feat: add pr skill for generating pull request descriptions

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: 2 people

scripts/build-skills.js

@@ -12,6 +12,8 @@ function stripTypes(code) {
     .replace(/^import\s+type\s+\{[^}]*\}\s+from\s+['"][^'"]+['"];?\s*$/gm, "")
     .replace(/:\s*SkillHandler/g, "")
     .replace(/:\s*SkillContext/g, "")
+    .replace(/:\s*(?:string|number|boolean)(?:\[\])?/g, "")
+    .replace(/\):\s*Promise<[^>]*>\s*\{/g, ") {")
     .replace(/\s+as\s+(string|boolean|number)/g, "");
 }
 

src/skills/built-in/pr/handler.ts

@@ -0,0 +1,81 @@
+import type { SkillHandler } from "../../types.js";
+import { execFile } from "node:child_process";
+import { promisify } from "node:util";
+import { streamQuery } from "../../handler-utils.js";
+
+const execFileAsync = promisify(execFile);
+
+const SYSTEM_PROMPT = `You are an expert at writing pull request descriptions. Generate a clear, well-structured PR description in Markdown.
+
+Use this format:
+
+## Summary
+- 2-3 bullet points explaining the purpose and motivation
+
+## Changes
+- List the key changes grouped logically
+- Reference specific files when helpful
+
+## Test plan
+- [ ] Checklist items describing how to verify the changes
+
+Output ONLY the PR description in Markdown, nothing else.`;
+
+async function gitCommand(
+  args: string[],
+  cwd: string,
+): Promise<string | null> {
+  try {
+    const result = await execFileAsync("git", args, {
+      cwd,
+      maxBuffer: 10 * 1024 * 1024,
+    });
+    return result.stdout.trim() || null;
+  } catch {
+    return null;
+  }
+}
+
+const handler: SkillHandler = async (ctx) => {
+  const base = (ctx.flags.base as string) || "main";
+  const cwd = ctx.context.cwd;
+
+  const [commitLog, diffStat, fullDiff] = await Promise.all([
+    gitCommand(["log", "--oneline", `${base}..HEAD`], cwd),
+    gitCommand(["diff", `${base}...HEAD`, "--stat"], cwd),
+    gitCommand(["diff", `${base}...HEAD`], cwd),
+  ]);
+
+  const diff = fullDiff || ctx.context.gitDiff;
+
+  if (!diff && !commitLog) {
+    ctx.logger.info(
+      `No changes found between '${base}' and HEAD. Check that you are on a feature branch.`,
+    );
+    return;
+  }
+
+  const parts = [];
+
+  if (commitLog) {
+    parts.push(`Commits on this branch:\n${commitLog}`);
+  }
+
+  if (diffStat) {
+    parts.push(`Changed files summary:\n${diffStat}`);
+  }
+
+  if (diff) {
+    parts.push(`Full diff:\n\`\`\`diff\n${diff}\n\`\`\``);
+  }
+
+  if (ctx.context.fileTree) {
+    parts.push(`Repository file tree:\n${ctx.context.fileTree}`);
+  }
+
+  const prompt = `Generate a pull request description for the following changes:\n\n${parts.join("\n\n")}`;
+
+  await streamQuery(ctx.agent, prompt, { systemPrompt: SYSTEM_PROMPT });
+};
+
+export default handler;

src/skills/built-in/pr/manifest.json

@@ -0,0 +1,12 @@
+{
+  "name": "pr",
+  "version": "1.0.0",
+  "description": "Generate a pull request description",
+  "inputs": {
+    "flags": [
+      { "name": "base", "short": "b", "type": "string", "description": "Base branch (default: main)", "default": "main" }
+    ],
+    "context": ["git-log", "git-diff", "file-tree"]
+  },
+  "aliases": ["pull-request"]
+}

src/utils/typescript.ts

@@ -12,6 +12,10 @@ export function stripTypes(code: string): string {
     // Remove type annotations on variables/parameters (`: Type`)
     .replace(/:\s*SkillHandler/g, "")
     .replace(/:\s*SkillContext/g, "")
+    // Remove function parameter type annotations (`: string`, `: string[]`, etc.)
+    .replace(/:\s*(?:string|number|boolean)(?:\[\])?/g, "")
+    // Remove return type annotations like `): Promise<...> {`
+    .replace(/\):\s*Promise<[^>]*>\s*\{/g, ") {")
     // Remove `as type` casts
     .replace(/\s+as\s+(string|boolean|number)/g, "");
 }