# Review by Staff Security Engineer (Round 4)

## Staff Security Engineer Review — Complete

VERDICT: **approve**

FINDINGS:
- **[src/colonyos/cli.py:2618-2622]**: `original_prompt` extracted from parent item is not re-sanitized — safe today but fragile if `source_value` population paths change
- **[src/colonyos/sanitize.py:66-67]**: Stripped Slack link URLs logged at DEBUG instead of INFO — may not appear in production logs for forensic audit
- **[src/colonyos/instructions/thread_fix.md]**: Agent runs with `bypassPermissions` — prompt-level instruction is the only control preventing push/exfiltration during Implement phase (pre-existing architectural risk)
- **[src/colonyos/cli.py:1990]**: No per-thread budget cap — fix rounds count against global daily budget only; `max_fix_rounds_per_thread=3` provides partial mitigation
- **[src/colonyos/orchestrator.py]**: No PRD/task SHA integrity verification (acknowledged as fast-follow in PRD)

SYNTHESIS:
This is a well-implemented feature from a security standpoint. The implementation demonstrates consistent defense-in-depth: branch names are validated with strict allowlists at three separate points, HEAD SHA verification guards against force-push tampering, the sanitization chain is complete (Slack link stripping → XML tag removal → role-anchoring wrapper), and fix items go through the same allowlist/budget/circuit-breaker controls as regular runs. The `parent_item_id` field provides audit trail linkage. All 515 tests pass. The concerns identified are hardening opportunities (re-sanitization of inherited prompts, audit log levels, artifact integrity hashing) rather than exploitable vulnerabilities. Approve.