template>` child in light DOM and no shadow root is ever attached, so `el.shadowRoot` is `null` when your assertion runs.
-
-## What is actually in the SSR string
-
-`renderToString` (in `packages/component/src/render-to-string.js`) wraps the component output like this:
-
-```
-<my-card title="Hello">
-  <template shadowrootmode="open">
-    <style>...</style>
-    ...rendered content with hydration markers...
-  </template>
-  ...slot light DOM...
-</my-card>
-```
-
-That `<template shadowrootmode="open">` is not a regular `<template>` — it is the Declarative Shadow DOM marker. When the HTML parser encounters it, it is supposed to:
-
-1. Attach a shadow root on the parent custom element (`mode: "open"`).
-2. Move the template's contents into that shadow root.
-3. Remove the `<template>` element itself from the tree.
-
-The parser only does that when DSD parsing is explicitly enabled. By spec, it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it. The `innerHTML` setter is intentionally NOT one of them — it has been the standard policy since DSD shipped, to avoid a subtle XSS escalation where existing code that injects untrusted HTML could now also be injecting shadow roots.
-
-So when you do `wrapper.innerHTML = html`:
-- The parser leaves `<template shadowrootmode="open">` as a literal `<template>` child of `<my-card>`.
-- No shadow root is attached.
-- The custom element upgrade fires `connectedCallback`, but because `this.shadowRoot` is `null`, the framework's branch for "DSD content present" is skipped entirely. (See `packages/component/src/engines/native/base.js`, `connectedCallback`: `const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;`.)
-- The framework then runs `fullRender` instead of `hydrate`. That eventually does call `attachShadow` and you get a shadow root populated by a fresh client render — but if you assert at the wrong moment (e.g. synchronously after appending), `el.shadowRoot` can still be `null`. Even if you wait for `rendered`, you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child.
-
-## The fix
-
-Use `Element.setHTMLUnsafe()`:
-
-```js
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);
-const el = wrapper.firstElementChild;
-
-const rendered = $(el).onNext('rendered');
-document.body.appendChild(el);
-await rendered;
-
-expect(el.shadowRoot).toBeTruthy();
-```
-
-`setHTMLUnsafe` is the element-instance API specifically designed for this case: it parses with DSD enabled, so `<template shadowrootmode="open">` becomes the element's shadow root before you ever touch the DOM. By the time you read `wrapper.firstElementChild.shadowRoot`, the shadow root exists with the server content in it. When you append to `document.body`, `connectedCallback` then takes the `hasServerContent` branch and calls `hydrate(prototypeTemplate)` rather than `fullRender(...)` — wiring reactive bindings to the existing per-item DOM the server emitted.
-
-The canonical comment from the framework's own hydration test (`packages/renderer/test/browser/ssr-hydration.test.js`, around line 54) makes the contract explicit:
-
-> setHTMLUnsafe processes `<template shadowrootmode>`; innerHTML does not. Without this, the custom element parses with no shadowRoot, hasServerContent is false, and connectedCallback runs fullRender instead of hydrate.
-
-## A few related gotchas worth pinning while you're here
-
-- **Do not use `DOMParser.parseFromString(html, 'text/html')` either.** By default it also does not parse DSD. The opt-in there is the static `Document.parseHTMLUnsafe(html)` (which returns a full `Document`); that works too if you need a whole-document parse, but for injecting a single component into an existing test page, `setHTMLUnsafe` on a wrapper element is the natural fit.
-- **`Template.isServer` matters in browser tests.** `renderToString` only emits the SSR (DSD) string when `Template.isServer` is `true`. In a browser test environment it defaults to `false`, so you will get client output unless you flip it. The framework's own helper does this:
-  ```js
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  try { html = renderToString(Component, attrs); }
-  finally { Template.isServer = wasServer; }
-  ```
-  If your wrapper assertion is failing on `el.shadowRoot` being null, this is the second thing to check after `setHTMLUnsafe` — without `Template.isServer = true`, `renderToString` may not have produced a DSD string in the first place.
-- **`rendered` is the right event to await for hydration.** The framework's `connectedCallback` schedules `hydrate` via `queueMicrotask`, so you cannot read `el.shadowRoot.querySelector(...)` synchronously after `appendChild`. `await $(el).onNext('rendered')` is what the in-repo tests use, and it resolves after `template.markRendered()` inside `hydrate`.
-- **Do not assert the absence of comment markers right after `rendered`.** The hydration scaffolding (`<!-- sui:v1: ... -->` comments and `data-sui-bind="..."` attributes) is removed in a `requestAnimationFrame` callback after hydration, one tick later than the `rendered` event. If your test wants to compare `shadowRoot.innerHTML` strings, strip them yourself, the way the in-repo tests do (`shadowHTML(el)` helper). Otherwise an assertion that "the per-item DOM the server emitted" matches your expected string will fail because the server's per-item DOM is still wrapped in those markers.
-
-## Why this trips people up
-
-`innerHTML` is the muscle-memory API for "parse this string into DOM," and `setHTMLUnsafe` looks like a scary scoped variant. It is actually the opposite: `setHTMLUnsafe` is more permissive (it allows DSD), and `innerHTML` is the "safe" default that strips it. For anything involving `renderToString` output from `@semantic-ui/component`, you want the more permissive one — the whole point of the SSR string is the DSD inside it.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json
deleted file mode 100644
index efc0863c3..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `Template.isServer` as the controlling flag",
-      "passed": true,
-      "evidence": "The answer's title section is 'The root cause: Template.isServer is computed from typeof window' and explicitly states 'It picks based on the static flag Template.isServer'. Also enumerates Template.isServer = false as the cause."
-    },
-    {
-      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
-      "passed": true,
-      "evidence": "Quotes the exact selection code from template.js line 292: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and explains the consequence."
-    },
-    {
-      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
-      "passed": true,
-      "evidence": "Section 'Why the output looks empty' states 'When template.render() ran through the client Renderer.render() ... it returned a DocumentFragment - not a string' and explains the fragment coerces to '[object DocumentFragment]', leaving the items never appearing."
-    },
-    {
-      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
-      "passed": true,
-      "evidence": "The fix section explicitly shows `const wasServer = Template.isServer; Template.isServer = true;` around the renderToString call, both as canonical pattern from the framework's own tests and as a fix for the user."
-    },
-    {
-      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
-      "passed": true,
-      "evidence": "Both code examples wrap renderToString in try/finally with `Template.isServer = wasServer` in finally, and adds 'Always restore in a finally - leaving Template.isServer = true for the rest of the test file will break any test that mounts a real component'."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md
deleted file mode 100644
index d29a768ca..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,128 +0,0 @@
-# Why `renderToString` returns an empty `<template>` in your Vitest browser test
-
-## The root cause: `Template.isServer` is computed from `typeof window`
-
-`renderToString` does not pick the server vs client renderer based on what you call. It picks based on the static flag `Template.isServer`, which is initialized once at module load from this expression in `@semantic-ui/utils`:
-
-```js
-// packages/utils/src/environment.js
-export const isServer = (() => {
-  return typeof window === 'undefined';
-})();
-```
-
-That value is then frozen onto the Template class:
-
-```js
-// packages/templating/src/template.js
-import { isServer } from '@semantic-ui/utils';
-// ...
-export const Template = class Template {
-  static isServer = isServer;
-  // ...
-};
-```
-
-And the engine selection inside `Template.initialize()` consults exactly that flag:
-
-```js
-// packages/templating/src/template.js (line 292)
-const RendererClass = (Template.isServer && engine.serverRenderer)
-  ? engine.serverRenderer
-  : engine.renderer;
-```
-
-In a Vitest **browser** test (`vitest --browser`, Playwright/WebDriver runner), `window` exists. So:
-
-- `isServer` is `false`
-- `Template.isServer` is `false`
-- `RendererClass` is `engine.renderer` — the **client** `Renderer`, not `ServerRenderer`
-
-You called `renderToString`, but the template was wired up with the client renderer that produces a live DOM `DocumentFragment`, not the server renderer that produces an HTML string.
-
-## Why the output looks empty
-
-`renderToString` then does this at line 67 of `packages/component/src/render-to-string.js`:
-
-```js
-let html = template.render();
-// ...
-html = expandCustomElements(html, { depth, hydrate, renderFn: renderToString });
-// ...
-return `<${tagName}...><template shadowrootmode="open">${css ? `<style>${css}</style>` : ''}${html}</template>...</${tagName}>`;
-```
-
-When `template.render()` ran through the client `Renderer.render()` (line 157 of `packages/renderer/src/engines/native/renderer.js`), it returned a `DocumentFragment` — not a string. Two things then happen:
-
-1. `expandCustomElements(html, ...)` walks `html` as a string (`html.length`, `html.indexOf('<')`, etc.). A `DocumentFragment` coerced to string is `"[object DocumentFragment]"`, which contains no `<` and no registered tag names. It passes through.
-2. The final template-literal interpolation coerces the fragment to a string. Depending on how your snapshot strips it, you can see an empty body or stray text — the items never appear because the each block was expanded into live DOM nodes inside a fragment that was never serialized to HTML.
-
-The data merge, the `each` block, and `defaultSettings` are all fine. None of the SSR string-emission path ran.
-
-## The fix: toggle `Template.isServer` around the call
-
-The framework's own SSR-in-browser tests do exactly this. From `packages/renderer/test/browser/ssr-hydration.test.js` (lines 39–52):
-
-```js
-async function ssrAndHydrate(opts, attrs = {}) {
-  const tag = uniqueTag();
-  const Component = defineComponent({ tagName: tag, renderingEngine: 'native', ...opts });
-
-  // Toggle Template.isServer so renderToString actually emits SSR HTML in
-  // the browser test env (it gates server vs client renderer selection).
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  let html;
-  try {
-    html = renderToString(Component, attrs);
-  }
-  finally {
-    Template.isServer = wasServer;
-  }
-  // ...
-}
-```
-
-For your test:
-
-```js
-import { Template } from '@semantic-ui/templating';
-import { renderToString } from '@semantic-ui/component';
-
-it('renders items', () => {
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  let html;
-  try {
-    html = renderToString(MyComponent, { items: [...] });
-  } finally {
-    Template.isServer = wasServer;
-  }
-  expect(html).toContain('<li>');
-});
-```
-
-Always restore in a `finally` — leaving `Template.isServer = true` for the rest of the test file will break any test that mounts a real component (mounting paths bail out of client-only logic, and `template.render()` returns strings instead of fragments).
-
-## If your test also injects the DSD into the page
-
-There's a second gotcha worth flagging because the same test file documents it (line 54): use `setHTMLUnsafe`, not `innerHTML`, when injecting the resulting DSD. `innerHTML` does not process `<template shadowrootmode>` — the custom element will parse with no `shadowRoot`, `connectedCallback` will see no DSD, and you'll get a full client render instead of hydration:
-
-```js
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);
-const el = wrapper.firstElementChild;
-document.body.appendChild(el); // triggers hydration
-```
-
-## Why the Node-side SSR path "just works"
-
-When you SSR from Node (Astro build, a Node script, a Node-environment Vitest test), `window` is undefined at module load, so `isServer === true` from the start. `Template.isServer` is correct without any toggling. The browser test environment is the one place this leaks because the `isServer` constant is captured eagerly, not recomputed per call — and there's no per-call override on `renderToString` to force the server engine.
-
-## Files referenced
-
-- `/home/jack/semantic/next/packages/component/src/render-to-string.js`
-- `/home/jack/semantic/next/packages/templating/src/template.js` (lines 43, 292)
-- `/home/jack/semantic/next/packages/utils/src/environment.js` (lines 5–7)
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/renderer.js` (lines 157–163)
-- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` (lines 39–67) — canonical pattern for this exact scenario
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json
deleted file mode 100644
index dc14369dd..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `Template.isServer` as the controlling flag",
-      "passed": true,
-      "evidence": "Section heading at line 3: 'Root cause: `Template.isServer` is `false` in a real browser'. Lines 14-21 trace it back to `@semantic-ui/utils` `isServer = typeof window === 'undefined'`. Lines 23-25 explicitly state that in browser env `Template.isServer` is `false`, selecting the client renderer."
-    },
-    {
-      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
-      "passed": true,
-      "evidence": "Lines 7-12 quote the exact selection code from `template.js:292`: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and frames it as 'The renderer that gets instantiated is selected here'."
-    },
-    {
-      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
-      "passed": true,
-      "evidence": "Lines 25-34: 'the client renderer (engines/native/renderer.js) is selected. Its render() returns a DocumentFragment, not a string'. Lines 36-65 then trace how the non-string DocumentFragment causes `expandCustomElements` to silently produce empty output, yielding the empty `<template shadowrootmode=\"open\"></template>` wrapper symptom (lines 67-69)."
-    },
-    {
-      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
-      "passed": true,
-      "evidence": "Line 80: 'Force `Template.isServer = true` for the duration of the `renderToString` call.' Lines 86-96 show the explicit `Template.isServer = true` toggle wrapping the `renderToString` call. Line 98 explains the timing: 'The flag has to be set before renderToString is invoked... and restored after'."
-    },
-    {
-      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
-      "passed": true,
-      "evidence": "Lines 86-95 show the canonical pattern: `const wasServer = Template.isServer; Template.isServer = true; try { return renderToString(...) } finally { Template.isServer = wasServer; }`. Line 103 reinforces the rationale: 'Don't set Template.isServer = true globally in a beforeAll - it will break any test in the same file that exercises the live client renderer'."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md
deleted file mode 100644
index b00247967..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-1-Template-isServer/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,119 +0,0 @@
-# Why `renderToString` emits an empty DSD in Vitest browser mode
-
-## Root cause: `Template.isServer` is `false` in a real browser
-
-`renderToString` is renderer-agnostic — it builds a `Template`, calls `template.initialize()`, then `template.render()`, and string-concatenates the result into the DSD wrapper. The renderer that gets instantiated is selected here:
-
-`packages/templating/src/template.js:292`
-```js
-const RendererClass = (Template.isServer && engine.serverRenderer)
-  ? engine.serverRenderer
-  : engine.renderer;
-```
-
-`Template.isServer` is initialized once, at module load, from `@semantic-ui/utils`:
-
-`packages/utils/src/environment.js:5`
-```js
-export const isServer = (() => {
-  return typeof window === 'undefined';
-})();
-```
-
-In Node SSR, `window` is undefined → `isServer === true` → the **server** renderer is selected → `template.render()` returns an HTML string → `renderToString` concatenates it into the DSD and you get fully-populated `each` output.
-
-In Vitest **browser** mode (`@vitest/browser` driving Chromium / Firefox / WebKit / Playwright), `window` is a real browser global. `typeof window === 'undefined'` is `false`, so `Template.isServer` is `false`, and the **client** renderer (`engines/native/renderer.js`) is selected. Its `render()` returns a `DocumentFragment`, not a string:
-
-`packages/renderer/src/engines/native/renderer.js:157`
-```js
-render() {
-  return this.readAST({ ast: this.ast, data: this.data, scope: this.scope });
-}
-// ...
-return fragment;  // DocumentFragment
-```
-
-## Why the inner template is *empty*, not garbled
-
-Look at what `renderToString` does with that value:
-
-`packages/component/src/render-to-string.js:67`
-```js
-let html = template.render();                // DocumentFragment in browser env
-html = expandCustomElements(html, { ... });  // string-only function
-```
-
-`expandCustomElements` is written for strings:
-
-`packages/component/src/expand-custom-elements.js:25`
-```js
-while (pos < html.length) {  // DocumentFragment.length is undefined
-  ...
-}
-```
-
-`pos < undefined` is `false`, so the loop body never runs and the function returns `''` (its `result` accumulator). Then the wrapper is built around an empty string:
-
-```js
-return `<${tagName}...>`
-  + `<template shadowrootmode="open">`
-  + (css ? `<style>${css}</style>` : '')
-  + html                          // ''
-  + `</template>`
-  + slotHTML
-  + `</${tagName}>`;
-```
-
-→ exactly the symptom you see:
-```
-<my-component><template shadowrootmode="open"></template></my-component>
-```
-
-(If your component happens to have a `css` block, you'll see a `<style>` inside the template but still no markup.)
-
-## The Node SSR path "just works" because of module load order
-
-When the test runner is Node (jsdom or node mode), `window` is undefined at the time `@semantic-ui/utils/environment.js` is first imported, so `isServer` evaluates to `true` and is captured into `Template.isServer`. Even if jsdom later adds a `window` global, the constant has already been frozen. That's why your Node-side rendering works and your browser-side rendering is empty — it's not about your component, your `defaultSettings`, your `each` block, or your data; it's purely about which renderer class got chosen at `initialize()` time.
-
-## Fix
-
-Force `Template.isServer = true` for the duration of the `renderToString` call. The repo's own browser tests do exactly this — see `packages/renderer/test/browser/ssr-hydration.test.js:39`:
-
-```js
-import { defineComponent, renderToString } from '@semantic-ui/component';
-import { Template } from '@semantic-ui/templating';
-
-function ssrInBrowser(Component, attrs) {
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  try {
-    return renderToString(Component, attrs);
-  }
-  finally {
-    Template.isServer = wasServer;
-  }
-}
-```
-
-Wrap your `renderToString` call in that `try/finally`. The flag has to be set **before** `renderToString` is invoked (because `template.initialize()` reads it once and instantiates the renderer right then) and restored after (so any subsequent client-side code in the same test — hydration, mount, reactivity assertions — still gets the DOM renderer). The flag is read on every `initialize()`, so per-call toggling is safe and doesn't leak across tests as long as the `finally` runs.
-
-A few practical notes:
-
-- Do this in a small helper rather than inline, and call it from every test that needs the SSR string. Forgetting the toggle is the single failure mode.
-- Don't set `Template.isServer = true` globally in a `beforeAll` — it will break any test in the same file that exercises the live client renderer (mount, hydrate, reactive update).
-- If you also want to verify hydration end-to-end (inject the DSD, let the browser parse `<template shadowrootmode="open">`, then upgrade the custom element), use `wrapper.setHTMLUnsafe(html)` instead of `innerHTML`. Plain `innerHTML` does not process declarative shadow DOM, so the element parses with no shadow root and `connectedCallback` falls back to a full client render — making your test a non-hydration test by accident. The browser test in `ssr-hydration.test.js:58` shows the pattern.
-- Nothing about `defaultSettings`, the `each` block, or your `items` data is involved. The component is fine. The fix is one line of test scaffolding.
-
-## Why the framework doesn't autodetect this
-
-`renderToString` could in principle override the engine selection itself (it already passes `renderingEngine: 'native'` to `proto.clone()`), but it currently delegates the server-vs-client decision to `Template.isServer`, which is a process-wide flag derived from `typeof window`. In the canonical use case — calling `renderToString` from a Node/Bun/Workers SSR path — that's correct and zero-config. The browser test environment is the edge case where the flag's heuristic is wrong, and the framework's own test suite handles it with the same toggle pattern shown above. Treat it as a known wart of running SSR code in a browser-mode test runner, not a bug in your component.
-
-## Relevant source files
-
-- `/home/jack/semantic/next/packages/component/src/render-to-string.js` — the entry point; line 67 calls `template.render()`, lines 84–90 build the DSD wrapper.
-- `/home/jack/semantic/next/packages/templating/src/template.js` — line 43 captures `Template.isServer` from `utils`; lines 292–294 select the server vs. client renderer class.
-- `/home/jack/semantic/next/packages/utils/src/environment.js` — line 5 defines `isServer = typeof window === 'undefined'`.
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/renderer.js` — line 157 `render()` returns a `DocumentFragment`.
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/server.js` — the alternative ServerRenderer that returns a string.
-- `/home/jack/semantic/next/packages/component/src/expand-custom-elements.js` — line 25 string-only `while (pos < html.length)` silently no-ops on a `DocumentFragment`.
-- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` — lines 39–67 are the canonical browser-test pattern (`Template.isServer = true` toggle plus `setHTMLUnsafe`).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json
deleted file mode 100644
index 88073fd7f..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
-      "passed": true,
-      "evidence": "Answer describes the lazy/eager paths in each.hydrate explicitly (lines 12-14) and frames the lazy path as 'a deliberate optimization' (line 105): 'if every per-item binding reads only iteration-local data, the items signal firing is the *only* thing that can ever invalidate them, so deferring wiring until that fire is safe and saves work.'"
-    },
-    {
-      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
-      "passed": true,
-      "evidence": "Lines 12-14: 'Lazy — only register a dependency on the items collection itself. Per-item bindings get no Reactions until the items signal fires for the first time, at which point `adoptServerItems` walks `<!--sui-item:v1:KEY-->` markers, reuses each item's server DOM, and wires per-item Reactions inside.'"
-    },
-    {
-      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
-      "passed": true,
-      "evidence": "Line 5: 'Your `items` Signal never mutates, so the each-block's lazy hydration optimization is *staying* lazy'. Line 54: 'Your items don't mutate, so `adoptServerItems` never runs, and the binding never gets a Reaction watching `state.activeID`.'"
-    },
-    {
-      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
-      "passed": true,
-      "evidence": "Line 5: 'The class binding has nothing watching `state.activeID` to invalidate.' Line 54: 'the binding never gets a Reaction watching `state.activeID`. That matches your symptoms exactly.' The whole 'Where your case lands' section traces `getItemClasses` through the classifier."
-    },
-    {
-      "text": "E: References the each-content-classifier (or equivalent fix shape: \"force eager adoption when bindings could read external state\") as the resolution",
-      "passed": true,
-      "evidence": "Answer extensively discusses `each-content-classifier.js` and `isEachContentSelfContained` (lines 16-33). Fix #3 (line 91) is explicit: 'Force eager wiring by adding any binding the classifier flags as external.' Files section also points to the classifier source path."
-    },
-    {
-      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
-      "passed": false,
-      "evidence": "No mention of `skipFirstWrite` anywhere in the answer (grep confirms zero occurrences). The answer discusses Reactions being 'wired' but never explains the skipFirstWrite mechanism — that the Reaction evaluates the binding once at hydrate time to register external deps without rewriting DOM. This mechanistic detail is missing."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md
deleted file mode 100644
index 15dd26464..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,113 +0,0 @@
-# Why your `{#each}` per-item class binding doesn't react after hydration
-
-## Short answer
-
-Your `items` Signal never mutates, so the each-block's "lazy" hydration optimization is *staying* lazy — and on the lazy path no per-item Reactions are wired. The class binding has nothing watching `state.activeID` to invalidate. Your standalone `reaction(() => state.activeID.get())` works because you wired it directly; the each block never wired the equivalent for `getItemClasses`.
-
-The fix in 90% of cases: rewrite the helper as an inline expression that the static classifier can see reads external state, or push the active state into the items themselves. The "load-bearing" fix: the classifier in `each-content-classifier.js` should be flagging this as not-self-contained, so if it isn't, that's a classifier bug worth filing — see "If the classifier should have caught this" below.
-
-## What's actually happening
-
-Each-block hydration in `packages/renderer/src/engines/native/blocks/each.js` has two paths:
-
-- **Lazy** — only register a dependency on the items collection itself. Per-item bindings get no Reactions until the items signal fires for the first time, at which point `adoptServerItems` walks `<!--sui-item:v1:KEY-->` markers, reuses each item's server DOM, and wires per-item Reactions inside.
-- **Eager** — call `adoptServerItems` immediately during `hydrate`, wiring per-item Reactions against the server-rendered DOM right away.
-
-The decision is made by `isEachContentSelfContained(node)` (`packages/renderer/src/engines/native/blocks/each-content-classifier.js`):
-
-```js
-// hydrate hook in each.js
-if (isEachContentSelfContained(node)) {
-  return;  // lazy — defer per-item wiring to first items mutation
-}
-// otherwise: adoptServerItems(...)  — eager wiring
-```
-
-The classifier is a static syntactic walk of the each's content AST. A per-item expression is "self-contained" only if every bare identifier resolves to one of:
-
-- iteration-local names (`as` name, `indexAs` name, plus implicit `this`/`index`/`key`)
-- a framework-shipped helper from `TemplateHelpers` (`PURE_HELPERS = new Set(Object.keys(TemplateHelpers))` captured once at module load)
-- a reserved JS keyword (`true`, `false`, `null`, ...)
-
-Anything else — a component method, a user-registered helper, a closure that reads `state.x` — flips the block to eager.
-
-## Where your case lands
-
-Your binding looks like:
-
-```
-<a class="{classMap getItemClasses item}">
-```
-
-`classMap` is a framework helper (it's in `TemplateHelpers`), so it doesn't disqualify. `item` is the iteration-local name (`as item`), also fine. The bare identifier that decides this is **`getItemClasses`**.
-
-Two scenarios — both ought to flip to eager but the symptom you describe means at least one didn't:
-
-**Scenario A — `getItemClasses` is a component method exposed via `createComponent`'s return value.** The classifier doesn't trace data context, so `getItemClasses` resolves as "not in local scope, not in `PURE_HELPERS`, not reserved" → returns `false` → eager path runs. This *should* work. If it isn't, the issue is somewhere else (see Scenario B and the "If the classifier should have caught this" check).
-
-**Scenario B — `getItemClasses` was added via `registerHelper(...)`.** The classifier captures `PURE_HELPERS` at module-import time:
-
-```js
-const PURE_HELPERS = new Set(Object.keys(TemplateHelpers));
-```
-
-If the helper was registered *before* `each-content-classifier.js` loaded, it lands in the snapshot and the classifier mistakes it for a pure helper → returns `true` → lazy path → never wires per-item Reactions on hydrate. Your items don't mutate, so `adoptServerItems` never runs, and the binding never gets a Reaction watching `state.activeID`. That matches your symptoms exactly.
-
-The classifier comment is explicit about this:
-
-> User-registered helpers (`Template.registerHelper`) are statically indistinguishable from component methods, so they fall into the "external" bucket via the identifier check. That's the correct call: a helper that reads state needs the per-binding Reaction to wire.
-
-That comment describes the intended behavior — but it's only true if the helper is registered *after* the classifier module load. The order-of-registration footgun is real.
-
-## How to verify which scenario you're in
-
-Quick check from devtools after the page loads (before any items mutation):
-
-```js
-const eachStart = $0.shadowRoot.querySelector('whatever-anchors-the-each');
-// Or: walk shadowRoot for sui-item:v1: comments — if they're still present
-// and the markers haven't been replaced by empty text nodes, the lazy path
-// won the classifier and no per-item Reactions exist.
-```
-
-If the `<!--sui-item:v1:KEY-->` comment markers are still present in the DOM after first paint, you're on the lazy path. After eager-path adoption (or any reconcile) those markers are replaced by empty text-node startMarkers.
-
-You can also test it directly: mutate `state.items` once (e.g. `state.items.push(state.items.shift())` or just `state.items.set([...state.items.get()])`). If the active class suddenly starts updating after that, you've confirmed the lazy path was the culprit — the items mutation triggered `adoptServerItems`, which wired the per-item Reactions.
-
-## Fixes
-
-In rough order of how I'd reach for them:
-
-**1. Move `active` into the items themselves.** The cleanest. Build a derived items list (or update `items[i].active` on `activeID` change) and template against `item.active` directly. Now the binding only reads iteration-local data, the lazy path is correct, and reactivity flows through the item signal as designed.
-
-**2. Inline the binding so the classifier can see the external read.** Replace `getItemClasses item` with the expression body inline:
-
-```
-<a class="{classMap (eq state.activeID item.id) 'active' true 'item'}">
-```
-
-Now the classifier sees `state` as a bare identifier in local scope check → not local, not pure → returns `false` → eager wiring → reactive. (Confirm the spelling of `eq` in your helpers — `isEqual` may be the framework name.)
-
-**3. Force eager wiring by adding any binding the classifier flags as external.** If you want to keep the helper, add anything else inside the each that statically reads a non-local name — even a no-op. The classifier returns `false` on the first not-self-contained node it finds, and the whole block flips to eager.
-
-**4. Defer registration so the classifier sees the helper as external.** Avoid relying on this — it's order-of-imports magic — but if you must keep `getItemClasses` registered as a helper *and* keep the binding shape, ensure the helper is registered after `@semantic-ui/renderer`'s each-content-classifier module loads. The cleanest version of this is "don't register state-reading helpers"; treat `registerHelper` as for pure functions only, per its design intent.
-
-## If the classifier should have caught this (Scenario A) but didn't
-
-If `getItemClasses` is a component method (not a registered helper) and the bug still reproduces, that's a classifier miss. Things to check before filing:
-
-- Is `getItemClasses` named exactly the same as a `TemplateHelpers` key? (Look at `packages/templating/src/template-helpers.js` — `classMap`, `classIf`, `eq`, `is`, `isNot`, `join`, etc.) A name collision would let the classifier mistake your method for a pure helper.
-- Is the AST node-shape what the classifier expects? Lisp-style `{classMap getItemClasses item}` should walk fine, but if your template authoring path is producing a different node `type` than `'expression'`, the classifier's switch may bail in the wrong direction.
-- Run `isEachContentSelfContained` directly against your each AST node and log the result. Cached on the AST node identity, so just call it.
-
-## The underlying principle
-
-Hydration trusts the server DOM and wires Reactions to it — it doesn't re-evaluate. Per-item Reactions are the wires that connect future state changes to the existing per-item DOM. The lazy path is a deliberate optimization: if every per-item binding reads only iteration-local data, the items signal firing is the *only* thing that can ever invalidate them, so deferring wiring until that fire is safe and saves work.
-
-When a binding actually reads external state, that assumption breaks: the items signal may never fire, the wires never go in, and external mutations have nothing to invalidate. Your case is the canonical example. The classifier is the gate — if it lets the wrong shape through to the lazy path, the binding goes dark exactly the way you're describing.
-
-## Files
-
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — the two hydrate paths (lines ~646-687) and `adoptServerItems` (lines ~505-616)
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — the static classifier; `PURE_HELPERS` snapshot is the load-order footgun
-- `/home/jack/semantic/next/packages/templating/src/template-helpers.js` — `TemplateHelpers` and `registerHelper`
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json
deleted file mode 100644
index aee8bb003..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
-      "passed": true,
-      "evidence": "Section 'What the each block does on hydrate' explicitly frames it as 'a deliberate optimization at hydrate time' and dedicates a paragraph (lines 55-59) to the rationale: 'the common case... the per-item binding reads only iteration-local data, the server-rendered DOM is already correct, and there is nothing to react to at hydrate time. Wiring N Reactions for N items at hydrate just to have them never fire is wasted work on first paint. Defer them and pay only on the first real change.'"
-    },
-    {
-      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
-      "passed": true,
-      "evidence": "Lines 35-53 quote the relevant `each.hydrate` code with `lookupExpression(node.over)` registering the items-collection dep, and explicitly state: 'Wiring inner Reactions is deferred to a function called `adoptServerItems`, which runs the first time `update` fires (i.e. the first time the items signal changes after hydrate).'"
-    },
-    {
-      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
-      "passed": true,
-      "evidence": "Lines 97-99: 'The killer detail: the items signal's only chance to wake the per-item bindings is to itself fire. Your items are set once from a prop. They never mutate. So the deferred wire-up never happens.' Also reinforced in lines 84-89 walking the post-hydrate timeline."
-    },
-    {
-      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
-      "passed": true,
-      "evidence": "Lines 75-91 directly link the bug: '`state.activeID` is *external* to the iteration scope. The per-item attribute binding's Reaction is the thing that needs to subscribe to it... Nothing in the each block is subscribed to `state.activeID`. The block does not invalidate.... Class string stays at whatever the server rendered.'"
-    },
-    {
-      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
-      "passed": true,
-      "evidence": "Section 'The framework fix (commit 0df8d554e)' (lines 102-135) names the file `packages/renderer/src/engines/native/blocks/each-content-classifier.js`, describes the classifier walking the each's content AST to answer 'could any binding inside this each read external state?', and concludes 'The classifier returns false → `each.hydrate` calls `adoptServerItems` *now* instead of deferring.'"
-    },
-    {
-      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
-      "passed": false,
-      "evidence": "The answer says per-item Reactions 'subscribe to `state.activeID` on their first run' (line 134) and that adoptServerItems 'walks the existing DOM (matched up to server item markers by key) and creates per-item Reactions on the already-rendered nodes', which captures the spirit of evaluation-as-subscription. However, the specific `skipFirstWrite: true` mechanism is never named, nor is the explicit notion that the Reaction trusts the SSR'd DOM and skips its first write so as not to clobber the server output. The rubric calls for the named flag/mechanism."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md
deleted file mode 100644
index d70d295b0..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-2-each-external-state/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,203 +0,0 @@
-# Why the per-item class doesn't react after hydration
-
-## Short answer
-
-Your `{#each}` block's per-item attribute Reactions never wired against
-`state.activeID`. The render-time path that would have wired them is gated on
-the items signal firing — and your items collection is set once and never
-mutates, so the per-item bindings never get a chance to subscribe to the
-external state their helper depends on.
-
-The fix is one of:
-
-1. Upgrade to a framework version that includes the eager-hydrate classifier
-   (commit `0df8d554e`, "Bug: Hydrate each items eagerly when bindings read
-   external state"). With that fix, the each block notices that the per-item
-   binding reads external state via a non-framework helper (`getItemClasses`)
-   and wires per-item Reactions during `hydrate` instead of deferring to the
-   first items mutation.
-2. If you're stuck on an older version, force the items signal to fire once
-   after hydration so the deferred wire-up path runs, e.g.
-   `state.items.notify()` in `onRendered`, or trigger a no-op
-   `state.items.set(state.items.get())` once. This is a workaround, not the
-   intended pattern.
-
-The rest of this doc explains *why* the deferred-wire optimization exists and
-*why* your shape is the precise one that breaks it — that context matters
-because the same pattern keeps biting people whose data arrives at hydrate
-time rather than after.
-
-## What the each block does on hydrate
-
-The native engine's each block (`packages/renderer/src/engines/native/blocks/each.js`)
-makes a deliberate optimization at hydrate time. From `each.hydrate`:
-
-```js
-hydrate({ node, lookupExpression, ... }) {
-  // Always register a dep on the collection so future mutations invalidate.
-  lookupExpression(node.over);
-  self.hasHydrated = true;
-
-  // ... possibly bail and DEFER per-item wiring ...
-}
-```
-
-Two things happen on hydrate:
-
-1. The block registers a dependency on the *items collection* signal so a
-   future mutation to the items array will rerun the block.
-2. It does **not** wire per-item Reactions for inner content. Per-item DOM
-   already exists (the server emitted it, bracketed by `<!--sui-item:v1:KEY-->`
-   markers). Wiring inner Reactions is deferred to a function called
-   `adoptServerItems`, which runs the first time `update` fires (i.e. the
-   first time the items signal changes after hydrate).
-
-The reason for the defer: the common case is `{#each item in items}<span>{item.name}</span>{/each}`
-— the per-item binding reads only iteration-local data, the server-rendered
-DOM is already correct, and there is nothing to react to at hydrate time. Wiring
-N Reactions for N items at hydrate just to have them never fire is wasted work
-on first paint. Defer them and pay only on the first real change.
-
-This optimization is unsafe whenever a per-item binding reads anything outside
-the iteration scope.
-
-## Why your case breaks
-
-Your binding looks like this:
-
-```hbs
-{#each item in items}
-  <a class="{classMap getItemClasses item}">{item.title}</a>
-{/each}
-```
-
-Where `getItemClasses` is a method that calls `state.activeID.get()`.
-
-`state.activeID` is *external* to the iteration scope. The per-item attribute
-binding's Reaction is the thing that needs to subscribe to it, because that
-Reaction is what writes the `class` attribute back to the DOM when activeID
-changes.
-
-But on the deferred path, that per-item Reaction is never created. Walk
-through what happens after hydrate:
-
-- Hydrate runs. The block registers a dep on `items` and bails (deferring per-
-  item wiring).
-- You mutate `state.activeID`.
-- Nothing in the each block is subscribed to `state.activeID`. The block does
-  not invalidate. `update` does not run. `adoptServerItems` does not run. No
-  per-item Reaction was ever wired against `state.activeID`.
-- Class string stays at whatever the server rendered.
-
-Your sanity check (`reaction(() => console.log(state.activeID.get()))`) works
-because *that* reaction subscribed at creation time. The Reactions inside the
-each block — the ones that would write the class attribute — were never
-created.
-
-The killer detail: the items signal's only chance to wake the per-item
-bindings is to itself fire. Your items are set once from a prop. They never
-mutate. So the deferred wire-up never happens.
-
-## The framework fix (commit 0df8d554e)
-
-The fix is a static classifier
-(`packages/renderer/src/engines/native/blocks/each-content-classifier.js`)
-that runs once per unique each-content AST shape (cached on AST identity, so
-it's effectively free per component instance). It walks the each's content
-AST and answers one question: "could any binding inside this each read
-external state?"
-
-The classifier knows about:
-
-- Iteration-local names (`item`, `index`, `key`, `this`, plus whatever the
-  user named in `as` / `,index` / `,key`)
-- The framework's pure helpers (`classMap`, `classIf`, `formatDate`,
-  `concat`, ... — everything in `TemplateHelpers`)
-- JS reserved names (`true`, `false`, `null`, `typeof`, ...)
-
-For each expression, every bare identifier head must resolve to one of those
-sets. If anything else appears (a component method, a user-registered helper,
-a state name closed over by an inline expression), the classifier returns
-"not self-contained."
-
-For your expression `{classMap getItemClasses item}`, the tokens are:
-
-- `classMap` — pure helper, OK
-- `getItemClasses` — not in the iteration scope, not in the pure-helper
-  registry → classifier returns false (external reads possible)
-- `item` — iteration-local, OK
-
-The classifier returns false → `each.hydrate` calls `adoptServerItems` *now*
-instead of deferring. `adoptServerItems` walks the existing DOM (matched up
-to server item markers by key) and creates per-item Reactions on the
-already-rendered nodes. Those Reactions subscribe to `state.activeID` on
-their first run, and from that point on, mutations propagate.
-
-There is a regression test pinning exactly your shape:
-`packages/renderer/test/browser/ssr-hydration.test.js:315` — "helper-call
-attribute inside each is reactive after hydration when items pre-populated".
-Its docstring is a transcription of this entire failure mode — it was
-discovered in production from a docs-site `inpage-menu` that wouldn't update
-its active-section indicator on scroll.
-
-## Things that won't fix it (so you can rule them out)
-
-- Replacing `classMap` with `classIf` or string concat — same shape,
-  `getItemClasses` (or whatever non-framework function you call) is still the
-  external-state read.
-- Using `state.activeID.peek()` instead of `.get()` — peek explicitly opts
-  out of dependency tracking. You'd lose reactivity *to* activeID, not gain
-  it.
-- Wrapping the helper call in a parent reactive context (e.g. the component's
-  `onRendered`) — that doesn't propagate down into the per-item Reactions
-  because the per-item Reactions are what need to exist in the first place.
-- Switching the items prop from a plain array to a Signal — the items signal
-  *is* already a Signal under the hood. The issue is not the items channel,
-  it's that the per-item bindings haven't been wired yet.
-
-## Things that will fix it
-
-- **Preferred:** upgrade to the framework version with the classifier fix.
-  No code change required on your side; the classifier inspects your AST
-  and sees `getItemClasses` is not a framework helper, switches to the
-  eager path, and your binding starts reacting.
-- **Workaround on older versions:** force the items signal to fire once
-  after hydrate so the deferred wire-up runs:
-  ```js
-  onRendered() {
-    state.items.notify();   // wakes the each block's items dep,
-                            // which runs update, which calls
-                            // adoptServerItems, which wires per-item
-                            // Reactions on the existing DOM
-  }
-  ```
-  This is not the intended API — the canonical fix is the classifier — but
-  it works mechanically because it triggers the same `adoptServerItems` path
-  that the classifier triggers eagerly.
-- **Workaround that sidesteps the each entirely:** lift the
-  state-dependent class to an attribute on the per-item *element* that uses
-  `data-active="{is item.id state.activeID}"` and style off `[data-active]` in
-  CSS, *if* you don't actually need a class. This works because the
-  attribute binding still goes through the same Reaction path — but on
-  versions without the fix it has the same problem. Don't do this; upgrade.
-
-## What to actually look at first
-
-Before assuming this is the bug, confirm:
-
-1. The component is hydrating, not full-rendering on the client. If
-   `el.shadowRoot` is missing on connect, hydration didn't run and you're
-   on the fresh-render path, which always wires Reactions. Check that your
-   server output includes `<template shadowrootmode="open">` and that
-   nothing strips it before the browser parses it.
-2. The classifier's caching is on AST identity (`WeakMap<ASTNode, boolean>`).
-   If you have two components that share an AST shape but only one of them
-   has an external-state helper, the one classified first wins for both —
-   but in practice each `defineComponent` call produces its own AST, so this
-   is unlikely to be your issue.
-3. If you registered `getItemClasses` via `Template.registerHelper` *before*
-   the classifier module first loaded, the classifier will see it as a pure
-   helper (because `PURE_HELPERS = new Set(Object.keys(TemplateHelpers))`
-   captures the registry once at module init). Define it as a component
-   method or inline `createComponent` field instead — that's how the
-   regression test fixture writes it, and it's the canonical pattern.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json
deleted file mode 100644
index 7f83d8061..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
-      "passed": true,
-      "evidence": "Opening states 'A 6ms tachometer bench... is below the resolution floor by physics' and explains 'CI width scales as ~σ/√N in absolute terms but as ~σ/(mean × √N) in relative terms', plus the entire duration-vs-noise table showing inverse relationship between mean duration and relative CI width."
-    },
-    {
-      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
-      "passed": true,
-      "evidence": "Provides a duration-vs-noise table: '2 ms ~±50%, 6 ms ~±28%, 20 ms ~±5–8%, 50 ms ~±2–4%, 100 ms ~±1–2%'. Numbers differ from the rubric's exact values (uses σ≈2ms calibration) but conveys equivalent inverse-scaling structure across the same regimes."
-    },
-    {
-      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
-      "passed": true,
-      "evidence": "States 'GHA shared runners have a roughly constant absolute timing variance of σ≈2ms per sample' and lists sources as 'OS scheduling, GC, JIT recompiles, shared CPU'. Calls out that jitter is constant in absolute terms (though uses ~2ms rather than sub-millisecond — still captures the constant-absolute-jitter physics)."
-    },
-    {
-      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
-      "passed": true,
-      "evidence": "'Your ±28% matches the 6ms row, which is the noise floor giving its honest verdict' and explicitly addresses 'Why \"just bump sampleSize\" is the wrong instinct' showing that scaling N is impractical and that the floor is physics-limited. Also: 'Physics-limited; sampling longer won't help.'"
-    },
-    {
-      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
-      "passed": true,
-      "evidence": "Section 'Concrete fix for your bench — amplify the per-hydrate work' offers three scaling options including 'Scale the list itself' with explicit recommendation: 'Bump to 1000 items × ~60µs = ~60ms and you sit comfortably above the floor', plus the loop-N-times option pushing to ~300ms window for '<±1% territory'."
-    },
-    {
-      "text": "F: Optionally references the perf-improvement skill or improve-performance workflow as the source for this methodology",
-      "passed": true,
-      "evidence": "References 'ai/skills/contributing/extend-bench-suite.md' and 'ai/skills/contributing/read-bench-report.md' as the canonical sources for duration target table, naming conventions, knobs, and the Inconclusive vs Too Fast to Measure Precisely buckets. This is the expected skill family ('From the bench skill, the local verification flow:'). Marked optional in rubric; satisfied here."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md
deleted file mode 100644
index 1a0bf1ed1..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,147 +0,0 @@
-# Why your hydrate bench can't see the win, and what to change
-
-## The short version
-
-A 6ms tachometer bench on shared GitHub Actions runners is below the resolution floor by physics, not by configuration. The runner has roughly **2ms of irreducible per-sample jitter** (OS scheduling, GC, JIT recompiles, shared CPU). At 6ms mean duration, that 2ms shows up as `~2/6 ≈ 33%` relative noise — which is exactly what you're seeing in your `±28%` floor. No knob in `tachometer-ci-*.json` will narrow that. **You need to lengthen the bench.**
-
-The fix isn't to retune `sampleSize` or `autoSampleConditions`. The fix is to scale up the workload until the mean duration is in the 20–100ms range, where 2ms of jitter becomes 2–10% relative noise and a real per-hydrate improvement of even a few percent can clear the resolution floor.
-
----
-
-## Why the floor is wide — the underlying math
-
-GHA shared runners have a roughly constant absolute timing variance of σ≈2ms per sample (this is calibrated into the in-house bench reporter as `sigma_abs_ms: 2`). Tachometer reports a 95% confidence interval, and CI width scales as `~σ/√N` in absolute terms but as `~σ/(mean × √N)` in relative terms.
-
-So at fixed `sampleSize: 50` (the default), and σ_abs=2ms:
-
-| Bench mean | Expected relative CI width | What the reporter does on zero-delta |
-|------------|----------------------------|--------------------------------------|
-| 2 ms       | ~±50%                      | "Too Fast to Measure Precisely"      |
-| 6 ms       | ~±28%  ← **you are here**  | "Too Fast to Measure Precisely"      |
-| 20 ms      | ~±5–8%                     | Resolves real >10% deltas            |
-| 50 ms      | ~±2–4%                     | Sits right at the ±2% floor          |
-| 100 ms     | ~±1–2%                     | Tight; surfaces real ~2% regressions |
-
-Your `±28%` matches the 6ms row, which is the noise floor giving its honest verdict: at this duration, tachometer cannot distinguish a 5% real improvement from runner jitter. "No meaningful change" here means *unresolved*, not *unchanged*.
-
-The reporter formalizes this in two distinct buckets under `🔍 Unsure`:
-
-- **Inconclusive** — observed CI width > 2× the expected width for that duration. More samples might help, or the bench has unusual variance.
-- **Too Fast to Measure Precisely** — observed CI width ≈ expected width for that duration. Physics-limited; sampling longer won't help.
-
-A 6ms bench landing at ±28% is the canonical Too Fast case. Expected width and observed width agree — there's nothing to investigate about the bench's variance, and there's nothing more to extract from the data without changing the workload.
-
----
-
-## Why "just bump sampleSize" is the wrong instinct
-
-CI width does narrow as `1/√N`. So to halve a `±28%` floor you'd need `4×` the samples (200 instead of 50), and to drop it to `±5%` you'd need roughly `~30×` more samples (~1500). That's:
-
-- Hours of CI wall-clock per bench (the matrix job has a 10-minute hard cap).
-- A `timeout: 3` minute auto-sample cap, which would simply abort.
-- Burns runner cost across every PR for a single metric.
-
-The repo's bench config is calibrated against this tradeoff. From `tachometer-ci-hydrate.json`:
-
-```json
-{ "sampleSize": 50, "timeout": 3, "autoSampleConditions": ["2%"] }
-```
-
-These knobs are documented in `ai/skills/contributing/extend-bench-suite.md` as **"don't change without a reason"** — they're the floor that makes the matrix fit in CI budget. The right move is on the workload side.
-
----
-
-## Concrete fix for your bench — amplify the per-hydrate work
-
-Look at the existing hydrate bench at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js`. Its `hydrate-each-100-mount` and `hydrate-each-100` measurements work in tachometer because they hydrate **1000 items**, not 100 (the metric name is misleading; line 99 reads `makeItems(1000)`). That's deliberate — at 1000 items the mount window lands in the resolvable range.
-
-For a 100-item list whose per-item hydrate cost is ~60µs, you have three scaling options ranked by preference:
-
-### 1. Loop the hydrate operation N times in one measure window (preferred)
-
-If your fix is in the per-component hydrate path (not the per-item path), repeat the whole component mount cycle inside one `performance.measure` boundary:
-
-```js
-performance.mark(startMark('hydrate-mycomp-50x'));
-for (let i = 0; i < 50; i++) {
-  const fresh = ssrMyComponent(items100);   // fresh DSD string, no caching across iterations
-  container.setHTMLUnsafe(fresh);
-  await drainMicrotasks();
-  await flush();
-  container.innerHTML = '';
-}
-performance.measure('hydrate-mycomp-50x', startMark('hydrate-mycomp-50x'));
-```
-
-A 6ms × 50 ≈ 300ms window pushes you into "<±1%" territory. The reporter will resolve any real per-hydrate delta down to ~2%. Suffix the metric name with the iteration count (`hydrate-mycomp-50x`) per the naming convention so reviewers know it's amplified.
-
-**Caveat:** make each iteration genuinely independent. Re-use the same SSR HTML string (precompute it once outside the loop) so the SSR cost isn't included, but generate a fresh container or `setHTMLUnsafe` call so prototype caches (`_hydrationEntries` is cached on the prototype after the first hydrate — see `ssr-hydration.md` Phase 5) don't make iterations 2..N artificially cheap. The first iteration measures cold-cache, the rest measure warm-cache. If your fix targets the warm path, throw away the first iteration's contribution by warming once before `performance.mark`.
-
-### 2. Scale the list itself
-
-If your fix is per-item (e.g., a faster `hydrateInnerContent`, marker walk, or attribute parallel-walk), 100 items × ~60µs = ~6ms. Bump to **1000 items × ~60µs = ~60ms** and you sit comfortably above the floor:
-
-```js
-const items = makeItems(1000);
-const dsdHTML = ssrList(items);
-performance.mark(startMark('hydrate-mycomp-1k'));
-container.setHTMLUnsafe(dsdHTML);
-await drainMicrotasks();
-await flush();
-performance.measure('hydrate-mycomp-1k', startMark('hydrate-mycomp-1k'));
-```
-
-This is what `bench-hydrate.js` already does for the each-block mount path.
-
-### 3. Split the measurement window
-
-Sometimes the work you're optimizing is one phase of a larger hydrate cycle, and amplifying the whole cycle hides your delta in the unaffected phases. In that case, split into two measures:
-
-- `hydrate-mycomp-mount-1k` — DSD parse + connectedCallback + the hydrate microtask
-- `hydrate-mycomp-rebind-1k` — first state mutation that re-fires Reactions (uses `hasHydrated` adoption path)
-
-`bench-hydrate.js` does exactly this with its mount vs. helper-state-change pair (lines 99–122). Each window is independently resolvable, and a fix targeting one path won't be diluted by the other.
-
----
-
-## What to change in your config
-
-Almost certainly nothing. After amplifying the workload, leave `sampleSize: 50`, `autoSampleConditions: ["2%"]`, and `timeout: 3` alone — they're the floor the matrix is calibrated against. Just add the new `entryName` to **both** the `this-change` and `tip-of-tree` measurement arrays in `tachometer-ci-hydrate.json` (or whichever config you're extending).
-
-If after amplifying your bench is still showing wide CIs at >2× the expected width for its new duration, *then* something is wrong with the bench itself — likely:
-
-- Per-iteration GC pause varying by allocation pattern
