fix: make generated commit trailers host-aware

document-release/SKILL.md.tmpl

@@ -277,9 +277,7 @@ committing.
 
 ```bash
 git commit -m "$(cat <<'EOF'
-docs: update project documentation for vX.Y.Z.W
-
-Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+docs: update project documentation for vX.Y.Z.W{{COMMIT_COAUTHOR_TRAILER_BLOCK}}
 EOF
 )"
 ```

scripts/gen-skill-docs.ts

@@ -60,6 +60,11 @@ interface TemplateContext {
   paths: HostPaths;
 }
 
+const HOST_COMMIT_COAUTHOR_TRAILERS: Record<Host, string> = {
+  claude: 'Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>',
+  codex: '',
+};
+
 // ─── Shared Design Constants ────────────────────────────────
 
 /** gstack's 10 AI slop anti-patterns — shared between DESIGN_METHODOLOGY and DESIGN_HARD_RULES */
@@ -2795,9 +2800,15 @@ function generateSlugSetup(ctx: TemplateContext): string {
   return `eval "$(${ctx.paths.binDir}/gstack-slug 2>/dev/null)" && mkdir -p ~/.gstack/projects/$SLUG`;
 }
 
+function generateCommitCoauthorTrailerBlock(ctx: TemplateContext): string {
+  const trailer = HOST_COMMIT_COAUTHOR_TRAILERS[ctx.host];
+  return trailer ? `\n\n${trailer}` : '';
+}
+
 const RESOLVERS: Record<string, (ctx: TemplateContext) => string> = {
   SLUG_EVAL: generateSlugEval,
   SLUG_SETUP: generateSlugSetup,
+  COMMIT_COAUTHOR_TRAILER_BLOCK: generateCommitCoauthorTrailerBlock,
   COMMAND_REFERENCE: generateCommandReference,
   SNAPSHOT_FLAGS: generateSnapshotFlags,
   PREAMBLE: generatePreamble,

ship/SKILL.md

@@ -1388,7 +1388,7 @@ Save this summary — it goes into the PR body in Step 8.
 5. Compose each commit message:
    - First line: `<type>: <summary>` (type = feat/fix/chore/refactor/docs)
    - Body: brief description of what this commit contains
-   - Only the **final commit** (VERSION + CHANGELOG) gets the version tag and co-author trailer:
+   - Only the **final commit** (VERSION + CHANGELOG) gets the version tag. If the current host uses a commit footer, include it only on that final commit:
 
 ```bash
 git commit -m "$(cat <<'EOF'

ship/SKILL.md.tmpl

@@ -399,13 +399,11 @@ Save this summary — it goes into the PR body in Step 8.
 5. Compose each commit message:
    - First line: `<type>: <summary>` (type = feat/fix/chore/refactor/docs)
    - Body: brief description of what this commit contains
-   - Only the **final commit** (VERSION + CHANGELOG) gets the version tag and co-author trailer:
+   - Only the **final commit** (VERSION + CHANGELOG) gets the version tag. If the current host uses a commit footer, include it only on that final commit:
 
 ```bash
 git commit -m "$(cat <<'EOF'
-chore: bump version and changelog (vX.Y.Z.W)
-
-Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
+chore: bump version and changelog (vX.Y.Z.W){{COMMIT_COAUTHOR_TRAILER_BLOCK}}
 EOF
 )"
 ```

test/gen-skill-docs.test.ts

@@ -175,6 +175,14 @@ describe('gen-skill-docs', () => {
     expect(browseTmpl).toContain('{{PREAMBLE}}');
   });
 
+  test('ship and document-release templates use host-aware commit trailer placeholder', () => {
+    const shipTmpl = fs.readFileSync(path.join(ROOT, 'ship', 'SKILL.md.tmpl'), 'utf-8');
+    const documentReleaseTmpl = fs.readFileSync(path.join(ROOT, 'document-release', 'SKILL.md.tmpl'), 'utf-8');
+
+    expect(shipTmpl).toContain('{{COMMIT_COAUTHOR_TRAILER_BLOCK}}');
+    expect(documentReleaseTmpl).toContain('{{COMMIT_COAUTHOR_TRAILER_BLOCK}}');
+  });
+
   test('generated SKILL.md contains contributor mode check', () => {
     const content = fs.readFileSync(path.join(ROOT, 'SKILL.md'), 'utf-8');
     expect(content).toContain('Contributor Mode');
@@ -1168,6 +1176,24 @@ describe('Codex generation (--host codex)', () => {
     const codexContent = fs.readFileSync(path.join(AGENTS_DIR, 'gstack-ship', 'SKILL.md'), 'utf-8');
     expect(codexContent).not.toContain('Codex design voice');
   });
+
+  test('codex host omits AI co-author trailers from ship and document-release commit examples', () => {
+    const shipContent = fs.readFileSync(path.join(AGENTS_DIR, 'gstack-ship', 'SKILL.md'), 'utf-8');
+    const documentReleaseContent = fs.readFileSync(path.join(AGENTS_DIR, 'gstack-document-release', 'SKILL.md'), 'utf-8');
+
+    expect(shipContent).not.toContain('Co-Authored-By:');
+    expect(documentReleaseContent).not.toContain('Co-Authored-By:');
+    expect(shipContent).not.toContain('noreply@anthropic.com');
+    expect(documentReleaseContent).not.toContain('noreply@anthropic.com');
+  });
+
+  test('Claude output preserves Claude co-author trailers in ship and document-release', () => {
+    const shipContent = fs.readFileSync(path.join(ROOT, 'ship', 'SKILL.md'), 'utf-8');
+    const documentReleaseContent = fs.readFileSync(path.join(ROOT, 'document-release', 'SKILL.md'), 'utf-8');
+
+    expect(shipContent).toContain('Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>');
+    expect(documentReleaseContent).toContain('Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>');
+  });
 });
 
 // ─── Setup script validation ─────────────────────────────────