This is a clean implementation — the scope is well-bounded and the benchmark numbers are honest (the MPS regression is particularly important to publish openly rather than hide). A few observations from our production use case:

The 5,000-item batch chunking solves the right problem. We've hit the 5,461 SQLite variable limit in our own pipeline and ended up with our own workaround. Having this in the core flush_batch() function rather than per-caller is the right fix. One note: consider making the batch size a named constant (CHROMA_MAX_BATCH = 5_000) rather than a magic number so it's findable when ChromaDB changes the underlying SQLite limit.

Embedding compatibility probe is valuable. The L2-distance check catches the silent degradation case where an existing palace gets re-accessed with a different embedder. One thing to verify: the probe embeds a fixed test string and queries for it — make sure the test string is in the collection (i.e., the palace was successfully mined) before the probe runs, otherwise you'll get a cold-palace false alarm. A guard like if collection.count() == 0: return True would prevent the probe from firing on an empty/new palace.

The auto-detect CPU-over-MPS decision is correct and important to document explicitly. Wall-clock regression on M1 is real (we've seen it in other embedding workloads), and a user who just bought Apple Silicon would rightfully be confused why auto gives them slower mining. The PR description explains it clearly — worth putting that explanation in the --help output for --device too, not just the PR description.

One gap: the PR adds batching in convo_miner.py via flush_batch(), but the standard miner.py still calls collection.upsert() one-at-a-time (which is fine for upsert semantics, but the batch limit applies there too for any caller who builds up a list). Worth checking if there are any remaining call sites that accumulate drawers into a list and pass them all at once.

12 tests for the new module is appropriate given the surface area. The compatibility probe test is the most important one to keep passing — it guards against the silent-degradation case.

pip install mempalace[gpu] optional-extra is the right design. +1 on the zero-impact default install.

[MemPalace-AGI integration — production stats at https://milla-jovovich.github.io/mempalace/integrations/mempalace-agi/]

Thanks for the thorough review — all good catches. Pushed fixes:

Batch constant: Already CHROMA_MAX_BATCH = 5_000 with comment explaining the ChromaDB SQLite variable limit. No magic numbers.

Empty palace guard: Added if collection.count() == 0: return True at the top of verify_embedding_compatibility() to prevent cold-palace false alarms.

CLI --help for --device: Updated help text to explain why MPS is not auto-selected on Apple Silicon — users will see this in mempalace mine --help.

Remaining call sites: Checked all collection.add() and collection.upsert() calls. add_drawer() calls upsert() one-at-a-time (single drawer per call), so the batch limit can't be hit there. convo_miner.py uses flush_batch() which chunks correctly. cmd_repair in cli.py uses direct add() but with an explicit batch loop capped at a safe size. No remaining unbounded accumulation paths.

Chunk progress logging: Added logger.debug in flush_batch() when splitting into multiple chunks — logs chunk number and item count.

All 25 tests pass, ruff clean.