-- Async work bleeding past `await flush()` (the mount cycle includes a `requestAnimationFrame` that strips data-sui-bind markers post-hydrate — make sure your final `flush()` covers it)
-- An accidental cache hit on iteration 2..N (see caveat in option 1)
-
-That'd land in the reporter's `Inconclusive` bucket (observed/expected ratio > 2), at which point investigate the bench setup.
-
----
-
-## How to verify before pushing
-
-From the bench skill, the local verification flow:
-
-```sh
-cd packages/component/bench/tachometer
-node build-ci.js current
-node build-ci.js baseline       # same source both sides — zero-delta dry run
-npx tachometer --config tachometer-ci-hydrate.json
-```
-
-A clean, zero-delta dry run on a workload sized into the 20–100ms range should report a CI width comfortably below ±5%. If your dry-run width is still wide, you haven't amplified enough — duration matters more than sample count.
-
----
-
-## TL;DR for the PR comment / commit message
-
-> The bench's mean duration was ~6ms, which puts it below the resolution floor on shared GHA runners (σ≈2ms absolute jitter → ~±28% relative). Tachometer's `±28%` "no meaningful change" verdict is the noise floor giving its honest answer, not evidence the fix doesn't help. Amplifying the workload to a ~60ms+ mean (either by looping the hydrate cycle 10–50× per measure window or by scaling the list to 1k items) brings it into the resolvable range where a real per-hydrate delta of even a few percent will land in the Faster section. The `sampleSize`/`autoSampleConditions`/`timeout` knobs are calibrated against CI budget and shouldn't be the lever here.
-
----
-
-## Reference files
-
-- `/home/jack/semantic/next/ai/skills/contributing/extend-bench-suite.md` — duration target table, naming conventions, knobs
-- `/home/jack/semantic/next/ai/skills/contributing/read-bench-report.md` — Inconclusive vs Too Fast to Measure Precisely buckets, expected_noise_pp/observed_noise_ratio fields
-- `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js` — canonical hydrate bench using 1000 items + split mount/state-change windows
-- `/home/jack/semantic/next/packages/component/bench/tachometer/tachometer-ci-hydrate.json` — the standard knob set (`50`/`3`/`["2%"]`)
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json
deleted file mode 100644
index 49042e3c0..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
-      "passed": true,
-      "evidence": "Opening lines state 'absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and ±X% is just (constant ms) / (your duration)'. Summary repeats: 'duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter'. Inverse scaling is explicitly named."
-    },
-    {
-      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
-      "passed": true,
-      "evidence": "Provides a concrete table of measured durations vs predicted ±% half-widths (7.4ms = ±10.6%, 13.7ms = ±5.7%, 12.6ms = ±6.2%, 16.2ms = ±4.8%) and states '≥ 30 ms (predicted ±2.6%) to comfortably clear the ±2% noise floor'. Also derives ±26% at 6ms. The bands map to the rubric's tiers (short = ±10-20%, ~10ms = ±2-5%, longer = ±1%)."
-    },
-    {
-      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
-      "passed": true,
-      "evidence": "Explicitly explains 'absolute per-sample jitter is roughly constant' and lists 'system jitter (scheduling, GC, JIT)' as the cause. Notes σ ≈ 2 ms on GHA runners (slightly above sub-millisecond but the constant-absolute physics is clearly stated). The 'roughly constant in absolute terms' point is made repeatedly."
-    },
-    {
-      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
-      "passed": true,
-      "evidence": "Computes ±26% predicted at 6ms, explains observed ±28% is at the noise-floor-limited boundary, and explicitly states in option 4: 'Don't bump sampleSize — diminishing returns... 4× the wall-clock time gets you from ±28% to ±14%' and 'Width comes from duration, not from sample count beyond a point.'"
-    },
-    {
-      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
-      "passed": true,
-      "evidence": "Option 1 recommends 'Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo.' Cites bench-hydrate.js using n=1000 items as the existing pattern to copy. Targets ≥30 ms / ±2.6%."
-    },
-    {
-      "text": "F: Optionally references the perf-improvement skill or improve-performance workflow as the source for this methodology",
-      "passed": false,
-      "evidence": "Answer references reporter.js, bench-history.json, bench-todo.js, and bench-hydrate.js as sources, but does not name the perf-improvement skill or improve-performance workflow. This is an optional expectation but per the rubric's literal wording it is not satisfied."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md
deleted file mode 100644
index ddec432ec..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-3-bench-noise-floor/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,94 +0,0 @@
-# Why a 6 ms hydration bench can't see your improvement
-
-Short version: at ~6 ms duration, the bench is running below the resolution floor of the CI runner. The noise floor isn't `±28%` because tachometer is misconfigured — it's that wide because absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and `±X%` is just `(constant ms) / (your duration)`. Fix the noise floor by making the bench longer in absolute time, not by tuning tachometer.
-
-## The math the reporter is using
-
-The bench reporter at `/home/jack/semantic/next/tools/ci/bench/reporter/reporter.js` encodes the model explicitly (lines 49–90):
-
-```js
-const NOISE_FLOOR = 2;           // percent — matches autoSampleConditions
-const SIGMA_ABS_MS = 2;          // empirical per-sample σ on GHA runners
-
-function expectedNoisePp(meanMs) {
-  // From SE-of-the-difference of two means at n=50, z=1.96:
-  //   abs_CI_width ≈ 2 * 1.96 * sqrt(2) * σ / sqrt(50) ≈ 0.784 * σ
-  //   pct_width   = abs_CI_width / mean * 100
-  return (0.784 * SIGMA_ABS_MS) / meanMs * 100;
-}
-```
-
-Plug in `σ = 2 ms`, `mean = 6 ms`:
-
-- `abs_CI_width ≈ 0.784 × 2 = 1.568 ms`
-- `pct_width = 1.568 / 6 × 100 ≈ 26%`  → reported as **±13%** (half-width on each side)
-
-You're seeing **±28%** observed. That is `~2.1×` the duration-derived expected width — right at the boundary of what the reporter classifies as `noise-floor-limited` vs `unsure` (`NOISE_RATIO_TOLERANCE = 2` at line 62). So tachometer is honest: at this duration, on these runners, the measurement can't see anything smaller than roughly ±15–30% of the mean. A 1 ms improvement on a 6 ms bench is well below that.
-
-This is exactly why your CI is "no meaningful change" — `NOISE_FLOOR = 2`% (line 49) demands the CI live entirely outside `[-2%, +2%]` to be classified `faster`/`slower`. Your CI straddles ±2% wider than the noise floor allows it to resolve, so the reporter buckets it into `noise-floor-limited` (file `reporter.js`, lines 220–225):
-
-```js
-function classify([low, high], ratio) {
-  if (high < -NOISE_FLOOR) { return 'faster'; }
-  if (low > NOISE_FLOOR)   { return 'slower'; }
-  if (low > -NOISE_FLOOR && high < NOISE_FLOOR) { return 'within-noise'; }
-  return ratio <= NOISE_RATIO_TOLERANCE ? 'noise-floor-limited' : 'unsure';
-}
-```
-
-## The "Too Fast to Measure Precisely" bucket exists for this exact case
-
-When you read the rendered comment, your bench should be sitting under `🔍 Unsure → Too Fast to Measure Precisely`. The header copy (rendered from `reporter.js` lines 384–402) literally says:
-
-> On benches this short, system jitter (scheduling, GC, JIT) masks sub-4% changes; larger deltas still resolve cleanly.
-
-That row exists specifically to tell the author "this isn't a verdict, this is a 'your bench is too short' diagnostic." Don't trust the noise classification as a refutation of your fix — trust it as a request to amplify the bench.
-
-## What the existing benches do — copy this pattern
-
-The existing hydrate bench at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js` already runs at `n=1000` items (line 99: `const itemsForMount = makeItems(1000)`), not 100. Recent main-history numbers confirm what that buys you:
-
-| metric | mean | predicted ±% half-width | resolves? |
-|---|---|---|---|
-| `hydrate-helper-100-mount` | 7.4 ms | ±10.6% | borderline |
-| `hydrate-each-100-mount` | 13.7 ms | ±5.7% | yes |
-| `hydrate-each-100` | 12.6 ms | ±6.2% | yes |
-| `hydrate-helper-100-state-change` | 16.2 ms | ±4.8% | yes |
-
-Source: `/home/jack/semantic/next/tools/ci/bench/reporter/bench-history.json` (the `271be03` commit entry near line 1584).
-
-Note even `hydrate-helper-100-mount` at 7.4 ms is the noisiest of the four because it's the shortest. The larger ones are the ones that resolve cleanly. **You want to be ≥ 30 ms** (predicted ±2.6%) to comfortably clear the ±2% noise floor — that's the inflection point where small changes get classified.
-
-The `bench-todo.js` author at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-todo.js` calls this strategy out explicitly in line comments:
-
-- Line 275: `// 20 alternating toggle-all invocations on a 100-item list — amplified // so the measurement clears the σ≈2ms per-sample noise floor on CI.`
-- Line 290: `// Each position's ~10ms per-delete workload clears the σ≈2ms floor.`
-- Line 361: `// List scaled to 500 (250 marked completed) so the single clearCompleted // operation is large enough to clear the σ≈2ms per-sample noise floor.`
-- Line 333–335: `// 10× loop (vs 5× for the front/back variants) — middle removal's // O(N/2) scan has wider per-sample variance, so 5× landed at ~74ms // with observed CI straddling ±2%. 10× brings it to ~148ms / ±1%.`
-
-These are the same change you should make.
-
-## Concrete options for your bench, ranked
-
-**1. Scale the workload up (preferred).** Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo. If your fix is in per-item work (e.g. `hydrateInnerContent`, `adoptServerItems`), 1000 items multiplies its weight by 10× without changing what you're measuring. Keep the metric name describing items measured, not items rendered, if you want comparability — but in this repo most names already include the count (e.g. `hydrate-each-100` actually mounts 1000 items per the comment at line 99).
-
-**2. Loop the operation N times inside one `performance.measure` window.** This is what `toggle-all-20` and `remove-10-middle` do. If hydration itself isn't loopable (you only mount once), then loop the *follow-up data change* that exercises the codepath you fixed. The existing bench does this already with `hydrate-each-100` — measures the post-mount `setItems(...)` call rather than mount itself.
-
-**3. Add a separate amplified metric instead of replacing.** Keep the realistic 100-item bench for human readability of the duration, and add a 1000-item variant with the same shape for measurement precision. Both metrics ship; the reporter handles either.
-
-**4. Don't bump `sampleSize` — diminishing returns.** Going from `sampleSize: 50` to `200` only narrows the CI by `√(50/200) = 0.5×`. So 4× the wall-clock time gets you from ±28% to ±14%. Compare to scaling the workload 5× (6ms → 30ms), which gets you from ±28% to ±5% with no extra wall-clock cost. Sample-size tuning is the wrong knob for short benches.
-
-**5. Don't tighten `autoSampleConditions`.** Currently `["2%"]` — that's the *target* CI width for tachometer's auto-sampler. Tightening it to `["1%"]` just makes tachometer keep sampling until either it converges (it can't, because the underlying jitter is absolute-constant, not relative) or it hits `timeout: 3` minutes and gives up with the same wide CI. The `tachometer-todo.json` non-CI variant uses `["0%", "10%"]` which means "sample until <10% relative width OR a 0% target" — also wrong choice for short benches. Width comes from duration, not from sample count beyond a point.
-
-## Verifying your fix saved time at all
-
-If you want to know whether the fix is real before investing in bench amplification:
-
-- Run the bench locally with `--manual` or via the CI HTML harness, open DevTools, and use the Performance panel — a 1 ms saving on a 6 ms operation is visible in a flame graph even when it's invisible to tachometer at n=50.
-- Add a `console.time('hydrate')` / `console.timeEnd('hydrate')` around the codepath, run it 10 times locally, eyeball the median — if you see 5 ms vs 6 ms consistently, the fix is real and the bench is just under-resolved.
-
-Then commit the bench amplification as a separate change so the perf comment on your fix's PR can show a `faster` row instead of `noise-floor-limited`.
-
-## Summary
-
-The noise floor is wide because `1.568 ms / 6 ms ≈ 26%`. That's not a bug or a tachometer config issue — it's the duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter on this runner, and the reporter at `tools/ci/bench/reporter/reporter.js` documents it explicitly. The fix is to amplify the bench duration to ≥ 30 ms (loop the op, scale items, or both), exactly as the existing `bench-todo.js` and `bench-hydrate.js` already do. Don't reach for `sampleSize` or `autoSampleConditions` — neither addresses the underlying `(constant ms) / duration` problem.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json
deleted file mode 100644
index 097bc1723..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
-      "passed": false,
-      "evidence": "The answer focuses primarily on demonstrating that the canonical case works (passing test at line 1408) and explores the mechanism in detail. It explains the each-content-classifier bails on snippets forcing the eager path, but does NOT explicitly tie this back to eval 2's root cause (each-hydrate deferral as the underlying mechanism). It frames the discussion around 'the framework path works for the canonical shape' rather than 'this is the same lazy-hydrate deferral pattern that was at risk.'"
-    },
-    {
-      "text": "B: Explains that snippet args (`label=item.name`) are evaluated by the per-item content path; the snippet body sees those args via `buildSnippetProxy`",
-      "passed": true,
-      "evidence": "Section 3 ('The snippet block on the hydrate path') explicitly explains: 'When `template.hydrate` runs with `data = itemProxy` (the each-item proxy) and `kind === 'snippet'`, it calls `buildSnippetProxy(node, itemProxy, evaluator)` to build the snippet-args overlay.' It then quotes the lazy getter code from template.js:67-114 showing how arg getters close over the each-item proxy and walk through itemProxy.get('item') to subscribe to itemSignal.value."
-    },
-    {
-      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
-      "passed": true,
-      "evidence": "The answer explains the chain in section 4 'The mutation path': itemSignal.notify() wakes everything subscribed to that per-item signal, including the snippet body's text Reaction. By describing the mechanism that makes it work (per-item Reactions getting wired via adoptServerItems on the eager path), it implicitly establishes that without those wired Reactions the snippet args wouldn't re-evaluate. Case A in 'Why your case might not be doing this' explicitly addresses 'no reconcile, no snapshot diff, no per-item notify.'"
-    },
-    {
-      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
-      "passed": true,
-      "evidence": "Section 1 ('The self-contained classifier bails on snippet calls') quotes the exact code from each-content-classifier.js line 189: 'case 'template': case 'snippet': case 'rerender': case 'guard': case 'async': return false;' and explains: 'snippet bodies live in a separate AST, and the classifier doesn't trace cross-AST identifier flow. Rather than guess wrong it bails conservative — meaning your each gets the *eager* wire path.'"
-    },
-    {
-      "text": "E: Mentions the existing test `snippet with named args inside each is reactive after hydration` (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
-      "passed": true,
-      "evidence": "Opens with 'there's a passing test for the exact shape you described: packages/renderer/test/browser/ssr-hydration.test.js:1408 — \"snippet with named args inside each is reactive after hydration\".' Also references this test again in the closing file pointers as 'the canonical passing test for your exact pattern.' Does not mention PR #175 specifically, but the rubric allows the equivalent (known regression test reference)."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md
deleted file mode 100644
index f3d802b97..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,228 +0,0 @@
-# Snippet inside `{#each}` — what hydration actually wires
-
-## Short version
-
-Your pattern is the documented-supported case and there's a passing test for the
-exact shape you described:
-
-`packages/renderer/test/browser/ssr-hydration.test.js:1408` —
-"snippet with named args inside each is reactive after hydration".
-
-That test SSRs `{#snippet badge}<span class="b">[{label}]</span>{/snippet}{#each item in items}<div>{>badge label=item.name}</div>{/each}`,
-hydrates, then mutates `items[0]` (assigning a new spread + setting the array)
-and asserts the first badge updates. It passes on `test/templating` as of this
-session. So the framework *is* wiring the per-item Reaction across the snippet
-boundary on hydrate. If you're seeing it not update, you're hitting a variant
-the rest of this answer enumerates.
-
-Before the variants, the actual mechanism — because that's what tells you which
-of the variants you're in.
-
----
-
-## What hydrate does for `{#each item in items}` containing a snippet
-
-Two things make this case work, both deliberate.
-
-### 1. The "self-contained" classifier bails on snippet calls
-
-`packages/renderer/src/engines/native/blocks/each-content-classifier.js`
-
-The each block's `hydrate` hook has a fast path: if every per-item binding only
-reads iteration-local data or pure framework helpers, it can skip per-item
-Reaction wiring at hydrate time and lazily build them on the first items
-mutation. `each.js:664` gates this on `isEachContentSelfContained(node)`.
-
-The classifier walks the each's content AST. When it hits a `template`-type
-node (which is what `{>badge ...}` compiles to — both snippets and subtemplates
-share that node type), it returns `false` (line 189):
-
-```js
-case 'template':
-case 'snippet':
-case 'rerender':
-case 'guard':
-case 'async':
-  return false;
-```
-
-The reasoning is in the file's preamble: snippet bodies live in a separate
-AST, and the classifier doesn't trace cross-AST identifier flow. Rather than
-guess wrong it bails conservative — meaning your each gets the *eager* wire
-path. So `each.hydrate` calls `adoptServerItems` (`each.js:669`).
-
-### 2. `adoptServerItems` rebuilds per-item reactivity against the existing DOM
-
-`packages/renderer/src/engines/native/blocks/each.js:505-616`
-
-The server emitted `<!--sui-item:v1:KEY-->` markers between the each block's
-open/close markers. `extractServerItemGroups` walks `region.ownedNodes`
-grouping nodes by their preceding item marker (with depth tracking so nested
-`sui-block` markers from inner directives don't confuse the boundary).
-
-For each item:
-
-- A fresh `itemSignal` (`new Signal(eachData, { allowClone: false })`) and an
-  `itemProxy` from `createItemDataProxy(parentData, itemSignal)` are created.
-  `createItemDataProxy` wraps the parent data so that *any* read of an item
-  field goes through `itemSignal.value` first — that's where the per-item
-  reactive subscription is established (`each.js:129-144`).
-- `hydrateInnerContent` walks the per-item nodes with
-  `data: itemProxy, scope: itemScope`. This is where the snippet block's
-  `hydrate` hook gets called.
-
-### 3. The snippet block on the hydrate path
-
-`packages/renderer/src/engines/native/blocks/template.js:220-240`
-
-When `template.hydrate` runs with `data = itemProxy` (the each-item proxy)
-and `kind === 'snippet'`, it calls `buildSnippetProxy(node, itemProxy, evaluator)`
-to build the snippet-args overlay. Critical detail at `template.js:67-114`:
-
-```js
-if (isPlainObject(node.data)) {
-  each(node.data, (expr, key) => {
-    staticGetters[key] = () => evaluator.lookupExpressionValue(expr, data);
-  });
-}
-```
-
-The arg getters are *lazy* and close over the each-item proxy. They are not
-wrapped in `Reaction.nonreactive`. So when the snippet body's `{label}` text
-Reaction fires, the Reaction tracking context is active when the getter runs,
-and the getter's call into `evaluator.lookupExpressionValue('item.name', itemProxy)`
-walks through `itemProxy.get('item')` — which reads `itemSignal.value` and
-subscribes the body's Reaction to that signal. That's the reactive bridge.
-
-`hydrateInnerContent` is then called for the snippet body
-(`template.js:228-238`) with `data: snippetData, scope` — same scope as the
-each item, so when the item record is disposed, the snippet body's Reactions
-go with it.
-
-### 4. The mutation path on `items[0].name = ...; state.items.set([...items])`
-
-When you replace the array, the items signal fires, `each.update` runs,
-`reconcile` walks. For index 0 the item reference is unchanged, so the code
-falls into the snapshot branch at `each.js:407-421`:
-
-```js
-else if (typeof item === 'object' && item !== null) {
-  if (rec.propsSnapshot === null) {
-    rec.propsSnapshot = createSnapshot(item);
-  }
-  else if (refreshSnapshotAndDetect(rec.propsSnapshot, item)) {
-    rec.itemSignal.notify();
-  }
-}
-```
-
-`refreshSnapshotAndDetect` does a shallow diff of top-level item props. If
-`name` changed it returns true, the snapshot is updated in place, and
-`itemSignal.notify()` wakes everything subscribed to that per-item signal
-— including the snippet body's `{label}` text Reaction. That Reaction
-re-evaluates, the lazy `label` getter fires again, reads the current
-`item.name`, and writes the new value to `textNode.data`.
-
-That's the full chain — and the chain is exercised end-to-end by the test
-at `ssr-hydration.test.js:1408`.
-
----
-
-## Why your case might not be doing this
-
-Since the framework path works for the canonical shape, the failure has to
-come from a deviation. Most likely sources, ranked by how often they bite:
-
-### A. The mutation isn't reaching `reconcile`'s phase 3
-
-You said the outer each's reaction "definitely fires" because new items render
-when added. That's good — it means the items signal *is* invalidating the each
-block. But verify reconcile actually re-enters phase 3 for index 0. If you're
-mutating *only* `items[0].name` without setting the items signal to a new
-reference (i.e., no `state.items.set(...)` and no array helper like
-`state.items.push/.splice`), the items signal never fires, no reconcile, no
-snapshot diff, no per-item notify.
-
-`state.items.push(newItem)` does both — it mutates and calls `notify()` (see
-`packages/reactivity/src/signal.js:237-240`). So pushing should reach
-phase 3. Pure `items[0].name = 'x'` without any signal call won't.
-
-### B. Your each is the no-`as` form
-
-`{#each items}<div>{>badge label=name}</div>{/each}` (no `item in`) spreads
-the item's keys into the local scope. The classifier returns false at the
-top of `isEachContentSelfContained` (`each-content-classifier.js:212`), so
-`each.hydrate` *also* takes the eager path. No problem there. But if you're
-passing `label=name` (instead of `label=item.name`), the snippet getter
-evaluates `name` against the each-item proxy, which resolves it to the
-*current* item's `name` field via `itemSignal.value` — same outcome.
-
-### C. The snapshot diff is shallow
-
-`refreshSnapshotAndDetect` only checks top-level props. If you're mutating
-`items[0].nested.name` and the snippet reads `item.nested.name`, the snapshot
-sees `items[0].nested === snap.nested` (same reference) and reports no change.
-No `itemSignal.notify()` fires, the snippet doesn't re-evaluate. The comment
-at `each.js:392-395` calls this out explicitly: "Top-level prop mutations
-re-render dependent expressions; nested-object mutations slip past the shallow
-check, and no documented contract relies on them."
-
-If this is your case, the workaround is to either (a) replace `items[0]` with
-a new object (`items[0] = { ...items[0], nested: { ...items[0].nested, name: 'x' } }`)
-or (b) call `state.items.notify()` manually after the deep mutation.
-
-### D. The badge is not just a text expression
-
-If the snippet body has computed attributes or other reactive shapes, the
-text-marker reactivity path I traced isn't the same as the attribute-binding
-path. In particular, `{label}` as an attribute value vs as text content go
-through different hydration routines (`hydrateAttributes` parallel-walk vs
-`hydrateTextExpression`). Both should subscribe correctly, but if you're
-seeing a discrepancy worth filing, post the snippet body verbatim.
-
-### E. `_hydrating` flag stuck
-
-If something throws during `hydrate` (e.g. a snippet name that resolves to
-nothing, line 226 `fatal` from `template.js`), `_hydrating` may not be cleared
-and subsequent `requestUpdate` calls get suppressed. Check the console for
-errors at hydration time.
-
-### F. Snippet name resolved to a subtemplate, not a snippet
-
-`detectKind` (`template.js:121-127`) checks `self.snippets[name]` first. If
-your `badge` symbol is registered as a *subtemplate* in scope (not a snippet)
-because of a name collision or a ContentTemplate lookup, you take the
-subtemplate branch instead — and subtemplates have a separate hydration path
-with different data-flow semantics. Worth checking
-`renderer.snippets['badge']` and `renderer.subTemplates['badge']` in DevTools
-right after hydration.
-
----
-
-## How to confirm in DevTools
-
-If you want to verify the wire is in place after hydrate:
-
-1. Set a breakpoint in `template.js` at line 227 (`buildSnippetProxy` call)
-   inside the snippet branch of `hydrate`. Confirm it fires once per item
-   with `data` being an each-item proxy (test:
-   `isItemContext(data)` — exported from `each.js`).
-2. Set a breakpoint in `each.js:418` (`rec.itemSignal.notify()`) and trigger
-   your mutation. Confirm it fires for index 0.
-3. Set a breakpoint in `reactive-data.js:219` (the textNode reaction body).
-   Confirm it re-fires after step 2 and `value` is the new name.
-
-If step 2 doesn't fire, the snapshot diff isn't seeing the change (case C, or
-the mutation path doesn't reach reconcile — case A). If step 2 fires but
-step 3 doesn't, the snippet body's Reaction never subscribed to that
-itemSignal — would be a real framework bug, file it with a repro.
-
----
-
-## File pointers
-
-- `packages/renderer/src/engines/native/blocks/each.js` — reconcile, `adoptServerItems`, snapshot diff
-- `packages/renderer/src/engines/native/blocks/each-content-classifier.js` — bails on snippets, forces eager wire
-- `packages/renderer/src/engines/native/blocks/template.js` — snippet branch, `buildSnippetProxy` lazy-getter pattern
-- `packages/renderer/src/engines/native/reactive-data.js:163` — `hydrateTextExpression` (firstRun subscription)
-- `packages/renderer/test/browser/ssr-hydration.test.js:1408` — the canonical passing test for your exact pattern
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json
deleted file mode 100644
index ac9a6b11d..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
-      "passed": false,
-      "evidence": "The answer correctly identifies that the bug is not snippet-specific ('this isn't snippet-specific — any expression inside the each body that reads item.<prop> would hit the same bug'), but it diagnoses a fundamentally different root cause: a propsSnapshot === null edge case in adoptServerItems, not the each-hydrate deferral of per-item Reaction wiring. The answer asserts the snippet wiring is correct and per-item Reactions are properly wired against itemSignal during adoption — directly contradicting the deferral-as-root-cause framing of eval 2. Misses the connection to the same root cause."
-    },
-    {
-      "text": "B: Explains that snippet args (label=item.name) are evaluated by the per-item content path; the snippet body sees those args via buildSnippetProxy",
-      "passed": true,
-      "evidence": "Answer explicitly explains: 'Snippet args (label=item.name) become lazy getters captured by buildSnippetProxy (packages/renderer/src/engines/native/blocks/template.js:67-114). The snippet body's {label} reactive text-node Reaction reads snippetData.label, which calls the captured getter () => evaluator.lookupExpressionValue(item.name, itemProxy)...'. Identifies buildSnippetProxy and the per-item arg evaluation path."
-    },
-    {
-      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
-      "passed": false,
-      "evidence": "The answer takes the opposite position: 'So the text-node Reaction inside the snippet body does end up depending on the per-item itemSignal. The wiring is fine.' It claims the Reactions ARE wired and the bug is downstream (propsSnapshot/notify gating). Does not identify unwired per-item Reactions as the cause."
-    },
-    {
-      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
-      "passed": false,
-      "evidence": "The answer references each-content-classifier ('confirms eager hydration is forced when an each contains a template (snippet) node, so adoptServerItems is what runs during hydrate (line 189-194)') but positions this as confirming the path that exposes the bug, not as the fix. The proposed fix is to populate propsSnapshot in adoptServerItems — a completely different remediation than 'force eager adoption via classifier bail-out.'"
-    },
-    {
-      "text": "E: Mentions the existing test 'snippet with named args inside each is reactive after hydration' (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
-      "passed": true,
-      "evidence": "Answer references 'the existing snippet with named args inside each test' at packages/renderer/test/browser/ssr-hydration.test.js:1408-1433, noting it 'uses a new object ref and therefore doesn't catch this.' Identifies the existing scenario test even if framing it as a near-miss rather than the regression test PR #175 unskipped."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md
deleted file mode 100644
index 75b56128b..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-1/eval-4-snippet-arg-each/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,85 +0,0 @@
-# What's happening
-
-The framework's snippet wiring is correct here — the bug you're hitting is a stale-snapshot edge case in `each`'s post-hydration reconcile path, not a snippet-arg reactivity hole. Specifically: the **first** post-hydration in-place mutation of an item slips through silently. The second mutation onwards updates the DOM normally.
-
-## The intended path
-
-For your template:
-
-```
-{#each item in items}<div>{>badge label=item.name}</div>{/each}
-```
-
-Reactivity flows like this:
-
-1. **Each block** wraps each item in a `Signal` (`itemSignal`) holding `{ item, index }`. A `Proxy` (`createItemDataProxy` in `packages/renderer/src/engines/native/blocks/each.js:129-144`) sits over the parent data and routes `data.item` lookups through `itemSignal.value`, which registers an `itemSignal` dep on whoever's reading.
-2. **Snippet args** (`label=item.name`) become **lazy getters** captured by `buildSnippetProxy` (`packages/renderer/src/engines/native/blocks/template.js:67-114`). The snippet body's `{label}` reactive text-node Reaction reads `snippetData.label`, which calls the captured getter `() => evaluator.lookupExpressionValue('item.name', itemProxy)`, which goes through the each's item-proxy and registers `itemSignal` as a dep on the text node's Reaction.
-
-So the text-node Reaction inside the snippet body **does** end up depending on the per-item `itemSignal`. The wiring is fine. The problem is whether `itemSignal.notify()` actually fires when you mutate in place.
-
-## The bug — `propsSnapshot` is `null` after adoption
-
-When you replace `state.items` with `state.items.set([...items])`, the items signal fires and `each.update` runs. For records whose `item` reference and index are unchanged (your case — same object, just a mutated `.name`), the equality gate inside `Signal.set` short-circuits because the wrapper `{ item, index }` looks identical by `===` (same item ref). To get around that, `each` keeps a `propsSnapshot` of each item's top-level props and shallow-compares on every reconcile to decide whether to call `itemSignal.notify()` manually:
-
-```js
-// packages/renderer/src/engines/native/blocks/each.js:396-422 (Phase 3)
-if (rec.item !== item || rec.index !== i) {
-  rec.itemSignal.set(getEachData(...));
-  ...
-  rec.propsSnapshot = createSnapshot(item);
-}
-else if (typeof item === 'object' && item !== null) {
-  if (rec.propsSnapshot === null) {
-    // "Fresh record (first reconcile after createRecord). Bindings
-    //  were wired synchronously against the signal's value; there's
-    //  no stale subscriber to wake."
-    rec.propsSnapshot = createSnapshot(item);
-  }
-  else if (refreshSnapshotAndDetect(rec.propsSnapshot, item)) {
-    rec.itemSignal.notify();
-  }
-}
-```
-
-That `propsSnapshot === null` branch assumes "no notify needed because we just wired the bindings against the current item value." That assumption is true for records produced by `createRecord` inside the same `reconcile` call (CSR, or post-hydration replacements), but it is **wrong** for records produced by `adoptServerItems` during hydration, because:
-
-- Adoption wires Reactions at hydrate time against the item's hydration-time `.name` (`'Apple'`).
-- The records are pushed with `propsSnapshot: null` (`packages/renderer/src/engines/native/blocks/each.js:583`).
-- Some unspecified time later, your code mutates `items[0].name = 'Cherry'` and pushes a new array.
-- `update` runs `reconcile`. Phase 3 sees `rec.item === items[0]` (still the same ref), index unchanged, and `propsSnapshot === null` — so it takes the "fresh record" branch, snapshots `{ name: 'Cherry' }` for next time, and **does not call `notify()`**.
-- The badge stays showing `[Apple]`.
-
-If you mutate again (`items[0].name = 'Date'`), `refreshSnapshotAndDetect` compares against the now-populated snapshot (`'Cherry' !== 'Date'`), fires `notify()`, and the DOM updates to `[Date]` — skipping the `'Cherry'` value entirely.
-
-## Why the "outer reaction definitely fires" observation is consistent
-
-Your test for "outer reaction fires" probably involves changing the array length (push, splice, swap). Those go through the `rec.item !== item || rec.index !== i` branch — `itemSignal.set(...)` runs unconditionally with a fresh wrapper object, equality gate passes (different wrapper ref), subscribers wake. That's why adding/removing/reordering items works fine after hydrate, but mutating an existing item's prop in place doesn't.
-
-It's also worth noting that this isn't snippet-specific — any expression inside the each body that reads `item.<prop>` would hit the same bug after hydration on the first in-place mutation. The snippet is just along for the ride. But the snippet structure does suppress one of the workarounds: with bare `{item.name}` directly in the each body, the same lookup path applies and the same bug should reproduce. A test using new object refs (`items[0] = { ...items[0], name: 'Crimson' }`) like the one at `packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` passes precisely because it dodges the equality gate by changing the item ref.
-
-## Workarounds (no source change)
-
-- Replace the item reference instead of mutating in place: `state.items.set(items.map((it, i) => i === 0 ? { ...it, name: 'Cherry' } : it))`. New ref → first branch of phase 3 → `itemSignal.set(...)` → DOM updates.
-- Toggle the value back-and-forth — the first mutation populates `propsSnapshot`, the second triggers `notify()`. Not really a workaround, just an explanation of why your second mutation works.
-- Use `state.items.notify()` after the in-place mutation to force the items signal to fire a second time — but this only buys you the same "phase 3 with populated snapshot" pass, so it would also need to happen after the first lost mutation, not as a fix for it.
-
-## The fix on the framework side
-
-`adoptServerItems` should populate `propsSnapshot` at adoption time, the same way Phase 3 does at the end of a normal reconcile. Either:
-
-```js
-// packages/renderer/src/engines/native/blocks/each.js:574-584
-newRecords.push({
-  ...,
-  propsSnapshot: createSnapshot(item),  // not null
-});
-```
-
-…or, equivalently, change the "fresh record" branch in Phase 3 to detect adoption explicitly. The first option is cleaner and matches the invariant the comment in Phase 3 already claims ("bindings were wired against the signal's value at the moment we set the snapshot").
-
-## Files to look at
-
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `adoptServerItems` (line 505), `reconcile` Phase 3 (line 396-422), `createSnapshot` / `refreshSnapshotAndDetect` (lines 86-122), `createItemDataProxy` (line 129).
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/template.js` — `buildSnippetProxy` lazy getters (line 67), snippet hydrate branch (line 224).
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — confirms eager hydration is forced when an each contains a `template` (snippet) node, so `adoptServerItems` is what runs during hydrate (line 189-194).
-- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` — the existing "snippet with named args inside each" test that uses a new object ref and therefore doesn't catch this.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json
deleted file mode 100644
index ceece3c83..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)",
-      "passed": true,
-      "evidence": "Step 2: 'when you write `wrapper.innerHTML = renderToString(...)`, the `<template shadowrootmode=\"open\">…</template>` stays as a literal `<template>` child of your custom element. It is not unwrapped. The element has no shadow root.' Also explicitly named in step 1: fragment parsers including `innerHTML` do not process DSD."
-    },
-    {
-      "text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API",
-      "passed": true,
-      "evidence": "The Fix section: 'Use **`setHTMLUnsafe`** (or `Document.parseHTMLUnsafe` for a document-scoped variant)' with a code example showing `wrapper.setHTMLUnsafe(html)`."
-    },
-    {
-      "text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`",
-      "passed": true,
-      "evidence": "Steps 3-5 lay out the full chain: constructor sees `this.shadowRoot` is null, `_hydrating` stays false; connectedCallback evaluates `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0` to false; component falls through to `this.fullRender(prototypeTemplate)` instead of hydrate."
-    },
-    {
-      "text": "D: Notes that the failure is silent (no error) — the test \"succeeds\" but is testing a different code path than intended",
-      "passed": true,
-      "evidence": "Opening line: 'There is no error — the element is in the page, the `rendered` event fires, but it fired for the wrong reason. You are not testing hydration; you are testing a fresh client render that happens to start from a server-rendered string.' Reinforced in the closing section: 'There is no error and no warning. Tests pass for the wrong reason.'"
-    },
-    {
-      "text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)",
-      "passed": true,
-      "evidence": "Step 1: 'The browser's **main HTML parser** processes `<template shadowrootmode=\"open\">` natively — that's why an SSR'd page works in production. But the **fragment parsers** (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) **do not**. The DSD spec deliberately opts those out because injecting attacker-controlled HTML into an existing shadow root is an XSS escalation vector.'"
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
deleted file mode 100644
index 7ddc321a8..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,64 +0,0 @@
-# Why `el.shadowRoot` is `null` in your hydration test
-
-## What's happening
-
-`wrapper.innerHTML = html` is silently throwing away the Declarative Shadow DOM. There is no error — the element is in the page, the `rendered` event fires, but it fired for the wrong reason. You are not testing hydration; you are testing a fresh client render that happens to start from a server-rendered string.
-
-The chain of events:
-
-1. The browser's **main HTML parser** processes `<template shadowrootmode="open">` natively — that's why an SSR'd page works in production. But the **fragment parsers** (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) **do not**. The DSD spec deliberately opts those out because injecting attacker-controlled HTML into an existing shadow root is an XSS escalation vector.
-2. So when you write `wrapper.innerHTML = renderToString(...)`, the `<template shadowrootmode="open">…</template>` stays as a literal `<template>` child of your custom element. It is not unwrapped. The element has no shadow root.
-3. The browser appends the element, the upgrade runs, and the constructor checks `if (this.shadowRoot)` to decide whether to set `_hydrating = true`. It's `null`, so the flag stays false.
-4. `connectedCallback` then evaluates `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0`. With a null `shadowRoot`, that's `false`.
-5. The component falls through to `this.fullRender(prototypeTemplate)` — the standard client path. `fullRender` calls `attachShadow({ mode: 'open' })` itself, builds the template from scratch, and emits the `rendered` event you're awaiting.
-6. Now `el.shadowRoot` is finally non-null, but the time-of-check vs. time-of-await ordering you wrote treats it as null, OR the assertion runs against a freshly-rendered shadow root that — depending on what your component does in `createComponent` — may not match what the server emitted (e.g. server-only branches, marker-derived per-item DOM, etc.).
-
-That last point is the real bite for your test: even if you'd later see a non-null `shadowRoot`, **you'd be asserting against a client render, not against the server's per-item DOM**. The test would pass or fail for entirely the wrong reason.
-
-## The fix
-
-Use **`setHTMLUnsafe`** (or `Document.parseHTMLUnsafe` for a document-scoped variant). Both go through HTML parser entry points that the spec explicitly enables for DSD processing:
-
-```js
-// Element-scoped — what you want for a wrapper div
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);
-const el = wrapper.firstElementChild;
-
-document.body.appendChild(el);
-await $(el).onNext('rendered');
-
-// Now el.shadowRoot is the DSD-parsed root, hasServerContent is true,
-// and connectedCallback takes the hydrate() path.
-```
-
-The "Unsafe" suffix is misleading in this context — it does not mean "unsafe in a test"; it means "this method bypasses the XSS-escalation guard that the regular fragment parsers enforce." For SSR test fixtures where you control the input string, it's exactly the right tool.
-
-This is the only DOM API change you need. Everything downstream — `el.shadowRoot` being non-null at constructor time, `_hydrating` flag set, `canHydrate()` finding the `sui:v1:` markers, `requestAnimationFrame(() => hydrate(...))` deferring one frame, the `rendered` event firing after the hydration wiring completes — all of that follows automatically once the parser actually creates the shadow root from the `<template shadowrootmode>`.
-
-## One related gotcha to check while you're in there
-
-If your test runs in a Vitest browser environment, also confirm that `renderToString` is producing real SSR output and not an empty DSD wrapper. `Template.isServer` is set once at module load from `typeof window === 'undefined'`. In the browser test env, `window` exists, so `Template.isServer === false`, and the renderer-selection inside `Template.initialize()` picks the client `Renderer` — which returns a `DocumentFragment` that the `renderToString` template literal coerces to `'[object DocumentFragment]'` (or empty after `expandCustomElements` no-ops on it). The DSD wrapper is emitted but the inside is empty.
-
-Wrap the call in a `try/finally` toggle:
-
-```js
-const wasServer = Template.isServer;
-Template.isServer = true;
-let html;
-try {
-  html = renderToString(Component, attrs);
-} finally {
-  Template.isServer = wasServer;
-}
-```
-
-The `finally` matters — leaving `Template.isServer = true` after the call would break any subsequent client-side mount in the same test run, because the renderer selection only happens once per `template.initialize()`.
-
-## Canonical reference
-
-The helper you should mirror is `ssrAndHydrate` in `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` (lines 39-67). It does exactly the two things above — `Template.isServer` toggle around `renderToString`, then `wrapper.setHTMLUnsafe(html)` instead of `innerHTML` — and is the pattern every SSR-hydration browser test in the repo is built on. If you can use it directly rather than rolling your own, do.
-
-## Why this matters beyond your single test
-
-This is one of the canonical silent-failure modes for SSR work in this framework. There is no error and no warning. Tests pass for the wrong reason; benches measure `fullRender` instead of `hydrate` and report wrong numbers. If you're authoring more SSR tests or perf benchmarks, treat `setHTMLUnsafe` + `Template.isServer` toggle as a single non-negotiable pair — they are the entry conditions for the hydration code path even existing.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json
deleted file mode 100644
index cee1093e4..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/grading.json
+++ /dev/null
@@ -1,7 +0,0 @@
-{"expectations": [
-  {"text": "A: Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec)", "passed": true, "evidence": "Short answer states 'The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not.' and explains the literal `<template>` is left in light DOM (lines 4-5, 30)."},
-  {"text": "B: Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API", "passed": true, "evidence": "Recommends `wrapper.setHTMLUnsafe(html)` as the primary fix (lines 5, 37-49) and also mentions `Document.parseHTMLUnsafe(html)` as an alternative (line 59)."},
-  {"text": "C: Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate`", "passed": true, "evidence": "Line 32-33 explicitly traces: no shadow root attached → `hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0` is false → 'framework then runs `fullRender` instead of `hydrate`'. References `connectedCallback` in `packages/component/src/engines/native/base.js`."},
-  {"text": "D: Notes that the failure is silent (no error) — the test 'succeeds' but is testing a different code path than intended", "passed": true, "evidence": "Line 33 notes 'eventually does call `attachShadow` and you get a shadow root populated by a fresh client render' and 'you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child' — this captures the silent-failure framing."},
-  {"text": "E: Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`)", "passed": false, "evidence": "Line 27 mentions 'it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it' — partially captures main-parser-enabled point, but does not explicitly enumerate the fragment parsers (`outerHTML`, `insertAdjacentHTML`) as the limited surface. The contrast between main parser vs fragment parsers is implied but not stated. Borderline; strict reading fails because the assertion specifically asks for the fragment-parser limitation framing."}
-]}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
deleted file mode 100644
index e7af4e86a..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-0-innerHTML-DSD/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,73 +0,0 @@
-# Why `el.shadowRoot` is null and how to fix it
-
-## Short answer
-
-Replace `wrapper.innerHTML = html` with `wrapper.setHTMLUnsafe(html)`. The element-instance method `setHTMLUnsafe` parses Declarative Shadow DOM (DSD); the `innerHTML` setter does not. With `innerHTML`, the `<template shadowrootmode="open">` that `renderToString` emits stays as a literal `<template>` child in light DOM and no shadow root is ever attached, so `el.shadowRoot` is `null` when your assertion runs.
-
-## What is actually in the SSR string
-
-`renderToString` (in `packages/component/src/render-to-string.js`) wraps the component output like this:
-
-```
-<my-card title="Hello">
-  <template shadowrootmode="open">
-    <style>...</style>
-    ...rendered content with hydration markers...
-  </template>
-  ...slot light DOM...
-</my-card>
-```
-
-That `<template shadowrootmode="open">` is not a regular `<template>` — it is the Declarative Shadow DOM marker. When the HTML parser encounters it, it is supposed to:
-
-1. Attach a shadow root on the parent custom element (`mode: "open"`).
-2. Move the template's contents into that shadow root.
-3. Remove the `<template>` element itself from the tree.
-
-The parser only does that when DSD parsing is explicitly enabled. By spec, it is enabled in two places: the initial document parse (HTML loaded over the network) and the DOM API methods that opt into it. The `innerHTML` setter is intentionally NOT one of them — it has been the standard policy since DSD shipped, to avoid a subtle XSS escalation where existing code that injects untrusted HTML could now also be injecting shadow roots.
-
-So when you do `wrapper.innerHTML = html`:
-- The parser leaves `<template shadowrootmode="open">` as a literal `<template>` child of `<my-card>`.
-- No shadow root is attached.
-- The custom element upgrade fires `connectedCallback`, but because `this.shadowRoot` is `null`, the framework's branch for "DSD content present" is skipped entirely. (See `packages/component/src/engines/native/base.js`, `connectedCallback`: `const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;`.)
-- The framework then runs `fullRender` instead of `hydrate`. That eventually does call `attachShadow` and you get a shadow root populated by a fresh client render — but if you assert at the wrong moment (e.g. synchronously after appending), `el.shadowRoot` can still be `null`. Even if you wait for `rendered`, you are no longer testing hydration; you're testing client render of an element that happened to have a stray light-DOM `<template>` child.
-
-## The fix
-
-Use `Element.setHTMLUnsafe()`:
-
-```js
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);
-const el = wrapper.firstElementChild;
-
-const rendered = $(el).onNext('rendered');
-document.body.appendChild(el);
-await rendered;
-
-expect(el.shadowRoot).toBeTruthy();
-```
-
-`setHTMLUnsafe` is the element-instance API specifically designed for this case: it parses with DSD enabled, so `<template shadowrootmode="open">` becomes the element's shadow root before you ever touch the DOM. By the time you read `wrapper.firstElementChild.shadowRoot`, the shadow root exists with the server content in it. When you append to `document.body`, `connectedCallback` then takes the `hasServerContent` branch and calls `hydrate(prototypeTemplate)` rather than `fullRender(...)` — wiring reactive bindings to the existing per-item DOM the server emitted.
-
-The canonical comment from the framework's own hydration test (`packages/renderer/test/browser/ssr-hydration.test.js`, around line 54) makes the contract explicit:
-
-> setHTMLUnsafe processes `<template shadowrootmode>`; innerHTML does not. Without this, the custom element parses with no shadowRoot, hasServerContent is false, and connectedCallback runs fullRender instead of hydrate.
-
-## A few related gotchas worth pinning while you're here
-
-- **Do not use `DOMParser.parseFromString(html, 'text/html')` either.** By default it also does not parse DSD. The opt-in there is the static `Document.parseHTMLUnsafe(html)` (which returns a full `Document`); that works too if you need a whole-document parse, but for injecting a single component into an existing test page, `setHTMLUnsafe` on a wrapper element is the natural fit.
-- **`Template.isServer` matters in browser tests.** `renderToString` only emits the SSR (DSD) string when `Template.isServer` is `true`. In a browser test environment it defaults to `false`, so you will get client output unless you flip it. The framework's own helper does this:
-  ```js
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  try { html = renderToString(Component, attrs); }
-  finally { Template.isServer = wasServer; }
-  ```
-  If your wrapper assertion is failing on `el.shadowRoot` being null, this is the second thing to check after `setHTMLUnsafe` — without `Template.isServer = true`, `renderToString` may not have produced a DSD string in the first place.
-- **`rendered` is the right event to await for hydration.** The framework's `connectedCallback` schedules `hydrate` via `queueMicrotask`, so you cannot read `el.shadowRoot.querySelector(...)` synchronously after `appendChild`. `await $(el).onNext('rendered')` is what the in-repo tests use, and it resolves after `template.markRendered()` inside `hydrate`.
-- **Do not assert the absence of comment markers right after `rendered`.** The hydration scaffolding (`<!-- sui:v1: ... -->` comments and `data-sui-bind="..."` attributes) is removed in a `requestAnimationFrame` callback after hydration, one tick later than the `rendered` event. If your test wants to compare `shadowRoot.innerHTML` strings, strip them yourself, the way the in-repo tests do (`shadowHTML(el)` helper). Otherwise an assertion that "the per-item DOM the server emitted" matches your expected string will fail because the server's per-item DOM is still wrapped in those markers.
-
-## Why this trips people up
-
-`innerHTML` is the muscle-memory API for "parse this string into DOM," and `setHTMLUnsafe` looks like a scary scoped variant. It is actually the opposite: `setHTMLUnsafe` is more permissive (it allows DSD), and `innerHTML` is the "safe" default that strips it. For anything involving `renderToString` output from `@semantic-ui/component`, you want the more permissive one — the whole point of the SSR string is the DSD inside it.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json
deleted file mode 100644
index 1ee09ce37..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `Template.isServer` as the controlling flag",
-      "passed": true,
-      "evidence": "Opens with 'Template.isServer is set once at module load from typeof window === undefined' and reiterates throughout: 'in the browser env, renderToString ends up using the client Renderer'. Summary explicitly names Template.isServer as root cause."
-    },
-    {
-      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
-      "passed": true,
-      "evidence": "Quotes the exact selection code from packages/templating/src/template.js:292: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and explains the consequence."
-    },
-    {
-      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
-      "passed": true,
-      "evidence": "States 'the client Renderer, which returns a DocumentFragment from render() rather than an HTML string. That fragment gets coerced into the surrounding template literal as [object DocumentFragment], then the string-only expandCustomElements no-ops on it, and the DSD wrapper is emitted with nothing inside the <template shadowrootmode=\"open\">'."
-    },
-    {
-      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
-      "passed": true,
-      "evidence": "Fix section prescribes 'Toggle Template.isServer = true around the call' with a code example setting `Template.isServer = true` before renderToString."
-    },
-    {
-      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
-      "passed": true,
-      "evidence": "Code example uses try/finally with `wasServer = Template.isServer` saved up front and `Template.isServer = wasServer` in the finally. Explicitly explains: 'The try/finally is load-bearing. If you leave Template.isServer = true after the call, any subsequent client-side hydration or mount in the same test breaks'."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md
deleted file mode 100644
index f994c34a6..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,94 +0,0 @@
-# Why `renderToString` is empty in your browser test
-
-You've hit a known silent-failure mode. Your component, settings, and template are all fine — the problem is that `renderToString` is picking the **client renderer** instead of the server one, because of how engine selection is gated.
-
-## What's happening
-
-`Template.isServer` is set **once at module load** from `typeof window === 'undefined'` (in `@semantic-ui/utils`). In a vitest browser test, `window` exists, so `Template.isServer === false` for the entire run.
-
-Inside `Template.initialize()` the engine selection looks like this (`packages/templating/src/template.js:292`):
-
-```js
-const RendererClass = (Template.isServer && engine.serverRenderer)
-  ? engine.serverRenderer
-  : engine.renderer;
-```
-
-So in the browser env, `renderToString` ends up using the **client `Renderer`**, which returns a `DocumentFragment` from `render()` rather than an HTML string. That fragment gets coerced into the surrounding template literal as `'[object DocumentFragment]'`, then the string-only `expandCustomElements` no-ops on it, and the DSD wrapper is emitted with nothing inside the `<template shadowrootmode="open">`.
-
-That matches your symptom exactly:
-
-```
-<my-component><template shadowrootmode="open"></template></my-component>
-```
-
-It's not your `each` block, not `defaultSettings`, not the data shape — it's the renderer selection. On Node the same code works because `window` is undefined and `Template.isServer` is `true`.
-
-## The fix
-
-Toggle `Template.isServer = true` around the call, with a `try/finally` so it gets restored:
-
-```js
-import { Template } from '@semantic-ui/templating';
-import { renderToString } from '@semantic-ui/component';
-
-const wasServer = Template.isServer;
-Template.isServer = true;
-let html;
-try {
-  html = renderToString(MyComponent, { items: [...] });
-} finally {
-  Template.isServer = wasServer;
-}
-```
-
-The `try/finally` is load-bearing. If you leave `Template.isServer = true` after the call, any subsequent client-side hydration or mount in the same test breaks, because renderer selection happens once per `template.initialize()` and you've now flipped every component into the server engine.
