# Review by Staff Security Engineer (Round 1)

## Review Complete — Staff Security Engineer

**VERDICT: approve**

### Summary

The implementation on branch `colonyos/when_a_slack_message_comes_i_want_it_to_be_proce_fd0c6a144b` is a clean, surgically scoped security improvement. All 8 functional requirements from the PRD are correctly implemented across a tight 3-file diff (+706 lines, mostly tests).

### Key Security Findings

| Area | Assessment |
|------|-----------|
| **Lock removal (FR-1/2)** | ✅ Correct. `triage_message()` is stateless — removing `agent_lock` is a least-privilege win that eliminates a DoS vector (pipeline starvation blocking intake). |
| **TOCTOU rate-limit fix (FR-6)** | ✅ `increment_hourly_count` and `check_rate_limit` are now atomic under the same `state_lock` acquisition. Burst abuse window closed. Fail-closed on triage failure. |
| **Redelivery loop prevention (FR-5)** | ✅ Both transient and non-transient failure paths mark `triage-error` under `state_lock`. Redelivery loop broken. |
| **Bounded retry (FR-4)** | ✅ Max 2 attempts, 3s backoff, shutdown-aware, fail-closed. Non-transient errors skip retry. |
| **Test coverage** | ✅ 14 new tests cover all security-relevant paths. All 2,649 tests pass (0 regressions). |
| **Secrets/credentials** | ✅ Clean — no sensitive material in diff. |

### One Minor Observation (informational, no action needed)
- The retry catch `(TimeoutError, ConnectionError, OSError)` has `ConnectionError` redundant with `OSError` (it's a subclass). Harmless — improves readability of intent.

Review artifact saved to `cOS_reviews/reviews/staff_security_engineer/20260331_150608_round1_you_are_a_code_assistant_working_on_behalf_of_the_engineering_team_the_following.md`.
