Surface database-open errors in the TUIs

ChatApp and InspectorApp assigned self.client before __aenter__
completed, so a failed open was masked by an AttributeError from
on_unmount tearing down the never-opened client.

CHANGELOG.md

@@ -8,6 +8,10 @@
 - MCP `ask_question` and `analyze` tools accept `images_base64`.
 - Chat TUI: `Ctrl+I` opens an image picker; attached images insert `[Image #N]` tokens in a multi-line prompt and are sent to the model with the message.
 
+### Fixed
+
+- Chat and inspector TUIs report the actual database-open error instead of an `AttributeError` from teardown.
+
 ## [0.69.0] - 2026-07-24
 
 ### Added

haiku_rag_slim/haiku/rag/chat/app.py

@@ -139,12 +139,15 @@ class ChatApp(App):
 
     async def on_mount(self) -> None:
         """Initialize the app when mounted."""
-        self.client = HaikuRAG(
+        client = HaikuRAG(
             db_path=self.db_path,
             config=self.config,
             read_only=self.read_only,
         )
-        await self.client.__aenter__()
+        # Assign only after a successful open: on_unmount must not tear down
+        # a client whose __aenter__ failed.
+        await client.__aenter__()
+        self.client = client
 
         self._agent = Agent(
             self._model,

haiku_rag_slim/haiku/rag/inspector/app.py

@@ -83,12 +83,15 @@ class InspectorApp(App):
     async def on_mount(self) -> None:
         """Initialize the app when mounted."""
         config = get_config()
-        self.client = HaikuRAG(
+        client = HaikuRAG(
             db_path=self.db_path,
             config=config,
             read_only=self.read_only,
         )
-        await self.client.__aenter__()
+        # Assign only after a successful open: on_unmount must not tear down
+        # a client whose __aenter__ failed.
+        await client.__aenter__()
+        self.client = client
 
         # Load initial documents
         doc_list = self.query_one(DocumentList)

tests/chat/test_chat_app.py

@@ -400,3 +400,15 @@ async def test_document_filter_cleared_when_empty(temp_db_path: Path):
             rag_state = RAGState.model_validate(app._state[RAG_STATE_NAMESPACE])
             assert rag_state.document_filter is None
             assert app._state["rag"]["document_filter"] is None
+
+
+@pytest.mark.asyncio
+async def test_chat_app_open_failure_surfaces_real_error(tmp_path: Path):
+    """A failed database open must surface its own error, not an
+    AttributeError from tearing down a client that never opened."""
+    from haiku.rag.chat.app import ChatApp
+
+    app = ChatApp(db_path=tmp_path / "missing.lancedb", capabilities=[])
+    with pytest.raises(FileNotFoundError):
+        async with app.run_test():
+            pass

tests/test_inspector.py

@@ -223,3 +223,15 @@ async def test_context_modal_suppresses_pictures_when_vision_disabled():
         await pilot.pause()
         modal = app.screen
         assert list(modal.query(TextualImage)) == []
+
+
+@pytest.mark.asyncio
+async def test_inspector_open_failure_surfaces_real_error(tmp_path):
+    """A failed database open must surface its own error, not an
+    AttributeError from tearing down a client that never opened."""
+    from haiku.rag.inspector.app import InspectorApp
+
+    app = InspectorApp(db_path=tmp_path / "missing.lancedb", read_only=True)
+    with pytest.raises(FileNotFoundError):
+        async with app.run_test():
+            pass