Reject reasoning text in session titles

tests/test_gui_server.py

@@ -22,6 +22,7 @@ from backend.api.server import (
     AgentState,
     create_app,
     _bash_bg_manager,
+    _clean_session_title,
     _derive_initial_session_title,
     _ensure_session_title,
     _generate_session_title,
@@ -860,6 +861,35 @@ class GuiServerTests(unittest.TestCase):
 
             self.assertIsNone(_read_session_title(directory, session_id))
 
+    def test_invalid_llm_title_is_not_preserved_as_previous_title(self) -> None:
+        with tempfile.TemporaryDirectory() as d:
+            root = Path(d)
+            _, state = _build_client(root)
+            session_id = 'invalid-llm-title'
+            directory = state.account_paths('alice')['sessions']
+            agent = state.agent_for('alice', session_id)
+
+            _save_in_progress_session(
+                directory=directory,
+                agent=agent,
+                session_id=session_id,
+                prompt='帮我生成一批地图导航测试数据。',
+            )
+            stored = load_agent_session(session_id, directory=directory)
+            save_agent_session(
+                replace(
+                    stored,
+                    session_metadata={
+                        **(stored.session_metadata or {}),
+                        'title': '<think>**Generating short title',
+                        'title_source': 'llm',
+                    },
+                ),
+                directory=directory,
+            )
+
+            self.assertIsNone(_read_session_title(directory, session_id))
+
     def test_session_title_refines_first_message_title_after_run(self) -> None:
         with tempfile.TemporaryDirectory() as d:
             root = Path(d)
@@ -960,6 +990,20 @@ class GuiServerTests(unittest.TestCase):
             self.assertEqual(config.base_url, 'http://model.mify.ai.srv/v1')
             client.complete.assert_called_once()
 
+    def test_clean_session_title_rejects_reasoning_leak(self) -> None:
+        self.assertIsNone(_clean_session_title('<think>**Generating short title'))
+        self.assertIsNone(
+            _clean_session_title(
+                '<think>reasoning</think>\nGenerating short Chinese title'
+            )
+        )
+
+    def test_clean_session_title_strips_markdown_and_prefix(self) -> None:
+        self.assertEqual(
+            _clean_session_title('**标题：地图导航测试数据。**'),
+            '地图导航测试数据',
+        )
+
     def test_clear_runtime_state(self) -> None:
         with tempfile.TemporaryDirectory() as d:
             client, _ = _build_client(Path(d))