Enhancement: Improve parallel-execute orchestration with merge validation

[shakestzd]

Problem

/slashsense:parallel-execute exists but has gaps:

• No cross-branch API validation
• Missing cost reporting
• No merge conflict prevention
• Manual merge order required

Real Example: DocuColab workflow had:

• Merge conflicts in __init__.py
• API inconsistencies (property vs method)
• Manual merge order coordination
• No final cost report

Impact

• 🐛 Quality: API bugs slip through
• ⏱️ Time: 11 min debugging post-merge
• 💰 Costs: No visibility into savings
• 🔧 Manual work: User must coordinate merges

Current Workflow

/slashsense:parallel-execute
  ├─ Creates worktrees ✅
  ├─ Spawns agents ✅
  ├─ Runs tasks ✅
  ├─ Reports completion ✅
  ├─ Cross-branch validation ❌ MISSING
  ├─ Merge coordination ❌ MISSING
  └─ Cost reporting ❌ MISSING

Proposed Enhancements

1. Cross-Branch API Validation

Before merging:

• Check for shared interfaces
• Compare implementations
• Run shared test suite
• Report incompatibilities
• Block merge if issues found

2. Intelligent Merge Coordination

Automatically:

• Determine merge order from dependencies
• Merge in correct sequence
• Handle common conflicts (imports, exports)
• Validate after each merge
• Rollback on failure

3. Cost Reporting

After completion:

• Show total cost
• Break down by agent
• Compare to baseline
• Display savings achieved

4. Conflict Prevention

Before spawning agents:

• Identify high-risk files (like __init__.py)
• Pre-assign ownership
• Create merge plan
• Set up validation checkpoints

Enhanced Workflow

/slashsense:parallel-execute

Phase 1: Planning
  ├─ Analyze task dependencies
  ├─ Identify shared interfaces
  ├─ Create conflict prevention plan
  └─ Estimate costs

Phase 2: Execution
  ├─ Create worktrees
  ├─ Spawn agents
  ├─ Monitor progress
  └─ Track costs

Phase 3: Validation
  ├─ Cross-branch API check
  ├─ Shared interface tests
  ├─ Report incompatibilities
  └─ Get user confirmation

Phase 4: Integration
  ├─ Merge in dependency order
  ├─ Validate after each merge
  ├─ Handle conflicts automatically
  └─ Rollback on failure

Phase 5: Reporting
  ├─ Show total cost
  ├─ Display savings
  ├─ Performance metrics
  └─ Recommendations

Implementation

Extend parallel-execute Command

<!-- .claude/commands/parallel-execute.md -->

## Phase 3: Cross-Branch Validation (NEW)

After all agents complete:

1. Detect shared interfaces
2. Run interface compliance checks
3. Compare API implementations
4. Run shared test suite
5. Report issues to user
6. Block merge if failures

## Phase 4: Intelligent Merging (NEW)

1. Build dependency graph
2. Determine merge order
3. Merge sequentially
4. Validate each merge
5. Handle common conflicts
6. Rollback if needed

## Phase 5: Cost Reporting (NEW)

1. Collect cost metrics from agents
2. Calculate total
3. Compare to baseline
4. Display savings
5. Generate recommendations

Acceptance Criteria

• Cross-branch validation runs before merge
• Merge order determined automatically
• Common conflicts handled (imports, exports)
• Validation after each merge
• Cost report displayed at end
• Rollback mechanism works
• User can override decisions

Estimated Effort

12-15 hours (medium complexity)

Benefits

• Prevents API bugs before merge
• Automates merge coordination
• Shows cost savings
• 90% reduction in post-merge debugging

Priority: High
Labels: enhancement, orchestration

Related Issues

• Feature: Agent Cost Advisor Skill - Help users discover cost-optimized agents #5 (Agent Cost Advisor)
• Feature: Cross-Branch API Validation for parallel-task-executor #6 (Cross-Branch Validation)
• Feature: Cost Tracking and Reporting for SlashSense Agents #7 (Cost Reporting)