-
-## If you also plan to inject the HTML and let it hydrate
-
-Don't use `innerHTML` — it does **not** process Declarative Shadow DOM. The fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) are opted out of DSD by spec for XSS reasons. Use `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`):
-
-```js
-const wrapper = document.createElement('div');
-wrapper.setHTMLUnsafe(html);   // shadow root attaches; innerHTML would not
-const el = wrapper.firstElementChild;
-document.body.appendChild(el); // triggers connectedCallback → hydrate
-```
-
-With `innerHTML` your test will silently appear to work but actually exercise `fullRender` (client-only) instead of `hydrate`, because `el.shadowRoot` is `null` when `connectedCallback` fires and `hasServerContent` is false.
-
-## Canonical helper to copy
-
-`packages/renderer/test/browser/ssr-hydration.test.js` has the canonical `ssrAndHydrate` helper that does both pieces correctly. Worth pattern-matching against rather than rolling your own:
-
-```js
-async function ssrAndHydrate(opts, attrs = {}) {
-  const tag = uniqueTag();
-  const Component = defineComponent({ tagName: tag, renderingEngine: 'native', ...opts });
-
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  let html;
-  try {
-    html = renderToString(Component, attrs);
-  } finally {
-    Template.isServer = wasServer;
-  }
-
-  const wrapper = document.createElement('div');
-  wrapper.setHTMLUnsafe(html);
-  const el = wrapper.firstElementChild;
-
-  const rendered = $(el).onNext('rendered');
-  document.body.appendChild(el);
-  await rendered;
-  return el;
-}
-```
-
-## Summary
-
-- **Root cause:** `Template.isServer` is computed once at module load from `typeof window`. In a browser test it's `false`, so `renderToString` selects the client `Renderer` (returns a `DocumentFragment`) instead of the `ServerRenderer` (returns a string). The DSD wrapper string is emitted but nothing fills the inside.
-- **Fix:** Set `Template.isServer = true` with `try/finally` around your `renderToString` call.
-- **If injecting + hydrating:** also use `setHTMLUnsafe`, never `innerHTML`. `innerHTML` skips DSD processing and your test will silently measure the wrong code path.
-- **Reference:** `packages/renderer/test/browser/ssr-hydration.test.js` (`ssrAndHydrate`).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json
deleted file mode 100644
index dc14369dd..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `Template.isServer` as the controlling flag",
-      "passed": true,
-      "evidence": "Section heading at line 3: 'Root cause: `Template.isServer` is `false` in a real browser'. Lines 14-21 trace it back to `@semantic-ui/utils` `isServer = typeof window === 'undefined'`. Lines 23-25 explicitly state that in browser env `Template.isServer` is `false`, selecting the client renderer."
-    },
-    {
-      "text": "B: Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer`",
-      "passed": true,
-      "evidence": "Lines 7-12 quote the exact selection code from `template.js:292`: `const RendererClass = (Template.isServer && engine.serverRenderer) ? engine.serverRenderer : engine.renderer;` and frames it as 'The renderer that gets instantiated is selected here'."
-    },
-    {
-      "text": "C: Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty",
-      "passed": true,
-      "evidence": "Lines 25-34: 'the client renderer (engines/native/renderer.js) is selected. Its render() returns a DocumentFragment, not a string'. Lines 36-65 then trace how the non-string DocumentFragment causes `expandCustomElements` to silently produce empty output, yielding the empty `<template shadowrootmode=\"open\"></template>` wrapper symptom (lines 67-69)."
-    },
-    {
-      "text": "D: Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call",
-      "passed": true,
-      "evidence": "Line 80: 'Force `Template.isServer = true` for the duration of the `renderToString` call.' Lines 86-96 show the explicit `Template.isServer = true` toggle wrapping the `renderToString` call. Line 98 explains the timing: 'The flag has to be set before renderToString is invoked... and restored after'."
-    },
-    {
-      "text": "E: Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected)",
-      "passed": true,
-      "evidence": "Lines 86-95 show the canonical pattern: `const wasServer = Template.isServer; Template.isServer = true; try { return renderToString(...) } finally { Template.isServer = wasServer; }`. Line 103 reinforces the rationale: 'Don't set Template.isServer = true globally in a beforeAll - it will break any test in the same file that exercises the live client renderer'."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md
deleted file mode 100644
index b00247967..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-1-Template-isServer/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,119 +0,0 @@
-# Why `renderToString` emits an empty DSD in Vitest browser mode
-
-## Root cause: `Template.isServer` is `false` in a real browser
-
-`renderToString` is renderer-agnostic — it builds a `Template`, calls `template.initialize()`, then `template.render()`, and string-concatenates the result into the DSD wrapper. The renderer that gets instantiated is selected here:
-
-`packages/templating/src/template.js:292`
-```js
-const RendererClass = (Template.isServer && engine.serverRenderer)
-  ? engine.serverRenderer
-  : engine.renderer;
-```
-
-`Template.isServer` is initialized once, at module load, from `@semantic-ui/utils`:
-
-`packages/utils/src/environment.js:5`
-```js
-export const isServer = (() => {
-  return typeof window === 'undefined';
-})();
-```
-
-In Node SSR, `window` is undefined → `isServer === true` → the **server** renderer is selected → `template.render()` returns an HTML string → `renderToString` concatenates it into the DSD and you get fully-populated `each` output.
-
-In Vitest **browser** mode (`@vitest/browser` driving Chromium / Firefox / WebKit / Playwright), `window` is a real browser global. `typeof window === 'undefined'` is `false`, so `Template.isServer` is `false`, and the **client** renderer (`engines/native/renderer.js`) is selected. Its `render()` returns a `DocumentFragment`, not a string:
-
-`packages/renderer/src/engines/native/renderer.js:157`
-```js
-render() {
-  return this.readAST({ ast: this.ast, data: this.data, scope: this.scope });
-}
-// ...
-return fragment;  // DocumentFragment
-```
-
-## Why the inner template is *empty*, not garbled
-
-Look at what `renderToString` does with that value:
-
-`packages/component/src/render-to-string.js:67`
-```js
-let html = template.render();                // DocumentFragment in browser env
-html = expandCustomElements(html, { ... });  // string-only function
-```
-
-`expandCustomElements` is written for strings:
-
-`packages/component/src/expand-custom-elements.js:25`
-```js
-while (pos < html.length) {  // DocumentFragment.length is undefined
-  ...
-}
-```
-
-`pos < undefined` is `false`, so the loop body never runs and the function returns `''` (its `result` accumulator). Then the wrapper is built around an empty string:
-
-```js
-return `<${tagName}...>`
-  + `<template shadowrootmode="open">`
-  + (css ? `<style>${css}</style>` : '')
-  + html                          // ''
-  + `</template>`
-  + slotHTML
-  + `</${tagName}>`;
-```
-
-→ exactly the symptom you see:
-```
-<my-component><template shadowrootmode="open"></template></my-component>
-```
-
-(If your component happens to have a `css` block, you'll see a `<style>` inside the template but still no markup.)
-
-## The Node SSR path "just works" because of module load order
-
-When the test runner is Node (jsdom or node mode), `window` is undefined at the time `@semantic-ui/utils/environment.js` is first imported, so `isServer` evaluates to `true` and is captured into `Template.isServer`. Even if jsdom later adds a `window` global, the constant has already been frozen. That's why your Node-side rendering works and your browser-side rendering is empty — it's not about your component, your `defaultSettings`, your `each` block, or your data; it's purely about which renderer class got chosen at `initialize()` time.
-
-## Fix
-
-Force `Template.isServer = true` for the duration of the `renderToString` call. The repo's own browser tests do exactly this — see `packages/renderer/test/browser/ssr-hydration.test.js:39`:
-
-```js
-import { defineComponent, renderToString } from '@semantic-ui/component';
-import { Template } from '@semantic-ui/templating';
-
-function ssrInBrowser(Component, attrs) {
-  const wasServer = Template.isServer;
-  Template.isServer = true;
-  try {
-    return renderToString(Component, attrs);
-  }
-  finally {
-    Template.isServer = wasServer;
-  }
-}
-```
-
-Wrap your `renderToString` call in that `try/finally`. The flag has to be set **before** `renderToString` is invoked (because `template.initialize()` reads it once and instantiates the renderer right then) and restored after (so any subsequent client-side code in the same test — hydration, mount, reactivity assertions — still gets the DOM renderer). The flag is read on every `initialize()`, so per-call toggling is safe and doesn't leak across tests as long as the `finally` runs.
-
-A few practical notes:
-
-- Do this in a small helper rather than inline, and call it from every test that needs the SSR string. Forgetting the toggle is the single failure mode.
-- Don't set `Template.isServer = true` globally in a `beforeAll` — it will break any test in the same file that exercises the live client renderer (mount, hydrate, reactive update).
-- If you also want to verify hydration end-to-end (inject the DSD, let the browser parse `<template shadowrootmode="open">`, then upgrade the custom element), use `wrapper.setHTMLUnsafe(html)` instead of `innerHTML`. Plain `innerHTML` does not process declarative shadow DOM, so the element parses with no shadow root and `connectedCallback` falls back to a full client render — making your test a non-hydration test by accident. The browser test in `ssr-hydration.test.js:58` shows the pattern.
-- Nothing about `defaultSettings`, the `each` block, or your `items` data is involved. The component is fine. The fix is one line of test scaffolding.
-
-## Why the framework doesn't autodetect this
-
-`renderToString` could in principle override the engine selection itself (it already passes `renderingEngine: 'native'` to `proto.clone()`), but it currently delegates the server-vs-client decision to `Template.isServer`, which is a process-wide flag derived from `typeof window`. In the canonical use case — calling `renderToString` from a Node/Bun/Workers SSR path — that's correct and zero-config. The browser test environment is the edge case where the flag's heuristic is wrong, and the framework's own test suite handles it with the same toggle pattern shown above. Treat it as a known wart of running SSR code in a browser-mode test runner, not a bug in your component.
-
-## Relevant source files
-
-- `/home/jack/semantic/next/packages/component/src/render-to-string.js` — the entry point; line 67 calls `template.render()`, lines 84–90 build the DSD wrapper.
-- `/home/jack/semantic/next/packages/templating/src/template.js` — line 43 captures `Template.isServer` from `utils`; lines 292–294 select the server vs. client renderer class.
-- `/home/jack/semantic/next/packages/utils/src/environment.js` — line 5 defines `isServer = typeof window === 'undefined'`.
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/renderer.js` — line 157 `render()` returns a `DocumentFragment`.
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/server.js` — the alternative ServerRenderer that returns a string.
-- `/home/jack/semantic/next/packages/component/src/expand-custom-elements.js` — line 25 string-only `while (pos < html.length)` silently no-ops on a `DocumentFragment`.
-- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js` — lines 39–67 are the canonical browser-test pattern (`Template.isServer = true` toggle plus `setHTMLUnsafe`).
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json
deleted file mode 100644
index 3d3676b77..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
-      "passed": true,
-      "evidence": "Answer states: 'each.hydrate is the only block hydrate hook in the framework that does not unconditionally wire per-item Reactions. It is a deliberate perf optimization' and explains the perf cost (~425ms for 1000 items)."
-    },
-    {
-      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
-      "passed": true,
-      "evidence": "Answer step 2-4 explicitly chains: 'It registers a dependency on the items collection signal (via lookupExpression(node.over))... It does not wire per-item Reactions... The lazy path defers wiring until the items signal first fires, then wires in place via adoptServerItems.'"
-    },
-    {
-      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
-      "passed": true,
-      "evidence": "Steps 3-4: 'Because items is set once from a prop and never mutates, the items signal never fires. Because the items signal never fires, each.update never runs, adoptServerItems never runs, and the per-item Reactions for {classMap getItemClasses item} are never wired.'"
-    },
-    {
-      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
-      "passed": true,
-      "evidence": "Diagnosis section explicitly traces `getItemClasses(item) reads state.activeID.get()` as the external signal, and step 5 states 'When you mutate state.activeID, there is no Reaction subscribed to it on the per-item bindings — so nothing invalidates and nothing re-renders the class.'"
-    },
-    {
-      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
-      "passed": true,
-      "evidence": "Fix section names 'packages/renderer/src/engines/native/blocks/each-content-classifier.js' as the static analyzer that 'walks the each block's content AST and decides whether every binding's identifier head resolves to iteration-vars ∪ pure-helper-registry ∪ reserved-names. each.hydrate consults it: self-contained → keep the lazy path; anything that could read external state → eager adoptServerItems'."
-    },
-    {
-      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
-      "passed": false,
-      "evidence": "Answer captures the spirit ('per-binding Reactions evaluating their expressions at wire time — which is exactly what didn't happen' and 'There is no \"register without running.\" Dependency.depend() is a no-op when Scheduler.current is null. The only way to register a dep on a signal is to read it inside a wired Reaction's compute callback') but does NOT explicitly mention the `skipFirstWrite: true` flag or that the Reactions trust the SSR'd DOM rather than re-rendering on first wire."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md
deleted file mode 100644
index c7f2718ce..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,69 +0,0 @@
-# Why the per-item class binding doesn't react
-
-## Diagnosis
-
-This is the canonical "each-block lazy hydrate, content reads external state" bug. It is the exact shape of the docs-site `inpage-menu` regression that PR #175 was written to address.
-
-### What's happening
-
-`each.hydrate` is the only block hydrate hook in the framework that does **not** unconditionally wire per-item Reactions. It is a deliberate perf optimization: per-item Reactions cost `item count × bindings per item` to wire, so on a 1000-item list eagerly wiring on hydrate added ~425ms in a previous experiment. The lazy path defers wiring until the items signal first fires, then wires in place via `adoptServerItems`.
-
-The deferral is correct **only when** every per-item binding depends on item-local data (the iteration variable, `index`/`key`, framework helpers like `classMap`, `activeIf`, `is`). Your binding violates that assumption:
-
-```
-{classMap getItemClasses item}
-   |
-   +-- getItemClasses(item) reads state.activeID.get()
-                                        ^^^^^^^^^^^^^^
-                                        external signal
-```
-
-### The silent-failure chain
-
-1. SSR renders the `<a>` elements with the correct `active` class for the initial `state.activeID`. The DOM looks fine.
-2. On hydrate, `each.hydrate` runs:
-   - It registers a dependency on the `items` collection signal (via `lookupExpression(node.over)`).
-   - It does **not** wire per-item Reactions. Instead it sets `self.hasHydrated = true` and returns. `adoptServerItems` is **not** called.
-3. Because `items` is set once from a prop and never mutates, the items signal never fires.
-4. Because the items signal never fires, `each.update` never runs, `adoptServerItems` never runs, and the per-item Reactions for `{classMap getItemClasses item}` are never wired.
-5. When you mutate `state.activeID`, there is no Reaction subscribed to it on the per-item bindings — so nothing invalidates and nothing re-renders the class.
-
-Your sanity-check `reaction(() => console.log(state.activeID.get()))` works because *that* Reaction is wired explicitly and registers its own dependency on `state.activeID` on first run. The framework's per-expression reactivity guarantee comes from per-binding Reactions evaluating their expressions at wire time — which is exactly what didn't happen for the items inside the `{#each}`.
-
-This is load-bearing: there is no "register without running." `Dependency.depend()` is a no-op when `Scheduler.current` is null. The only way to register a dep on a signal is to read it inside a wired Reaction's compute callback. No wired Reaction on the per-item binding means no dep on `state.activeID`, which means no reactivity. Hydration markers being clean and the SSR'd class being correct is a red herring — it just means the server-side render of the initial state was right.
-
-## Fix
-
-PR #175 introduced a static analyzer at `packages/renderer/src/engines/native/blocks/each-content-classifier.js` that walks the each block's content AST and decides whether every binding's identifier head resolves to `iteration-vars ∪ pure-helper-registry ∪ reserved-names`. `each.hydrate` consults it: self-contained → keep the lazy path; anything that could read external state → eager `adoptServerItems` so per-item Reactions register their external deps now.
-
-If the framework version you're on includes that classifier, **the fix is upstream** — `getItemClasses` reads `state.activeID`, the helper isn't in the framework's pure-helper registry (`TemplateHelpers`), the classifier returns false, and `each.hydrate` will eagerly wire. Verify by checking whether `packages/renderer/src/engines/native/blocks/each-content-classifier.js` exists in your install, and whether `each.js`'s `hydrate` function calls `isEachContentSelfContained(node)`. If both are present, the bug is something else (e.g., your each block uses no-`as` syntax — the classifier conservatively bails, but you'd then *not* see this bug because conservative bails go eager).
-
-If you're on a version *before* the classifier shipped (or if for some reason `getItemClasses` is not visible to the analyzer — e.g., it's registered as a user helper via `Template.registerHelper` and the classifier's identifier check sees it as external — which is the *correct* call in that case), the workarounds available to you in user-land are:
-
-1. **Inline the active check at the call site.** Move the binding into syntax the classifier can trace, or — pre-classifier — into syntax that doesn't hide the external read inside a helper:
-
-   ```
-   {#each item in items}
-     <a class="{classMap (object active=(eq state.activeID item.id)) item=true}">
-       {item.title}
-     </a>
-   {/each}
-   ```
-
-   This still reads external state, so on a pre-classifier version it still bugs out — but on a classifier version it's properly classified as external, and the helper registry recognizes `classMap` and `eq` as pure.
-
-2. **Make the items signal fire whenever `state.activeID` changes.** Re-assigning `state.items.set(state.items.get())` after each `state.activeID` mutation forces `each.update` to run, which calls `adoptServerItems`, which wires the per-item Reactions and registers their deps on `state.activeID` going forward. This is a one-time wire — you only need to nudge once after hydrate. Ugly but mechanically correct.
-
-3. **Force a re-mount of the each block** by wrapping it in a `{#rerender}` keyed on a version counter you bump on each `activeID` change. Throws away the per-item DOM and re-renders client-side — works but defeats hydration.
-
-The first option is the right user-land fix on a classifier-aware version; option 2 is the diagnostic that proves the diagnosis (if mutating items once unsticks the reactivity, you've confirmed the lazy-hydrate gate is the culprit). Option 3 is a hammer.
-
-## Why this is silent
-
-There is no error, no warning, no DevTools breadcrumb. The SSR'd DOM is correct, the hydration markers are clean, the items array is intact, the `state.activeID` signal mutates and any *direct* reaction to it fires. Only the per-item bindings are missing their subscriptions. The lazy-hydrate optimization trades correctness for the assumption that per-item bindings are item-local — and external-state reads inside per-item bindings violate that assumption invisibly.
-
-## Key files
-
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `each.hydrate`, the deferral gate, and `adoptServerItems`
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — `isEachContentSelfContained`, the static analyzer that decides lazy vs eager
-- `/home/jack/semantic/next/packages/renderer/test/unit/each-content-classifier.test.js` — coverage for item-local, external-read, and conservative-bail cases
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json
deleted file mode 100644
index aee8bb003..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
-      "passed": true,
-      "evidence": "Section 'What the each block does on hydrate' explicitly frames it as 'a deliberate optimization at hydrate time' and dedicates a paragraph (lines 55-59) to the rationale: 'the common case... the per-item binding reads only iteration-local data, the server-rendered DOM is already correct, and there is nothing to react to at hydrate time. Wiring N Reactions for N items at hydrate just to have them never fire is wasted work on first paint. Defer them and pay only on the first real change.'"
-    },
-    {
-      "text": "B: Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires",
-      "passed": true,
-      "evidence": "Lines 35-53 quote the relevant `each.hydrate` code with `lookupExpression(node.over)` registering the items-collection dep, and explicitly state: 'Wiring inner Reactions is deferred to a function called `adoptServerItems`, which runs the first time `update` fires (i.e. the first time the items signal changes after hydrate).'"
-    },
-    {
-      "text": "C: Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever",
-      "passed": true,
-      "evidence": "Lines 97-99: 'The killer detail: the items signal's only chance to wake the per-item bindings is to itself fire. Your items are set once from a prop. They never mutate. So the deferred wire-up never happens.' Also reinforced in lines 84-89 walking the post-hydrate timeline."
-    },
-    {
-      "text": "D: Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost",
-      "passed": true,
-      "evidence": "Lines 75-91 directly link the bug: '`state.activeID` is *external* to the iteration scope. The per-item attribute binding's Reaction is the thing that needs to subscribe to it... Nothing in the each block is subscribed to `state.activeID`. The block does not invalidate.... Class string stays at whatever the server rendered.'"
-    },
-    {
-      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
-      "passed": true,
-      "evidence": "Section 'The framework fix (commit 0df8d554e)' (lines 102-135) names the file `packages/renderer/src/engines/native/blocks/each-content-classifier.js`, describes the classifier walking the each's content AST to answer 'could any binding inside this each read external state?', and concludes 'The classifier returns false → `each.hydrate` calls `adoptServerItems` *now* instead of deferring.'"
-    },
-    {
-      "text": "F: Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
-      "passed": false,
-      "evidence": "The answer says per-item Reactions 'subscribe to `state.activeID` on their first run' (line 134) and that adoptServerItems 'walks the existing DOM (matched up to server item markers by key) and creates per-item Reactions on the already-rendered nodes', which captures the spirit of evaluation-as-subscription. However, the specific `skipFirstWrite: true` mechanism is never named, nor is the explicit notion that the Reaction trusts the SSR'd DOM and skips its first write so as not to clobber the server output. The rubric calls for the named flag/mechanism."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md
deleted file mode 100644
index d70d295b0..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-2-each-external-state/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,203 +0,0 @@
-# Why the per-item class doesn't react after hydration
-
-## Short answer
-
-Your `{#each}` block's per-item attribute Reactions never wired against
-`state.activeID`. The render-time path that would have wired them is gated on
-the items signal firing — and your items collection is set once and never
-mutates, so the per-item bindings never get a chance to subscribe to the
-external state their helper depends on.
-
-The fix is one of:
-
-1. Upgrade to a framework version that includes the eager-hydrate classifier
-   (commit `0df8d554e`, "Bug: Hydrate each items eagerly when bindings read
-   external state"). With that fix, the each block notices that the per-item
-   binding reads external state via a non-framework helper (`getItemClasses`)
-   and wires per-item Reactions during `hydrate` instead of deferring to the
-   first items mutation.
-2. If you're stuck on an older version, force the items signal to fire once
-   after hydration so the deferred wire-up path runs, e.g.
-   `state.items.notify()` in `onRendered`, or trigger a no-op
-   `state.items.set(state.items.get())` once. This is a workaround, not the
-   intended pattern.
-
-The rest of this doc explains *why* the deferred-wire optimization exists and
-*why* your shape is the precise one that breaks it — that context matters
-because the same pattern keeps biting people whose data arrives at hydrate
-time rather than after.
-
-## What the each block does on hydrate
-
-The native engine's each block (`packages/renderer/src/engines/native/blocks/each.js`)
-makes a deliberate optimization at hydrate time. From `each.hydrate`:
-
-```js
-hydrate({ node, lookupExpression, ... }) {
-  // Always register a dep on the collection so future mutations invalidate.
-  lookupExpression(node.over);
-  self.hasHydrated = true;
-
-  // ... possibly bail and DEFER per-item wiring ...
-}
-```
-
-Two things happen on hydrate:
-
-1. The block registers a dependency on the *items collection* signal so a
-   future mutation to the items array will rerun the block.
-2. It does **not** wire per-item Reactions for inner content. Per-item DOM
-   already exists (the server emitted it, bracketed by `<!--sui-item:v1:KEY-->`
-   markers). Wiring inner Reactions is deferred to a function called
-   `adoptServerItems`, which runs the first time `update` fires (i.e. the
-   first time the items signal changes after hydrate).
-
-The reason for the defer: the common case is `{#each item in items}<span>{item.name}</span>{/each}`
-— the per-item binding reads only iteration-local data, the server-rendered
-DOM is already correct, and there is nothing to react to at hydrate time. Wiring
-N Reactions for N items at hydrate just to have them never fire is wasted work
-on first paint. Defer them and pay only on the first real change.
-
-This optimization is unsafe whenever a per-item binding reads anything outside
-the iteration scope.
-
-## Why your case breaks
-
-Your binding looks like this:
-
-```hbs
-{#each item in items}
-  <a class="{classMap getItemClasses item}">{item.title}</a>
-{/each}
-```
-
-Where `getItemClasses` is a method that calls `state.activeID.get()`.
-
-`state.activeID` is *external* to the iteration scope. The per-item attribute
-binding's Reaction is the thing that needs to subscribe to it, because that
-Reaction is what writes the `class` attribute back to the DOM when activeID
-changes.
-
-But on the deferred path, that per-item Reaction is never created. Walk
-through what happens after hydrate:
-
-- Hydrate runs. The block registers a dep on `items` and bails (deferring per-
-  item wiring).
-- You mutate `state.activeID`.
-- Nothing in the each block is subscribed to `state.activeID`. The block does
-  not invalidate. `update` does not run. `adoptServerItems` does not run. No
-  per-item Reaction was ever wired against `state.activeID`.
-- Class string stays at whatever the server rendered.
-
-Your sanity check (`reaction(() => console.log(state.activeID.get()))`) works
-because *that* reaction subscribed at creation time. The Reactions inside the
-each block — the ones that would write the class attribute — were never
-created.
-
-The killer detail: the items signal's only chance to wake the per-item
-bindings is to itself fire. Your items are set once from a prop. They never
-mutate. So the deferred wire-up never happens.
-
-## The framework fix (commit 0df8d554e)
-
-The fix is a static classifier
-(`packages/renderer/src/engines/native/blocks/each-content-classifier.js`)
-that runs once per unique each-content AST shape (cached on AST identity, so
-it's effectively free per component instance). It walks the each's content
-AST and answers one question: "could any binding inside this each read
-external state?"
-
-The classifier knows about:
-
-- Iteration-local names (`item`, `index`, `key`, `this`, plus whatever the
-  user named in `as` / `,index` / `,key`)
-- The framework's pure helpers (`classMap`, `classIf`, `formatDate`,
-  `concat`, ... — everything in `TemplateHelpers`)
-- JS reserved names (`true`, `false`, `null`, `typeof`, ...)
-
-For each expression, every bare identifier head must resolve to one of those
-sets. If anything else appears (a component method, a user-registered helper,
-a state name closed over by an inline expression), the classifier returns
-"not self-contained."
-
-For your expression `{classMap getItemClasses item}`, the tokens are:
-
-- `classMap` — pure helper, OK
-- `getItemClasses` — not in the iteration scope, not in the pure-helper
-  registry → classifier returns false (external reads possible)
-- `item` — iteration-local, OK
-
-The classifier returns false → `each.hydrate` calls `adoptServerItems` *now*
-instead of deferring. `adoptServerItems` walks the existing DOM (matched up
-to server item markers by key) and creates per-item Reactions on the
-already-rendered nodes. Those Reactions subscribe to `state.activeID` on
-their first run, and from that point on, mutations propagate.
-
-There is a regression test pinning exactly your shape:
-`packages/renderer/test/browser/ssr-hydration.test.js:315` — "helper-call
-attribute inside each is reactive after hydration when items pre-populated".
-Its docstring is a transcription of this entire failure mode — it was
-discovered in production from a docs-site `inpage-menu` that wouldn't update
-its active-section indicator on scroll.
-
-## Things that won't fix it (so you can rule them out)
-
-- Replacing `classMap` with `classIf` or string concat — same shape,
-  `getItemClasses` (or whatever non-framework function you call) is still the
-  external-state read.
-- Using `state.activeID.peek()` instead of `.get()` — peek explicitly opts
-  out of dependency tracking. You'd lose reactivity *to* activeID, not gain
-  it.
-- Wrapping the helper call in a parent reactive context (e.g. the component's
-  `onRendered`) — that doesn't propagate down into the per-item Reactions
-  because the per-item Reactions are what need to exist in the first place.
-- Switching the items prop from a plain array to a Signal — the items signal
-  *is* already a Signal under the hood. The issue is not the items channel,
-  it's that the per-item bindings haven't been wired yet.
-
-## Things that will fix it
-
-- **Preferred:** upgrade to the framework version with the classifier fix.
-  No code change required on your side; the classifier inspects your AST
-  and sees `getItemClasses` is not a framework helper, switches to the
-  eager path, and your binding starts reacting.
-- **Workaround on older versions:** force the items signal to fire once
-  after hydrate so the deferred wire-up runs:
-  ```js
-  onRendered() {
-    state.items.notify();   // wakes the each block's items dep,
-                            // which runs update, which calls
-                            // adoptServerItems, which wires per-item
-                            // Reactions on the existing DOM
-  }
-  ```
-  This is not the intended API — the canonical fix is the classifier — but
-  it works mechanically because it triggers the same `adoptServerItems` path
-  that the classifier triggers eagerly.
-- **Workaround that sidesteps the each entirely:** lift the
-  state-dependent class to an attribute on the per-item *element* that uses
-  `data-active="{is item.id state.activeID}"` and style off `[data-active]` in
-  CSS, *if* you don't actually need a class. This works because the
-  attribute binding still goes through the same Reaction path — but on
-  versions without the fix it has the same problem. Don't do this; upgrade.
-
-## What to actually look at first
-
-Before assuming this is the bug, confirm:
-
-1. The component is hydrating, not full-rendering on the client. If
-   `el.shadowRoot` is missing on connect, hydration didn't run and you're
-   on the fresh-render path, which always wires Reactions. Check that your
-   server output includes `<template shadowrootmode="open">` and that
-   nothing strips it before the browser parses it.
-2. The classifier's caching is on AST identity (`WeakMap<ASTNode, boolean>`).
-   If you have two components that share an AST shape but only one of them
-   has an external-state helper, the one classified first wins for both —
-   but in practice each `defineComponent` call produces its own AST, so this
-   is unlikely to be your issue.
-3. If you registered `getItemClasses` via `Template.registerHelper` *before*
-   the classifier module first loaded, the classifier will see it as a pure
-   helper (because `PURE_HELPERS = new Set(Object.keys(TemplateHelpers))`
-   captures the registry once at module init). Define it as a component
-   method or inline `createComponent` field instead — that's how the
-   regression test fixture writes it, and it's the canonical pattern.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json
deleted file mode 100644
index 6dd313e6a..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
-      "passed": true,
-      "evidence": "Stated explicitly: 'Relative noise is `absolute_jitter / bench_duration`, so it scales inversely with how long the bench takes' and 'The floor is a function of duration, not sample count.'"
-    },
-    {
-      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
-      "passed": true,
-      "evidence": "Reproduces the table verbatim under 'Why the floor is ±28%': '~2ms | ±10-20%', '~10ms | ±2-5%', '~50ms+ | ±1% or tighter' (with the ~6ms row added for context)."
-    },
-    {
-      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
-      "passed": true,
-      "evidence": "States: 'Per-sample timing jitter on a CI runner — OS scheduling, GC pauses, JIT recompilations — is roughly constant in absolute terms, typically σ≈1-2ms.' Note: the rubric says 'typically sub-millisecond' while the answer says σ≈1-2ms; the qualitative claim (constant absolute jitter, named sources) matches."
-    },
-    {
-      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
-      "passed": true,
-      "evidence": "States: 'At 6ms, ~2ms of absolute jitter is ~33% relative — exactly where your ±28% lives' and explicitly: 'Even pushing `sampleSize` to 200+ would only narrow the CI within the noise floor — it would not push *below* it. The floor is a function of duration, not sample count.'"
-    },
-    {
-      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
-      "passed": true,
-      "evidence": "Section 'What to change about the bench' recommends amplifying per-sample work; option 1: 'Bump item count (most reliable) ... 1000 items ... pushes it into the 50-100ms range where ±1% becomes resolvable.' Concrete next step: 'Bump items to 1000.'"
-    },
-    {
-      "text": "F: Optionally references the perf-improvement skill or `improve-performance` workflow as the source for this methodology",
-      "passed": true,
-      "evidence": "References section explicitly cites 'ai/skills/workflows/contributing/improve-performance.md — duration/noise table, tuning-knob semantics' and also 'ai/skills/contributing/read-bench-report.md'."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md
deleted file mode 100644
index e535c0b6d..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,86 +0,0 @@
-# Why your 6ms hydrate bench can't see the fix — and what to change
-
-## Short answer
-
-A ±28% noise floor on a 6ms bench means tachometer is correctly reporting that the measurement *cannot resolve* changes smaller than ~28%. This isn't a tachometer bug, a sample-size problem, or a config-tuning problem — it is the physical floor of what a 6ms wall-clock bench can detect on a CI runner. Your fix may be very real; the bench is simply too short to see it.
-
-The fix is **not** to crank `sampleSize` or tighten `autoSampleConditions`. The fix is to **amplify per-sample work** so the bench duration moves into a band where small relative changes survive the absolute jitter floor.
-
----
-
-## Why the floor is ±28%
-
-Per-sample timing jitter on a CI runner — OS scheduling, GC pauses, JIT recompilations — is roughly **constant in absolute terms**, typically σ≈1-2ms. Relative noise is `absolute_jitter / bench_duration`, so it scales inversely with how long the bench takes:
-
-| Bench duration | Expected relative noise floor |
-|---|---|
-| ~2ms  | ±10-20% |
-| ~6ms  | ~±25-30% (your bench) |
-| ~10ms | ±2-5% |
-| ~50ms+ | ±1% or tighter |
-
-At 6ms, ~2ms of absolute jitter is ~33% relative — exactly where your ±28% lives. The reporter's `Expected Noise` column predicts this from duration, and your bench's CI width matches it. That's the diagnostic signal: **observed CI ≈ expected noise floor → bench is noise-floor-limited, not under-sampled.**
-
-Why this is not a sampling problem:
-- The 95% CI is built from sample variance. Tachometer's `autoSampleConditions` only controls the *resolution it chases* — it doesn't relax the CI itself. Asking for ±1% on a 6ms bench means tachometer keeps sampling until it hits `timeout`, then gives up "Unsure."
-- Sample-size scaling is √N. To halve a CI you need 4× samples, and per-config wall-clock time grows accordingly. Even pushing `sampleSize` to 200+ would only narrow the CI within the noise floor — it would not push *below* it. The floor is a function of duration, not sample count.
-
----
-
-## What to change about the bench
-
-Increase per-sample work until duration is in the ±2-5% band (~10ms+), ideally toward ±1% (~50ms+). Three knobs, in order of preference:
-
-### 1. Bump item count (most reliable)
-
-The canonical hydrate bench at `packages/component/bench/tachometer/bench-hydrate.js` uses **1000 items**, not 100, despite the metric being named `hydrate-each-100`. The name is historical; the size was chosen to push the measure window past the noise floor. A 100-item list typically produces a 5-10ms hydrate; a 1000-item list pushes it into the 50-100ms range where ±1% becomes resolvable.
-
-If you copied the `-100` naming from another bench, leave the metric name alone — what matters is that the per-sample workload is large enough.
-
-### 2. Split mount vs. first-data-change into separate windows
-
-The canonical bench measures hydration in two distinct `performance.measure` windows:
-
-- `hydrate-each-100-mount` — DSD parse + `connectedCallback` + the hydrate microtask + the post-hydrate rAF. This catches regressions that move per-item wiring earlier (e.g. an eager `adoptServerItems` in `each.hydrate`).
-- `hydrate-each-100` — the first-data-change adoption pass after mount. This catches regressions in the AST→entries cache (`renderer.js buildStringCache`) — on a cache miss the path reverts to a full `buildHTMLStringPure` per item.
-
-If your fix targets only one of these phases, putting them in one combined measure dilutes the signal. Split them — and pick the window that contains your fix.
-
-### 3. Loop the operation N times inside one `performance.measure`
-
-If item count is fixed by what you're benching, loop the hydration cycle N times inside a single measure. A 100-item × 10-cycle measure gets you the same ~60ms duration as a 1000-item × 1-cycle one, with the same noise-floor benefit. The mount path needs `setHTMLUnsafe` each iteration (not `innerHTML` — that does *not* process DSD, see below) and a fresh container.
-
----
-
-## Don't reach for these (they look like the fix, but aren't)
-
-- **Cranking `sampleSize` past 50** — narrows CI inside the floor, doesn't lower the floor. Wastes per-config timeout budget.
-- **Tightening `autoSampleConditions` to `["1%"]` or `["0%"]`** — tells tachometer to keep chasing resolution it physically can't reach. The run burns its `timeout` and emits Unsure verdicts. Set the threshold *above* the predicted noise floor, not below it.
-- **Re-running the bench expecting noise to "settle"** — it won't. The floor is inherent to the duration; subsequent runs will look the same.
-- **Trusting the cross-session "regressed from peak" column** — that comparison operates on absolute ms across runs on different runner conditions and produces phantom regressions on PRs that didn't change perf. Read the within-session `vs main` column. (The schema_v2 reporter overhaul addresses this.)
-
----
-
-## Sanity check before you re-bench
-
-When `tachometer` says "no meaningful change," confirm the bench is actually exercising the hydrate path you changed. Two silent failure modes — both common, both produce a bench that "works" while measuring the wrong thing — are worth verifying before scaling up:
-
-1. **`innerHTML` doesn't process Declarative Shadow DOM.** Only `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) attaches the shadow root from `<template shadowrootmode="open">`. If your bench uses `innerHTML`, the custom element's `shadowRoot` is `null` when `connectedCallback` fires, `hasServerContent` is false, and the element falls through to `fullRender` instead of `hydrate`. Your bench measures fresh client render.
-
-2. **`renderToString` returns an empty body in browser test env unless `Template.isServer = true`.** That flag is set once at module load from `typeof window === 'undefined'`. In Chrome (which is where tachometer runs), it's `false`, the client `Renderer` is selected, and the DSD wrapper is emitted around an empty string. The canonical `bench-hydrate.js` sidesteps this by driving `ServerRenderer` directly off the cloned template's AST in the browser — note the lack of a top-level `renderToString` call. If you're calling `renderToString` from the bench, wrap it in a `try/finally` that toggles `Template.isServer`.
-
-If either of these is in play, your fix never had a chance to register because the bench was never running the hydrate code path. Verify the SSR'd HTML contains hydration markers (`<!--sui:v1:N-->` / `<!--sui-block:v1:N-->`) and that the post-DSD shadow root is non-empty before any JS runs.
-
----
-
-## Concrete next step
-
-Bump items to 1000 (or loop the 100-item op 10×), re-run, and confirm the `Expected Noise` column drops into the ±1-3% range. Then your real fix should be visible — or the bench will tell you, with statistical confidence, that it isn't.
-
-## References
-
-- `packages/component/bench/tachometer/bench-hydrate.js` — canonical 1000-item dual-window pattern
-- `ai/skills/authoring/ssr-hydration.md` — Gotcha 3 (noise floor scaling) and Gotchas 1-2 (silent-failure traps)
-- `ai/skills/workflows/contributing/improve-performance.md` — duration/noise table, tuning-knob semantics
-- `ai/skills/contributing/read-bench-report.md` — how to read `Expected Noise` vs. observed CI width in the reporter
-- `tools/ci/bench/reporter/reporter.js` — the `Expected Noise` column emitter
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json
deleted file mode 100644
index 49042e3c0..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/grading.json
+++ /dev/null
@@ -1,34 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies that bench noise floor scales inversely with bench duration",
-      "passed": true,
-      "evidence": "Opening lines state 'absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and ±X% is just (constant ms) / (your duration)'. Summary repeats: 'duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter'. Inverse scaling is explicitly named."
-    },
-    {
-      "text": "B: Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1%",
-      "passed": true,
-      "evidence": "Provides a concrete table of measured durations vs predicted ±% half-widths (7.4ms = ±10.6%, 13.7ms = ±5.7%, 12.6ms = ±6.2%, 16.2ms = ±4.8%) and states '≥ 30 ms (predicted ±2.6%) to comfortably clear the ±2% noise floor'. Also derives ±26% at 6ms. The bands map to the rubric's tiers (short = ±10-20%, ~10ms = ±2-5%, longer = ±1%)."
-    },
-    {
-      "text": "C: Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond",
-      "passed": true,
-      "evidence": "Explicitly explains 'absolute per-sample jitter is roughly constant' and lists 'system jitter (scheduling, GC, JIT)' as the cause. Notes σ ≈ 2 ms on GHA runners (slightly above sub-millisecond but the constant-absolute physics is clearly stated). The 'roughly constant in absolute terms' point is made repeatedly."
-    },
-    {
-      "text": "D: Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it",
-      "passed": true,
-      "evidence": "Computes ±26% predicted at 6ms, explains observed ±28% is at the noise-floor-limited boundary, and explicitly states in option 4: 'Don't bump sampleSize — diminishing returns... 4× the wall-clock time gets you from ±28% to ±14%' and 'Width comes from duration, not from sample count beyond a point.'"
-    },
-    {
-      "text": "E: Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band",
-      "passed": true,
-      "evidence": "Option 1 recommends 'Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo.' Cites bench-hydrate.js using n=1000 items as the existing pattern to copy. Targets ≥30 ms / ±2.6%."
-    },
-    {
-      "text": "F: Optionally references the perf-improvement skill or improve-performance workflow as the source for this methodology",
-      "passed": false,
-      "evidence": "Answer references reporter.js, bench-history.json, bench-todo.js, and bench-hydrate.js as sources, but does not name the perf-improvement skill or improve-performance workflow. This is an optional expectation but per the rubric's literal wording it is not satisfied."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md
deleted file mode 100644
index ddec432ec..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-3-bench-noise-floor/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,94 +0,0 @@
-# Why a 6 ms hydration bench can't see your improvement
-
-Short version: at ~6 ms duration, the bench is running below the resolution floor of the CI runner. The noise floor isn't `±28%` because tachometer is misconfigured — it's that wide because absolute per-sample jitter is roughly constant (~2 ms σ on the GHA runners this repo uses) and `±X%` is just `(constant ms) / (your duration)`. Fix the noise floor by making the bench longer in absolute time, not by tuning tachometer.
-
-## The math the reporter is using
-
-The bench reporter at `/home/jack/semantic/next/tools/ci/bench/reporter/reporter.js` encodes the model explicitly (lines 49–90):
-
-```js
-const NOISE_FLOOR = 2;           // percent — matches autoSampleConditions
-const SIGMA_ABS_MS = 2;          // empirical per-sample σ on GHA runners
-
-function expectedNoisePp(meanMs) {
-  // From SE-of-the-difference of two means at n=50, z=1.96:
-  //   abs_CI_width ≈ 2 * 1.96 * sqrt(2) * σ / sqrt(50) ≈ 0.784 * σ
-  //   pct_width   = abs_CI_width / mean * 100
-  return (0.784 * SIGMA_ABS_MS) / meanMs * 100;
-}
-```
-
-Plug in `σ = 2 ms`, `mean = 6 ms`:
-
-- `abs_CI_width ≈ 0.784 × 2 = 1.568 ms`
-- `pct_width = 1.568 / 6 × 100 ≈ 26%`  → reported as **±13%** (half-width on each side)
-
-You're seeing **±28%** observed. That is `~2.1×` the duration-derived expected width — right at the boundary of what the reporter classifies as `noise-floor-limited` vs `unsure` (`NOISE_RATIO_TOLERANCE = 2` at line 62). So tachometer is honest: at this duration, on these runners, the measurement can't see anything smaller than roughly ±15–30% of the mean. A 1 ms improvement on a 6 ms bench is well below that.
-
-This is exactly why your CI is "no meaningful change" — `NOISE_FLOOR = 2`% (line 49) demands the CI live entirely outside `[-2%, +2%]` to be classified `faster`/`slower`. Your CI straddles ±2% wider than the noise floor allows it to resolve, so the reporter buckets it into `noise-floor-limited` (file `reporter.js`, lines 220–225):
-
-```js
-function classify([low, high], ratio) {
-  if (high < -NOISE_FLOOR) { return 'faster'; }
-  if (low > NOISE_FLOOR)   { return 'slower'; }
-  if (low > -NOISE_FLOOR && high < NOISE_FLOOR) { return 'within-noise'; }
-  return ratio <= NOISE_RATIO_TOLERANCE ? 'noise-floor-limited' : 'unsure';
-}
-```
-
-## The "Too Fast to Measure Precisely" bucket exists for this exact case
-
-When you read the rendered comment, your bench should be sitting under `🔍 Unsure → Too Fast to Measure Precisely`. The header copy (rendered from `reporter.js` lines 384–402) literally says:
-
-> On benches this short, system jitter (scheduling, GC, JIT) masks sub-4% changes; larger deltas still resolve cleanly.
-
-That row exists specifically to tell the author "this isn't a verdict, this is a 'your bench is too short' diagnostic." Don't trust the noise classification as a refutation of your fix — trust it as a request to amplify the bench.
-
-## What the existing benches do — copy this pattern
-
-The existing hydrate bench at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-hydrate.js` already runs at `n=1000` items (line 99: `const itemsForMount = makeItems(1000)`), not 100. Recent main-history numbers confirm what that buys you:
-
-| metric | mean | predicted ±% half-width | resolves? |
-|---|---|---|---|
-| `hydrate-helper-100-mount` | 7.4 ms | ±10.6% | borderline |
-| `hydrate-each-100-mount` | 13.7 ms | ±5.7% | yes |
-| `hydrate-each-100` | 12.6 ms | ±6.2% | yes |
-| `hydrate-helper-100-state-change` | 16.2 ms | ±4.8% | yes |
-
-Source: `/home/jack/semantic/next/tools/ci/bench/reporter/bench-history.json` (the `271be03` commit entry near line 1584).
-
-Note even `hydrate-helper-100-mount` at 7.4 ms is the noisiest of the four because it's the shortest. The larger ones are the ones that resolve cleanly. **You want to be ≥ 30 ms** (predicted ±2.6%) to comfortably clear the ±2% noise floor — that's the inflection point where small changes get classified.
-
-The `bench-todo.js` author at `/home/jack/semantic/next/packages/component/bench/tachometer/bench-todo.js` calls this strategy out explicitly in line comments:
-
-- Line 275: `// 20 alternating toggle-all invocations on a 100-item list — amplified // so the measurement clears the σ≈2ms per-sample noise floor on CI.`
-- Line 290: `// Each position's ~10ms per-delete workload clears the σ≈2ms floor.`
-- Line 361: `// List scaled to 500 (250 marked completed) so the single clearCompleted // operation is large enough to clear the σ≈2ms per-sample noise floor.`
-- Line 333–335: `// 10× loop (vs 5× for the front/back variants) — middle removal's // O(N/2) scan has wider per-sample variance, so 5× landed at ~74ms // with observed CI straddling ±2%. 10× brings it to ~148ms / ±1%.`
-
-These are the same change you should make.
-
-## Concrete options for your bench, ranked
-
-**1. Scale the workload up (preferred).** Move from 100 items to whatever clears 30 ms in absolute time. For pure hydration, that's typically 500–1000 items in this repo. If your fix is in per-item work (e.g. `hydrateInnerContent`, `adoptServerItems`), 1000 items multiplies its weight by 10× without changing what you're measuring. Keep the metric name describing items measured, not items rendered, if you want comparability — but in this repo most names already include the count (e.g. `hydrate-each-100` actually mounts 1000 items per the comment at line 99).
-
-**2. Loop the operation N times inside one `performance.measure` window.** This is what `toggle-all-20` and `remove-10-middle` do. If hydration itself isn't loopable (you only mount once), then loop the *follow-up data change* that exercises the codepath you fixed. The existing bench does this already with `hydrate-each-100` — measures the post-mount `setItems(...)` call rather than mount itself.
-
-**3. Add a separate amplified metric instead of replacing.** Keep the realistic 100-item bench for human readability of the duration, and add a 1000-item variant with the same shape for measurement precision. Both metrics ship; the reporter handles either.
-
-**4. Don't bump `sampleSize` — diminishing returns.** Going from `sampleSize: 50` to `200` only narrows the CI by `√(50/200) = 0.5×`. So 4× the wall-clock time gets you from ±28% to ±14%. Compare to scaling the workload 5× (6ms → 30ms), which gets you from ±28% to ±5% with no extra wall-clock cost. Sample-size tuning is the wrong knob for short benches.
-
-**5. Don't tighten `autoSampleConditions`.** Currently `["2%"]` — that's the *target* CI width for tachometer's auto-sampler. Tightening it to `["1%"]` just makes tachometer keep sampling until either it converges (it can't, because the underlying jitter is absolute-constant, not relative) or it hits `timeout: 3` minutes and gives up with the same wide CI. The `tachometer-todo.json` non-CI variant uses `["0%", "10%"]` which means "sample until <10% relative width OR a 0% target" — also wrong choice for short benches. Width comes from duration, not from sample count beyond a point.
-
-## Verifying your fix saved time at all
-
-If you want to know whether the fix is real before investing in bench amplification:
-
-- Run the bench locally with `--manual` or via the CI HTML harness, open DevTools, and use the Performance panel — a 1 ms saving on a 6 ms operation is visible in a flame graph even when it's invisible to tachometer at n=50.
-- Add a `console.time('hydrate')` / `console.timeEnd('hydrate')` around the codepath, run it 10 times locally, eyeball the median — if you see 5 ms vs 6 ms consistently, the fix is real and the bench is just under-resolved.
-
-Then commit the bench amplification as a separate change so the perf comment on your fix's PR can show a `faster` row instead of `noise-floor-limited`.
-
-## Summary
-
-The noise floor is wide because `1.568 ms / 6 ms ≈ 26%`. That's not a bug or a tachometer config issue — it's the duration-derived statistical floor for the σ ≈ 2 ms per-sample jitter on this runner, and the reporter at `tools/ci/bench/reporter/reporter.js` documents it explicitly. The fix is to amplify the bench duration to ≥ 30 ms (loop the op, scale items, or both), exactly as the existing `bench-todo.js` and `bench-hydrate.js` already do. Don't reach for `sampleSize` or `autoSampleConditions` — neither addresses the underlying `(constant ms) / duration` problem.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json
deleted file mode 100644
index 3c6d9ad37..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
-      "passed": true,
-      "evidence": "Opens with 'This is the **lazy each-block hydration** trap' and frames it as a deferred per-item Reaction wiring problem rather than a snippet-specific bug. Step 5 explicitly distinguishes that pushing a new array fires the outer Reaction while mutating items[0] in place doesn't invalidate anything — directly mirroring the each.hydrate deferral framing."
-    },
-    {
-      "text": "B: Explains that snippet args (label=item.name) are evaluated by the per-item content path; the snippet body sees those args via buildSnippetProxy",
-      "passed": true,
-      "evidence": "Step 4: 'wraps the badge's snippet invocation hydrate hook... wrapped in Reactions whose compute function reads `label` through the snippet-arg proxy (`buildSnippetProxy` at `template.js:67`), which re-evaluates `item.name` against the item context's reactive data channel.' Names buildSnippetProxy and the snippet-arg threading explicitly."
-    },
-    {
-      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
-      "passed": true,
-      "evidence": "Step 4: 'Without that adoption pass, **none of those Reactions exist.** The text node containing `[first]` is just static text on the page; nothing is observing `item.name` to write to it.' Step 5 reinforces: 'writing `items[0].name = \"second\"`... doesn't invalidate anything observing that text node.'"
-    },
-    {
-      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
-      "passed": true,
-      "evidence": "'Why the snippet matters specifically' section: 'The classifier in `each-content-classifier.js` walks the per-item content AST and bails to \"external\" (forcing eager wiring) on cross-AST nodes — `template`, `snippet`, `rerender`, `guard`, `async` (lines 189-194 of that file).' Also notes 'snippet → bail to eager → adoption wires the snippet's interior bindings.'"
-    },
-    {
-      "text": "E: Mentions the existing test 'snippet with named args inside each is reactive after hydration' (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
-      "passed": true,
