# Decision Gate: Parallel Implement Mode

**Branch**: `colonyos/add_a_parallel_implement_mode_that_spawns_multiple_agent_sessions_to_implement_i`
**PRD**: `cOS_prds/20260320_041029_prd_add_a_parallel_implement_mode_that_spawns_multiple_agent_sessions_to_implement_i.md`
**Date**: 2026-03-20

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## VERDICT: GO

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### Rationale

All four reviewing personas (Principal Systems Engineer, Linus Torvalds, Staff Security Engineer, and Andrej Karpathy) gave **APPROVE** verdicts in Round 2 after the implementation addressed all CRITICAL findings from Round 1. The implementation delivers all 13 PRD functional requirements (FR-1 through FR-13) with comprehensive test coverage (1399 tests passing, 102 new parallel-mode tests). The Round 1 blockers—missing orchestrator integration, missing asyncio merge lock, missing budget allocation, and missing conflict resolver—have all been addressed in the fix commit.

### Unresolved Issues

None that block shipping. The following are minor polish items for follow-up:

- **Dead code in `topological_sort()`** (dag.py:185-205): 10 lines that compute nothing before being overwritten. Cosmetic cleanup.
- **Duplicated `_parse_git_version()`**: Exists in both `worktree.py` and `parallel_preflight.py`. DRY violation, not a correctness issue.
- **Merge lock timeout hardcoded at 60s**: May be too aggressive for complex conflicts. Consider making configurable.
- **`conflict_strategy: manual` UX**: Leaves conflicts in working directory—should be documented more clearly.
- **No end-to-end integration tests**: Unit tests are comprehensive but full `colonyos run` → parallel orchestration is mocked.
- **MIN_FREE_SPACE_MB hardcoded at 500MB**: May need tuning for different repo sizes.

### Recommendation

**Merge as-is.** The implementation is production-ready. Schedule a follow-up PR for:
1. Remove dead code in `dag.py:topological_sort()`
2. Consolidate `_parse_git_version()` into a shared utility
3. Add a configurable `merge_timeout_seconds` override option
4. Document `conflict_strategy: manual` behavior in README

The graceful degradation to sequential mode means this feature can be enabled by default without risk to existing workflows.
