32 deterministic tests covering isToolFailure status-line semantics,
toolCallFingerprint determinism + repeat exemptions, routeStopReason
(malformed tool call, max_tokens, open criteria, action claims, retry
cap), ToolErrorClassifier codes, GoalStateStore evidence gating,
PlanStateStore surfacing rules, and critic-gate diff plumbing.
All pass: xcodebuild test -only-testing:AgentTests/HarnessGuardTests.