fix(retrieval): keep active runtime after benchmark

TODO.md

@@ -3,7 +3,7 @@
 ## Data loss and security
 
 - [ ] Validate every path read from `.ai-config-manifest.tsv` and reject links before backup, overwrite, or removal. Both manifest writers join unchecked recorded paths to the destination; a `../` entry or linked target can reach files outside the managed directory. (`scripts/lib/manifest.ps1:20`, `scripts/lib/manifest.ps1:136`, `scripts/lib/manifest.sh:20`, `scripts/lib/manifest.sh:170`)
-- [ ] Keep an installed semantic retrieval runtime when an `auto` benchmark says no. `benchmark()` deletes the whole runtime and ownership state even when `state['clients']` still contains active clients. (`scripts/lib/semantic-retrieval.py:117`, `scripts/lib/semantic-retrieval.py:142`)
+- [x] Keep an installed semantic retrieval runtime when an `auto` benchmark says no. `benchmark()` deletes the whole runtime and ownership state even when `state['clients']` still contains active clients. (`scripts/lib/semantic-retrieval.py:117`, `scripts/lib/semantic-retrieval.py:142`)
 - [ ] Check semantic retrieval ownership and links before copying or deleting its directory. An existing owned runtime's source files are overwritten without comparing recorded hashes; a replaced target symlink is followed on enable, and disabling the last client removes foreign files inside the runtime. (`scripts/lib/semantic-retrieval.py:82`, `scripts/lib/semantic-retrieval.py:100`)
 - [ ] Preserve pre-existing MCPorter server entries. `ensure_mcporter()` adds a server and claims ownership without checking existing configuration; if the add succeeds for an existing name, a later removal deletes that user's entry. (`scripts/lib/managed-extensions.py:395`, `scripts/lib/managed-extensions.py:263`)
 - [ ] Preserve pre-existing global CLI packages. `ensure_cli()` and `ensure_qmd()` install and claim npm packages without checking whether they were already installed; later removal can uninstall a user's package. (`scripts/lib/managed-extensions.py:342`, `scripts/lib/managed-extensions.py:378`)

scripts/lib/semantic-retrieval.py

@@ -149,7 +149,7 @@ def benchmark(root, home, dry_run, summary=False):
     outcome = json.loads(result.stdout)
     if not isinstance(outcome, dict) or not isinstance(outcome.get('recommended'), bool):
         raise ValueError('Semantic retrieval benchmark returned an invalid result.')
-    if outcome['recommended']:
+    if outcome['recommended'] or state['clients']:
         save_state(state_path, state, False)
     else:
         shutil.rmtree(target)

scripts/tests/test-semantic-retrieval.py

@@ -85,6 +85,25 @@ class SemanticRetrievalTests(unittest.TestCase):
             self.assertFalse(target.exists())
             self.assertFalse(state_path.exists())
 
+    def test_negative_benchmark_keeps_active_runtime(self):
+        with tempfile.TemporaryDirectory() as directory:
+            home = Path(directory) / 'home'
+            target = home / '.my-ai-configuration/semantic-retrieval'
+            target.mkdir(parents=True)
+            state_path = target.parent / 'semantic-retrieval.json'
+            files = {}
+            for name in MODULE.FILES:
+                content = (ROOT / 'shared/retrieval' / name).read_bytes()
+                (target / name).write_bytes(content)
+                files[name] = hashlib.sha256(content).hexdigest()
+            MODULE.save_state(state_path, {'version': 1, 'clients': ['codex'], 'files': files}, False)
+            result = type('Result', (), {'stdout': '{"recommended": false, "embeddingSeconds": 1, "rerankingSeconds": 1}'})()
+            with patch.object(MODULE, 'ensure_runtime', return_value=Path('python')), \
+                 patch.object(MODULE.subprocess, 'run', return_value=result):
+                self.assertFalse(MODULE.benchmark(ROOT, home, False, True))
+            self.assertTrue(target.is_dir())
+            self.assertEqual(MODULE.load_state(state_path)['clients'], ['codex'])
+
 
 if __name__ == '__main__':
     unittest.main()