Chroma 1.5.x can return ``None`` inside the ``metadatas`` / ``documents``
lists of a query/get result for partially-flushed rows. The codebase
already has a systemic None-guard pattern (merged #999, #1013, #1019)
but three call sites were still unguarded:
* ``mcp_server.tool_check_duplicate`` (``mcp_server.py:487-488``) —
``meta = results["metadatas"][0][i]`` followed by ``meta.get(...)``
raises ``AttributeError: 'NoneType' object has no attribute 'get'``.
The broad ``except Exception`` wrapper (line 504) swallows it and
returns an uninformative ``"Duplicate check failed"``.
* ``layers.Layer1.generate`` (``layers.py:126``) — iterates
``zip(docs, metas)`` and calls ``meta.get(key)`` in the importance
loop. A single None metadata blows up the entire wake-up render.
* ``layers.Layer2.retrieve`` (``layers.py:224``) — same pattern, same
crash path for the on-demand render.
Apply the same ``meta = meta or {}`` / ``doc = doc or ""`` idiom used
by the merged guards in the search path. Three-line additions, no
behaviour change on well-formed results.
Tests added:
* ``test_check_duplicate_handles_none_metadata`` — mocks the collection
query to return ``None`` for one metadata and document, asserts the
call does not crash and the sentinel-rendered entry has wing/room "?"
and empty content.
* ``test_layer1_handles_none_metadata`` / ``_handles_none_document``
* ``test_layer2_handles_none_metadata``
Relationship to other open PRs:
* **#1019** guarded ``searcher.py`` loops. This PR extends the same
guard to the three call sites #1019 did not touch.
* **#979** fixed ``tool_check_duplicate`` negative similarity but left
the None-metadata path unguarded.
* Does not overlap **#1013** (``Layer3.search_raw``) or **#999**.
Four more MCP handlers iterate a metadata list and call m.get(...)
unconditionally. When the cache contains a None entry (drawers with no
metadata, common on older mining paths), the try block catches the
AttributeError and marks the response "partial: true" with an
error message — visible as {"error": "'NoneType' object has no
attribute 'get'", "partial": true} returned from mempalace_status even
though the palace data is otherwise fetchable.
Same m = m or {} guard we applied to searcher.py (d3a2d22, a51c3c2)
and miner.status() (66f08a1). None-metadata drawers now roll up under
the existing "unknown" fallback bucket instead of poisoning the
response with a misleading partial flag.
Regression test: mock the metadata cache with a None in the middle,
assert tool_status returns clean counts and no error/partial fields.
Verified the test fails without the guard.
998 tests pass.
tool_status() called _get_collection() with the default create=False,
which throws when the ChromaDB collection does not exist yet (valid
palace, zero drawers). The exception was swallowed and status returned
"No palace found" even though init had completed successfully.
Switching to create=True bootstraps an empty collection on first
status call, matching what the write path already does.
Fix suggested by @hkevinchu in the issue.
ChromaDB defaults HNSW index to L2 (Euclidean) distance, but
MemPalace scoring uses 1-distance which requires cosine (range 0-2).
Add metadata={"hnsw:space": "cosine"} to the 4 production and 3 test
call sites that were missing it.
Closes#218
When external tools write to the palace database (CLI mining, scripts), the MCP server's cached ChromaDB collection becomes stale — its HNSW index doesn't know about new vectors. Develop already invalidates on inode changes (catches rebuilds) but not on mtime changes (misses in-place writes).
This PR:
- Adds st_mtime tracking alongside st_ino in _get_client; invalidates the cached client on either change.
- Adds the mempalace_reconnect MCP tool for explicit cache flush.
Original author: @jphein (#663). Original approval: @Ari4ka.
Skips test_missing_db_invalidates_cache on Windows (ChromaDB holds chroma.sqlite3 open).
The initialize handler hardcoded protocolVersion "2024-11-05", which
causes newer MCP clients (e.g. Claude Code) to reject the connection
when they negotiate "2025-11-25" or later.
Echo the client's requested version if it is in the supported set,
otherwise fall back to the latest supported version. This keeps
backwards compatibility with older clients while allowing newer ones
to connect.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
- Switch CI install step from `pip install -r requirements.txt` to
`pip install -e ".[dev]"` since requirements.txt was removed
- Add noqa: E402 to intentionally-late imports in conftest.py
(HOME must be isolated before mempalace imports)
- Remove unused KnowledgeGraph import in test_knowledge_graph.py
- Apply ruff formatting to test files
eldar702