# Review by Staff Security Engineer (Round 2)

## Security Review Complete

I have completed my security review of the parallel implement mode implementation. Here's my assessment:

### VERDICT: approve

### Key Findings

**Positive Security Patterns:**
1. **Path traversal protection** - Worktree manager correctly validates task IDs with regex and explicit checks for `..`, `/`, and `\`
2. **No command injection vectors** - All subprocess calls use list-based arguments, no `shell=True`
3. **Budget isolation** - Per-task budget allocation limits blast radius from runaway agents
4. **Audit logging** - Merge lock acquisition/release timestamps logged for forensics
5. **Configuration validation** - Invalid config values raise errors early
6. **No hardcoded secrets** - Clean grep of all new files

**Areas of Note (Medium/Low severity):**
1. Worktree isolation is filesystem-only, not security sandboxing - agents still run with full user privileges
2. Conflict resolution agent has broad repo access without explicit scope constraints in instructions
3. Error messages logged without sanitization could potentially leak secrets
4. Worktree cleanup failures are logged as warnings rather than failures

### Test Coverage
All 102 parallel-mode tests pass, including security-critical tests for path traversal validation, cycle detection (prevents infinite loops), and budget allocation.

### Synthesis
The implementation demonstrates good security hygiene for this threat model. The concerns identified relate to inherent limitations of running AI agents with user privileges, not implementation bugs. I recommend approval with a suggestion to document that parallel mode provides *conflict isolation*, not *security sandboxing*.
