# Review by Principal Systems Engineer (Google/Stripe caliber) (Round 2)

## Review Complete

**All 2841 tests pass.** 5 commits, +373 / -1 lines across 4 production/test files.

### FR Checklist — All 7 requirements implemented:

| Requirement | Status |
|---|---|
| FR-1: `reactions_remove` on Protocol | ✅ |
| FR-2: `remove_reaction()` helper | ✅ |
| FR-3: Both completion paths updated | ✅ |
| FR-4: try/except + debug logging | ✅ |
| FR-5: Remove before add ordering | ✅ |
| FR-6: `:tada:` on success only | ✅ |
| FR-7: Unit tests | ✅ (15 new tests) |

### Key Systems Engineering Assessment

**Failure isolation is correct.** Each of the three Slack API calls (remove `:eyes:`, add status emoji, add `:tada:`) is in its own independent try/except. At 3am when Slack is flapping, a failed `:eyes:` removal cannot block the completion signal. No blast radius.

**No race conditions.** Sequential calls within a single thread on a single message. Slack's reactions API is idempotent.

**One non-blocking observation:** The duplicated 18-line completion block appears in both main and fix paths. If a third path appears, extract a `_complete_with_reactions()` helper.

VERDICT: **approve**

FINDINGS:
- [src/colonyos/cli.py]: Both completion paths are structurally identical — extract a helper if a third path appears
- [tests/test_cli.py]: Tests replicate call sequence rather than exercising QueueExecutor directly — pragmatic trade-off
- [src/colonyos/slack.py]: `remove_reaction()` correctly delegates exception handling to callers

SYNTHESIS:
This is a textbook minimal change. 19 lines of production code following existing patterns exactly, with correct failure isolation so no cosmetic emoji operation can ever block the pipeline. The `remove_reaction()` helper mirrors `react_to_message()` in signature and behavior. All 2841 tests pass. Ship it.