feat(review): add a combined "Copy for AI agents" block to the PR comment

src/review/unified-comment.ts

@@ -477,6 +477,18 @@ function taskList(items: string[]): string {
     .join("\n");
 }
 
+/** A single copy-paste-ready plain-text prompt combining every blocker into one instruction an AI coding
+ *  agent can act on directly — mirrors CodeRabbit's combined "Prompt for AI agents" feature (per their own
+ *  docs: gathers every fix prompt from a review into ONE structured instruction instead of one per finding,
+ *  specifically to cut the repeated copy-paste this produced before). A GitHub-rendered fenced code block
+ *  gets its own copy icon for free — no custom JS needed, just plain text inside the fence. The sole caller
+ *  only invokes this inside its own `blockersAll.length` guard, so an empty list never reaches here. */
+function buildAiContextBlock(blockers: string[], open: boolean): string {
+  const items = blockers.map((line, i) => `${i + 1}. ${line}`).join("\n\n");
+  const body = "```\nFix the following blocker(s) from this PR review:\n\n" + items + "\n```";
+  return details("📋 Copy for AI agents", body, "paste into your coding agent", open);
+}
+
 function actionReasonBullets(reason: string): string {
   const reasons = reason
     .split(/[;\n]+/)
@@ -661,6 +673,10 @@ export function renderUnifiedReviewComment(input: UnifiedReviewInput, ctx: Unifi
       ? appendMoreFooter(bullets(blockersTrunc.shown), blockersTrunc.hiddenCount)
       : `_+${blockersTrunc.hiddenCount} more_`;
     blocks.push(`**${heading}**\n${blockersBody}`);
+    // The FULL (pre-display-truncation) blocker set, not blockersTrunc.shown -- an AI agent benefits from
+    // every blocker, not just the human-scannable capped subset shown above. Never gated by verbosity: this
+    // is an extension of the blockers themselves (never gated), not decorative detail like Nits.
+    blocks.push(buildAiContextBlock(blockersAll, collapsiblesOpen));
   }
 
   // Category breakdown (#2150): a compact, deterministic one-liner of the finding mix (e.g. "2 correctness ·

test/unit/unified-comment-bridge.test.ts

@@ -714,10 +714,11 @@ describe("single AI pass: the bridge RECOVERS the consensus defect, never re-der
       changedFiles: 4,
       footerMarkdown: footer,
     });
-    // The defect title appears EXACTLY ONCE in the whole comment (the Code-review blocker bullet), never
-    // duplicated into the gate signal row (which only renders the conclusion-derived "Blocking" status text).
+    // The defect title appears in the Code-review blocker bullet AND once more inside the "Copy for AI
+    // agents" block (a deliberate copyable rendition) -- but never a THIRD time duplicated into the gate
+    // signal row (which only renders the conclusion-derived "Blocking" status text).
     const occurrences = body.split(defectTitle).length - 1;
-    expect(occurrences, "consensus defect title must appear exactly once").toBe(1);
+    expect(occurrences, "consensus defect title must appear exactly twice (blocker bullet + AI-context block)").toBe(2);
     // It is rendered under the blocked-reasons heading (the Code-review side), confirming where the one copy lives.
     expect(body).toMatch(/Why this is blocked|Concerns raised/);
   });
@@ -774,8 +775,10 @@ describe("gate blockers render in 'Why this is blocked' (FIX D1)", () => {
       changedFiles: 3,
       footerMarkdown: footer,
     });
-    // The defect surfaces exactly once (recovered via consensusDefect; excluded from the folded gate blockers).
-    expect(body.split(title).length - 1).toBe(1);
+    // The defect surfaces as ONE blocker (recovered via consensusDefect; excluded from the folded gate
+    // blockers so it isn't double-counted as two separate findings) -- which then legitimately renders in
+    // two places: the blocker bullet and the "Copy for AI agents" block.
+    expect(body.split(title).length - 1).toBe(2);
   });
 
   it("renders BOTH the recovered consensus defect AND a separate non-AI gate blocker", () => {
@@ -836,9 +839,13 @@ describe("gate blockers render in 'Why this is blocked' (FIX D1)", () => {
       changedFiles: 10,
       footerMarkdown: footer,
     });
-    // Exactly once: under "Why this is blocked" only, never ALSO restated under "Suggested Action".
-    expect(body.split(blockerTitle).length - 1).toBe(1);
-    expect(body).toContain("Why this is blocked");
+    // Never restated under "Suggested Action" (the original #5347 bug) -- the text before "Why this is
+    // blocked" must not contain it. It legitimately appears twice total: once under "Why this is blocked",
+    // once more inside the "Copy for AI agents" block (a deliberate, separate copyable rendition).
+    const [beforeWhyBlocked, afterWhyBlocked] = body.split("Why this is blocked");
+    expect(beforeWhyBlocked).not.toContain(blockerTitle);
+    expect(afterWhyBlocked).toContain(blockerTitle);
+    expect(body.split(blockerTitle).length - 1).toBe(2);
   });
 
