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

## Review Complete — Principal Systems Engineer (Google/Stripe caliber), Round 3

**VERDICT: approve** ✅

### Summary

All **19 functional requirements** from the PRD are fully implemented. **660 tests pass, 0 failures.** No TODOs, no placeholder code, no secrets, no new dependencies.

### Key Reliability Strengths

- **Fail-closed everywhere**: `generate_repo_map()` is wrapped in `try/except Exception` in both pipeline and CEO entry points. A map crash produces a warning log and the pipeline continues unharmed. Blast radius = zero.
- **No race conditions**: Map generated once as a string, passed by value to all 8 phases. No mutable shared state, no caching, no invalidation complexity.
- **Bounded resources**: 30s subprocess timeout, 2000-file cap with warning, 1MB file size guard against OOM on generated megafiles.
- **Debuggable from logs**: Warning on `git ls-files` failure, file count cap, parse skips. `_log()` shows injected char count per phase.

### Non-blocking Findings (3, all cosmetic)

| # | File | Finding |
|---|------|---------|
| 1 | `cli.py:1283` | `type(repo_map_config)(...)` → should be `dataclasses.replace()` (fragile if subclassed) |
| 2 | `repo_map.py:27-28` | Duplicated comment "Hardcoded sensitive file patterns..." — leftover from `_MAX_PARSE_SIZE` insertion |
| 3 | `repo_map.py:rank_by_relevance` | O(files × keywords × symbols) — fine under 2000-file cap, worth noting for future profiling |

Review saved to `cOS_reviews/reviews/principal_systems_engineer/20260331_round3_build_a_repomap_module.md`.