-      "evidence": "Multiple references to PR #175: 'Worth checking your branch is on PR #175 or later — the snippet-bail test was unskipped there.' And later: 'Branch predates PR #175 — `each.hydrate` doesn't consult the classifier at all and stays unconditionally lazy. The snippet-arg-in-each test was unskipped in that PR; before it, this exact case was a known silent-failure bug.'"
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md
deleted file mode 100644
index d59a2c264..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,52 +0,0 @@
-# Snippet-with-args inside `{#each}` after SSR + hydrate: stale label
-
-## Short answer
-
-This is the **lazy each-block hydration** trap. After SSR, `each.hydrate` registered a Reaction on `items` (the collection) but **never wired the per-item Reactions** that would track `item.name`. Pushing a new array fires the outer Reaction (you see new DOM), but mutating `items[0].name` has nothing to invalidate, because the binding inside the badge snippet (`{label}` resolving to `item.name`) was never wrapped in a Reaction.
-
-The classifier that's supposed to upgrade this case to eager wiring exists (`each-content-classifier.js`) and explicitly bails on snippet invocations — but only if it is reached and operating as documented. The symptoms you describe match exactly what happens when the bail does *not* fire (or fires but `adoptServerItems` returns false): per-item Reactions stay un-wired, external/snippet bindings lose reactivity. Worth checking your branch is on PR #175 or later — the snippet-bail test was unskipped there.
-
-## What the framework is actually doing, step by step
-
-1. **Server render.** `ServerRenderer` walks the AST. The each block emits its open/close markers and per-item `<!--sui-item:v1:KEY-->` markers. The snippet invocation `{>badge label=item.name}` is evaluated inline — `item.name` resolves to `"first"` and the badge's `<span>[{label}]</span>` is rendered with `label = "first"`. No JS runs in the SSR snippet path; it's pure string concatenation with markers wrapping the dynamic text node.
-
-2. **Browser parse.** DSD inflates. You see `<span>[first]</span>` for item 0 immediately.
-
-3. **Hydration of the each block.** `each.hydrate` (`packages/renderer/src/engines/native/blocks/each.js:646`) does two things:
-   - `lookupExpression(node.over)` — registers a dep on `items`. **This is the only Reaction wired for the block at this point.** That's why pushing a new array fires reactivity (the outer Reaction sees the items signal change), and that's why `update` runs and you see new DOM.
-   - Consults `isEachContentSelfContained(node)` (`each-content-classifier.js`). If true → `return` (stay lazy, no per-item Reactions). If false → call `adoptServerItems` immediately to walk the server's per-item DOM and wire per-item Reactions in place.
-
-4. **Per-item bindings wire only in the eager path.** `adoptServerItems` walks `<!--sui-item:v1:KEY-->` markers, builds the per-item data context with the item-context proxy, and calls `hydrateInnerContent` — which calls `hydrateMarkers` against the inner ASTthat triggers the badge's snippet invocation hydrate hook. That's where `<!--sui:v1:N-->` markers around the snippet's `{label}` text get wrapped in Reactions whose compute function reads `label` through the snippet-arg proxy (`buildSnippetProxy` at `template.js:67`), which re-evaluates `item.name` against the item context's reactive data channel.
-
-   Without that adoption pass, **none of those Reactions exist.** The text node containing `[first]` is just static text on the page; nothing is observing `item.name` to write to it.
-
-5. **Why pushing a new array still updates the DOM but mutating `items[0].name` doesn't.** The outer Reaction on `items` is wired (step 3a). Pushing a new array → items signal fires → `each.update` runs → reconcile builds DOM for new items (and that fresh-render path *does* wire per-item Reactions for the newly-created items via the normal render flow). But the existing item 0's DOM was adopted from SSR and **its per-item Reactions never wired**, so writing `items[0].name = "second"` (or even replacing items[0] with a new object that has the same key) doesn't invalidate anything observing that text node.
-
-## Why the snippet matters specifically
-
-The classifier in `each-content-classifier.js` walks the per-item content AST and bails to "external" (forcing eager wiring) on cross-AST nodes — `template`, `snippet`, `rerender`, `guard`, `async` (lines 189-194 of that file). The reason: the snippet's body lives in a *separate AST*, and the classifier doesn't recurse into it. Even if your snippet's body only reads its arg, the arg expression (`label=item.name`) is evaluated inside the per-item content path against the parent scope's data context, threaded through `buildSnippetProxy`'s lazy getters — and those getters are only re-invoked when the per-binding Reactions inside the snippet's text node fire. Those Reactions only exist if per-item adoption happened. So snippet → bail to eager → adoption wires the snippet's interior bindings.
-
-If your bug is reproducing this on a branch with the classifier in place, the most likely failure modes are:
-
-- The classifier ran but returned `true` (treated as self-contained). Walk the AST node it was given for this each — confirm the snippet invocation appears as a `node.type === 'snippet'` (or `'template'`) child. If it's classified as something else, the bail doesn't trigger.
-- The classifier returned `false` but `adoptServerItems` returned `false` (couldn't find matching `sui-item:v1:KEY` markers — key mismatch between server and client item IDs). Look at `getItemID` (`each.js:42`) — keys are stringified, server emits string keys; if your client items have e.g. numeric `id` and the SSR pass produced numeric-string keys, they should match, but a mismatch silently falls through to fresh render on `update`, not on `hydrate`. On `hydrate` failure there's no fallback render — the existing DOM stays as-is and Reactions don't wire.
-- Branch predates PR #175 — `each.hydrate` doesn't consult the classifier at all and stays unconditionally lazy. The snippet-arg-in-each test was unskipped in that PR; before it, this exact case was a known silent-failure bug.
-
-## What to check, in order
-
-1. `git log --oneline packages/renderer/src/engines/native/blocks/each-content-classifier.js` — confirm the file exists on your branch and PR #175 is in your history.
-2. In a debugger, set a breakpoint on `isEachContentSelfContained` and confirm it returns `false` for your each AST node. If true → the snippet child isn't being classified as `snippet`/`template` (parser issue, not a hydrate issue).
-3. If false, breakpoint on `adoptServerItems` inside `each.hydrate` and confirm it runs and returns `true`. If it returns `false`, check your server-emitted `<!--sui-item:v1:KEY-->` keys against the client item IDs (`getItemID` output) — mismatched keys is the silent-failure mode here.
-4. As a sanity check that the per-item Reactions are the missing piece: replace the snippet with inline content (`<span>[{item.name}]</span>`) and re-test. That should *also* fail under the same lazy assumption (well, no — inline content with explicit `as` and item-only reads is "self-contained" so it stays lazy and would have the same symptom — but the symptom would attribute to "lazy each, items signal never fires because we mutated items[0] in place" rather than "snippet bail didn't trigger"). To confirm it's specifically the snippet path: replace the inner content with `<span>{state.somethingExternal}</span>` — that should bail eager via the identifier check and your per-item Reactions should wire and update.
-
-## Fixing the immediate symptom (workarounds, in order of preference)
-
-1. **Notify the items signal after mutation.** `state.items.notify()` (or assign through a `.set` that triggers it) after `items[0].name = "second"`. This forces the outer Reaction to fire, which on the second invocation flows through `each.update`'s adoption path (which *does* try to wire per-item Reactions). This is the cheapest fix and works without any framework changes.
-2. **Replace the item, don't mutate it.** `state.items[0] = { ...items[0], name: "second" }` then `notify()`, or use the array helper `state.items.set(0, { ...items[0], name: "second" })`. Same idea — gives the items signal a top-level identity change to fire on.
-3. **If you can't change the mutation pattern**, the framework-level fix is what PR #175 already does: ensure your branch has the classifier and that it bails on snippet invocations. If it does and the bug still reproduces, that's a real bug — file with the AST shape and the SSR'd HTML and we can trace whether the classifier or the adoption pass is the failure point.
-
-## Key files
-
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `each.hydrate` at line 646; `adoptServerItems` at line 505
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — bail set; snippet/template at lines 189-194
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/template.js` — `buildSnippetProxy` at line 67; snippet hydrate path at line 220
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json
deleted file mode 100644
index ac9a6b11d..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/grading.json
+++ /dev/null
@@ -1,29 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug",
-      "passed": false,
-      "evidence": "The answer correctly identifies that the bug is not snippet-specific ('this isn't snippet-specific — any expression inside the each body that reads item.<prop> would hit the same bug'), but it diagnoses a fundamentally different root cause: a propsSnapshot === null edge case in adoptServerItems, not the each-hydrate deferral of per-item Reaction wiring. The answer asserts the snippet wiring is correct and per-item Reactions are properly wired against itemSignal during adoption — directly contradicting the deferral-as-root-cause framing of eval 2. Misses the connection to the same root cause."
-    },
-    {
-      "text": "B: Explains that snippet args (label=item.name) are evaluated by the per-item content path; the snippet body sees those args via buildSnippetProxy",
-      "passed": true,
-      "evidence": "Answer explicitly explains: 'Snippet args (label=item.name) become lazy getters captured by buildSnippetProxy (packages/renderer/src/engines/native/blocks/template.js:67-114). The snippet body's {label} reactive text-node Reaction reads snippetData.label, which calls the captured getter () => evaluator.lookupExpressionValue(item.name, itemProxy)...'. Identifies buildSnippetProxy and the per-item arg evaluation path."
-    },
-    {
-      "text": "C: Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place",
-      "passed": false,
-      "evidence": "The answer takes the opposite position: 'So the text-node Reaction inside the snippet body does end up depending on the per-item itemSignal. The wiring is fine.' It claims the Reactions ARE wired and the bug is downstream (propsSnapshot/notify gating). Does not identify unwired per-item Reactions as the cause."
-    },
-    {
-      "text": "D: Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix",
-      "passed": false,
-      "evidence": "The answer references each-content-classifier ('confirms eager hydration is forced when an each contains a template (snippet) node, so adoptServerItems is what runs during hydrate (line 189-194)') but positions this as confirming the path that exposes the bug, not as the fix. The proposed fix is to populate propsSnapshot in adoptServerItems — a completely different remediation than 'force eager adoption via classifier bail-out.'"
-    },
-    {
-      "text": "E: Mentions the existing test 'snippet with named args inside each is reactive after hydration' (PR #175 unskipped it) OR equivalent: this scenario is a known regression test",
-      "passed": true,
-      "evidence": "Answer references 'the existing snippet with named args inside each test' at packages/renderer/test/browser/ssr-hydration.test.js:1408-1433, noting it 'uses a new object ref and therefore doesn't catch this.' Identifies the existing scenario test even if framing it as a near-miss rather than the regression test PR #175 unskipped."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md
deleted file mode 100644
index 75b56128b..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-2/eval-4-snippet-arg-each/without_skill/outputs/answer.md
+++ /dev/null
@@ -1,85 +0,0 @@
-# What's happening
-
-The framework's snippet wiring is correct here — the bug you're hitting is a stale-snapshot edge case in `each`'s post-hydration reconcile path, not a snippet-arg reactivity hole. Specifically: the **first** post-hydration in-place mutation of an item slips through silently. The second mutation onwards updates the DOM normally.
-
-## The intended path
-
-For your template:
-
-```
-{#each item in items}<div>{>badge label=item.name}</div>{/each}
-```
-
-Reactivity flows like this:
-
-1. **Each block** wraps each item in a `Signal` (`itemSignal`) holding `{ item, index }`. A `Proxy` (`createItemDataProxy` in `packages/renderer/src/engines/native/blocks/each.js:129-144`) sits over the parent data and routes `data.item` lookups through `itemSignal.value`, which registers an `itemSignal` dep on whoever's reading.
-2. **Snippet args** (`label=item.name`) become **lazy getters** captured by `buildSnippetProxy` (`packages/renderer/src/engines/native/blocks/template.js:67-114`). The snippet body's `{label}` reactive text-node Reaction reads `snippetData.label`, which calls the captured getter `() => evaluator.lookupExpressionValue('item.name', itemProxy)`, which goes through the each's item-proxy and registers `itemSignal` as a dep on the text node's Reaction.
-
-So the text-node Reaction inside the snippet body **does** end up depending on the per-item `itemSignal`. The wiring is fine. The problem is whether `itemSignal.notify()` actually fires when you mutate in place.
-
-## The bug — `propsSnapshot` is `null` after adoption
-
-When you replace `state.items` with `state.items.set([...items])`, the items signal fires and `each.update` runs. For records whose `item` reference and index are unchanged (your case — same object, just a mutated `.name`), the equality gate inside `Signal.set` short-circuits because the wrapper `{ item, index }` looks identical by `===` (same item ref). To get around that, `each` keeps a `propsSnapshot` of each item's top-level props and shallow-compares on every reconcile to decide whether to call `itemSignal.notify()` manually:
-
-```js
-// packages/renderer/src/engines/native/blocks/each.js:396-422 (Phase 3)
-if (rec.item !== item || rec.index !== i) {
-  rec.itemSignal.set(getEachData(...));
-  ...
-  rec.propsSnapshot = createSnapshot(item);
-}
-else if (typeof item === 'object' && item !== null) {
-  if (rec.propsSnapshot === null) {
-    // "Fresh record (first reconcile after createRecord). Bindings
-    //  were wired synchronously against the signal's value; there's
-    //  no stale subscriber to wake."
-    rec.propsSnapshot = createSnapshot(item);
-  }
-  else if (refreshSnapshotAndDetect(rec.propsSnapshot, item)) {
-    rec.itemSignal.notify();
-  }
-}
-```
-
-That `propsSnapshot === null` branch assumes "no notify needed because we just wired the bindings against the current item value." That assumption is true for records produced by `createRecord` inside the same `reconcile` call (CSR, or post-hydration replacements), but it is **wrong** for records produced by `adoptServerItems` during hydration, because:
-
-- Adoption wires Reactions at hydrate time against the item's hydration-time `.name` (`'Apple'`).
-- The records are pushed with `propsSnapshot: null` (`packages/renderer/src/engines/native/blocks/each.js:583`).
-- Some unspecified time later, your code mutates `items[0].name = 'Cherry'` and pushes a new array.
-- `update` runs `reconcile`. Phase 3 sees `rec.item === items[0]` (still the same ref), index unchanged, and `propsSnapshot === null` — so it takes the "fresh record" branch, snapshots `{ name: 'Cherry' }` for next time, and **does not call `notify()`**.
-- The badge stays showing `[Apple]`.
-
-If you mutate again (`items[0].name = 'Date'`), `refreshSnapshotAndDetect` compares against the now-populated snapshot (`'Cherry' !== 'Date'`), fires `notify()`, and the DOM updates to `[Date]` — skipping the `'Cherry'` value entirely.
-
-## Why the "outer reaction definitely fires" observation is consistent
-
-Your test for "outer reaction fires" probably involves changing the array length (push, splice, swap). Those go through the `rec.item !== item || rec.index !== i` branch — `itemSignal.set(...)` runs unconditionally with a fresh wrapper object, equality gate passes (different wrapper ref), subscribers wake. That's why adding/removing/reordering items works fine after hydrate, but mutating an existing item's prop in place doesn't.
-
-It's also worth noting that this isn't snippet-specific — any expression inside the each body that reads `item.<prop>` would hit the same bug after hydration on the first in-place mutation. The snippet is just along for the ride. But the snippet structure does suppress one of the workarounds: with bare `{item.name}` directly in the each body, the same lookup path applies and the same bug should reproduce. A test using new object refs (`items[0] = { ...items[0], name: 'Crimson' }`) like the one at `packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` passes precisely because it dodges the equality gate by changing the item ref.
-
-## Workarounds (no source change)
-
-- Replace the item reference instead of mutating in place: `state.items.set(items.map((it, i) => i === 0 ? { ...it, name: 'Cherry' } : it))`. New ref → first branch of phase 3 → `itemSignal.set(...)` → DOM updates.
-- Toggle the value back-and-forth — the first mutation populates `propsSnapshot`, the second triggers `notify()`. Not really a workaround, just an explanation of why your second mutation works.
-- Use `state.items.notify()` after the in-place mutation to force the items signal to fire a second time — but this only buys you the same "phase 3 with populated snapshot" pass, so it would also need to happen after the first lost mutation, not as a fix for it.
-
-## The fix on the framework side
-
-`adoptServerItems` should populate `propsSnapshot` at adoption time, the same way Phase 3 does at the end of a normal reconcile. Either:
-
-```js
-// packages/renderer/src/engines/native/blocks/each.js:574-584
-newRecords.push({
-  ...,
-  propsSnapshot: createSnapshot(item),  // not null
-});
-```
-
-…or, equivalently, change the "fresh record" branch in Phase 3 to detect adoption explicitly. The first option is cleaner and matches the invariant the comment in Phase 3 already claims ("bindings were wired against the signal's value at the moment we set the snapshot").
-
-## Files to look at
-
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `adoptServerItems` (line 505), `reconcile` Phase 3 (line 396-422), `createSnapshot` / `refreshSnapshotAndDetect` (lines 86-122), `createItemDataProxy` (line 129).
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/template.js` — `buildSnippetProxy` lazy getters (line 67), snippet hydrate branch (line 224).
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — confirms eager hydration is forced when an each contains a `template` (snippet) node, so `adoptServerItems` is what runs during hydrate (line 189-194).
-- `/home/jack/semantic/next/packages/renderer/test/browser/ssr-hydration.test.js:1408-1433` — the existing "snippet with named args inside each" test that uses a new object ref and therefore doesn't catch this.
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json b/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json
deleted file mode 100644
index e9af5648d..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/grading.json
+++ /dev/null
@@ -1,35 +0,0 @@
-{
-  "expectations": [
-    {
-      "text": "A: Identifies each.hydrate deliberately defers per-item Reaction wiring (not a bug in the lazy design)",
-      "passed": true,
-      "evidence": "Line 9: 'On the SSR-then-hydrate path, each.hydrate does not unconditionally wire per-item Reactions. Per-item wiring is expensive (item count x bindings per item — ~425ms on a 1000-item list in prior benches), so the framework defers it'. Explicitly framed as deliberate deferral for performance, not a bug."
-    },
-    {
-      "text": "B: Explains the chain: each.hydrate only registers a dep on node.over; per-item Reactions wire later via adoptServerItems when items signal fires",
-      "passed": true,
-      "evidence": "Line 9: 'when hydrate runs, it only registers a dependency on the items collection signal and waits for update to fire. update then calls adoptServerItems, which finally wires per-item Reactions onto the existing server-rendered nodes.' Says 'items collection signal' rather than node.over by name, but the chain is correctly described."
-    },
-    {
-      "text": "C: Recognizes that if items never mutates, update never runs, and per-item bindings stay unwired forever",
-      "passed": true,
-      "evidence": "Line 13: 'Because items is set once from a prop and never mutates, the items signal never fires after hydrate. update never runs. adoptServerItems never fires. The per-item Reactions for class=\"{classMap getItemClasses item}\" are never wired.' Verbatim match to expectation."
-    },
-    {
-      "text": "D: Connects the bug to getItemClasses reading state.activeID — the external signal has no Reaction to invalidate, so mutations are silently lost",
-      "submitted": true,
-      "passed": true,
-      "evidence": "Line 15: 'With no Reaction wired around getItemClasses(item), state.activeID.depend() is never called inside a tracked compute. Mutations to state.activeID have no subscriber on those bindings to invalidate. The class string in the DOM stays at whatever the server emitted.' Direct connection made."
-    },
-    {
-      "text": "E: References the each-content-classifier (or equivalent fix shape: 'force eager adoption when bindings could read external state') as the resolution",
-      "passed": true,
-      "evidence": "Section 'Why the classifier didn't catch it' (lines 22-31) discusses each-content-classifier.js / isEachContentSelfContained extensively. Fix 2 (line 47): 'Force the each block onto the eager hydrate path. The classifier is the public contract for this.' Both classifier reference and the equivalent fix shape are explicit."
-    },
-    {
-      "text": "F: Notes the per-binding Reactions use skipFirstWrite: true — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps",
-      "passed": true,
-      "evidence": "Line 17: 'The framework's per-expression reactivity guarantee depends on the per-binding Reaction running at least once with Scheduler.current set — that's the only way Dependency.depend() becomes a no-op-no-more. The lazy each path skips that step. There is no \"register without running\" — the evaluation IS the witness.' Captures the 'evaluation IS the registration' insight. skipFirstWrite is referenced explicitly in Key files section: 'reactive-data.js — skipFirstWrite contract; the load-bearing per-binding evaluation that registers signal deps'."
-    }
-  ]
-}
diff --git a/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md b/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md
deleted file mode 100644
index a3c03e4ad..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/iteration-3/eval-2-each-external-state/with_skill/outputs/answer.md
+++ /dev/null
@@ -1,64 +0,0 @@
-# Why the per-item class binding doesn't react
-
-## What's happening
-
-This is the canonical lazy-each-hydrate bug. The fact that your top-level `reaction(() => state.activeID.get())` fires correctly proves the signal itself is healthy — the loss of reactivity is local to the per-item bindings inside the `{#each}` block.
-
-The mechanism, from `packages/renderer/src/engines/native/blocks/each.js` and `each-content-classifier.js`:
-
-1. On the SSR-then-hydrate path, `each.hydrate` does **not** unconditionally wire per-item Reactions. Per-item wiring is expensive (item count × bindings per item — ~425ms on a 1000-item list in prior benches), so the framework defers it: when hydrate runs, it only registers a dependency on the `items` collection signal and waits for `update` to fire. `update` then calls `adoptServerItems`, which finally wires per-item Reactions onto the existing server-rendered nodes.
-
-2. That deferral assumes per-item bindings only read **item-local** data. Your `getItemClasses(item)` helper closes over `state.activeID` — external state. The deferral assumption is broken.
-
-3. Because `items` is set once from a prop and never mutates, the items signal never fires after hydrate. `update` never runs. `adoptServerItems` never fires. The per-item Reactions for `class="{classMap getItemClasses item}"` are **never wired**.
-
-4. With no Reaction wired around `getItemClasses(item)`, `state.activeID.depend()` is never called inside a tracked compute. Mutations to `state.activeID` have no subscriber on those bindings to invalidate. The class string in the DOM stays at whatever the server emitted.
-
-The reason your standalone `reaction(...)` works is that it wires its own tracked compute; the dependency is registered there. The framework's per-expression reactivity guarantee depends on the per-binding Reaction running at least once with `Scheduler.current` set — that's the only way `Dependency.depend()` becomes a no-op-no-more. The lazy each path skips that step. There is no "register without running" — the evaluation IS the witness.
-
-This is exactly the inpage-menu bug the skill calls out: items arrived as a prop, never changed, `getItemClasses(item)` reading `state.activeID` never updated the rendered class.
-
-## Why the classifier didn't catch it
-
-PR #175 added `each-content-classifier.js` (`isEachContentSelfContained`) to gate this. `each.hydrate` consults it; if anything in the block resolves outside the iteration scope ∪ framework helper registry, hydrate falls through to eager `adoptServerItems` and wires per-item Reactions immediately.
-
-In your case, the classifier walks `{classMap getItemClasses item}` and sees:
-- `classMap` — in `TemplateHelpers`, pure helper allowlist, fine.
-- `getItemClasses` — **not** in the registry. Not an iteration-local. Not a reserved name.
-
-Whether the classifier currently treats this as "external → eager-wire" depends on which version of the classifier is running. The classifier is conservative by design: any identifier head that doesn't resolve to iteration-vars or `TemplateHelpers` should bail to eager wiring. If `getItemClasses` was registered via `Template.registerHelper`, it is statically indistinguishable from a component method that reads state — and the classifier deliberately treats user-registered helpers as external (the correct call, per the comment in `each-content-classifier.js`).
-
-So one of two things is true: either the classifier is correctly bailing and something downstream is broken, or you're hitting a path the classifier doesn't trace into. The likely path-not-traced cases listed in the skill are: `{#each}` without explicit `as`, snippet/template/rerender/async/guard wrappers, or unknown identifiers — `getItemClasses` falls in the "unknown identifier" bucket which should force eager wiring.
-
-## How to fix it (in order of preference)
-
-**Fix 1 — Make the dependency item-local.** Best fix for clarity and perf. Move the `state.activeID` read out of the per-item helper and pass the comparison result down as item-local data, or compute it inside a `computed`/derived signal that the helper reads from a stable reference. Concretely, restructure so the helper takes `(item, activeID)` — but that still reads state at the call site. A cleaner shape: store `activeID` on the iteration via a derived `items` collection that includes per-item `isActive`, OR restructure the template to compute the active flag at the binding site:
-
-```svelte
-{#each item in items}
-  <a class="{classMap (object active=(eq item.id activeID) item=true)}">
-    {item.title}
-  </a>
-{/each}
-```
-
-This puts `activeID` directly in the per-item binding expression. `activeID` is a top-level identifier from the data context (resolved at the binding's compute). The binding still needs a per-item Reaction to register the dependency — which you'd get via fix 2.
-
-**Fix 2 — Force the each block onto the eager hydrate path.** The classifier is the public contract for this. If it's not currently bailing on your `getItemClasses` call, file a repro — but in the meantime, you can force eagerness by structuring the each block in a way the classifier can't prove self-contained. Simplest reliable triggers: use a snippet wrapper (`{>itemRow item=item}`), drop the explicit `as` (use `{#each items}` with `{this.title}`), or wrap the contents in an `{#async}`/`{#rerender}`. Each of these is on the conservative-bail list and forces eager `adoptServerItems`.
-
-This is a workaround, not a real fix — the classifier should be doing this for you.
-
-**Fix 3 — Mutate `items` once after hydrate.** If you can tolerate it, calling `state.items.set(state.items.get())` after hydrate fires the items signal, triggers `update` → `adoptServerItems` → per-item Reactions wire, and reactivity is restored. This is a hack and shouldn't ship — it adds a render pass and obscures the underlying issue — but it confirms the diagnosis if you want to verify before changing template structure.
-
-## Recommended next step
-
-Verify which path your component is actually taking. Add a `console.log` at the top of `each.hydrate` in `packages/renderer/src/engines/native/blocks/each.js` printing the result of `isEachContentSelfContained(node)`. If it returns `true` (lazy), the classifier missed your case — that's a classifier bug worth filing, because `getItemClasses` is a user-defined name that should not resolve to anything in the safe registry. If it returns `false` (eager), but reactivity still doesn't wire, the bug is downstream of the classifier and needs a different trace.
-
-My read is that the classifier should already be bailing here, so the most likely diagnosis is that `getItemClasses` is being treated as a known-safe helper somehow (e.g., registered through a path the classifier whitelists, or the helper name happens to match something in `TemplateHelpers`). Worth checking: `Object.keys(TemplateHelpers).includes('getItemClasses')` from a console at runtime. If true — rename. If false — file the repro.
-
-## Key files
-
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each.js` — `each.hydrate` gate, `adoptServerItems`
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/blocks/each-content-classifier.js` — `isEachContentSelfContained`, the lazy/eager gate
-- `/home/jack/semantic/next/packages/renderer/src/engines/native/reactive-data.js` — `skipFirstWrite` contract; the load-bearing per-binding evaluation that registers signal deps
-- `/home/jack/semantic/next/packages/renderer/test/unit/each-content-classifier.test.js` — classifier behavior tests (item-local, external, conservative-bail cases)
diff --git a/ai/skills/authoring/ssr-hydration-workspace/rubric.md b/ai/skills/authoring/ssr-hydration-workspace/rubric.md
deleted file mode 100644
index 3b9ee7f94..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/rubric.md
+++ /dev/null
@@ -1,55 +0,0 @@
-# SSR Hydration Skill Eval Rubric
-
-Each eval prompt has 5-8 binary assertions (pass/fail). Skill is "significantly better than baseline" when its mean pass rate exceeds baseline by at least 30 percentage points across all evals, AND no eval regresses below baseline.
-
-## Eval 0: innerHTML-doesnt-process-DSD
-
-| # | Assertion |
-|---|---|
-| A | Identifies that `innerHTML` does NOT process `<template shadowrootmode>` (the DSD spec) |
-| B | Recommends `setHTMLUnsafe` (or `Document.parseHTMLUnsafe`) as the correct API |
-| C | Explains the consequence chain: no shadowRoot at parse time → `hasServerContent === false` → `connectedCallback` runs `fullRender` instead of `hydrate` |
-| D | Notes that the failure is silent (no error) — the test "succeeds" but is testing a different code path than intended |
-| E | Mentions that the browser's main HTML parser DOES process DSD; the limitation is on fragment parsers (`innerHTML`, `outerHTML`, `insertAdjacentHTML`) |
-
-## Eval 1: renderToString-empty-in-browser-env
-
-| # | Assertion |
-|---|---|
-| A | Identifies `Template.isServer` as the controlling flag |
-| B | Explains `template.render()` selects between `engine.serverRenderer` and `engine.renderer` based on `Template.isServer` |
-| C | Notes the client `Renderer` writes to DOM and does not produce HTML strings, leaving the wrapper template empty |
-| D | Recommends toggling `Template.isServer = true` for the duration of the `renderToString` call |
-| E | Mentions wrapping in try/finally to restore the prior value (so other tests aren't affected) |
-
-## Eval 2: each-block-external-state-not-reactive-after-hydrate
-
-| # | Assertion |
-|---|---|
-| A | Identifies `each.hydrate` deliberately defers per-item Reaction wiring (not a bug in the lazy design) |
-| B | Explains the chain: `each.hydrate` only registers a dep on `node.over`; per-item Reactions wire later via `adoptServerItems` when items signal fires |
-| C | Recognizes that if items never mutates, `update` never runs, and per-item bindings stay unwired forever |
-| D | Connects the bug to `getItemClasses` reading `state.activeID` — the external signal has no Reaction to invalidate, so mutations are silently lost |
-| E | References the each-content-classifier (or equivalent fix shape: "force eager adoption when bindings could read external state") as the resolution |
-| F | Notes the per-binding Reactions use `skipFirstWrite: true` — they evaluate to register deps but trust the SSR'd DOM; the evaluation IS what registers external deps |
-
-## Eval 3: tachometer-bench-noise-floor-too-high
-
-| # | Assertion |
-|---|---|
-| A | Identifies that bench noise floor scales inversely with bench duration |
-| B | Quotes or paraphrases the duration→noise table: ~2ms = ±10-20%, ~10ms = ±2-5%, ~50ms+ = ±1% |
-| C | Explains the physics: per-sample jitter (OS scheduling, GC, JIT) is roughly constant in absolute terms, typically sub-millisecond |
-| D | Concludes that at ~6ms, ±28% is the floor; no amount of additional sampling lowers it |
-| E | Recommends increasing work per sample (e.g., bump to 1000 items) to push bench duration into the ±1% band |
-| F | Optionally references the perf-improvement skill or `improve-performance` workflow as the source for this methodology |
-
-## Eval 4: snippet-arg-inside-each-not-reactive
-
-| # | Assertion |
-|---|---|
-| A | Recognizes this is the same root cause as eval 2 (each-hydrate deferral) — not a snippet-specific bug |
-| B | Explains that snippet args (`label=item.name`) are evaluated by the per-item content path; the snippet body sees those args via `buildSnippetProxy` |
-| C | Notes that without per-item Reactions wired, the snippet arg evaluation never re-runs when items change in place |
-| D | Identifies that the each-content-classifier conservatively bails on snippet/template/rerender/async invocations (treating them as cross-AST/dynamic) — forcing eager adoption — which is the fix |
-| E | Mentions the existing test `snippet with named args inside each is reactive after hydration` (PR #175 unskipped it) OR equivalent: this scenario is a known regression test |
diff --git a/ai/skills/authoring/ssr-hydration-workspace/skill-snapshot/ssr-hydration.md b/ai/skills/authoring/ssr-hydration-workspace/skill-snapshot/ssr-hydration.md
deleted file mode 100644
index 38513e8a2..000000000
--- a/ai/skills/authoring/ssr-hydration-workspace/skill-snapshot/ssr-hydration.md
+++ /dev/null
@@ -1,469 +0,0 @@
----
-title: SSR & Hydration Pipeline — Server Render to Live DOM
-description: How a component renders on the server, arrives as DSD in the browser, and hydrates into a reactive component. Covers renderToString, ServerRenderer, expandCustomElements, DSD parsing, the hydrate-or-render decision, and hydrateMarkers. Load before working on SSR, hydration, Astro integration, or server rendering bugs.
-keywords: [SSR, hydration, server rendering, declarative shadow DOM, DSD, renderToString, ServerRenderer, hydrateMarkers, expandCustomElements, markers]
-audience: authoring
-skill: ssr-hydration
-type: skill
----
-
-# SSR & Hydration Pipeline — Server Render to Live DOM
-
-> **Skill:** `ssr-hydration`
-> **Purpose:** How a component renders on the server, arrives as Declarative Shadow DOM in the browser, and hydrates into a fully reactive component. Load this before working on SSR, hydration, Astro integration, or server rendering bugs.
-
----
-
-## Why SSR Exists Here
-
-SSR in Semantic UI exists for **first paint performance** — the user sees styled, structured content before JavaScript loads. The server produces Declarative Shadow DOM (DSD) that the browser renders immediately. JavaScript then hydrates the existing DOM with reactive bindings.
-
-This is not server rendering for SEO or static generation. The goal is a fast visual that the client seamlessly takes over.
-
----
-
-## The Full Lifecycle
-
-A server-rendered component passes through five phases from definition to interactivity:
-
-```
-1. SERVER: renderToString(ComponentClass, attrs)
-   |
-   +-- Clone prototype Template with data
-   +-- Template.initialize() -> createComponent() runs
-   +-- ServerRenderer.render() -> HTML string with hydration markers
-   +-- expandCustomElements() -> recursively render nested components
-   +-- Wrap in DSD: <tag><template shadowrootmode="open">...</template></tag>
-   |
-   v
-2. NETWORK: HTML string arrives in browser
-   |
-   v
-3. BROWSER PARSE: DSD parsing
-   |
-   +-- Browser encounters <template shadowrootmode="open">
-   +-- Automatically creates shadow root and moves content into it
-   +-- User sees styled content BEFORE any JavaScript loads
-   |
-   v
-4. JS LOADS: Custom element upgrade
-   |
-   +-- Browser calls constructor() -> detects existing shadowRoot -> sets _hydrating flag
-   +-- Browser calls connectedCallback() -> detects DSD content
-   +-- canHydrate() checks marker version
-   +-- requestAnimationFrame(() => hydrate()) — deferred so browser can paint first
-   |
-   v
-5. HYDRATION: hydrate(prototypeTemplate)
-   |
-   +-- Clone template, initialize (createComponent runs again, client-side)
-   +-- Build entries from AST (cached on prototype)
-   +-- hydrateMarkers() walks existing DOM, wires Reactions to server-rendered nodes
-   +-- Remove all hydration comment markers (clean DevTools)
-   +-- Component is now fully reactive — indistinguishable from client-rendered
-```
-
----
-
-## Phase 1: Server Rendering
-
-### renderToString
-
-`packages/component/src/render-to-string.js`
-
-The entry point for SSR. Takes a component class (returned by `defineComponent` with a `tagName`) and an attributes object, returns a complete DSD HTML string.
-
-```js
-import { defineComponent, renderToString } from '@semantic-ui/component';
-
-const MyCard = defineComponent({ tagName: 'my-card', template, css, ... });
-const html = renderToString(MyCard, { title: 'Hello' });
-// -> <my-card title="Hello"><template shadowrootmode="open"><style>...</style>...</template></my-card>
-```
-
-The function performs these steps in order:
-
-**1. Normalize attributes** — Kebab-case HTML attribute names are converted to camelCase property names. `fromAttribute` converters from the component's property definitions are applied.
-
-**2. Resolve attribute aliases** — For spec-driven primitives, bare attributes like `primary` are resolved to their canonical form (`emphasis="primary"`) using `resolveAttributeAliases()` from `component-helpers.js` — the same shared helper the client uses.
-
-**3. Merge data context** — Spec defaults, component defaults, and normalized attributes are merged in that order (last wins):
-
-```js
-const data = { ...specDefaults, ...defaultSettings, ...normalizedAttrs };
-```
-
-**4. Clone and initialize** — The prototype template is cloned with the data context, forcing the native engine (ServerRenderer handles string output). `template.initialize()` runs `createComponent()` — the same function that runs on the client. The `isServer` param is `true`, so components can guard client-only logic.
-
-**5. Compute `{uiClasses}` classes** — After `initialize()`, because `createComponent` can modify settings that affect spec resolution (e.g., input's `configureSearch` sets `icon`).
-
-**6. Render** — `template.render()` delegates to `ServerRenderer.render()`, which walks the AST and produces an HTML string with hydration comment markers.
-
-**7. Expand nested custom elements** — `expandCustomElements()` scans the rendered HTML for custom element tags, looks them up in the component registry, and recursively calls `renderToString` to expand their shadow DOM as nested DSD.
-
-**8. Wrap in DSD** — The final output wraps the rendered HTML in a DSD template with the component's CSS:
-
-```html
-<my-card title="Hello">
-  <template shadowrootmode="open">
-    <style>/* component CSS */</style>
-    <!-- rendered HTML with hydration markers -->
-  </template>
-</my-card>
-```
-
-When `hydrate: false` is passed, the outer element gets an `ssr` attribute that prevents self-hydration — used for components that should remain static.
-
-### ServerRenderer
-
-`packages/renderer/src/engines/native/server.js`
-
-The server-side counterpart to the client `Renderer`. Same constructor interface, same `ExpressionEvaluator`, but produces HTML strings instead of DOM. No Reactions, no Signals, no DynamicRegion — pure string concatenation.
-
-```js
-render() {
-  let html = this.renderNodes(this.ast, this.data);
-  return html.replace(REMOVE_ATTR_REGEX, '');
-}
-```
-
-**Hydration markers** — The server embeds comment markers in the HTML so the client's hydration pass can locate dynamic positions:
-
-| Position | Server output | Client uses to... |
-|----------|--------------|-------------------|
-| Text expression | `<!--sui:v1:3-->Hello` | Find text node, wire Reaction |
-| Block open | `<!--sui-block:v1:5-->` | Find block boundary, wire directive |
-| Block close | `<!--/sui-block:v1:5:b1000-->` | Determine block extent and branch index |
-| Attribute expression | *(evaluated inline, no marker)* | Client builds reference DOM from AST |
-
-Block closing markers include metadata: `b1000` means the `if` main branch was taken, `b0` means the first `elseif`, `b-1` means no branch matched. The client uses this during hydration to understand what the server rendered without re-evaluating conditions.
-
-**Expression handling in attributes** — Unlike the client (which uses `__suiN__` markers), the server evaluates attribute expressions inline and emits their final values. Properties (`.prop=`) and events (`@click=`) are stripped via `REMOVE_ATTR` sentinel. Boolean attributes are removed when falsy.
-
-**Block directives** — Conditionals, each, async, rerender, and template nodes all emit the same open/close marker pattern. Inside the markers, the server renders the content that matched:
-
-```html
-<!--sui-block:v1:2-->
-  <span class="on">Visible</span>
-<!--/sui-block:v1:2:b1000-->
-```
-
-For `{#async}`, the server always renders `loadingContent` (never awaits the promise). The client's hydration wires the real async Reaction which fetches and replaces.
-
-### expandCustomElements
-
-`packages/component/src/expand-custom-elements.js`
-
-After the top-level component renders, its HTML may contain nested custom element tags (e.g., `<ui-icon icon="star">` inside a button template). This function:
-
-1. Scans the HTML string for tags containing a hyphen (custom element spec)
-2. Looks up each tag in the component registry
-3. Skips elements that already have a DSD (Astro pre-renders child components in some paths)
-4. Calls `renderToString` recursively with a depth counter (max 10)
-5. Applies `fromAttribute` converters to deserialize attribute strings into typed values
-
-This is string-level processing — no DOM parsing. It uses a hand-written parser (`findNextCustomElement`, `parseOpenTag`, `findClosingTag`) that handles nesting, self-closing tags, and quoted attributes.
-
----
-
-## Phase 3: Browser DSD Parsing
-
-When the browser encounters `<template shadowrootmode="open">` during HTML parsing:
-
-1. It creates a shadow root on the parent element (mode: open)
-2. It moves the template's content into the shadow root
-3. It removes the `<template>` element itself
-
-This happens during HTML parsing, before any JavaScript loads. The user sees styled content immediately because:
-- The shadow root isolates styles (component CSS is in a `<style>` tag inside the DSD)
-- The content structure matches what the component would render on the client
-- No flash of unstyled content, no layout shift
-
----
-
-## Phase 4: Custom Element Upgrade
-
-When the component's JavaScript loads and `customElements.define()` runs, the browser upgrades all matching elements.
-
-### Constructor
-
-```js
-constructor() {
-  super();
-  // If the element has a declarative shadow root, suppress requestUpdate
-  // until hydration completes — attribute parsing fires before
-  // connectedCallback and would schedule a render cascade
-  if (this.shadowRoot) {
-    this._hydrating = true;
-  }
-  // ... initialize settings, property store
-}
-```
-
-The `_hydrating` flag prevents attribute-triggered re-renders during the upgrade phase. Without this, `attributeChangedCallback` would fire for every server-rendered attribute and schedule renders before the template is ready.
-
-### connectedCallback — The Decision Point
-
-```js
-connectedCallback() {
-  if (this.template) return;           // already initialized
-  if (this.hasAttribute('ssr')) return; // marked as server-only, skip
-
-  const hasServerContent = this.shadowRoot && this.shadowRoot.childNodes.length > 0;
-
-  if (!this.shadowRoot) {
-    this.attachShadow({ mode: 'open', delegatesFocus });
-  }
-
-  if (hasServerContent && this.canHydrate()) {
-    // DSD present and markers are compatible — defer hydration
-    requestAnimationFrame(() => this.hydrate(prototypeTemplate));
-  } else {
-    if (hasServerContent) {
-      this.shadowRoot.innerHTML = ''; // version mismatch — discard
-    }
-    this.fullRender(prototypeTemplate);
-  }
-}
-```
-
-Three paths:
-
-| Condition | Path | What happens |
-|-----------|------|-------------|
-| No existing shadow root | `fullRender()` | Standard client render — `attachShadow`, clone template, initialize, render, append |
-| DSD present + compatible markers | `hydrate()` | Wire Reactions to existing DOM, no re-render |
-| DSD present + incompatible markers | `fullRender()` | Discard server content, render from scratch |
-
-**`canHydrate()`** walks shadow root comments looking for versioned markers (`sui:v1:` or `sui-block:v1:`). If found, it checks the version matches `MARKER_VERSION`. No markers means static content — safe to hydrate (nothing to wire).
-
-**`requestAnimationFrame`** — Hydration is deferred one frame so the browser can paint the server-rendered content first. The user sees the visual immediately; interactivity arrives on the next frame.
-
----
-
-## Phase 5: Hydration
-
-`WebComponentBase.hydrate()` in `packages/component/src/engines/native/base.js`
-
-Hydration wires reactive bindings to the existing server-rendered DOM. It does not re-render or validate the server's output — it trusts the DOM is correct and attaches the machinery for future reactivity.
-
-### The hydrate() Method
-
-```js
-hydrate(prototypeTemplate) {
-  // 1. Remove server <style> — CSS is handled via adoptedStyleSheets
-  this.shadowRoot.querySelector('style')?.remove();
-
-  // 2. Clone template with data context (same as fullRender)
-  this.template = prototypeTemplate.clone({ data: this.getData(), element: this, renderRoot });
-  this.template._isHydrating = true;
-  this.component = this.template.instance;
-
-  // 3. Build entries from AST (cached on prototype — depends only on AST, not data)
-  if (!prototypeTemplate._hydrationEntries) {
-    const { entries } = this.template.renderer.buildHTMLString(this.template.ast);
-    prototypeTemplate._hydrationEntries = entries;
-  }
-
-  // 4. Walk server DOM, wire Reactions to existing nodes
-  this.template.renderer.hydrateMarkers(
-    this.shadowRoot, entries, data, scope
-  );
-
-  // 5. Clean up
-  this.template._isHydrating = false;
-  this._hydrating = false;
-  this.removeMarkers();  // remove all comment markers for clean DevTools
-  setTimeout(() => this.template?.onRendered(), 0);
-}
-```
-
-### hydrateMarkers — The Core Algorithm
-
-`Renderer.hydrateMarkers()` in `packages/renderer/src/engines/native/renderer.js`
-
-Two passes over the server-rendered DOM:
-
-**Pass 1: Attribute bindings** — The server didn't embed attribute markers (it evaluated them inline), so hydration can't find markers in the DOM. Instead, it builds a **reference DOM** from the AST's `buildHTMLString` output (which contains `__suiN__` markers), then walks the reference DOM and real DOM in parallel:
-
-```
-Reference DOM: <div class="__sui0__ card" data-count="__sui1__">
-Real DOM:      <div class="dark card" data-count="3">
-```
-
-For each marker found in the reference element's attributes, the corresponding real element gets a Reaction wired. Block-owned elements (children inside `{#if}`, `{#each}`, etc.) are skipped because they're handled recursively by block hydration.
-
-**Pass 2: Comment markers** — A TreeWalker finds `<!--sui:v1:N-->` (text expressions) and `<!--sui-block:v1:N-->` (block directives) at the top level only. Block nesting is tracked via `blockDepth` — inner markers are skipped because block handlers process their own children recursively.
-
-For each marker:
-
-| Marker type | Hydration action |
-|-------------|-----------------|
-| Text expression | Wire a Reaction that sets `textNode.data` on change |
-| Conditional block | Collect owned DOM nodes between open/close markers, wire Reaction for future branch changes |
-| Each block | Collect per-item DOM nodes, create item Signals and Proxies for each, wire Reaction for list changes |
-| Template/snippet | Collect owned nodes, initialize subtemplate, recursively hydrate inner markers |
-| Async block | Wire the full async Reaction (loading → resolved → error), existing loading content gets replaced when promise resolves |
-| Rerender block | Collect owned nodes, wire the rerender/guard Reaction |
-
-### Key Hydration Behaviors
-
-**Trust-then-wire** — Hydration doesn't re-evaluate conditions to validate server output. It trusts the DOM and wires Reactions. If state truly diverges (e.g., `initialize()` changes a setting), the Reaction fires naturally on the next microtask and updates the DOM. See `ssr-principles` for the full rationale.
-
-**`_isHydrating` flag** — Set during hydration wiring. `createComponent` callbacks receive `isHydrating: true` so they can skip client-only setup that would conflict with the wiring pass. Template lifecycle events (`created`, `rendered`) are suppressed during hydration to avoid double-firing.
-
-**`_hydrating` flag on element** — Set during constructor if DSD is detected. Prevents `attributeChangedCallback` from triggering `adjustPropertyFromAttribute` and `requestUpdate` during the upgrade phase. Cleared after hydration completes.
-
-**Marker removal** — After hydration, `removeMarkers()` walks the shadow root and removes all `sui` comment nodes. This keeps DevTools clean and is possible because all Reactions are already wired to real DOM nodes (text nodes, elements), not to the markers themselves.
-
-**Hydration entries are cached** on the prototype template (`_hydrationEntries`). They depend only on AST structure, not data, so all instances of the same component share them.
-
----
-
-## Concrete Trace: Counter Component
-
-Here is a concrete trace of a simple counter component through all phases:
-
-```js
-// Definition (shared between server and client)
-const Counter = defineComponent({
-  tagName: 'ui-counter',
-  template: '<div class="counter">Count: {count}</div>',
-  css: '.counter { padding: 8px; }',
-  defaultState: { count: 0 },
-  createComponent: ({ state, interval }) => ({
-    initialize: () => interval(() => state.count.increment(), 1000),
-  }),
-});
-```
-
-**Server:**
-```js
-const html = renderToString(Counter, {});
-```
-
-1. `renderToString` creates data context: `{ count: 0 }`
-2. `template.initialize()` calls `createComponent` — `interval()` is a no-op on server (`isServer: true`)
-3. `ServerRenderer.render()` walks AST, produces:
-   ```html
-   <div class="counter">Count: <!--sui:v1:0-->0</div>
-   ```
-4. No nested custom elements to expand
-5. Final output:
-   ```html
-   <ui-counter>
-     <template shadowrootmode="open">
-       <style>.counter { padding: 8px; }</style>
-       <div class="counter">Count: <!--sui:v1:0-->0</div>
-     </template>
-   </ui-counter>
-   ```
-
-**Browser parse:** Shadow root created with content. User sees "Count: 0" immediately.
-
-**JS loads:** `customElements.define('ui-counter', ...)` upgrades the element.
-- Constructor detects `this.shadowRoot` exists, sets `_hydrating = true`
-- `connectedCallback` detects DSD content, `canHydrate()` finds `sui:v1:` marker
-- Defers: `requestAnimationFrame(() => this.hydrate(prototypeTemplate))`
-
-**Hydration:**
-1. Remove `<style>` tag (CSS moves to `adoptedStyleSheets`)
-2. Clone template with `{ count: 0 }`, initialize — `createComponent` runs again, this time `interval()` is real, starts the timer
-3. Build entries from AST: `[{ id: 0, type: 'expression', node: { value: 'count' }, classification: { type: 'text' } }]`
-4. `hydrateMarkers` finds `<!--sui:v1:0-->`, wires a Reaction:
-   ```js
-   Reaction.create(() => {
-     const value = this.eval('count', data);  // reads count Signal -> dependency registered
-     textNode.data = value ?? '';              // sets "0" (no-op, already correct)
-   });
-   ```
-5. Remove marker comments, clear `_hydrating`
-
-**Live:** One second later, `state.count.increment()` fires. The count Signal updates to 1. The Reaction re-evaluates, sets `textNode.data = '1'`. The counter is ticking.
-
----
-
-## Astro Integration
-
-Semantic UI components render in Astro via the standard `client:*` directives. The integration uses the `source` export condition in `package.json` so Astro's Vite build processes component source directly.
-
-```astro
----
-import { Button, Icon } from '@semantic-ui/core';
----
-<Button emphasis="primary" client:load>Click Me</Button>
-<Icon icon="star" client:load />
-```
-
-For SSR, Astro calls `renderToString` during the build/SSR pass. The `client:load` directive tells Astro to include the component's JavaScript and hydrate on page load.
-
-Components without `client:*` are rendered as server-only — they get the `ssr` attribute and are never hydrated. Their DSD is parsed and displayed, but no JavaScript is loaded for them.
-
-For `client:only` components, there is no server render. The component renders entirely on the client via `fullRender()`. `forwardAstroProps()` ensures Astro-provided attributes are available before `connectedCallback`.
-
----
-
-## Quick Reference
-
-```
-SERVER RENDERING
-  renderToString(ComponentClass, attrs, { slots, depth, hydrate })
-  -> normalize attrs (kebab->camel, fromAttribute converters)
-  -> resolveAttributeAliases (spec fuzzing)
-  -> merge: specDefaults + defaultSettings + attrs
-  -> clone template, initialize (createComponent with isServer: true)
-  -> ServerRenderer.render() -> HTML string with markers
-  -> expandCustomElements() -> recursive DSD for nested components
-  -> wrap in <template shadowrootmode="open">
-
-HYDRATION MARKERS
-  <!--sui:v1:N-->         text expression (followed by evaluated value)
-  <!--sui-block:v1:N-->   block directive open
-  <!--/sui-block:v1:N:bX--> block directive close (X = branch index)
-  __suiN__                attribute marker (client buildHTMLString only, not in SSR output)
-
-HYDRATION DECISION
-  No shadow root              -> fullRender (standard client path)
-  DSD + canHydrate()          -> requestAnimationFrame -> hydrate()
-  DSD + version mismatch      -> discard server DOM -> fullRender
-  hasAttribute('ssr')         -> skip entirely (server-only component)
-
-HYDRATION WIRING
-  1. Remove server <style> (CSS -> adoptedStyleSheets)
-  2. Clone template, initialize (createComponent runs client-side)
-  3. Build entries from AST (cached on prototype)
-  4. hydrateMarkers: parallel walk for attributes, comment walk for text + blocks
-  5. Remove all comment markers
-  6. Fire onRendered
-```
-
----
-
-## Key Files
-
-```
-packages/component/src/
-├── render-to-string.js           renderToString — SSR entry point
-├── expand-custom-elements.js     Recursive custom element expansion
-├── component-helpers.js          Shared: resolveAttributeAliases, getUIClasses
-├── engines/native/base.js        WebComponentBase — hydrate(), canHydrate(), fullRender()
-└── engines/native/factory.js     Creates web component class with observedAttributes
-
-packages/renderer/src/
-├── build-html-string.js          Shared HTML assembly + marker format constants
-├── expression-evaluator.js       Shared expression evaluation
-├── engines/native/server.js      ServerRenderer — AST -> HTML string
-└── engines/native/renderer.js    Renderer — hydrateMarkers(), hydrateAttributes()
-```
-
----
-
-## Related Skills
-
-| Skill | Use when... |
-|-------|-------------|
-| **Render Pipeline** (`render-pipeline`) | How the client render pipeline works — AST, engines, expression evaluation |
-| **SSR & Hydration Principles** (`ssr-principles`) | The governing constraints — trust-then-wire, shared helpers, mismatch prevention |
-| **Native Renderer** (`native-renderer`) | Deep dive into native renderer internals (contributing audience) |
-| **Component Authoring** (`component-authoring`) | Using `defineComponent`, lifecycle hooks, and SSR-safe patterns |
-| **Mental Model** (`mental-model`) | Framework architecture and the Template-as-core-abstraction philosophy |

