# Review by Principal Systems Engineer (Google/Stripe caliber) (Round 4)

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## Principal Systems Engineer Review — Round 3

VERDICT: **approve**

FINDINGS:
- [orchestrator.py:3996-4006]: Missing UI completion callback in sequential path — parallel branch calls `impl_ui.phase_complete()`/`phase_error()` but sequential returns without an overall completion signal to the UI. Cosmetic only.
- [orchestrator.py:4030]: Fallback path from parallel-returns-None doesn't log that parallel was attempted. Minor debuggability gap for 3am incidents.
- [orchestrator.py:3982-3990]: Parallel path missing `memory_store` and `user_injection_provider` args (pre-existing, not introduced by this PR).
- [orchestrator.py]: Budget savings not redistributed across tasks — by-design per PRD, noted for follow-up.
- [orchestrator.py]: Sequential git operations (diff → add) are non-atomic — safe in single-agent-sequential context, documented for future readers.

SYNTHESIS:
All 10 functional requirements are implemented and tested. The implementation correctly eliminates merge conflicts by making sequential execution the default, with each task committed individually in topological order before the next starts. The DAG-aware failure propagation (BLOCKED status through transitive dependencies, independent tasks continue) is the hardest part and it's done correctly with thorough test coverage. Security layering — selective staging, secret filtering, commit sanitization, subprocess timeouts, audit logging — is solid and independently tested. 81+ tests pass with zero regressions. The 5 non-blocking findings are all LOW/INFO severity (cosmetic UI gap, pre-existing asymmetries, documentation). This is ready to ship.
