feat(prompts): inventory skill metadata and duplicate names

scripts/lib/prompt-inventory.py

@@ -0,0 +1,47 @@
+import argparse
+from collections import Counter
+from pathlib import Path
+import re
+
+
+def inventory(roots):
+    names = Counter()
+    count = metadata_bytes = body_bytes = 0
+    for root in roots:
+        for path in sorted(root.rglob('SKILL.md')):
+            content = path.read_text(encoding='utf-8-sig')
+            count += 1
+            body_bytes += len(content.encode('utf-8'))
+            header = re.match(r'\A---\r?\n(.*?)^---\s*$', content, re.MULTILINE | re.DOTALL)
+            if header:
+                metadata_bytes += len(header.group(1).encode('utf-8'))
+                name = re.search(r'^name:\s*(.+)$', header.group(1), re.MULTILINE)
+                if name:
+                    names[name.group(1).strip().strip('\"\'')] += 1
+    return count, metadata_bytes, body_bytes, sorted(name for name, total in names.items() if total > 1)
+
+
+def report(label, roots, warn_duplicates=True):
+    count, metadata, bodies, duplicates = inventory(roots)
+    print(f'{label}: {count} skill files, {metadata} frontmatter bytes (~{(metadata + 3) // 4} tokens), {bodies} lazy file bytes')
+    if duplicates and warn_duplicates:
+        print(f'WARN {label}: repeated skill names ({len(duplicates)}): {", ".join(duplicates)}')
+
+
+def main():
+    parser = argparse.ArgumentParser()
+    parser.add_argument('--home', type=Path, default=Path.home())
+    args = parser.parse_args()
+    root = Path(__file__).resolve().parents[2]
+    for client in ('codex', 'claude'):
+        report(f'Generated {client} catalog', [root / 'generated' / f'{client}-bash' / 'skills'])
+        directories = [args.home / f'.{client}' / 'skills']
+        if client == 'codex':
+            directories.append(args.home / '.agents' / 'skills')
+        report(f'Installed {client} user catalog', directories)
+        report(f'Cached {client} plugins (all versions)', [args.home / f'.{client}' / 'plugins' / 'cache'], warn_duplicates=False)
+    print('Coverage: baseline covers generated instructions only. Inventory is not measured session context; plugin caches include inactive versions. Client prompts, tool schemas and dynamic hook output are excluded. Token counts use bytes/4 estimates.')
+
+
+if __name__ == '__main__':
+    main()

scripts/test-prompt-inventory.py

@@ -0,0 +1,29 @@
+import importlib.util
+from pathlib import Path
+from tempfile import TemporaryDirectory
+import unittest
+
+
+SPEC = importlib.util.spec_from_file_location('prompt_inventory', Path(__file__).parent / 'lib/prompt-inventory.py')
+MODULE = importlib.util.module_from_spec(SPEC)
+SPEC.loader.exec_module(MODULE)
+
+
+class PromptInventoryTests(unittest.TestCase):
+    def test_counts_metadata_separately_and_reports_duplicate_names(self):
+        with TemporaryDirectory() as temporary:
+            root = Path(temporary)
+            metadata = 'name: "example"\ndescription: Example skill.\n'
+            for name in ('first', 'second'):
+                directory = root / name
+                directory.mkdir()
+                (directory / 'SKILL.md').write_text(f'---\n{metadata}---\n\nBody\n---\nMore body', encoding='utf-8-sig')
+            count, header_bytes, body_bytes, duplicates = MODULE.inventory([root, root / 'missing'])
+            self.assertEqual(count, 2)
+            self.assertEqual(header_bytes, 2 * len(metadata.encode()))
+            self.assertGreater(body_bytes, header_bytes)
+            self.assertEqual(duplicates, ['example'])
+
+
+if __name__ == '__main__':
+    unittest.main()