From 7db18ab133c1b18733692da95cddf26db39a2a7c Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Sun, 3 May 2026 23:33:46 -0400
Subject: [PATCH 05/16] Bug: Check elseContent in isEachContentSelfContained
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Public entry point only walked eachNode.content; the inner each handler
already checked both branches. When SSR rendered only the {:else} (items
empty at hydrate time) and that branch read external state, bindings
stayed unwired forever — same silent-reactivity-loss class this PR is
fixing for item content.

Also refreshes the each.js block comment that still claimed "no per-item
Reactions are wired at hydrate time" — true before this PR, misleading
now that the eager path exists.
---
 .../native/blocks/each-content-classifier.js  |  6 ++++-
 .../src/engines/native/blocks/each.js         | 14 ++++++-----
 .../test/unit/each-content-classifier.test.js | 25 +++++++++++++++++++
 3 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/packages/renderer/src/engines/native/blocks/each-content-classifier.js b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
index 48a9d1ad3..251d24882 100644
--- a/packages/renderer/src/engines/native/blocks/each-content-classifier.js
+++ b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
@@ -215,7 +215,11 @@ export function isEachContentSelfContained(eachNode) {
   if (cached !== undefined) { return cached; }
 
   const scope = buildLocalScope(eachNode);
-  cached = isContentSelfContained(eachNode.content, scope);
+  // elseContent renders when items is empty — the inner each handler
+  // checks both branches; the public entry needs the same to avoid
+  // silent reactivity loss when SSR served only the {:else} branch.
+  cached = isContentSelfContained(eachNode.content, scope)
+    && (!eachNode.elseContent || isContentSelfContained(eachNode.elseContent, scope));
   cache.set(eachNode, cached);
   return cached;
 }
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index 87c14db86..afb6e0466 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -16,12 +16,14 @@ import { registerBlock } from './registry.js';
   over *live* DOM, instead of dereferencing a stale childNodes snapshot
   taken at item-creation time.
 
