Engineering

The database-touching tests run against a real pgvector container, not a mock DB. CI runs ruff, mypy, the suite against PostgreSQL under coverage, the suite again at the declared dependency floor, and pip-audit over a checked-in uv.lock. These are gates, not reports.

Type checking arrived late and is worth being specific about, because "we added mypy" is usually a non-event. 81% of functions here already carried a return annotation and nothing verified any of them. Running the checker over that found two things a green test suite had not: RECALL_TRANSPORT was an unvalidated environment string flowing into a Literal-typed SDK parameter — a typo reached mcp.run() as an arbitrary value after startup had already opened a store and read the token file — and ensure_schema indexed a None row when pointed at an existing table that was not a recall table. Both now fail early and by name. The gate is disallow_untyped_defs, not a permissive baseline: a partially-checked package stops checking wherever an annotation is missing, so a lenient gate passes while its coverage shrinks.

Tests are written to fail for the right reason. A representative sample:

• the RLS tests connect as a role that cannot bypass RLS, because as a superuser they would pass while testing nothing;
• the cross-tenant test asserts the other tenant's row exists before checking it is invisible, so a silently failed write cannot make it green;
• the supersession-cache test counts real table scans, so a "fix" that quietly became rescan every search would be caught;
• the metrics test asserts the counters move on the real retrieval path — instrumentation that is never wired up reports zero forever and reads as "nothing is going wrong".

Several defects were found only by running the library against a real corpus and a real server, and each has a regression test quoting the input that caused it: a single NUL byte in one file aborting a 792-file index; every declared supersession edge failing on reference formatting; five tests that encoded the developer's own environment and failed on a correctly-configured host.