# Review by Staff Security Engineer (Round 1)

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## Review Complete — Staff Security Engineer

**VERDICT: approve**

### Key Security Findings

**Strengths:**
- **Tool restriction enforced at runtime** — The verify agent's read-only access (`["Read", "Bash", "Glob", "Grep"]`) is enforced via `allowed_tools` parameter, not just instructions. Defense-in-depth done right.
- **Two-agent audit separation** — Verify (observe) and fix (modify) are distinct phase invocations with separate `PhaseResult` entries, enabling clean post-incident forensics.
- **Budget guards prevent runaway costs** — Mirrors the existing review-fix loop pattern. No unbounded loops possible.
- **Hard-block on persistent failure** — Core invariant holds: never open a known-broken PR.
- **All 3093 tests pass** including 205 new/modified verify-related tests.

**Minor Concerns (non-blocking):**
1. **`_verify_detected_failures()` has no direct unit tests** and defaults to fail-open (empty output = tests passed). Recommend adding edge-case unit tests.
2. **Resume gap** — `_compute_next_phase("learn")` returns `None`, so auto-resume from a verify failure needs manual intervention.
3. **Unsanitized test output in fix prompt** — accepted risk, consistent with existing threat model.

Full review written to `cOS_reviews/reviews/staff_security_engineer/20260401_230000_round1_...md`.
