# Review by Principal Systems Engineer (Google/Stripe caliber) (Round 3)

## Review Complete — Principal Systems Engineer (Round 1)

All 9 functional requirements from the PRD are implemented. All 3110 tests pass with zero regressions. The implementation is clean, pattern-consistent, and well-tested.

**Key observations:**

1. **`_verify_detected_failures()`** — Correctly implements structured sentinel parsing (`VERIFY_RESULT: PASS/FAIL`) with safe regex fallback. 16 unit tests cover edge cases including the critical false-positive on `"0 failed"`.

2. **Verify-fix loop** — Clean `for attempt in range(max + 1)` structure with budget guards before both verify and fix agents. Mirrors the existing review-fix pattern exactly.

3. **Two-agent separation** — Read-only verify (`allowed_tools=["Read", "Bash", "Glob", "Grep"]`) vs. write-enabled fix preserves audit boundaries.

4. **Hard-block invariant** — `_fail_run_log()` + early return guarantees no broken PR ever reaches main.

5. **Resume support** — `_compute_next_phase("learn") → "verify" → "deliver"` and `_SKIP_MAP` entries enable correct resume from failed verify runs.

**Non-blocking trade-offs:** Phase.FIX reuse, fail-open on ambiguous output, no haiku default for verify. All acceptable for v1.

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VERDICT: **approve**

FINDINGS:
- [src/colonyos/orchestrator.py]: `_verify_detected_failures()` correctly implements structured sentinel parsing with regex fallback — all 16 edge-case unit tests pass
- [src/colonyos/orchestrator.py]: Verify-fix loop follows established review-fix pattern (budget guards, heartbeat, two-agent separation, `_append_phase`)
- [src/colonyos/orchestrator.py]: `_compute_next_phase()` and `_SKIP_MAP` correctly route learn → verify → deliver for resume support
- [src/colonyos/orchestrator.py]: Hard-block via `_fail_run_log()` + early return ensures no broken PR is ever opened — the core invariant holds
- [src/colonyos/config.py]: `VerifyConfig` with validation, `PhasesConfig.verify`, round-trip serialization — clean config integration
- [src/colonyos/instructions/verify.md]: Sentinel contract (`VERIFY_RESULT: PASS/FAIL`) makes verify output reliably parseable
- [tests/test_verify_phase.py]: 621 lines covering all happy paths, failure modes, budget exhaustion, resume, and integration scenarios

SYNTHESIS:
This is a clean, well-scoped implementation that follows every established pattern in the codebase. The critical engineering decisions are sound: two-agent separation preserves audit boundaries, budget guards prevent runaway costs, the hard-block invariant guarantees no broken PR reaches main, and the structured sentinel approach to output parsing eliminates the class of false-positive bugs that plagued the initial implementation. The 55 new tests cover the decision boundaries thoroughly — particularly the `_verify_detected_failures()` function which is the most failure-prone component. The implementation adds exactly the right amount of complexity: no over-abstraction, no premature optimization, no config knobs that aren't immediately useful. Ship it.