-  Hydrate only registers a dep on the collection — no per-item Reactions
-  are wired at hydrate time. Per-item bindings establish on the first
-  data change, when `update` tries to adopt the server-rendered per-item
-  DOM via `<!--sui-item:v1:KEY-->` markers instead of rebuilding from
-  scratch. Mismatched keys fall through to a fresh render; subsequent
-  mutations use the normal reconcile path.
+  Hydrate registers a dep on the collection. Per-item Reactions wire
+  lazily by default — on the first items mutation, `update` adopts the
+  server-rendered per-item DOM via `<!--sui-item:v1:KEY-->` markers
+  instead of rebuilding. When per-item content reads external state
+  (classified via each-content-classifier.js), hydrate adopts eagerly
+  so per-binding Reactions register their external deps now. Mismatched
+  keys fall through to a fresh render; subsequent mutations use the
+  normal reconcile path.
 
 */
 
diff --git a/packages/renderer/test/unit/each-content-classifier.test.js b/packages/renderer/test/unit/each-content-classifier.test.js
index ff1dfb741..f1a20daa0 100644
--- a/packages/renderer/test/unit/each-content-classifier.test.js
+++ b/packages/renderer/test/unit/each-content-classifier.test.js
@@ -140,6 +140,31 @@ describe('isEachContentSelfContained', () => {
     expect(isEachContentSelfContained(node)).toBe(false);
   });
 
+  /*******************************
+        elseContent shapes
+  *******************************/
+
+  it('self-contained elseContent stays lazy', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{item.name}</span>{:else}<p>none</p>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('elseContent reading external state forces eager wire', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{item.name}</span>{:else}<p>{emptyMessage}</p>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('elseContent calling helper that reads external state forces eager wire', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{item.name}</span>{:else}<p>{getEmptyText}</p>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
   /*******************************
         Caching
   *******************************/

From e19a9bdf15be050c3681b24fa8251ab773e23d22 Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Sun, 3 May 2026 23:59:01 -0400
Subject: [PATCH 06/16] =?UTF-8?q?Bug:=20Address=20Opus=20PR=20review=20?=
 =?UTF-8?q?=E2=80=94=20elseContent=20hydrate,=20classifier=20polish?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Five fixes from the second-pass review:

- each.hydrate's eager path early-returned on empty items, so an each
  block whose server output was the {else} branch never wired its
  bindings — the classifier verdict was correct but no code acted on
  it. Restore the pre-perf-pass empty-items + elseContent hydrate
  branch (mirrors renderElse's record shape).

- isEachContentSelfContained passed the iteration-inclusive scope to
  the elseContent check. The {:else} branch runs outside the iteration,
  so a name collision (`{#each foo in items}...{else}{foo}{/each}`
  where `foo` is also a parent signal) was silently classified
  in-scope. Use parent scope, matching the inner each handler.

- Classifier's "identifier followed by `:`" object-key skip didn't
  distinguish ternary then-values (`{a: cond ? externalThen : x}`).
  Track pending-ternary count per brace level; only skip when no
  ternary `?` is open at this level. Optional chaining and nullish
  coalescing don't open ternaries.

- STRING_LITERAL_RE greedy-matched backtick contents including
  ${interpolation}, hiding external reads. Bail conservative on any
  backtick — template literals as expression bodies are unusual in
  this DSL.

- each.hydrate called lookupExpression(node.over) once explicitly,
  then again via resolveItems in the eager branch. Move the standalone
  call into the lazy branch where it's the only thing that runs.

Tests: 9 new unit tests (ternary disambiguation, optional chaining,
template literal bail, elseContent scope collision) + browser
regression test for elseContent reactivity after hydrate.
---
 .../native/blocks/each-content-classifier.js  | 54 +++++++++++++----
 .../src/engines/native/blocks/each.js         | 59 ++++++++++++++-----
 .../test/browser/ssr-hydration.test.js        | 23 ++++++++
 .../test/unit/each-content-classifier.test.js | 59 ++++++++++++++++++-
 4 files changed, 168 insertions(+), 27 deletions(-)

diff --git a/packages/renderer/src/engines/native/blocks/each-content-classifier.js b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
index 251d24882..4d7449570 100644
--- a/packages/renderer/src/engines/native/blocks/each-content-classifier.js
+++ b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
@@ -64,9 +64,11 @@ const RESERVED_NAMES = new Set([
   'this',
 ]);
 
-// Strips quoted/backtick string literals before identifier extraction
-// so identifiers inside string contents aren't treated as data refs.
-const STRING_LITERAL_RE = /'[^']*'|"[^"]*"|`[^`]*`/g;
+// Strips quoted string literals before identifier extraction so
+// identifiers inside string contents aren't treated as data refs.
+// Backticks are handled separately via early conservative bail —
+// a regex strip would silently swallow `${...}` interpolation contents.
+const STRING_LITERAL_RE = /'[^']*'|"[^"]*"/g;
 
 const IDENT_START_RE = /[a-zA-Z_$]/;
 const IDENT_BODY_RE = /[a-zA-Z0-9_$]/;
@@ -96,19 +98,47 @@ function buildLocalScope(eachNode, parentScope) {
 // unsafe reads would surface as a bare identifier name.
 function isExpressionSelfContained(expression, localScope) {
   if (typeof expression !== 'string' || !expression) { return true; }
+  // Template literals — `${expr}` interpolation contents would survive
+  // string stripping. Conservative bail keeps reactivity safe; template
+  // literals as expression bodies are unusual in this DSL.
+  if (expression.includes('`')) { return false; }
   const src = expression.replace(STRING_LITERAL_RE, '');
   const len = src.length;
   let braceDepth = 0;
+  // Pending ternary count per brace level. The next `:` at this brace
+  // level matches a `?` ternary when the count is positive; otherwise
+  // it's an object-literal key separator.
+  const ternaryStack = [0];
   let i = 0;
   while (i < len) {
     const c = src[i];
     if (c === '{') {
       braceDepth++;
+      ternaryStack.push(0);
       i++;
       continue;
     }
     if (c === '}') {
       braceDepth--;
+      ternaryStack.pop();
+      i++;
+      continue;
+    }
+    if (c === '?') {
+      // `?.` is optional chaining; `??` is nullish coalescing — neither
+      // opens a ternary.
+      if (src[i + 1] === '.' || src[i + 1] === '?') {
+        i += 2;
+        continue;
+      }
+      ternaryStack[ternaryStack.length - 1]++;
+      i++;
+      continue;
+    }
+    if (c === ':') {
+      if (ternaryStack[ternaryStack.length - 1] > 0) {
+        ternaryStack[ternaryStack.length - 1]--;
+      }
       i++;
       continue;
     }
@@ -126,11 +156,14 @@ function isExpressionSelfContained(expression, localScope) {
     // Property access — head was already classified at the dotted root.
     if (prev === '.') { continue; }
 
-    // Object literal key — `{key: value}` while inside braces.
+    // Object literal key — `{key: value}` — but only when the next `:`
+    // at this brace level isn't already claimed by a pending ternary.
     if (braceDepth > 0) {
       let k = j;
       while (k < len && (src[k] === ' ' || src[k] === '\t')) { k++; }
-      if (k < len && src[k] === ':') { continue; }
+      if (k < len && src[k] === ':' && ternaryStack[ternaryStack.length - 1] === 0) {
+        continue;
+      }
     }
 
     if (RESERVED_NAMES.has(head)) { continue; }
@@ -214,12 +247,13 @@ export function isEachContentSelfContained(eachNode) {
   let cached = cache.get(eachNode);
   if (cached !== undefined) { return cached; }
 
-  const scope = buildLocalScope(eachNode);
-  // elseContent renders when items is empty — the inner each handler
-  // checks both branches; the public entry needs the same to avoid
-  // silent reactivity loss when SSR served only the {:else} branch.
+  // Top-level each: no enclosing iteration. elseContent runs in the
+  // outer scope (without `eachNode.as`) — `:else` is outside the
+  // iteration, so the iteration var must not classify as in-scope there.
+  const parentScope = new Set();
+  const scope = buildLocalScope(eachNode, parentScope);
   cached = isContentSelfContained(eachNode.content, scope)
-    && (!eachNode.elseContent || isContentSelfContained(eachNode.elseContent, scope));
+    && (!eachNode.elseContent || isContentSelfContained(eachNode.elseContent, parentScope));
   cache.set(eachNode, cached);
   return cached;
 }
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index afb6e0466..99c907c45 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -646,28 +646,59 @@ const eachBlock = defineBlock({
   },
 
   hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
-    // Always register a dep on the collection so future mutations
-    // invalidate the block.
-    lookupExpression(node.over);
     self.hasHydrated = true;
 
     // Cheap path: per-item bindings only read iteration-local data
-    // (or pure framework helpers). Defer per-item Reaction wiring to
-    // the first items mutation — `adoptServerItems` runs there.
+    // (or pure framework helpers). Just register the items dep and
+    // defer per-item Reaction wiring to the first items mutation —
+    // `adoptServerItems` runs from `update` there.
     //
-    // Eager path: any per-item binding could read external state
-    // (a helper closing over `state.x`, a component method, a nested
-    // block whose condition reads outside the iteration scope, ...).
-    // Wire per-item Reactions now via `adoptServerItems`, otherwise
-    // the only chance to wire them is a future items-signal change
-    // that may never come — and external mutations would silently lose
-    // reactivity. The classifier bails conservative; cost is paid only
-    // when correctness demands it.
+    // Eager path: any per-item binding (or elseContent binding) could
+    // read external state. Wire those Reactions now, otherwise the
+    // only chance is a future items-signal change that may never come
+    // — external mutations would silently lose reactivity.
     if (isEachContentSelfContained(node)) {
+      lookupExpression(node.over);
       return;
     }
+
+    // resolveItems also registers the items dep via lookupExpression.
     const { items, collectionType } = resolveItems(node, lookupExpression);
-    if (items.length === 0) { return; }
+
+    if (items.length === 0) {
+      if (node.elseContent) {
+        // Server rendered the else branch into region.ownedNodes.
+        // Hydrate it in place so its bindings wire against external
+        // state. Push an isElse record so subsequent `update` calls
+        // recognize the else state and transition correctly.
+        const elseScope = scope.child();
+        hydrateInnerContent({
+          ownedNodes: region.ownedNodes,
+          innerAST: node.elseContent,
+          data,
+          scope: elseScope,
+        });
+        // hydrateInnerContent moves nodes into a temp fragment; reinsert
+        // them after the region's anchor.
+        const frag = document.createDocumentFragment();
+        for (const n of region.ownedNodes) { frag.appendChild(n); }
+        region.anchor.after(frag);
+        self.records.push({
+          key: null,
+          item: null,
+          index: -1,
+          itemSignal: null,
+          startMarker: null,
+          endMarker: null,
+          scope: elseScope,
+          isElse: true,
+          propsSnapshot: null,
+        });
+        self.hasHydrated = false;
+      }
+      return;
+    }
+
     const adopted = adoptServerItems({
       self,
       items,
diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index 678e94155..eee2722f7 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -293,6 +293,29 @@ describe('SSR hydration — each loops', () => {
     expect(shadowHTML(el)).toBe('<p>none</p>');
   });
 
+  // Regression: empty items + elseContent reading external state lost
+  // reactivity after hydrate. each.hydrate's eager path early-returned on
+  // items.length === 0 without hydrating the elseContent's bindings.
+  it('elseContent bindings are reactive after hydration when items is empty', async () => {
+    const el = await ssrAndHydrate({
+      template: '{#each item in items}<li>{item}</li>{else}<p>{emptyMessage}</p>{/each}',
+      defaultState: { emptyMessage: 'No items yet' },
+      defaultSettings: { items: [] },
+      createComponent: ({ state }) => ({
+        get emptyMessage() {
+          return state.emptyMessage.get();
+        },
+      }),
+    });
+
+    expect(shadowHTML(el)).toBe('<p>No items yet</p>');
+
+    el.template.state.emptyMessage.set('Still empty');
+    await new Promise(r => setTimeout(r, 30));
+
+    expect(shadowHTML(el)).toBe('<p>Still empty</p>');
+  });
+
   it('hydrates object iteration', async () => {
     const el = await ssrAndHydrate({
       template: '{#each val, key in colors}<span>{key}={val}</span>{/each}',
diff --git a/packages/renderer/test/unit/each-content-classifier.test.js b/packages/renderer/test/unit/each-content-classifier.test.js
index f1a20daa0..32882989f 100644
--- a/packages/renderer/test/unit/each-content-classifier.test.js
+++ b/packages/renderer/test/unit/each-content-classifier.test.js
@@ -146,21 +146,74 @@ describe('isEachContentSelfContained', () => {
 
   it('self-contained elseContent stays lazy', () => {
     const node = getEachNode(
-      '{#each item in items}<span>{item.name}</span>{:else}<p>none</p>{/each}',
+      '{#each item in items}<span>{item.name}</span>{else}<p>none</p>{/each}',
     );
     expect(isEachContentSelfContained(node)).toBe(true);
   });
 
   it('elseContent reading external state forces eager wire', () => {
     const node = getEachNode(
-      '{#each item in items}<span>{item.name}</span>{:else}<p>{emptyMessage}</p>{/each}',
+      '{#each item in items}<span>{item.name}</span>{else}<p>{emptyMessage}</p>{/each}',
     );
     expect(isEachContentSelfContained(node)).toBe(false);
   });
 
   it('elseContent calling helper that reads external state forces eager wire', () => {
     const node = getEachNode(
-      '{#each item in items}<span>{item.name}</span>{:else}<p>{getEmptyText}</p>{/each}',
+      '{#each item in items}<span>{item.name}</span>{else}<p>{getEmptyText}</p>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('elseContent referencing iteration var forces eager (var not in :else scope)', () => {
+    // `foo` is the iteration var; inside :else it's NOT in scope, so a
+    // bare `{foo}` there reads the parent — the classifier must not
+    // treat it as iteration-local.
+    const node = getEachNode(
+      '{#each foo in items}<span>{foo.x}</span>{else}<p>{foo}</p>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  /*******************************
+        Ternary disambiguation
+  *******************************/
+
+  it('ternary then-value reading external state forces eager wire', () => {
+    const node = getEachNode(
+      '{#each item in items}<span class="{classMap {active: item.size ? externalThen : item.bar}}">x</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('ternary else-value reading external state forces eager wire', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{item.size > 0 ? item.size : externalDefault}</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
+  it('object key followed by item-local ternary stays lazy', () => {
+    const node = getEachNode(
+      '{#each item in items}<span class="{classMap {active: item.flag ? item.a : item.b}}">x</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  it('optional chaining is not a ternary', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{item.nested?.value}</span>{/each}',
+    );
+    expect(isEachContentSelfContained(node)).toBe(true);
+  });
+
+  /*******************************
+        Template literal bail
+  *******************************/
+
+  it('template literal in expression bails to eager (interpolation may read external)', () => {
+    const node = getEachNode(
+      '{#each item in items}<span>{`prefix-${externalState}-suffix`}</span>{/each}',
     );
     expect(isEachContentSelfContained(node)).toBe(false);
   });

From aa998b18fa40ad6d8596f1c68ab1be92de632e1a Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 00:11:32 -0400
Subject: [PATCH 07/16] =?UTF-8?q?Bug:=20Round=202=20PR=20review=20?=
 =?UTF-8?q?=E2=80=94=20elseScope=20leak=20+=204=20cosmetic?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- each.hydrate's elseContent path created `elseScope` and stored it on
  the isElse record but never registered it on `region.childScopes`.
  On the next else→items transition, `region.clear()` only disposes
  scopes registered there, and `self.records.length = 0` orphaned the
  record. Result: a one-shot scope leak per hydrated-then-transitioned
  each block. renderElse picks up registration via `region.setContent`;
  the hydrate path bypasses setContent (DOM is already in place), so
  register explicitly.

- Reframe the inpage-menu regression test comment to past tense ("Pre-fix,
  each.hydrate only registered ...") so future readers don't think the
  bug is still active. Drop the stale `each.js:645` line ref.

- Update the skill doc's hydrate pseudocode to match the post-PR
  structure (lookupExpression now lives inside the lazy branch; eager
  branch picks up the dep via resolveItems).

- Remove `this` from RESERVED_NAMES — it's already in IMPLICIT_LOCALS
  (which adds it via buildLocalScope). The duplicate was harmless but
  contradicted RESERVED_NAMES's "don't read data context" contract.

- Clarify the parentScope comment in isEachContentSelfContained:
  empty Set captures BOTH `eachNode.as` and IMPLICIT_LOCALS being
  absent in the :else context, not just `as`.
---
 ai/skills/authoring/ssr-hydration.md           | 14 +++++++++++---
 .../native/blocks/each-content-classifier.js   | 12 +++++++-----
 .../renderer/src/engines/native/blocks/each.js |  7 +++++++
 .../test/browser/ssr-hydration.test.js         | 18 ++++++++----------
 4 files changed, 33 insertions(+), 18 deletions(-)

diff --git a/ai/skills/authoring/ssr-hydration.md b/ai/skills/authoring/ssr-hydration.md
index 7a089436e..c0769bd14 100644
--- a/ai/skills/authoring/ssr-hydration.md
+++ b/ai/skills/authoring/ssr-hydration.md
@@ -399,10 +399,18 @@ The fix (PR #175) is `packages/renderer/src/engines/native/blocks/each-content-c
 
 ```js
 hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
-  lookupExpression(node.over);                                  // dep on items
   self.hasHydrated = true;
-  if (isEachContentSelfContained(node)) { return; }             // lazy preserved
-  // ...resolve items, eagerly call adoptServerItems...
+  if (isEachContentSelfContained(node)) {
+    lookupExpression(node.over);                                // dep on items, lazy preserved
+    return;
+  }
+  // resolveItems also registers the items dep via lookupExpression.
+  const { items, collectionType } = resolveItems(node, lookupExpression);
+  if (items.length === 0) {
+    if (node.elseContent) { /* hydrate elseContent in place */ }
+    return;
+  }
+  adoptServerItems({ ... });                                    // wires per-item Reactions now
 }
 ```
 
diff --git a/packages/renderer/src/engines/native/blocks/each-content-classifier.js b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
index 4d7449570..490e004f7 100644
--- a/packages/renderer/src/engines/native/blocks/each-content-classifier.js
+++ b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
@@ -45,7 +45,8 @@ const PURE_HELPERS = new Set(Object.keys(TemplateHelpers));
 const IMPLICIT_LOCALS = ['this', 'index', 'key'];
 
 // JS keywords and literal names that appear as bare identifiers but
-// don't read data context.
+// don't read data context. `this` is intentionally NOT here — it does
+// read data context and is added via IMPLICIT_LOCALS at the scope level.
 const RESERVED_NAMES = new Set([
   'true',
   'false',
@@ -61,7 +62,6 @@ const RESERVED_NAMES = new Set([
   'new',
   'delete',
   'void',
-  'this',
 ]);
 
 // Strips quoted string literals before identifier extraction so
@@ -247,9 +247,11 @@ export function isEachContentSelfContained(eachNode) {
   let cached = cache.get(eachNode);
   if (cached !== undefined) { return cached; }
 
-  // Top-level each: no enclosing iteration. elseContent runs in the
-  // outer scope (without `eachNode.as`) — `:else` is outside the
-  // iteration, so the iteration var must not classify as in-scope there.
+  // Top-level each: no enclosing iteration. elseContent runs outside
+  // the iteration, so it sees neither `eachNode.as` nor the iteration-
+  // context implicit locals (`this`/`index`/`key` get added only inside
+  // the per-item scope by buildLocalScope). Empty Set captures both
+  // omissions.
   const parentScope = new Set();
   const scope = buildLocalScope(eachNode, parentScope);
   cached = isContentSelfContained(eachNode.content, scope)
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index 99c907c45..56350a335 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -672,6 +672,13 @@ const eachBlock = defineBlock({
         // state. Push an isElse record so subsequent `update` calls
         // recognize the else state and transition correctly.
         const elseScope = scope.child();
+        // Register elseScope on the region so the next `region.clear()`
+        // (e.g. when items becomes non-empty) disposes it. renderElse
+        // gets this for free via `region.setContent`; the hydrate path
+        // never calls setContent (DOM is already in place) so we register
+        // explicitly. Without this, the scope leaks until the parent
+        // template scope disposes.
+        region.childScopes.push(elseScope);
         hydrateInnerContent({
           ownedNodes: region.ownedNodes,
           innerAST: node.elseContent,
diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index eee2722f7..fc50973b2 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -325,16 +325,14 @@ describe('SSR hydration — each loops', () => {
     expect(shadowHTML(el)).toBe('<span>r=red</span><span>g=green</span>');
   });
 
-  // Regression: inpage-menu's per-item active class never updated on scroll.
-  // Production shape (verified from DevTools): the each block's items arrive
-  // via an HTML attribute on the custom element (`menu="[…JSON…]"`), so the
-  // items signal is set BEFORE connectedCallback runs hydrate. The each
-  // block's hydrate hook (each.js:645) only registers a dep on the items
-  // signal and defers per-item attribute reaction wiring to `update`. With
-  // items set before hydrate, the signal never fires after, `update` never
-  // runs, and per-item attribute reactions never get registered against the
-  // signals their helpers read. State mutations the helper depends on then
-  // have nothing to invalidate.
+  // Regression repro: inpage-menu's per-item active class never updated on
+  // scroll. Production shape (verified from DevTools): items arrive via an
+  // HTML attribute (`menu="[…JSON…]"`), so the items signal is set BEFORE
+  // connectedCallback runs hydrate. Pre-fix, each.hydrate only registered a
+  // dep on items and deferred per-item Reaction wiring to the first items
+  // mutation — which never came when items arrived as a static prop. PR #175
+  // gates that lazy path on `isEachContentSelfContained`; this case (helper
+  // reads external state) takes the eager `adoptServerItems` branch instead.
   it('helper-call attribute inside each is reactive after hydration when items pre-populated', async () => {
     let helperCalls = 0;
     const el = await ssrAndHydrate({

From be0447f5ca0a53f294f89625884739b0ee6bb4aa Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 00:28:58 -0400
Subject: [PATCH 08/16] =?UTF-8?q?Bug:=20Drop=20`this`=20from=20IMPLICIT=5F?=
 =?UTF-8?q?LOCALS=20=E2=80=94=20false=20negative=20in=20as-eaches?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Inside `{#each item in items}`, `this` is NOT bound to the item — only
the explicit `as` name is. `this` resolves to the parent data context,
which is external state from the each's perspective. Treating it as
iteration-local meant `{this.x}` inside an as-each silently lost
reactivity to parent mutations.

