The product code was right; the test was wrong, and wrong in a way that made
two assertions fail and two others pass vacuously.
`build_write_path_hint` returns early when a write matched nothing at all — no
staleness, no synced record, no prior-art menu, no shape signal. The rule arm
sits deliberately on the FAR side of that guard, because it runs a semantic
search and hoisting it would mean an embedding query on every write in the
session. My fixture stubbed every other arm to empty, so it hit the early
return and the rule arm never ran: `record_rule_surfaced` was called zero
times, and "the recorder was not called" is also what two of the four tests
were asserting for their own reasons.
The fixture now supplies one prior-art hit — 0.72 against a 0.6 threshold, so
it clears the band and the top_k slice — with a comment saying the hit is the
arm's precondition rather than scenery.
And the gate got its own test, because the fixture now depends on it: a write
matching nothing must NOT reach the arm. Without that, a future change to the
guard would make every assertion in this file pass without exercising
anything. #3311 is explicit that the gate stays until the arm's precision is
fixed, so the test says to go read that issue rather than update the
assertion.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01TcCs1CcQ1ormdnzSshKqvN
bvandeusenandClaude Opus 5
70761b16d9