# Review by Staff Security Engineer (Round 1)

I don't see any budget allocation or enforcement in the parallel orchestrator. The PRD FR-7 requires:
- Each parallel agent receives a budget of `budget.per_phase / max_parallel_agents`
- Enforce budgets strictly per-agent to contain blast radius

This is another significant gap from a security perspective - runaway agents could consume more budget than intended.

Now let me write my review output:

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## Security Review: Parallel Implement Mode

### Assessment Summary

I have completed my security-focused review of the implementation on branch `colonyos/add_a_parallel_implement_mode_that_spawns_multiple_agent_sessions_to_implement_i`.

### Checklist Assessment

**Completeness:**
- ✅ Core parallel orchestration architecture implemented
- ✅ DAG parsing with cycle detection implemented
- ✅ Git worktree isolation implemented
- ✅ UI integration for task prefixes implemented
- ✅ Stats integration for parallelism metrics implemented
- ⚠️ Missing: Merge lock with timeout (FR-5.2) - no asyncio.Lock implementation
- ⚠️ Missing: Per-agent budget enforcement (FR-7) - no budget partitioning or enforcement

**Quality:**
- ✅ All 1382 tests pass
- ✅ No linting errors
- ✅ Code follows existing project conventions
- ✅ No unnecessary dependencies added

**Safety:**
- ✅ No secrets or credentials in committed code
- ✅ Task ID validation prevents path traversal via `_validate_task_id()` and strict regex
- ✅ Git worktrees provide filesystem isolation between agents
- ⚠️ **Concern**: No per-agent budget caps - a runaway agent could consume the entire run budget
- ⚠️ **Concern**: No merge lock - race conditions possible during concurrent merges
- ⚠️ **Concern**: Missing audit trail for lock acquisition timestamps

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VERDICT: request-changes

FINDINGS:
- [src/colonyos/parallel_orchestrator.py]: Missing asyncio.Lock with 60-second timeout for merge operations (FR-5.2). Concurrent merges could race without this safeguard.
- [src/colonyos/parallel_orchestrator.py]: No per-agent budget allocation or enforcement (FR-7). A misbehaving agent could consume unlimited budget, violating blast radius containment.
- [src/colonyos/parallel_orchestrator.py]: No timestamp logging for lock acquisition as required by FR-5.2 audit trail requirement.
- [src/colonyos/worktree.py]: Task ID validation is present (good), but the validation in WorktreeManager could be bypassed if merge_worktrees() is called with task IDs that didn't flow through create_worktree(). The DAG regex limits this risk but defense-in-depth would add validation at merge time too.

SYNTHESIS:
From a security perspective, the implementation demonstrates solid fundamentals: proper input validation for task IDs to prevent path traversal attacks, filesystem isolation via git worktrees, and existing patterns are followed. However, three critical security requirements from the PRD are not implemented: (1) the merge lock mechanism that prevents race conditions during concurrent branch merges, (2) per-agent budget enforcement to contain blast radius from runaway agents, and (3) audit trail logging for lock operations. Without the merge lock, concurrent agents could produce corrupted merges. Without budget enforcement, a single agent could exhaust the entire run budget, starving other tasks and potentially running up unexpected costs. These gaps represent real blast radius and observability risks in a system that spawns multiple autonomous agents with full repo permissions.