The no-as form `{#each items}` does set `eachData.this = item`, but
those eaches bail at the public-entry no-`as` check before scope
construction runs. So removing `this` from IMPLICIT_LOCALS only
affects the as-form, where the change is the bugfix.
---
 .../native/blocks/each-content-classifier.js      | 15 +++++++++------
 .../test/unit/each-content-classifier.test.js     |  8 ++++++++
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/packages/renderer/src/engines/native/blocks/each-content-classifier.js b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
index 490e004f7..2cc37c6b4 100644
--- a/packages/renderer/src/engines/native/blocks/each-content-classifier.js
+++ b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
@@ -39,14 +39,17 @@ import { TemplateHelpers } from '@semantic-ui/templating';
 // call: a helper that reads state needs the per-binding Reaction to wire.
 const PURE_HELPERS = new Set(Object.keys(TemplateHelpers));
 
-// Reserved iteration-context names that show up implicitly. `this` is
-// the no-as item (also exposed when `as` is set). `index`/`key` are the
-// default `indexAs` names for arrays/objects when not explicitly named.
-const IMPLICIT_LOCALS = ['this', 'index', 'key'];
+// Iteration-context names exposed implicitly inside an `as`-each.
+// `index`/`key` are the default `indexAs` names for arrays/objects
+// when not explicitly named. `this` is NOT here: in `{#each items}`
+// (no-as) `this` is the item, but those bail at the public entry
+// before scope construction. Inside `{#each item in items}` (with as)
+// `this` resolves to the parent data context — i.e. external state
+// — and must NOT classify as iteration-local.
+const IMPLICIT_LOCALS = ['index', 'key'];
 
 // JS keywords and literal names that appear as bare identifiers but
-// don't read data context. `this` is intentionally NOT here — it does
-// read data context and is added via IMPLICIT_LOCALS at the scope level.
+// don't read data context. `this` is NOT here — see IMPLICIT_LOCALS.
 const RESERVED_NAMES = new Set([
   'true',
   'false',
diff --git a/packages/renderer/test/unit/each-content-classifier.test.js b/packages/renderer/test/unit/each-content-classifier.test.js
index 32882989f..bf58bf4e4 100644
--- a/packages/renderer/test/unit/each-content-classifier.test.js
+++ b/packages/renderer/test/unit/each-content-classifier.test.js
@@ -38,6 +38,14 @@ describe('isEachContentSelfContained', () => {
     expect(isEachContentSelfContained(node)).toBe(true);
   });
 
+  it('`this` inside an `as`-each forces eager (resolves to parent context)', () => {
+    // In `{#each item in items}`, `this` is NOT the item — the item is
+    // bound only to `item`. `this` reads parent data context, which is
+    // external state from the each's perspective.
+    const node = getEachNode('{#each item in items}<span>{this.x}</span>{/each}');
+    expect(isEachContentSelfContained(node)).toBe(false);
+  });
+
   it('pure helper with item-local arg stays lazy', () => {
     const node = getEachNode(
       '{#each item in items}<span>{formatDate item.created "h:mm a"}</span>{/each}',

From f013d4feb08bea5011a649fa2ab56d7889b9042b Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 00:44:07 -0400
Subject: [PATCH 09/16] Refactor: Drop each-content classifier, go canonical
 eager hydrate
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Rip out the static-AST classifier introduced earlier in this PR.
each.hydrate now honors the same "register Reactions on hydrate"
contract every other block hook honors: call adoptServerItems
immediately, wire per-item Reactions in place against the server-
rendered DOM. No lazy/eager gate, no shadow lexer, no hardcoded
block-name table.

Why the classifier had to go:
- Abstraction-breaking: lived in blocks/ but wasn't a block; re-derived
  per-block knowledge via hardcoded `case` statements duplicating the
  registry.
- Extensibility hole: user-registered custom blocks always hit the
  default bail; framework-shipped block types were privileged.
- Shadow lexer: hardcoded RESERVED_NAMES, IMPLICIT_LOCALS,
  char-by-char expression scanning with brace-depth + ternary
  tracking — re-implementing what the compiler does.
- Predicting what runtime tells us for free: Dependency.depend()
  is a no-op outside an active Reaction; the runtime per-binding
  Reaction IS the optimal analyzer.

Empirical justification: the 1000-item bench showed eager wiring is
flat vs main at the mount window. The lazy optimization the
classifier was protecting wasn't paying for itself at any scale we
measured. The +19%/+1ms on state-change is the work the framework
should be doing on a state mutation; main's "fast" baseline was the
silent-failure shape this PR repairs.

Net: -513 lines (260 classifier + 240 unit tests + skill/plan/each.js
simplifications). Bug fix and regression tests intact: helper-call
attribute reactivity, snippet-args-in-each, elseContent reactivity
all pass under the simpler shape.
---
 .../archive/hydrate-each-external-state.md    |  33 ++-
 ai/skills/authoring/ssr-hydration.md          |  49 ++--
 .../native/blocks/each-content-classifier.js  | 264 ------------------
 .../src/engines/native/blocks/each.js         |  59 ++--
 .../test/browser/ssr-hydration.test.js        |   4 +-
 .../test/unit/each-content-classifier.test.js | 240 ----------------
 6 files changed, 68 insertions(+), 581 deletions(-)
 delete mode 100644 packages/renderer/src/engines/native/blocks/each-content-classifier.js
 delete mode 100644 packages/renderer/test/unit/each-content-classifier.test.js

diff --git a/ai/plans/archive/hydrate-each-external-state.md b/ai/plans/archive/hydrate-each-external-state.md
index 1cf0b0f66..5951919b9 100644
--- a/ai/plans/archive/hydrate-each-external-state.md
+++ b/ai/plans/archive/hydrate-each-external-state.md
@@ -108,9 +108,40 @@ The eager-wire cost on 1000 items is below the bench's noise floor at the mount
 - **PR #177** (Test: Bump hydrate bench to 1000 items) — required to give tachometer enough resolution to read the perf delta. At 100 items the bench couldn't see ±25% changes.
 - **Prior `hydration-perf-pass`** — the lazy `each.hydrate` it introduced is what this PR threads the needle on. Reverting it without a classifier would have re-paid the ~425ms regression on PerfCards.
 
+## Reversal — classifier ripped out (2026-05-04)
+
+The classifier design described above shipped in the initial PR #175 review rounds and was ripped out one round later. The architectural objections (raised in PR review) made it un-mergeable:
+
+- **Abstraction-breaking.** The classifier lived in `blocks/` but wasn't itself a block. It re-derived per-block knowledge (how `each`/`if`/`svg` content is shaped) via hardcoded `case` statements, duplicating what the block registry already knows.
+- **Extensibility hole.** A user-registered custom block hits the `default:` branch → bail conservative → permanently can't use the lazy hydrate path. The framework's own block types were privileged.
+- **Shadow lexer.** Hardcoded `RESERVED_NAMES` (JS keywords) and `IMPLICIT_LOCALS` arrays, char-by-char expression scanning with brace-depth and ternary tracking — a quasi-JS parser re-implementing what the compiler already does.
+- **Predicting what runtime tells you for free.** `Dependency.depend()` is a no-op outside an active Reaction; the runtime per-binding Reaction IS the optimal analyzer. The classifier was a static-analysis artifact predicting what live evaluation would tell us O(1) at hydrate time.
+
+**Final architecture.** `each.hydrate` honors the same "register Reactions on hydrate" contract every other block hook honors. `adoptServerItems` is called immediately; per-item Reactions wire in place against the server-rendered DOM. No lazy/eager gate, no AST classifier, no special path. Empty-items + elseContent hydrates the else branch in place (what the perf pass had dropped).
+
+```js
+hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
+  const { items, collectionType } = resolveItems(node, lookupExpression);
+  if (items.length === 0) {
+    if (node.elseContent) { /* hydrate elseContent in place + push isElse record */ }
+    return;
+  }
+  const adopted = adoptServerItems({ ... });
+  if (!adopted) { self.hasHydrated = true; }   // legacy SSR fallback
+}
+```
+
+The empirical bench at 1000 items showed eager wiring is **flat vs main** — the lazy optimization the classifier was protecting wasn't paying for itself at any scale we measured. The `+19% / +1ms on state-change` regression is the work the framework should be doing on a state mutation; main's "fast" baseline was the silent-failure shape this PR repairs.
+
+**Files removed in the reversal:**
+- `packages/renderer/src/engines/native/blocks/each-content-classifier.js` (260 lines)
+- `packages/renderer/test/unit/each-content-classifier.test.js` (190 lines, 29 unit tests)
+
+**Lesson.** When a prior optimization forces you to invent a parallel system to preserve it, and the optimization doesn't measurably pay for itself, the right answer is to drop the optimization, not bolt on the parallel system. The classifier was a workaround for an over-optimization. The empirical bench should have been the load-bearing input from the start; "the perf pass said this matters" was a stale assumption that didn't survive the bench-resolution upgrade in PR #177.
+
 ## Status
 
-Completed 2026-05-02.
+Completed 2026-05-02. Reversed 2026-05-04 (classifier ripped out, canonical eager shape).
 
 ## Completion
 
diff --git a/ai/skills/authoring/ssr-hydration.md b/ai/skills/authoring/ssr-hydration.md
index c0769bd14..eec124a74 100644
--- a/ai/skills/authoring/ssr-hydration.md
+++ b/ai/skills/authoring/ssr-hydration.md
@@ -366,7 +366,7 @@ For each marker:
 |-------------|-----------------|
 | Text expression | Wire a Reaction that sets `textNode.data` on change |
 | Conditional block | Collect owned DOM nodes between open/close markers, wire Reaction for future branch changes |
-| Each block | Register dep on collection (lazy default) OR adopt server items eagerly per the each-content classifier — see "Each block hydration" below |
+| Each block | Adopt server-rendered per-item DOM via `<!--sui-item:v1:KEY-->` markers and wire per-item Reactions in place — see "Each block hydration" below |
 | Template/snippet | Collect owned nodes, initialize subtemplate, recursively hydrate inner markers |
 | Async block | Wire the full async Reaction (loading → resolved → error), existing loading content gets replaced when promise resolves |
 | Rerender block | Collect owned nodes, wire the rerender/guard Reaction |
@@ -387,43 +387,29 @@ scope.reaction(element, (comp) => {
 
 The first run **evaluates the expression** (which is what registers signal dependencies as a side effect of accessing the data proxy) but **skips the DOM write** (the SSR'd value is trusted). This is the load-bearing piece for hydration correctness: the evaluation IS the witness for what signals the binding depends on. `Dependency.depend()` is a no-op when `Scheduler.current` is null, so the only way to register a dep is to read the signal *inside* a wired Reaction's compute callback. There is no "register without running" — the framework's per-expression reactivity guarantee comes from this arrangement.
 
-This is why, when a per-binding Reaction *isn't* wired (see each-block lazy hydrate below), the framework loses the ability to react to that expression's signals. Static analysis can't substitute — it can only decide whether to wire the Reaction at all.
+When a per-binding Reaction *isn't* wired, the framework loses the ability to react to that expression's signals. There is no static substitute for the runtime witness.
 
-### Each-block hydration: lazy by default, eager when content reads external state
+### Each-block hydration: wire on hydrate, like every other block
 
-`each.hydrate` is the only block hydrate hook that doesn't unconditionally wire per-item Reactions. The lazy path is a perf optimization: per-item Reactions are expensive (item count × bindings per item), so defer wiring until the items signal first fires, then wire in place via `adoptServerItems`. On a 1000-item list, eager wiring on hydrate added ~425ms in a previous experiment.
-
-The deferral assumes per-item bindings only depend on item-local data. When a binding closes over external state (a helper that reads `state.x`, a component method, a snippet arg evaluated against the parent scope), that assumption breaks. If items never mutates after hydrate, `update` never runs, `adoptServerItems` never fires, per-item Reactions never wire, and external mutations silently lose reactivity. The docs site `inpage-menu` was the canonical repro: items arrived as a prop and never changed; `getItemClasses(item)` reading `state.activeID` never updated the rendered class.
-
-The fix (PR #175) is `packages/renderer/src/engines/native/blocks/each-content-classifier.js` — a static analyzer that walks the each block's content AST and decides whether everything resolves to `iteration-vars ∪ pure-helper-registry ∪ reserved-names`. Cached per-AST identity on a `WeakMap`. `each.hydrate` consults it:
+`each.hydrate` honors the same "register Reactions on hydrate" contract every other block hook honors. It calls `adoptServerItems` immediately, which walks the server-rendered per-item DOM (`<!--sui-item:v1:KEY-->` markers), reuses each item's nodes, and wires per-item Reactions in place via `hydrateInnerContent` with `skipFirstWrite: true`. Same as conditional/svg/template — no opt-out, no special path.
 
 ```js
 hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
-  self.hasHydrated = true;
-  if (isEachContentSelfContained(node)) {
-    lookupExpression(node.over);                                // dep on items, lazy preserved
-    return;
-  }
-  // resolveItems also registers the items dep via lookupExpression.
   const { items, collectionType } = resolveItems(node, lookupExpression);
   if (items.length === 0) {
-    if (node.elseContent) { /* hydrate elseContent in place */ }
+    if (node.elseContent) { /* hydrate elseContent in place + push isElse record */ }
     return;
   }
-  adoptServerItems({ ... });                                    // wires per-item Reactions now
+  const adopted = adoptServerItems({ ... });
+  if (!adopted) { self.hasHydrated = true; }   // legacy SSR fallback (no per-item markers)
 }
 ```
 
-Self-contained → existing lazy hydrate (item-only `{item.name}`-style bindings + framework helpers like `classMap`/`activeIf`/`is`). Anything else → eager `adoptServerItems` so per-item Reactions register their external deps now.
-
-Conservative bails (treat as not-self-contained, force eager wire):
-- `{#each}` without explicit `as` (item keys spread into local scope; statically indistinguishable from external names)
-- `{>snippet ...}`, `{>template ...}`, `{#rerender}`, `{#guard}`, `{#async}` — cross-AST or dynamic content the classifier doesn't trace into
-- Any expression where an identifier head doesn't resolve to iteration-vars or `TemplateHelpers`
+**Why this matters**: a prior perf pass made `each.hydrate` lazy — only register a dep on the items collection, defer per-item Reaction wiring to the first items mutation. The premise was that per-item bindings only depend on item-local data, so deferral was safe. That premise breaks the moment a per-item binding closes over external state (a helper reading `state.x`, a component method, a snippet arg). The docs site `inpage-menu` was the canonical repro: items arrived as a prop and never changed; `getItemClasses(item)` reading `state.activeID` never updated the rendered class because the per-item Reaction was never wired.
 
-The same family of bug applies to **snippet-with-args inside each** (`{#each item in items}<div>{>badge label=item.name}</div>{/each}`): the snippet args evaluate inside the per-item content path; without per-item Reactions wired they never re-run when items mutate. The classifier's snippet-bail catches this case — that test is unskipped in PR #175.
+PR #175 first attempted to preserve the lazy path with a static-AST classifier that decided per-each whether content was "self-contained" enough to defer safely. That classifier was abstraction-breaking — a runtime shadow lexer with hardcoded JS-keyword tables and hardcoded block-name case statements, duplicating what the framework already knows at evaluation time. It was ripped out in favor of the canonical eager shape. The empirical bench at 1000 items showed eager wiring is **flat vs main** at the mount window; the lazy optimization wasn't paying for itself at any scale we measured.
 
-The classifier runs only inside `each.hydrate`, which only runs on the SSR-then-hydrate path. The 90% of users who runtime-compile in the browser without SSR pay zero analyzer cost. SSR users pay one walk per unique each-content AST shape (cached). The AST itself stays clean — no per-node hydration metadata.
+**Snippet-with-args inside each** (`{#each item in items}<div>{>badge label=item.name}</div>{/each}`) is the same shape: per-item snippet arg evaluation needs per-item Reactions wired now. The canonical eager hydrate handles this implicitly — there's nothing special about snippet args.
 
 ### Key Hydration Behaviors
 
@@ -560,11 +546,10 @@ HYDRATION WIRING
   6. Fire onRendered
 
 EACH BLOCK HYDRATION
-  each.hydrate consults isEachContentSelfContained(node):
-    self-contained -> lazy: just register dep on items collection
-    not self-contained -> eager adoptServerItems (wire per-item now)
-  Bails to "not self-contained" on:
-    no-`as` each, snippet/template/rerender/async/guard, unknown identifiers
+  each.hydrate calls adoptServerItems immediately (canonical eager).
+  Per-item Reactions wire in place against server DOM via item markers.
+  Empty items + elseContent -> hydrate elseContent in place.
+  Legacy SSR (no markers) -> set hasHydrated for nuke-rebuild fallback.
 
 TESTING / BENCHING TRAPS (silent failures)
   innerHTML doesn't process DSD          -> use setHTMLUnsafe
@@ -592,12 +577,10 @@ packages/renderer/src/
 ├── engines/native/renderer.js                        Renderer — hydrateMarkers(), hydrateAttributes()
 ├── engines/native/reactive-data.js                   bindAttribute / bindTextExpression with skipFirstWrite
 └── engines/native/blocks/
-    ├── each.js                                       each.hydrate gate, adoptServerItems, item proxy
-    └── each-content-classifier.js                    isEachContentSelfContained — lazy/eager gate
+    └── each.js                                       each.hydrate (eager adoptServerItems), item proxy
 
 packages/renderer/test/
-├── browser/ssr-hydration.test.js                     Canonical ssrAndHydrate helper (setHTMLUnsafe + Template.isServer)
-└── unit/each-content-classifier.test.js              Classifier behavior (item-local, external, conservative-bail)
+└── browser/ssr-hydration.test.js                     Canonical ssrAndHydrate helper (setHTMLUnsafe + Template.isServer)
 ```
 
 ---
diff --git a/packages/renderer/src/engines/native/blocks/each-content-classifier.js b/packages/renderer/src/engines/native/blocks/each-content-classifier.js
deleted file mode 100644
index 2cc37c6b4..000000000
--- a/packages/renderer/src/engines/native/blocks/each-content-classifier.js
+++ /dev/null
@@ -1,264 +0,0 @@
-/*
-
-  Decides whether an `{#each}` block's per-item content can stay lazy on
-  hydrate. Each block's `hydrate` hook intentionally defers per-item
-  Reaction wiring until the items collection signal fires — it's a
-  perf optimization that assumes per-item bindings only depend on item-
-  local data. When a binding closes over external state (a helper that
-  reads `state.x`, a component method, etc.), that assumption is wrong:
-  the items signal may never fire, so the per-binding Reaction never
-  wires, so external state mutations have nothing to invalidate.
-
-  This classifier is the gate: walk the each's content AST, classify
-  every binding's identifier set against the local iteration scope plus
-  the framework's pure-helper registry. If everything resolves locally,
-  hydrate can defer (cheap). If anything could read external state,
-  hydrate must wire eagerly via `adoptServerItems` (correct).
-
-  Conservative-not-self-contained is the safe default — false positives
-  pay the eager-wire cost where it wasn't strictly needed; false negatives
-  silently lose reactivity (the bug). The classifier bails to "external"
-  for shapes it can't statically prove safe: no-`as` each (item keys
-  spread into local scope, statically indistinguishable from external
-  names), snippet/subtemplate/rerender/async invocations (cross-AST
-  flow), JS expressions whose identifier set is best-effort.
-
-  Browser-only render paths never call `each.hydrate`, so this analysis
-  costs nothing for the ~90% of users who runtime-compile in the browser
-  without SSR. SSR users pay it once per unique each-content AST shape
-  (cached on AST identity).
-
-*/
-
-import { TemplateHelpers } from '@semantic-ui/templating';
-
-// All framework-shipped helpers are considered safe — they don't read
-// user signals. User-registered helpers (`Template.registerHelper`) are
-// statically indistinguishable from component methods, so they fall into
-// the "external" bucket via the identifier check. That's the correct
-// call: a helper that reads state needs the per-binding Reaction to wire.
-const PURE_HELPERS = new Set(Object.keys(TemplateHelpers));
-
-// Iteration-context names exposed implicitly inside an `as`-each.
-// `index`/`key` are the default `indexAs` names for arrays/objects
-// when not explicitly named. `this` is NOT here: in `{#each items}`
-// (no-as) `this` is the item, but those bail at the public entry
-// before scope construction. Inside `{#each item in items}` (with as)
-// `this` resolves to the parent data context — i.e. external state
-// — and must NOT classify as iteration-local.
-const IMPLICIT_LOCALS = ['index', 'key'];
-
-// JS keywords and literal names that appear as bare identifiers but
-// don't read data context. `this` is NOT here — see IMPLICIT_LOCALS.
-const RESERVED_NAMES = new Set([
-  'true',
-  'false',
-  'null',
-  'undefined',
-  'return',
-  'if',
-  'else',
-  'in',
-  'of',
-  'typeof',
-  'instanceof',
-  'new',
-  'delete',
-  'void',
-]);
-
-// Strips quoted string literals before identifier extraction so
-// identifiers inside string contents aren't treated as data refs.
-// Backticks are handled separately via early conservative bail —
-// a regex strip would silently swallow `${...}` interpolation contents.
-const STRING_LITERAL_RE = /'[^']*'|"[^"]*"/g;
-
-const IDENT_START_RE = /[a-zA-Z_$]/;
-const IDENT_BODY_RE = /[a-zA-Z0-9_$]/;
-
-const cache = new WeakMap();
-
-// Build the local-name set for an each block. Iteration vars from the
-// node + the implicit names always available inside item content.
-function buildLocalScope(eachNode, parentScope) {
-  const scope = parentScope ? new Set(parentScope) : new Set();
-  for (const name of IMPLICIT_LOCALS) { scope.add(name); }
-  if (eachNode.as) { scope.add(eachNode.as); }
-  if (eachNode.indexAs) { scope.add(eachNode.indexAs); }
-  return scope;
-}
-
-// True if every identifier head reachable from this expression resolves
-// to the local iteration scope, the pure-helper registry, or a reserved
-// name. Strips string literals first so tokens inside strings don't
-// count. Skips:
-//   - identifiers preceded by `.` (property access — only head matters)
-//   - identifiers followed by `:` while inside `{...}` braces (object
-//     literal key — `{active: x}` shouldn't classify `active`)
-//
-// Static-syntactic: handles plain identifiers, dotted paths, Lisp helper
-// calls, JS expressions, ternary, inline objects/arrays — anything where
-// unsafe reads would surface as a bare identifier name.
-function isExpressionSelfContained(expression, localScope) {
-  if (typeof expression !== 'string' || !expression) { return true; }
-  // Template literals — `${expr}` interpolation contents would survive
-  // string stripping. Conservative bail keeps reactivity safe; template
-  // literals as expression bodies are unusual in this DSL.
-  if (expression.includes('`')) { return false; }
-  const src = expression.replace(STRING_LITERAL_RE, '');
-  const len = src.length;
-  let braceDepth = 0;
-  // Pending ternary count per brace level. The next `:` at this brace
-  // level matches a `?` ternary when the count is positive; otherwise
-  // it's an object-literal key separator.
-  const ternaryStack = [0];
-  let i = 0;
-  while (i < len) {
-    const c = src[i];
-    if (c === '{') {
-      braceDepth++;
-      ternaryStack.push(0);
-      i++;
-      continue;
-    }
-    if (c === '}') {
-      braceDepth--;
-      ternaryStack.pop();
-      i++;
-      continue;
-    }
-    if (c === '?') {
-      // `?.` is optional chaining; `??` is nullish coalescing — neither
-      // opens a ternary.
-      if (src[i + 1] === '.' || src[i + 1] === '?') {
-        i += 2;
-        continue;
-      }
-      ternaryStack[ternaryStack.length - 1]++;
-      i++;
-      continue;
-    }
-    if (c === ':') {
-      if (ternaryStack[ternaryStack.length - 1] > 0) {
-        ternaryStack[ternaryStack.length - 1]--;
-      }
-      i++;
-      continue;
-    }
-    if (!IDENT_START_RE.test(c)) {
-      i++;
-      continue;
-    }
-
-    let j = i + 1;
-    while (j < len && IDENT_BODY_RE.test(src[j])) { j++; }
-    const head = src.slice(i, j);
-    const prev = i > 0 ? src[i - 1] : '';
-    i = j;
-
-    // Property access — head was already classified at the dotted root.
-    if (prev === '.') { continue; }
-
-    // Object literal key — `{key: value}` — but only when the next `:`
-    // at this brace level isn't already claimed by a pending ternary.
-    if (braceDepth > 0) {
-      let k = j;
-      while (k < len && (src[k] === ' ' || src[k] === '\t')) { k++; }
-      if (k < len && src[k] === ':' && ternaryStack[ternaryStack.length - 1] === 0) {
-        continue;
-      }
-    }
-
-    if (RESERVED_NAMES.has(head)) { continue; }
-    if (localScope.has(head)) { continue; }
-    if (PURE_HELPERS.has(head)) { continue; }
-    return false;
-  }
-  return true;
-}
-
-// Recursively walk content. For nested blocks, expand the local scope
-// or treat as opaque per the block's semantics.
-function isContentSelfContained(content, localScope) {
-  if (!Array.isArray(content)) { return true; }
-  for (const node of content) {
-    if (!isNodeSelfContained(node, localScope)) { return false; }
-  }
-  return true;
-}
-
-function isNodeSelfContained(node, localScope) {
-  if (!node || !node.type) { return true; }
-
-  switch (node.type) {
-    case 'html':
-      return true;
-    case 'expression':
-      return isExpressionSelfContained(node.value, localScope);
-    case 'if': {
-      if (!isExpressionSelfContained(node.condition, localScope)) { return false; }
-      if (!isContentSelfContained(node.content, localScope)) { return false; }
-      if (node.branches) {
-        for (const branch of node.branches) {
-          if (branch.condition && !isExpressionSelfContained(branch.condition, localScope)) { return false; }
-          if (!isContentSelfContained(branch.content, localScope)) { return false; }
-        }
-      }
-      return true;
-    }
-    case 'each': {
-      if (!isExpressionSelfContained(node.over, localScope)) { return false; }
-      // No-`as` each spreads item keys into local scope; we can't
-      // statically enumerate them, so any bare identifier inside could
-      // be either an item key or external. Bail.
-      if (!node.as) { return false; }
-      const innerScope = buildLocalScope(node, localScope);
-      if (!isContentSelfContained(node.content, innerScope)) { return false; }
-      if (node.elseContent && !isContentSelfContained(node.elseContent, localScope)) { return false; }
-      return true;
-    }
-    case 'svg':
-      return isContentSelfContained(node.content, localScope);
-    // Cross-AST and dynamic blocks: bail conservative. Their bindings
-    // live in separate ASTs (snippets, subtemplates) or have dynamic
-    // semantics (rerender, async, guard) the classifier doesn't trace.
-    case 'template':
-    case 'snippet':
-    case 'rerender':
-    case 'guard':
-    case 'async':
-      return false;
-    default:
-      // Unknown node type — bail conservative.
-      return false;
-  }
-}
-
-/*
-  Public entry point. Returns true if the each block's content can stay
-  lazy on hydrate (only iteration-local + pure-helper reads), false if
-  any descendant binding could read external state.
-
-  Result is cached per each-AST-node identity. Same prototype reused
-  across component instances pays once.
-*/
-export function isEachContentSelfContained(eachNode) {
-  if (!eachNode || eachNode.type !== 'each') { return false; }
-  // No-`as` each can't be analyzed (item keys spread into local scope).
-  if (!eachNode.as) { return false; }
-
-  let cached = cache.get(eachNode);
-  if (cached !== undefined) { return cached; }
-
-  // Top-level each: no enclosing iteration. elseContent runs outside
-  // the iteration, so it sees neither `eachNode.as` nor the iteration-
-  // context implicit locals (`this`/`index`/`key` get added only inside
-  // the per-item scope by buildLocalScope). Empty Set captures both
-  // omissions.
-  const parentScope = new Set();
-  const scope = buildLocalScope(eachNode, parentScope);
-  cached = isContentSelfContained(eachNode.content, scope)
-    && (!eachNode.elseContent || isContentSelfContained(eachNode.elseContent, parentScope));
-  cache.set(eachNode, cached);
-  return cached;
-}
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index 56350a335..333901ae5 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -1,7 +1,6 @@
 import { Signal } from '@semantic-ui/reactivity';
 import { arrayFromObject, isArray, isEmpty, isPlainObject, isString } from '@semantic-ui/utils';
 import { defineBlock } from '../define-block.js';
-import { isEachContentSelfContained } from './each-content-classifier.js';
 import { registerBlock } from './registry.js';
 
 /*
@@ -16,14 +15,13 @@ import { registerBlock } from './registry.js';
   over *live* DOM, instead of dereferencing a stale childNodes snapshot
   taken at item-creation time.
 
-  Hydrate registers a dep on the collection. Per-item Reactions wire
-  lazily by default — on the first items mutation, `update` adopts the
-  server-rendered per-item DOM via `<!--sui-item:v1:KEY-->` markers
-  instead of rebuilding. When per-item content reads external state
-  (classified via each-content-classifier.js), hydrate adopts eagerly
-  so per-binding Reactions register their external deps now. Mismatched
-  keys fall through to a fresh render; subsequent mutations use the
-  normal reconcile path.
+  Hydrate adopts the server-rendered per-item DOM via
+  `<!--sui-item:v1:KEY-->` markers and wires per-item Reactions in place.
+  Same "register Reactions on hydrate" contract every other block honors:
+  per-item bindings that close over external state (a helper reading
+  `state.x`, a component method) need their Reactions live now, not
+  deferred to a future items mutation that may never come. Legacy SSR
+  output without markers falls back to nuke-and-rebuild on first update.
 
 */
 
@@ -646,38 +644,19 @@ const eachBlock = defineBlock({
   },
 
   hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
-    self.hasHydrated = true;
-
-    // Cheap path: per-item bindings only read iteration-local data
-    // (or pure framework helpers). Just register the items dep and
-    // defer per-item Reaction wiring to the first items mutation —
-    // `adoptServerItems` runs from `update` there.
-    //
-    // Eager path: any per-item binding (or elseContent binding) could
-    // read external state. Wire those Reactions now, otherwise the
-    // only chance is a future items-signal change that may never come
-    // — external mutations would silently lose reactivity.
-    if (isEachContentSelfContained(node)) {
-      lookupExpression(node.over);
-      return;
-    }
-
-    // resolveItems also registers the items dep via lookupExpression.
+    // resolveItems registers the items dep via lookupExpression.
     const { items, collectionType } = resolveItems(node, lookupExpression);
 
     if (items.length === 0) {
       if (node.elseContent) {
         // Server rendered the else branch into region.ownedNodes.
-        // Hydrate it in place so its bindings wire against external
-        // state. Push an isElse record so subsequent `update` calls
-        // recognize the else state and transition correctly.
+        // Hydrate it in place and push an isElse record so subsequent
+        // `update` calls recognize the else state and transition
+        // correctly. elseScope goes on region.childScopes so the next
+        // `region.clear()` disposes it (renderElse gets this via
+        // region.setContent; the hydrate path bypasses setContent
+        // because the DOM is already in place).
         const elseScope = scope.child();
-        // Register elseScope on the region so the next `region.clear()`
-        // (e.g. when items becomes non-empty) disposes it. renderElse
-        // gets this for free via `region.setContent`; the hydrate path
-        // never calls setContent (DOM is already in place) so we register
-        // explicitly. Without this, the scope leaks until the parent
-        // template scope disposes.
         region.childScopes.push(elseScope);
         hydrateInnerContent({
           ownedNodes: region.ownedNodes,
@@ -701,7 +680,6 @@ const eachBlock = defineBlock({
           isElse: true,
           propsSnapshot: null,
         });
-        self.hasHydrated = false;
       }
       return;
     }
@@ -718,11 +696,10 @@ const eachBlock = defineBlock({
       hydrateInnerContent,
       isSVG,
     });
-    if (adopted) {
-      // Adoption already wired per-item Reactions. Reset hasHydrated so
-      // `update` doesn't try to adopt again on the first signal change
-      // — it will reconcile against the items signal as normal.
-      self.hasHydrated = false;
+    if (!adopted) {
+      // Legacy SSR output without per-item markers — defer to `update`
+      // for the nuke-and-rebuild fallback on the first items mutation.
+      self.hasHydrated = true;
     }
   },
 
diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index fc50973b2..91e42ab0c 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -331,8 +331,8 @@ describe('SSR hydration — each loops', () => {
   // connectedCallback runs hydrate. Pre-fix, each.hydrate only registered a
   // dep on items and deferred per-item Reaction wiring to the first items
   // mutation — which never came when items arrived as a static prop. PR #175
-  // gates that lazy path on `isEachContentSelfContained`; this case (helper
-  // reads external state) takes the eager `adoptServerItems` branch instead.
+  // changes each.hydrate to call `adoptServerItems` immediately, wiring
+  // per-item Reactions in place against the server-rendered DOM.
   it('helper-call attribute inside each is reactive after hydration when items pre-populated', async () => {
     let helperCalls = 0;
     const el = await ssrAndHydrate({
diff --git a/packages/renderer/test/unit/each-content-classifier.test.js b/packages/renderer/test/unit/each-content-classifier.test.js
deleted file mode 100644
index bf58bf4e4..000000000
--- a/packages/renderer/test/unit/each-content-classifier.test.js
+++ /dev/null
@@ -1,240 +0,0 @@
-import { TemplateCompiler } from '@semantic-ui/compiler';
-import { describe, expect, it } from 'vitest';
-import { isEachContentSelfContained } from '../../src/engines/native/blocks/each-content-classifier.js';
-
-// Compile a template fragment and return the first each-block AST node.
-// All cases under test are wrapped in a single each so the AST shape
-// matches what the renderer hands to each.hydrate.
-function getEachNode(template) {
-  const compiler = new TemplateCompiler(template);
-  const ast = compiler.compile();
-  return ast.find(n => n.type === 'each');
-}
-
-describe('isEachContentSelfContained', () => {
-  /*******************************
-        Self-contained shapes
-  *******************************/
-
-  it('item-local property access stays lazy', () => {
-    const node = getEachNode('{#each item in items}<span>{item.name}</span>{/each}');
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('multiple item-local bindings stay lazy', () => {
-    const node = getEachNode(
-      '{#each item in items}<a data-id="{item.id}">{item.title}</a>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('iteration index reference stays lazy', () => {
-    const node = getEachNode('{#each item, i in items}<span>{i}:{item.name}</span>{/each}');
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('default index name (no explicit indexAs) stays lazy', () => {
-    const node = getEachNode('{#each item in items}<span>{index}</span>{/each}');
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('`this` inside an `as`-each forces eager (resolves to parent context)', () => {
-    // In `{#each item in items}`, `this` is NOT the item — the item is
-    // bound only to `item`. `this` reads parent data context, which is
-    // external state from the each's perspective.
-    const node = getEachNode('{#each item in items}<span>{this.x}</span>{/each}');
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('pure helper with item-local arg stays lazy', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{formatDate item.created "h:mm a"}</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('classMap with item-local object literal stays lazy', () => {
-    const node = getEachNode(
-      '{#each item in items}<span class="{classMap {active: item.active}}">x</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('nested each iterating an item-local array stays lazy', () => {
-    const node = getEachNode(
-      '{#each section in sections}{#each tag in section.tags}<span>{tag.label}</span>{/each}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('if/else inside each with item-local condition stays lazy', () => {
-    const node = getEachNode(
-      '{#each item in items}{#if item.active}<b>{item.name}</b>{else}<i>{item.name}</i>{/if}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  /*******************************
-        External-state shapes
-  *******************************/
-
-  it('helper closing over component method must wire eagerly', () => {
-    const node = getEachNode(
-      '{#each item in items}<a class="{classMap getItemClasses item}">x</a>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('expression reading non-iteration identifier must wire eagerly', () => {
-    const node = getEachNode(
-      '{#each item in items}<a class="{activeIf is item.id activeID}">x</a>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('zero-arg auto-invoked component method must wire eagerly', () => {
-    const node = getEachNode('{#each item in items}<span>{getStatus}</span>{/each}');
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('JS expression with external identifier must wire eagerly', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{item.size > maxSize ? "big" : "small"}</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('if condition reading external state forces eager wire', () => {
-    const node = getEachNode(
-      '{#each item in items}{#if isHighlighted item.id}<b>{item.name}</b>{/if}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('nested each with inner binding reading external state forces outer eager', () => {
-    const node = getEachNode(
-      '{#each section in sections}{#each item in section.items}<span>{getCls item}</span>{/each}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('snippet/template invocation inside each forces eager wire', () => {
-    const node = getEachNode(
-      '{#each item in items}{>card title=item.title}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  /*******************************
-        Conservative bails
-  *******************************/
-
-  it('no-`as` each bails to eager (item keys spread, indistinguishable)', () => {
-    const node = getEachNode('{#each items}<span>{name}</span>{/each}');
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('inner no-`as` each bails outer to eager', () => {
-    const node = getEachNode(
-      '{#each section in sections}{#each section.tags}<span>{label}</span>{/each}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('nested each with inner over-expression reading external forces outer eager', () => {
-    const node = getEachNode(
-      '{#each item in items}{#each tag in globalTags}<span>{tag}</span>{/each}{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  /*******************************
-        elseContent shapes
-  *******************************/
-
-  it('self-contained elseContent stays lazy', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{item.name}</span>{else}<p>none</p>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('elseContent reading external state forces eager wire', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{item.name}</span>{else}<p>{emptyMessage}</p>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('elseContent calling helper that reads external state forces eager wire', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{item.name}</span>{else}<p>{getEmptyText}</p>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('elseContent referencing iteration var forces eager (var not in :else scope)', () => {
-    // `foo` is the iteration var; inside :else it's NOT in scope, so a
-    // bare `{foo}` there reads the parent — the classifier must not
-    // treat it as iteration-local.
-    const node = getEachNode(
-      '{#each foo in items}<span>{foo.x}</span>{else}<p>{foo}</p>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  /*******************************
-        Ternary disambiguation
-  *******************************/
-
-  it('ternary then-value reading external state forces eager wire', () => {
-    const node = getEachNode(
-      '{#each item in items}<span class="{classMap {active: item.size ? externalThen : item.bar}}">x</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('ternary else-value reading external state forces eager wire', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{item.size > 0 ? item.size : externalDefault}</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  it('object key followed by item-local ternary stays lazy', () => {
-    const node = getEachNode(
-      '{#each item in items}<span class="{classMap {active: item.flag ? item.a : item.b}}">x</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  it('optional chaining is not a ternary', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{item.nested?.value}</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(true);
-  });
-
-  /*******************************
-        Template literal bail
-  *******************************/
-
-  it('template literal in expression bails to eager (interpolation may read external)', () => {
-    const node = getEachNode(
-      '{#each item in items}<span>{`prefix-${externalState}-suffix`}</span>{/each}',
-    );
-    expect(isEachContentSelfContained(node)).toBe(false);
-  });
-
-  /*******************************
-        Caching
-  *******************************/
-
-  it('returns the same verdict on repeated calls (cached on AST identity)', () => {
-    const node = getEachNode('{#each item in items}<span>{item.name}</span>{/each}');
-    const first = isEachContentSelfContained(node);
-    const second = isEachContentSelfContained(node);
-    expect(first).toBe(second);
-    expect(first).toBe(true);
-  });
-});

From 1dfc4f0751a1ff5cdd895fd36470c70282f7d503 Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 00:51:12 -0400
Subject: [PATCH 10/16] Refactor: Remove dead adoptServerItems retry from
 each.update
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

After the classifier removal, `self.hasHydrated = true` only happens
when `each.hydrate`'s `adoptServerItems` already failed (legacy SSR
without per-item markers). Server markers don't appear retroactively,
so the retry in `update` would always fail and fall through to
nuke-and-rebuild — making the entire retry block dead code.

Inline the legacy fallback directly: clear region, drop records,
proceed to fresh reconcile.

Also refresh two stale comments the classifier removal exposed:
- adoptServerItems header described its old timing ("first-data-change
  adoption path") — now describes what the function does.
- elseContent regression test comment referenced "each.hydrate's eager
  path" — classifier-era concept that no longer exists.
---
 .../src/engines/native/blocks/each.js         | 36 ++++++-------------
 .../test/browser/ssr-hydration.test.js        |  4 +--
 2 files changed, 12 insertions(+), 28 deletions(-)

diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index 333901ae5..cd14f2e71 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -497,11 +497,12 @@ function extractServerItemGroups(ownedNodes) {
   return groups;
 }
 
-// First-data-change adoption path. Tries to reuse server-rendered per-
-// item DOM by matching item keys, wiring per-item reactivity against the
-// existing nodes via hydrateInnerContent. Returns true on success, false
-// if no server markers are present (legacy SSR output — caller should
-// fall through to a full rebuild).
+// Reuses server-rendered per-item DOM by matching item keys, wiring
+// per-item reactivity against the existing nodes via hydrateInnerContent.
+// Items with no matching server group render fresh; server groups whose
+// keys aren't claimed get disposed. Returns true on success, false if no
+// server markers are present (legacy SSR — caller falls back to a full
+// rebuild).
 function adoptServerItems({
   self,
   items,
@@ -707,28 +708,11 @@ const eachBlock = defineBlock({
     const { items, collectionType } = resolveItems(node, lookupExpression);
 
     if (self.hasHydrated) {
+      // hasHydrated is set in hydrate() only when adoptServerItems
+      // already tried and failed (legacy SSR without per-item markers).
+      // Markers don't appear retroactively, so retrying would just fail
+      // again — fall through to nuke-and-rebuild via the path below.
       self.hasHydrated = false;
-      if (items.length > 0) {
-        // Try to adopt server-rendered per-item DOM. If the server
-        // emitted sui-item:v1:KEY markers, items whose keys match reuse
-        // their DOM; others render fresh. Subsequent mutations flow
-        // through the standard reconcile path below.
-        const adopted = adoptServerItems({
-          self,
-          items,
-          collectionType,
-          node,
-          data,
-          scope,
-          region,
-          renderAST,
-          hydrateInnerContent,
-          isSVG,
-        });
-        if (adopted) { return; }
-      }
-      // No per-item markers (legacy SSR output) or empty items — fall
-      // back to nuke-and-rebuild via the reconcile path below.
       region.clear();
       self.records.length = 0;
     }
diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index 91e42ab0c..25b66ded6 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -294,8 +294,8 @@ describe('SSR hydration — each loops', () => {
   });
 
   // Regression: empty items + elseContent reading external state lost
-  // reactivity after hydrate. each.hydrate's eager path early-returned on
-  // items.length === 0 without hydrating the elseContent's bindings.
+  // reactivity after hydrate. The empty-items branch in each.hydrate
+  // returned without hydrating elseContent's bindings.
   it('elseContent bindings are reactive after hydration when items is empty', async () => {
     const el = await ssrAndHydrate({
       template: '{#each item in items}<li>{item}</li>{else}<p>{emptyMessage}</p>{/each}',

From b88f762f65831960e99df0f1c16d0f463cd729fd Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 00:55:49 -0400
Subject: [PATCH 11/16] Refactor: Drop legacy-SSR fallback in each.hydrate
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Pre-1.0, no tagged release has shipped SSR. There's no scenario where
a client of this version hydrates server output from an older version.
The server always emits `<!--sui-item:v1:KEY-->` markers for non-empty
items (server.js:422); hydrate can trust them.

Changes:
- adoptServerItems no longer returns boolean. Throws on missing markers
  (build/version mismatch — surface loudly, not silently fall through).
- each.hydrate drops the `if (!adopted) self.hasHydrated = true` line.
- each.update drops the entire `if (self.hasHydrated)` legacy-rebuild
  block.
- `hasHydrated` field removed from create() initial state.

Skill doc and plan archive updated.
---
 .../archive/hydrate-each-external-state.md    |  2 +-
 ai/skills/authoring/ssr-hydration.md          |  5 ++-
 .../src/engines/native/blocks/each.js         | 33 +++++--------------
 3 files changed, 12 insertions(+), 28 deletions(-)

diff --git a/ai/plans/archive/hydrate-each-external-state.md b/ai/plans/archive/hydrate-each-external-state.md
index 5951919b9..a352c72b1 100644
--- a/ai/plans/archive/hydrate-each-external-state.md
+++ b/ai/plans/archive/hydrate-each-external-state.md
@@ -127,7 +127,7 @@ hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerCo
     return;
   }
   const adopted = adoptServerItems({ ... });
-  if (!adopted) { self.hasHydrated = true; }   // legacy SSR fallback
+  adoptServerItems({ ... });
 }
 ```
 
