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

**135 tests pass. All 5 functional requirements implemented. All previous-round findings addressed.**

VERDICT: approve

FINDINGS:
- [src/colonyos/orchestrator.py]: FINDINGS parser state machine could misclassify a `-` prefixed non-finding line after blank lines — not triggered by review template in practice, worst case is one extra truncated line.
- [src/colonyos/orchestrator.py]: Silent swallow of ValueError/TypeError in cost/duration formatting — a logger.debug would aid future debugging.
- [src/colonyos/orchestrator.py]: _truncate_slack_message hard-cut fallback doesn't respect grapheme cluster boundaries — cosmetic only, Slack handles gracefully.

SYNTHESIS:
This is production-ready. The implementation is exactly what I want to see from a reliability perspective: deterministic post-processing of existing artifacts, no new external calls, graceful degradation at every layer. The three-tier fallback in `_extract_review_findings_summary()` (FINDINGS → SYNTHESIS → first line) is the correct pattern for consuming stochastic LLM output. The double-sanitization boundary (`sanitize_untrusted_content` → `sanitize_for_slack`) is applied consistently at content ingress, not at output — correct architecture. Named constants make every truncation limit auditable. The `_truncate_slack_message` function ensures no message blows past the 3,000-char cap regardless of input pathology. All three previous-round findings (truncation constant, bare link regex gap, audit logging) have been cleanly addressed with corresponding test coverage. The remaining observations are debuggability nits, not correctness or safety issues. Ship it.

Review artifact saved to `cOS_reviews/reviews/principal_systems_engineer/20260331_201500_round4_when_you_output_followups_in_the_thread_on_slack_a938599349.md`.