Agent Skills: Worktree Merge

Worktree Merge

Merge parallel worktrees into unified branch after parallel implementation.

<ARH_INTEGRATION> Adaptive Response Handler for conflict resolution dialogue:

• RESEARCH_REQUEST ("research", "check", "verify") -> Dispatch subagent to analyze git history
• UNKNOWN ("don't know", "not sure") -> Dispatch analysis subagent to show context
• CLARIFICATION (ends with ?) -> Answer, then re-ask original question
• SKIP ("skip", "move on") -> Mark as manual resolution needed </ARH_INTEGRATION>

MUST:

1. ALWAYS perform 3-way analysis - no exceptions, no shortcuts
2. Respect interface contracts - parallel work was built against explicit contracts
3. Document reasoning - every resolution decision must be justified
4. Verify everything - tests are mandatory after each round

Skipping steps = lost features. Rushing = broken integrations. Undocumented decisions = confusion. </CRITICAL>

Invariant Principles

1. Interface contracts are law - Parallel work built against explicit contracts. Violations block merge.
2. 3-way analysis mandatory - Base vs ours vs theirs. No blind ours/theirs acceptance.
3. Test after each round - Catch integration failures immediately. No "test at end" batching.
4. Dependency order prevents cascading conflicts - Merge foundations first.
5. Document every decision - Reasoning trail for each conflict resolution.

Pre-Conflict Gate

When dispatching a conflict resolution subagent:

1. Subagent prompt MUST instruct it to invoke resolving-merge-conflicts via the Skill tool
2. Subagent prompt MUST include interface contract context from the implementation plan
3. Do NOT resolve conflicts inline in the orchestrator context

If you catch yourself resolving a conflict without having loaded the skill: STOP. Dispatch a subagent that loads it. </CRITICAL>

Inputs/Outputs

| Input | Required | Description | |-------|----------|-------------| | base_branch | Yes | Branch all worktrees branched from | | worktrees | Yes | List: worktree paths, purposes, dependencies | | interface_contracts | Yes | Path to implementation plan defining contracts | | test_command | No | Defaults to project standard |

| Output | Type | Description | |--------|------|-------------| | unified_branch | Git branch | All worktree changes merged | | merge_log | Inline | Decision trail for each conflict | | verification_report | Inline | Test results and contract status |

Pre-Flight

If NO to any: STOP and address before proceeding. </analysis>

Workflow

Phase 1: Merge Order

Build dependency graph:

| Round | Criteria | Example | |-------|----------|---------| | 1 | No dependencies (foundations) | setup-worktree | | 2 | Depends only on Round 1 | api-worktree, ui-worktree | | N | Depends only on prior rounds | integration-worktree |

Create merge plan:

## Merge Order
### Round 1 (no dependencies)
- [ ] setup-worktree -> base-branch

### Round 2 (depends on Round 1)
- [ ] api-worktree -> base-branch (parallel)
- [ ] ui-worktree -> base-branch (parallel)

### Round 3 (depends on Round 2)
- [ ] integration-worktree -> base-branch

<RULE>ALWAYS create checklist via TodoWrite before starting merge operations.</RULE>

Phase 2: Sequential Round Merging

Dispatch: /merge-worktree-execute

Phase 3: Conflict Resolution

Dispatch: /merge-worktree-resolve

Phases 4-5: Final Verification + Cleanup

Dispatch: /merge-worktree-verify

Conflict Synthesis Patterns

| Pattern | Scenario | Resolution | |---------|----------|------------| | Same Interface | Both implemented a shared interface method | Check contract for expected behavior. Choose contract-compliant version. If both match, synthesize best parts. If neither matches, fix to match. | | Overlapping Utilities | Both added similar helper functions | Same purpose: keep one, update callers. Different purposes: rename to clarify, keep both. | | Import Conflicts | Both added imports | Merge all imports, remove duplicates, sort per project conventions. | | Test Conflicts | Both added tests | Keep ALL tests from both. Ensure no duplicate test names. Verify no conflicting shared fixtures. |

Error Handling

| Error | Response | |-------|----------| | Uncommitted changes in worktree | AskUserQuestion: "Worktree [path] has uncommitted changes. Options: (1) Commit with message '[suggested]', (2) Stash and proceed, (3) Abort for manual handling" | | Tests fail after merge | STOP. Do NOT proceed to next round. Invoke systematic-debugging. Fix. Retest. Only continue when passing. | | Interface contract violation | CRITICAL: "Contract violation detected. Contract: [spec]. Expected: [X]. Actual: [Y]. Location: [file:line]. MUST fix before merge proceeds." |

Rollback Procedure

If merge goes wrong after commit:

# Identify pre-merge commit
git log --oneline -5

# Reset to before merge (preserve working tree)
git reset --soft HEAD~1

# Or hard reset if working tree also corrupted
git reset --hard [pre-merge-commit-sha]

# Re-attempt with lessons learned

Self-Check

<RULE>Before completing worktree merge, verify ALL items. If ANY unchecked: STOP and fix.</RULE>

• [ ] Merged worktrees in dependency order?
• [ ] Ran tests after EACH round?
• [ ] Performed 3-way analysis for ALL conflicts?
• [ ] Verified interface contracts are honored?
• [ ] Ran auditing-green-mirage on tests?
• [ ] Ran code review on final result?
• [ ] Deleted all worktrees after success?
• [ ] All tests passing?

Success Criteria

• All worktrees merged into base branch
• All interface contracts verified
• All tests passing
• Code review passes
• All worktrees cleaned up
• Single unified branch ready for next steps

<FINAL_EMPHASIS> Your reputation depends on merging parallel work without losing features or introducing bugs. Every conflict requires 3-way analysis. Every round requires testing. Every merge requires verification. Interface contracts are mandatory, not suggestions. No feature left behind. No bug introduced. You'd better be sure. </FINAL_EMPHASIS>