   it("a manual-review HOLD (no gate blockers) still shows its own top-level reason, unaffected by the #5347 fix", () => {

test/unit/unified-comment.test.ts

@@ -241,7 +241,9 @@ describe("renderUnifiedReviewComment", () => {
       { ...base, decision: "close", blockers: ["Same issue", "same issue", "Same issue"] },
       {},
     );
-    expect(md.match(/Same issue/gi)?.length).toBe(1);
+    // Deduped down to ONE unique blocker, which then legitimately renders in TWO places: the "Why this is
+    // blocked" bullet list, and once more inside the "Copy for AI agents" code block.
+    expect(md.match(/Same issue/gi)?.length).toBe(2);
   });
 
   it("omits optional chrome when the host provides none", () => {
@@ -481,7 +483,8 @@ describe("renderUnifiedReviewComment", () => {
 
   it("skips empty blocker lines and caps long nit lists at 12", () => {
     const withEmpty = renderUnifiedReviewComment({ ...base, decision: "close", blockers: ["", "   ", "Real blocker"] }, {});
-    expect(withEmpty.match(/Real blocker/g)?.length).toBe(1);
+    // The one real blocker renders in TWO places: "Why this is blocked" and the "Copy for AI agents" block.
+    expect(withEmpty.match(/Real blocker/g)?.length).toBe(2);
     const capped = renderUnifiedReviewComment({ ...base, decision: "merge", nits: Array.from({ length: 13 }, (_, i) => `Distinct nit ${i + 1}`) }, {});
     expect(capped).toContain("Distinct nit 12");
     expect(capped).not.toContain("Distinct nit 13");
@@ -535,6 +538,59 @@ describe("renderUnifiedReviewComment", () => {
   });
 });
 
+describe("'Copy for AI agents' block", () => {
+  it("omits the section entirely when there are no blockers", () => {
+    const md = renderUnifiedReviewComment({ ...base, decision: "merge" }, {});
+    expect(md).not.toContain("Copy for AI agents");
+  });
+
+  it("renders every blocker as a numbered item inside a fenced code block", () => {
+    const md = renderUnifiedReviewComment({ ...base, decision: "close", blockers: ["First issue.", "Second issue."] }, {});
+    expect(md).toContain("<details><summary><b>📋 Copy for AI agents</b> — paste into your coding agent</summary>");
+    // The whole comment is wrapped in a `> ` blockquote alert, so each line below carries that prefix.
+    expect(md).toContain("> ```\n> Fix the following blocker(s) from this PR review:");
+    expect(md).toContain("> 1. First issue.");
+    expect(md).toContain("> 2. Second issue.");
+  });
+
+  it("uses the FULL blocker set, not the display-truncated one, when maxFindingsCaps.blockers is set", () => {
+    const md = renderUnifiedReviewComment(
+      { ...base, decision: "close", blockers: ["Alpha", "Beta", "Gamma"], maxFindingsCaps: { blockers: 1, nits: null } },
+      {},
+    );
+    // Human-facing bullets are capped at 1 (plus a "+N more" footer)...
+    expect(md).toMatch(/Alpha[\s\S]*_\+2 more_/);
+    // ...but the AI-context block still gets every blocker, since an agent benefits from full context.
+    const aiSection = md.split("📋 Copy for AI agents")[1]!;
+    expect(aiSection).toContain("Alpha");
+    expect(aiSection).toContain("Beta");
+    expect(aiSection).toContain("Gamma");
+  });
+
+  it("is NOT dropped by comment_verbosity: quiet (it extends the never-gated blockers, not decorative detail)", () => {
+    const md = renderUnifiedReviewComment(
+      { ...base, decision: "close", blockers: ["a real blocker"] },
+      { commentVerbosity: "quiet" },
+    );
+    expect(md).toContain("Copy for AI agents");
+  });
+
+  it("renders pre-expanded (<details open>) under comment_verbosity: detailed, matching every other collapsible", () => {
+    const md = renderUnifiedReviewComment(
+      { ...base, decision: "close", blockers: ["a real blocker"] },
+      { commentVerbosity: "detailed" },
+    );
+    expect(md).toContain("<details open><summary><b>📋 Copy for AI agents</b>");
+  });
+
+  it("escapes angle brackets inside the fenced block, same as every other public-facing field", () => {
+    const md = renderUnifiedReviewComment({ ...base, decision: "close", blockers: ["Uses <script>alert(1)</script>."] }, {});
+    const aiSection = md.split("📋 Copy for AI agents")[1]!;
+    expect(aiSection).toContain("&lt;script&gt;alert(1)&lt;/script&gt;");
+    expect(aiSection).not.toContain("<script>");
+  });
+});
+
 function reviewNote(rec: ReviewRecommendation, extra: Partial<ReviewNotes> = {}): DualReviewNote {
   return {
     model: "test-model",