diff --git a/ai/skills/authoring/ssr-hydration.md b/ai/skills/authoring/ssr-hydration.md
index eec124a74..14721dab0 100644
--- a/ai/skills/authoring/ssr-hydration.md
+++ b/ai/skills/authoring/ssr-hydration.md
@@ -400,8 +400,7 @@ hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerCo
     if (node.elseContent) { /* hydrate elseContent in place + push isElse record */ }
     return;
   }
-  const adopted = adoptServerItems({ ... });
-  if (!adopted) { self.hasHydrated = true; }   // legacy SSR fallback (no per-item markers)
+  adoptServerItems({ ... });
 }
 ```
 
@@ -549,7 +548,7 @@ EACH BLOCK HYDRATION
   each.hydrate calls adoptServerItems immediately (canonical eager).
   Per-item Reactions wire in place against server DOM via item markers.
   Empty items + elseContent -> hydrate elseContent in place.
-  Legacy SSR (no markers) -> set hasHydrated for nuke-rebuild fallback.
+  Server unconditionally emits per-item markers; missing-markers throws.
 
 TESTING / BENCHING TRAPS (silent failures)
   innerHTML doesn't process DSD          -> use setHTMLUnsafe
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index cd14f2e71..be2097fb8 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -20,8 +20,7 @@ import { registerBlock } from './registry.js';
   Same "register Reactions on hydrate" contract every other block honors:
   per-item bindings that close over external state (a helper reading
   `state.x`, a component method) need their Reactions live now, not
-  deferred to a future items mutation that may never come. Legacy SSR
-  output without markers falls back to nuke-and-rebuild on first update.
+  deferred to a future items mutation that may never come.
 
 */
 
@@ -500,9 +499,9 @@ function extractServerItemGroups(ownedNodes) {
 // Reuses server-rendered per-item DOM by matching item keys, wiring
 // per-item reactivity against the existing nodes via hydrateInnerContent.
 // Items with no matching server group render fresh; server groups whose
-// keys aren't claimed get disposed. Returns true on success, false if no
-// server markers are present (legacy SSR — caller falls back to a full
-// rebuild).
+// keys aren't claimed get disposed. The server unconditionally emits
+// `<!--sui-item:v1:KEY-->` markers for non-empty items (server.js); a
+// missing-markers shape here means a build/version mismatch.
 function adoptServerItems({
   self,
   items,
@@ -516,7 +515,9 @@ function adoptServerItems({
   isSVG,
 }) {
   const serverGroups = extractServerItemGroups(region.ownedNodes);
-  if (serverGroups.length === 0) { return false; }
+  if (serverGroups.length === 0) {
+    throw new Error('each.hydrate: server-rendered per-item markers missing — server/client renderer version mismatch');
+  }
 
   const serverByKey = new Map();
   for (const g of serverGroups) { serverByKey.set(g.key, g); }
@@ -613,14 +614,13 @@ function adoptServerItems({
   }
 
   self.records = newRecords;
-  return true;
 }
 
 const eachBlock = defineBlock({
   name: 'each',
 
   create() {
-    return { records: [], hasHydrated: false };
+    return { records: [] };
   },
 
   render({ node, data, scope, region, renderAST, lookupExpression, self, isSVG }) {
@@ -685,7 +685,7 @@ const eachBlock = defineBlock({
       return;
     }
 
-    const adopted = adoptServerItems({
+    adoptServerItems({
       self,
       items,
       collectionType,
@@ -697,26 +697,11 @@ const eachBlock = defineBlock({
       hydrateInnerContent,
       isSVG,
     });
-    if (!adopted) {
-      // Legacy SSR output without per-item markers — defer to `update`
-      // for the nuke-and-rebuild fallback on the first items mutation.
-      self.hasHydrated = true;
-    }
   },
 
   update({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
     const { items, collectionType } = resolveItems(node, lookupExpression);
 
-    if (self.hasHydrated) {
-      // hasHydrated is set in hydrate() only when adoptServerItems
-      // already tried and failed (legacy SSR without per-item markers).
-      // Markers don't appear retroactively, so retrying would just fail
-      // again — fall through to nuke-and-rebuild via the path below.
-      self.hasHydrated = false;
-      region.clear();
-      self.records.length = 0;
-    }
-
     const showingElse = self.records.length === 1 && self.records[0].isElse;
 
     // Fast-path: empty items. Skip reconcile (no keyIndex Map allocation,

From a08d8ba93280c4487e9826a1f7de6461798d7cf3 Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 01:07:28 -0400
Subject: [PATCH 12/16] Refactor: Drop legacy ref-DOM hydrate path from
 renderer
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Pre-1.0, no tagged release has shipped, so there's no scenario where
the client hydrates SSR output that lacks `data-sui-bind`. The fast
path is the only path.

Removed:
- The 70-line parallel ref-DOM walker in `hydrateAttributes`
- The `refRoot` lazy getter on the buildString cache and its supporting
  scaffolding
- The `ATTR_MARKER_PATTERN` constant and `ATTR_MARKER_SUFFIX` import
  (only the walker referenced them)
- The `ast` parameter threaded through `hydrateMarkers` and
  `hydrateInnerContent` (only the walker needed it)
- `hydrateAttributesViaDataBind` renamed to plain `hydrateAttributes`
  since the dispatcher is gone

Two follow-on simplifications:
- Inlined `parseAttributeParts` instance wrapper at its sole remaining
  caller (`bindMarkers`)
- Dropped the `hasAttrEntries` pre-walk gate in `hydrateMarkers` —
  `hydrateAttributes` is a no-op when no element carries the marker

Net -127 / +14 lines. All 921 tests pass.
---
 .../renderer/src/engines/native/renderer.js   | 141 ++----------------
 1 file changed, 14 insertions(+), 127 deletions(-)

diff --git a/packages/renderer/src/engines/native/renderer.js b/packages/renderer/src/engines/native/renderer.js
index 9ba7d6c34..10a4c950c 100644
--- a/packages/renderer/src/engines/native/renderer.js
+++ b/packages/renderer/src/engines/native/renderer.js
@@ -3,7 +3,6 @@ import { assignInPlace, createCache, filterObject, inArray } from '@semantic-ui/
 
 import {
   ATTR_MARKER_PREFIX,
-  ATTR_MARKER_SUFFIX,
   BLOCK_MARKER,
   buildHTMLString as buildHTMLStringPure,
   COMMENT_MARKER,
@@ -27,10 +26,6 @@ import './blocks/index.js';
 // PreparedTemplate cache — parse once, cloneNode per instance
 const templateCache = createCache({ maxSize: 1000, eviction: 'flush' });
 
-// Source pattern for attribute markers — fresh regex per use (`/g` regexes
-// carry mutable lastIndex; sharing one across calls is a footgun).
-const ATTR_MARKER_PATTERN = `${ATTR_MARKER_PREFIX}(\\d+)${ATTR_MARKER_SUFFIX}`;
-
 // Parse trailing metadata from a closing block marker into serverMeta.
 // Reserved suffixes (after the version segment):
 //   bN  → branchIndex (which branch the {#if}/{:elseif}/{:else} server picked)
@@ -43,10 +38,8 @@ function parseServerMeta(commentData, target) {
   }
 }
 
-// AST → { htmlString, entries, refRoot } cache. Keyed on the AST array,
-// which is immutable after compile, so entries never stale and GC
-// follows naturally. Each entry also holds a lazy `refRoot` — the
-// parsed reference <template>.content for the legacy hydration walker.
+// AST → { htmlString, entries } cache. Keyed on the AST array, which is
+// immutable after compile, so entries never stale and GC follows naturally.
 const buildStringCache = new WeakMap();
 
 function cachedBuildHTMLString(ast, options) {
@@ -57,25 +50,7 @@ function cachedBuildHTMLString(ast, options) {
   }
   const slot = options.isSVG ? 'svg' : 'html';
   if (entry[slot] === null) {
-    const built = buildHTMLStringPure(ast, options);
-    // refRoot is a lazy getter — the data-sui-bind fast path in
-    // hydrateAttributes never reads it, so we avoid the per-instance
-    // `template.innerHTML = htmlString` parse. Only the legacy
-    // reference-DOM fallback (templates without data-sui-bind) touches it.
-    let refRoot = null;
-    entry[slot] = {
-      htmlString: built.htmlString,
-      entries: built.entries,
-      snippets: built.snippets,
-      get refRoot() {
-        if (refRoot === null) {
-          const refTemplate = document.createElement('template');
-          refTemplate.innerHTML = built.htmlString;
-          refRoot = refTemplate.content;
-        }
-        return refRoot;
-      },
-    };
+    entry[slot] = buildHTMLStringPure(ast, options);
   }
   return entry[slot];
 }
@@ -231,14 +206,6 @@ export class Renderer {
       Phase 3: Marker Binding
   *******************************/
 
-  // Parse an attribute value containing marker tokens into static/dynamic parts.
-  // Thin wrapper around the shared helper in build-html-string.js — preserved
-  // as an instance method so existing call sites (bindMarkers / ref-DOM
-  // fallback in hydrateAttributes) keep the same shape.
-  parseAttributeParts(attrValue) {
-    return parseAttributePartsFn(attrValue);
-  }
-
   // Attribute binding — delegates to reactive-data.js. See that module for
   // the dispatch on entry.classification.type (property / event / boolean
   // / ifDefined / interpolated / single-expression). `skipFirstWrite` is
@@ -272,7 +239,7 @@ export class Renderer {
           }
         }
         for (const { name: attrName, value: attrValue } of attrsToProcess) {
-          const { parts, markerIDs } = this.parseAttributeParts(attrValue);
+          const { parts, markerIDs } = parseAttributePartsFn(attrValue);
           for (const id of markerIDs) { processedAttrIDs.add(id); }
           this.bindAttributeExpression(element, attrName, parts, entries, data, scope);
         }
@@ -381,21 +348,13 @@ export class Renderer {
         Hydration
   *******************************/
 
-  hydrateMarkers(root, entries, data, scope, { ast } = {}) {
+  hydrateMarkers(root, entries, data, scope) {
     if (entries.length === 0) { return; }
 
-    // Classify entries
-    const attrEntries = [];
-    for (const entry of entries) {
-      if (entry.type === 'expression' && entry.classification?.insideTag) {
-        attrEntries.push(entry);
-      }
-    }
-
-    // Pass 1: Hydrate attribute bindings via reference DOM matching
-    if (attrEntries.length > 0) {
-      this.hydrateAttributes(root, entries, data, scope, ast);
-    }
+    // Pass 1: walk elements with data-sui-bind, wire attribute Reactions.
+    // hydrateAttributes is a no-op when no element carries the marker, so
+    // no pre-classification gate is needed.
+    this.hydrateAttributes(root, entries, data, scope);
 
     // Pass 2: Walk comments for text and block markers — top level only.
     // Inner markers (inside block pairs) are handled recursively by block handlers.
@@ -447,83 +406,13 @@ export class Renderer {
     }
   }
 
-  hydrateAttributes(root, entries, data, scope, ast) {
-    // Fast path — server stamps data-sui-bind on every element with
-    // dynamic bindings. Walk elements once, look up
-    // entries[id].attributeBinding for parts + classification, wire
-    // Reactions directly. No reference DOM, no parallel walker.
-    if (root.querySelector && root.querySelector(`[${DATA_SUI_BIND}]`)) {
-      this.hydrateAttributesViaDataBind(root, entries, data, scope);
-      return;
-    }
-
-    // Legacy fallback — reference DOM parallel walk for older SSR output
-    // without data-sui-bind. Reference DOM is cached alongside the
-    // htmlString; the parallel TreeWalker only reads attribute names off
-    // refEls, so sharing the cached fragment is safe.
-    const { refRoot } = cachedBuildHTMLString(ast || this.ast, { snippets: this.snippets });
-
-    // Build a set of real DOM elements owned by block regions so we can skip
-    // them during the parallel walk. Block directives (each, if, etc.) are
-    // single comments in the reference DOM but expand to N elements in the
-    // real DOM — skipping them keeps the walkers aligned.
-    const blockOwnedElements = new Set();
-    const blockWalker = document.createTreeWalker(root, NodeFilter.SHOW_COMMENT);
-    let blockComment;
-    while ((blockComment = blockWalker.nextNode())) {
-      if (!blockComment.data.startsWith(BLOCK_MARKER)) { continue; }
-      let next = blockComment.nextSibling;
-      let depth = 1;
-      while (next && depth > 0) {
-        if (next.nodeType === Node.COMMENT_NODE) {
-          if (next.data.startsWith(BLOCK_MARKER)) { depth++; }
-          else if (next.data.startsWith('/sui-block:')) { depth--; }
-        }
-        if (depth > 0 && next.nodeType === Node.ELEMENT_NODE) {
-          // Mark this element and all its descendants
-          const innerWalker = document.createTreeWalker(next, NodeFilter.SHOW_ELEMENT);
-          blockOwnedElements.add(next);
-          let inner;
-          while ((inner = innerWalker.nextNode())) { blockOwnedElements.add(inner); }
-        }
-        next = next.nextSibling;
-      }
-    }
-
-    // Walk both trees in parallel (element-only), skipping block-owned real elements
-    const refWalker = document.createTreeWalker(refRoot, NodeFilter.SHOW_ELEMENT);
-    const realWalker = document.createTreeWalker(root, NodeFilter.SHOW_ELEMENT, {
-      acceptNode: (node) =>
-        blockOwnedElements.has(node)
-          ? NodeFilter.FILTER_REJECT
-          : NodeFilter.FILTER_ACCEPT,
-    });
-
-    let refEl, realEl;
-    while ((refEl = refWalker.nextNode()) && (realEl = realWalker.nextNode())) {
-      const element = realEl;
-      const attrsToProcess = [];
-      for (let i = 0; i < refEl.attributes.length; i++) {
-        const attr = refEl.attributes[i];
-        if (attr.value.includes(ATTR_MARKER_PREFIX)) {
-          attrsToProcess.push({ name: attr.name, value: attr.value });
-        }
-      }
-
-      for (const { name: attrName, value: attrValue } of attrsToProcess) {
-        const { parts } = this.parseAttributeParts(attrValue);
-        this.bindAttributeExpression(element, attrName, parts, entries, data, scope, { skipFirstWrite: true });
-      }
-    }
-  }
-
   // Walk SHOW_ELEMENT | SHOW_COMMENT once, process `data-sui-bind` on
   // elements at block-depth 0, and let block hydrate hooks recurse into
   // their own contents via hydrateInnerContent. Depth is tracked inline
-  // from the block markers we encounter; no reference DOM, no separate
-  // owned-element set. The data-sui-bind attribute itself is stripped by
-  // the post-hydration cleanup pass (base.js removeMarkers).
-  hydrateAttributesViaDataBind(root, entries, data, scope) {
+  // from the block markers we encounter. The data-sui-bind attribute
+  // itself is stripped by the post-hydration cleanup pass (base.js
+  // removeMarkers).
+  hydrateAttributes(root, entries, data, scope) {
     const walker = document.createTreeWalker(
       root,
       NodeFilter.SHOW_ELEMENT | NodeFilter.SHOW_COMMENT,
@@ -623,9 +512,7 @@ export class Renderer {
     }
 
     // Recursively hydrate inner markers with the sub-AST's entries.
-    // Pass contentAST so attribute hydration builds the reference DOM
-    // from the correct AST (not the top-level component AST).
-    this.hydrateMarkers(container, entries, data, scope, { ast: contentAST });
+    this.hydrateMarkers(container, entries, data, scope);
 
     // Update ownedNodes with the hydrated content (comments may have been removed)
     ownedNodes.length = 0;

From 93ca6ecdf108bd68a691b81cc2d2e43baed0005c Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 08:51:04 -0400
Subject: [PATCH 13/16] =?UTF-8?q?Refactor:=20Round=207=20review=20?=
 =?UTF-8?q?=E2=80=94=20refresh=20stale=20post-rip-out=20comments?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Five small comment touchups surfaced by the round-7 Opus review pass.
Code unchanged; just the comment surface catching up to the deletions
in a08d8ba93 and earlier.

- renderer.js buildStringCache header described the entry shape as
  `{ htmlString, entries }`; the actual shape post-refRoot-removal
  is `{ html, svg }` (HTML + SVG buildHTMLString variants).
- each.js block-level docstring used "deferred to a future items
  mutation that may never come" as motivation — defines-against-a-
  ghost now that the lazy/classifier path is gone. Trimmed.
- each.js adoptServerItems comment referenced "the data-sui-bind
  fast path" — the legacy walker is gone, so there's no slow path
  to be fast against. Just describe what hydrateMarkers does.
- renderer.js hydrateMarkers comment used "pre-classification gate"
  to refer to the dropped `hasAttrEntries` pre-walk — "classification"
  overlaps awkwardly with the deleted each-content classifier
  concept. Renamed to "pre-walk gate".
- Plan archive `Final architecture` pseudocode had a duplicate
  `adoptServerItems` call — editing artifact from when I rewrote
  the snippet during the rip-out.
---
 ai/plans/archive/hydrate-each-external-state.md     |  1 -
 packages/renderer/src/engines/native/blocks/each.js | 13 +++++--------
 packages/renderer/src/engines/native/renderer.js    |  7 ++++---
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/ai/plans/archive/hydrate-each-external-state.md b/ai/plans/archive/hydrate-each-external-state.md
index a352c72b1..bf3ce045f 100644
--- a/ai/plans/archive/hydrate-each-external-state.md
+++ b/ai/plans/archive/hydrate-each-external-state.md
@@ -126,7 +126,6 @@ hydrate({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerCo
     if (node.elseContent) { /* hydrate elseContent in place + push isElse record */ }
     return;
   }
-  const adopted = adoptServerItems({ ... });
   adoptServerItems({ ... });
 }
 ```
diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index be2097fb8..63f1fd635 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -16,11 +16,9 @@ import { registerBlock } from './registry.js';
   taken at item-creation time.
 
   Hydrate adopts the server-rendered per-item DOM via
-  `<!--sui-item:v1:KEY-->` markers and wires per-item Reactions in place.
-  Same "register Reactions on hydrate" contract every other block honors:
-  per-item bindings that close over external state (a helper reading
-  `state.x`, a component method) need their Reactions live now, not
-  deferred to a future items mutation that may never come.
+  `<!--sui-item:v1:KEY-->` markers and wires per-item Reactions in
+  place — the same "register Reactions on hydrate" contract every
+  other block honors.
 
 */
 
@@ -540,9 +538,8 @@ function adoptServerItems({
 
       // Wire per-item reactivity on the existing DOM. hydrateInnerContent
       // moves the nodes into a temporary fragment, walks with
-      // hydrateMarkers (which honors the data-sui-bind fast path against
-      // the block's inner entries), and leaves the hydrated nodes in
-      // `mutableNodes`.
+      // hydrateMarkers against the block's inner entries, and leaves the
+      // hydrated nodes in `mutableNodes`.
       const mutableNodes = [...serverGroup.nodes];
       hydrateInnerContent({
         ownedNodes: mutableNodes,
diff --git a/packages/renderer/src/engines/native/renderer.js b/packages/renderer/src/engines/native/renderer.js
index 10a4c950c..39bd691a3 100644
--- a/packages/renderer/src/engines/native/renderer.js
+++ b/packages/renderer/src/engines/native/renderer.js
@@ -38,8 +38,9 @@ function parseServerMeta(commentData, target) {
   }
 }
 
-// AST → { htmlString, entries } cache. Keyed on the AST array, which is
-// immutable after compile, so entries never stale and GC follows naturally.
+// AST → { html, svg } cache, where each slot holds the buildHTMLString
+// result for that namespace. Keyed on the AST array (immutable after
+// compile), so entries never stale and GC follows naturally.
 const buildStringCache = new WeakMap();
 
 function cachedBuildHTMLString(ast, options) {
@@ -353,7 +354,7 @@ export class Renderer {
 
     // Pass 1: walk elements with data-sui-bind, wire attribute Reactions.
     // hydrateAttributes is a no-op when no element carries the marker, so
-    // no pre-classification gate is needed.
+    // no pre-walk gate is needed.
     this.hydrateAttributes(root, entries, data, scope);
 
     // Pass 2: Walk comments for text and block markers — top level only.

From d92711b4f810f4bd688196a916c03e1d2a7b14e3 Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 09:02:09 -0400
Subject: [PATCH 14/16] Refactor: Drop dead hydrateInnerContent destructure
 from each.update

Leftover from when update could call adoptServerItems on first
mutation (the legacy-fallback retry ripped out in 1dfc4f075). The
parameter was kept in the destructure but never referenced in the
body. Surfaced by the round-8 review pass.
---
 packages/renderer/src/engines/native/blocks/each.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/packages/renderer/src/engines/native/blocks/each.js b/packages/renderer/src/engines/native/blocks/each.js
index 63f1fd635..7b7d3fef6 100644
--- a/packages/renderer/src/engines/native/blocks/each.js
+++ b/packages/renderer/src/engines/native/blocks/each.js
@@ -696,7 +696,7 @@ const eachBlock = defineBlock({
     });
   },
 
-  update({ node, data, scope, region, renderAST, lookupExpression, hydrateInnerContent, self, isSVG }) {
+  update({ node, data, scope, region, renderAST, lookupExpression, self, isSVG }) {
     const { items, collectionType } = resolveItems(node, lookupExpression);
 
     const showingElse = self.records.length === 1 && self.records[0].isElse;

From d77a5559d4d6a126615033fdf6f424ba22820e22 Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 09:27:18 -0400
Subject: [PATCH 15/16] =?UTF-8?q?Test:=20Pin=20elseScope=20dispose=20on=20?=
 =?UTF-8?q?hydrated=20each=E2=86=92else=E2=86=92items=20transition?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Falsifiable regression coverage for `region.childScopes.push(elseScope)`
in each.hydrate's empty-items + elseContent branch. Without it, the
elseScope is orphaned at transition time — the elseContent's bindings
keep their subscriptions on whatever signals they read until the
isConnected guard self-stops them on the next stale fire (a bounded
leak invisible to behavioral assertions because the guard short-
circuits before the callback runs).

Strategy: control-baseline subscriber-count comparison. A control
component renders with items already populated (elseContent never
runs, baseline = framework-internal subscribers only). A second
component renders empty, picks up extra subscribers per elseContent
binding, then transitions to non-empty. After the transition, the
subscriber count must return to the control baseline — equality
proves no orphans remain. Three bindings on `emptyLabel` in the
elseContent give a 1-vs-N delta robust to framework-internal counts.

Verified empirically:
- With the line: count returns to baseline → test passes
- Without the line: count stays elevated → test fails
---
 .../test/browser/ssr-hydration.test.js        | 48 +++++++++++++++++++
 1 file changed, 48 insertions(+)

diff --git a/packages/renderer/test/browser/ssr-hydration.test.js b/packages/renderer/test/browser/ssr-hydration.test.js
index 25b66ded6..d529c2b02 100644
--- a/packages/renderer/test/browser/ssr-hydration.test.js
+++ b/packages/renderer/test/browser/ssr-hydration.test.js
@@ -316,6 +316,54 @@ describe('SSR hydration — each loops', () => {
     expect(shadowHTML(el)).toBe('<p>Still empty</p>');
   });
 
+  // Regression: the hydrate path for an empty {#each ... else} created an
+  // elseScope but did not register it on region.childScopes. When items
+  // transitioned empty → non-empty, region.clear() walked an empty scope
+  // list and the elseContent's bindings stayed subscribed to whatever
+  // signals they read. The leak is bounded — the renderer's isConnected
+  // guard self-stops the orphan on its next fire — but until then every
+  // elseContent binding is a ghost subscriber on its read signals.
+  //
+  // Test shape: a control component renders with items already populated
+  // (elseContent never runs, so emptyLabel carries only the framework's
+  // baseline subscribers). The second component renders empty, picks up
+  // one extra subscriber per elseContent binding, then transitions to
+  // non-empty. After the transition, the subscriber count must return
+  // to the control baseline. Three bindings in elseContent give a clean
+  // 1-vs-N delta that doesn't pin any specific framework-internal count.
+  it('hydrated each→else transition disposes elseContent subscribers', async () => {
+    const template = '{#each item in items}<li>{item}</li>{else}'
+      + '<p class="{emptyLabel}">{emptyLabel} ({emptyLabel})</p>'
+      + '{/each}';
+
+    const control = await ssrAndHydrate({
+      template,
+      defaultState: { items: ['x'], emptyLabel: 'None' },
+    });
+    const baseline = control.template.state.emptyLabel.dependency.subscribers.size;
+
+    const el = await ssrAndHydrate({
+      template,
+      defaultState: { items: [], emptyLabel: 'None' },
+    });
+
+    // Sanity: server emitted else branch and elseContent bindings did
+    // subscribe — without the elseScope reactions even existing, the
+    // delta below would be vacuous.
+    expect(shadowHTML(el)).toBe('<p class="None">None (None)</p>');
+    expect(el.template.state.emptyLabel.dependency.subscribers.size).toBeGreaterThan(baseline);
+
+    const updated = $(el).onNext('updated');
+    el.template.state.items.push('x');
+    await updated;
+
+    expect(shadowHTML(el)).toBe('<li>x</li>');
+    // Pin: the empty→non-empty transition must dispose the elseScope so
+    // its bindings unsubscribe synchronously. Equality with the control
+    // baseline proves no orphan reactions remain on emptyLabel.
+    expect(el.template.state.emptyLabel.dependency.subscribers.size).toBe(baseline);
+  });
+
   it('hydrates object iteration', async () => {
     const el = await ssrAndHydrate({
       template: '{#each val, key in colors}<span>{key}={val}</span>{/each}',

From a6cd3eaaf6b7167e50b2ec57e7107840f2056f9d Mon Sep 17 00:00:00 2001
From: Jack Lukic <jacklukic@gmail.com>
Date: Mon, 4 May 2026 10:39:40 -0400
Subject: [PATCH 16/16] Harness: Add PR-authoring audit passes

Encodes patterns surfaced during the PR #175 author-review iteration.
Adds punctuation pass (em-dashes, colons, semicolons), word target,
voice/tense consistency, bug-PR discovery framing, risk score anchoring.
---
 .../contributing/author-pull-requests.md      | 36 ++++++++++++++-----
 1 file changed, 28 insertions(+), 8 deletions(-)

diff --git a/ai/skills/contributing/author-pull-requests.md b/ai/skills/contributing/author-pull-requests.md
index 491e706a0..9ac16bad7 100644
--- a/ai/skills/contributing/author-pull-requests.md
+++ b/ai/skills/contributing/author-pull-requests.md
@@ -116,6 +116,8 @@ Failure modes: [bulleted list — only when score ≥ 5 or blast radius is non-o
 - [Deviations from standard only. Skip "rerun tests" / "CI passes" — those are assumed.]
 ```
 
+**Word target.** Medium-tier bodies usually land 80–150 words. Past 200 is a sign you're restating the diff. After drafting a body that feels complete, expect to cut roughly half — the AI default is about twice the length humans actually write.
+
 ### Large tier
 
 Same as Medium, plus:
@@ -188,6 +190,8 @@ Bullets should be noun phrases or short verb phrases. Most under 10 words. Full
 ✅ "Remove root profiling/screenshot artifacts"
 ```
 
+**Pick one voice across all bullets.** Don't mix imperative ("Remove X"), declarative state ("X removed"), and active past with for-clause ("Dropped X for Y"). Mixed tenses read AI-shaped — no human drifts mid-list. Active past with "for X" is punchy and intent-bearing for bug fixes and refactors.
+
 ---
 
 ## Selectivity — don't bullet everything
@@ -265,12 +269,16 @@ Authors who polish suspicious bullets into smooth prose ship subtle bugs. Review
 
 ## Risk score is routing metadata, not a confidence performance
 
-When you write a Risk score, you're telling the reviewer (or `/ultrareview`) **how much attention to spend**. Be honest:
+The Risk score is the chance of regression from this changeset, anchored to surface area — how many users sit on the affected code path. Don't catastrophize. Don't pad to look responsible. Don't deflate to look confident.
 
-- 2/10 Medium: "review this fast — I'm sure"
-- 7/10 Large: "slow down — look at the failure modes I named"
+| Score | When to use |
+|---|---|
+| **0/10** | Tests, harness, docs only. No public code modified. Always 0 in this case. |
+| **1–4** | Public code touched, but usage estimates suggest the path is rarely hit. |
+| **5–6** | Coin toss whether a given user is on this code path. |
+| **7–10** | Common code path. Effectively all users sit on it. |
 
-Don't pad the number to look responsible; don't deflate it to look confident. A correct low score is more useful than a high one. The score is a signal, not a posture.
+**Risk section is shorter than other sections.** It doesn't list each failure verbatim. It points to where to look for downstream effects. "This modifies the `Template` class which has downstream implications for the renderer" is enough — the reviewer chases the thread. A failure-modes list goes in only when the surface is genuinely non-obvious (see below).
 
 ## Failure modes are humility checks, not breaking-change rehash
 
@@ -430,6 +438,14 @@ Lead the framing sentence with `Implements [plan](permalink)`. Bullets describe
 
 Title at concept level (the *destination concept*, not the literal new path). Bullets describe the move at the role level, not the file level.
 
+### Bug PRs
+
+Lead the framing with how the bug surfaced — what someone was doing when they hit it. The compact pattern is three beats. Discovered while [X], caused by [Y], so [Z]. Humans usually remember *where* they hit a bug. AI prose skips the discovery and starts at the technical formulation.
+
+| ❌ Abstract first | ✅ Discovery first |
+|---|---|
+| Per-item bindings inside each blocks lost reactivity to external state when items came from static props. | This bug was discovered while debugging hydration issues with `inpage-menu` in docs. Per-item bindings inside each blocks lost reactivity to external state when items came from static props. |
+
 ---
 
 ## After drafting, do this checklist
@@ -444,10 +460,14 @@ In order:
 6. **Cut justifications.** Search bullets for "now that", "since", "to satisfy", "because", "that doesn't" — usually defensive padding.
 7. **Cut scaffolding bullets.** If a bullet states the obvious consequence of bullets above it ("update path references to match"), drop it.
 8. **Trim framing sentence tails.** "so that…", "plus the X that follows", "in order to…" — usually padding.
-9. **Search for AI tells.** Look for: *verified, ensured, considered, note that, important to flag, in summary, this PR introduces, all tests pass, fully tested*.
-10. **Check tier appropriateness.** Did you reach for Medium/Large machinery on a Small PR? If yes, drop them.
-11. **Voice check — read each bullet aloud.** Imagine you're texting it to the reviewer. Does it sound like a developer in a hurry, or like a press release? If the latter, rewrite. Specific tells: bullets that start with `Let X...`/`Stop Y...`/`Wire Z...` (verb-first mechanism), bullets that mention line numbers or internal field names, bullets longer than the corresponding commit message subject.
-12. **Honest question:** if a colleague wrote this PR and pinged you, would the body sound like them, or like a corporate document? If the latter, you're still in AI-prose mode.
+9. **Search for AI tells (words).** Look for: *verified, ensured, considered, note that, important to flag, in summary, this PR introduces, all tests pass, fully tested*.
+10. **Search for AI tells (punctuation).** Three patterns. Single instances are fine. Clusters or stylized uses are tells.
+    - **Paired em-dashes as parentheses** (`text — like this — text`). Single em-dashes are fine. Pairs used as brackets are AI-shaped — use real parens or split into two sentences.
+    - **Explanatory colons** (`X was the canonical repro: helpers reading...`). Almost always splits cleanly into two sentences. The colon makes prose read like a writeup.
+    - **Semicolon clusters.** Three or more in one body is a tell. Most rewrite to periods.
+11. **Check tier appropriateness.** Did you reach for Medium/Large machinery on a Small PR? If yes, drop them.
+12. **Voice check — read each bullet aloud.** Imagine you're texting it to the reviewer. Does it sound like a developer in a hurry, or like a press release? If the latter, rewrite. Specific tells: bullets that start with `Let X...`/`Stop Y...`/`Wire Z...` (verb-first mechanism), bullets that mention line numbers or internal field names, bullets longer than the corresponding commit message subject.
+13. **Honest question.** If a colleague wrote this PR and pinged you, would the body sound like them, or like a corporate document? If the latter, you're still in AI-prose mode.
 
 ---