fix: add codex skill metadata for gstack skills (#339)

test/gen-skill-docs.test.ts

@@ -942,6 +942,14 @@ describe('Codex generation (--host codex)', () => {
     }
   });
 
+  test('root gstack bundle has OpenAI metadata for Codex skill browsing', () => {
+    const rootMetadata = path.join(ROOT, 'agents', 'openai.yaml');
+    expect(fs.existsSync(rootMetadata)).toBe(true);
+    const content = fs.readFileSync(rootMetadata, 'utf-8');
+    expect(content).toContain('display_name: "gstack"');
+    expect(content).toContain('Use $gstack to locate the bundled gstack skills.');
+  });
+
   test('codexSkillName mapping: root is gstack, others are gstack-{dir}', () => {
     // Root → gstack
     expect(fs.existsSync(path.join(AGENTS_DIR, 'gstack', 'SKILL.md'))).toBe(true);
@@ -971,6 +979,17 @@ describe('Codex generation (--host codex)', () => {
     }
   });
 
+  test('all Codex skills have agents/openai.yaml metadata', () => {
+    for (const skill of CODEX_SKILLS) {
+      const metadata = path.join(AGENTS_DIR, skill.codexName, 'agents', 'openai.yaml');
+      expect(fs.existsSync(metadata)).toBe(true);
+      const content = fs.readFileSync(metadata, 'utf-8');
+      expect(content).toContain(`display_name: "${skill.codexName}"`);
+      expect(content).toContain('short_description:');
+      expect(content).toContain('allow_implicit_invocation: true');
+    }
+  });
+
   test('no .claude/skills/ in Codex output', () => {
     for (const skill of CODEX_SKILLS) {
       const content = fs.readFileSync(path.join(AGENTS_DIR, skill.codexName, 'SKILL.md'), 'utf-8');

test/helpers/codex-session-runner.ts

@@ -98,7 +98,8 @@ export function parseCodexJSONL(lines: string[]): ParsedCodexJSONL {
 
 /**
  * Install a SKILL.md into a temp HOME directory for Codex to discover.
- * Creates ~/.codex/skills/{skillName}/SKILL.md in the temp HOME.
+ * Creates ~/.codex/skills/{skillName}/SKILL.md in the temp HOME and copies
+ * agents/openai.yaml when present so Codex sees the same metadata as a real install.
  *
  * Returns the temp HOME path. Caller is responsible for cleanup.
  */
@@ -116,6 +117,13 @@ export function installSkillToTempHome(
     fs.copyFileSync(srcSkill, path.join(destDir, 'SKILL.md'));
   }
 
+  const srcOpenAIYaml = path.join(skillDir, 'agents', 'openai.yaml');
+  if (fs.existsSync(srcOpenAIYaml)) {
+    const destAgentsDir = path.join(destDir, 'agents');
+    fs.mkdirSync(destAgentsDir, { recursive: true });
+    fs.copyFileSync(srcOpenAIYaml, path.join(destAgentsDir, 'openai.yaml'));
+  }
+
   return home;
 }