[PoC] Jujutsu VCS Integration - Evidence-Based Validation #50
Description
Jujutsu VCS Integration - Proof of Concept Plan
🎯 Executive Summary
Objective: Validate whether Jujutsu VCS integration provides measurable benefits for the Agentic QE Fleet before committing to full implementation.
Approach: Evidence-based, risk-managed, incremental validation
Timeline: 2 weeks PoC → Decision point → 12 weeks full implementation (if approved)
Budget: 80 hours (1 engineer for 2 weeks)
📊 Baseline Metrics (Current System)
System State (as of 2025-11-15)
- Total Test Files: 1,256
- QE Agents: 102 agent definitions
- Monthly Commits: 142 commits (last 30 days)
- Version Control: Git (standard)
- No existing VCS abstraction layer
- No concurrent agent workspace isolation
Current Pain Points (TO BE VALIDATED)
- ❓ Agent workspace conflicts (frequency: unknown)
- ❓ Git staging overhead (time: unmeasured)
- ❓ Concurrent execution bottlenecks (occurrence: unknown)
- ❓ Conflict resolution time (baseline: not tracked)
CRITICAL: We need to measure these before claiming improvements.
🎯 Phase 1: Proof of Concept (2 Weeks)
Week 1: Installation & Validation
Day 1-2: Environment Setup
Goal: Confirm Jujutsu works in our environment
Tasks:
[ ] Install Jujutsu via package manager
[ ] Test basic jj commands in DevPod
[ ] Install agentic-jujutsu crate
[ ] Verify WASM bindings compile
[ ] Test basic WASM operationsSuccess Criteria:
- ✅ Jujutsu CLI works in DevPod
- ✅ WASM bindings compile without errors
- ✅ Can create/commit/query changes via WASM
Failure Exit: If WASM bindings don't work → Stop, document blockers, report findings
Day 3-5: Performance Baseline
Goal: Measure actual Git vs Jujutsu performance
Benchmark Tests:
// Test 1: Create workspace
measure(() => git.clone(repo))
measure(() => jj.init(repo))
// Test 2: Commit changes
measure(() => {
git.add('.');
git.commit('message');
})
measure(() => {
jj.commit('message'); // Auto-staging
})
// Test 3: Concurrent operations
measure(() => {
// 3 agents editing simultaneously
git.branch('agent-1'); git.checkout('agent-1');
git.branch('agent-2'); git.checkout('agent-2');
git.branch('agent-3'); git.checkout('agent-3');
})
measure(() => {
// 3 Jujutsu workspaces
jj.workspace.create('agent-1');
jj.workspace.create('agent-2');
jj.workspace.create('agent-3');
})
// Test 4: Conflict scenarios
// Create intentional conflicts, measure resolution timeDeliverable: Performance report with REAL numbers
Example Output:
## Performance Benchmark Results
| Operation | Git (ms) | Jujutsu (ms) | Improvement |
|-----------|----------|--------------|-------------|
| Create workspace | 450ms | 120ms | 3.75x faster |
| Commit changes | 85ms | 15ms | 5.67x faster |
| 3 concurrent workspaces | 1,200ms | 180ms | 6.67x faster |
| Resolve conflict (auto) | N/A | 450ms | New capability |
**Overall**: 4-7x performance improvement in tested scenarios
**Caveat**: Tested on DevPod with sample repo (50MB)Week 2: Integration Prototype
Day 6-8: Minimal VCS Adapter
Goal: Build simplest possible abstraction
Code:
// /src/vcs/base-adapter.ts
interface VCSAdapter {
commit(message: string): Promise<void>;
createWorkspace(name: string): Promise<Workspace>;
getCurrentChanges(): Promise<Change[]>;
}
// /src/vcs/jujutsu-adapter.ts
class JujutsuAdapter implements VCSAdapter {
// Minimal implementation using agentic-jujutsu
}
// /src/vcs/git-adapter.ts
class GitAdapter implements VCSAdapter {
// Wrapper around existing Git calls
}Success Criteria:
- ✅ Both adapters implement same interface
- ✅ Tests pass for both implementations
- ✅ Can swap adapters via config
Day 9-10: Single Agent Integration
Goal: Test with ONE agent (qe-test-generator)
Integration:
// Modify qe-test-generator to use VCS adapter
const adapter = VCSAdapterFactory.create(); // Auto-detect
await adapter.createWorkspace('test-gen-workspace');
await generateTests();
await adapter.commit('Generated tests for UserService');Test Scenarios:
- Generate tests with Git adapter → measure time
- Generate tests with Jujutsu adapter → measure time
- Run 3 concurrent test generations → measure conflicts
Success Criteria:
- ✅ Agent works with both adapters
- ✅ Jujutsu shows measurable performance improvement
- ✅ No breaking changes to existing workflow
📈 Success Metrics (Evidence-Based)
Minimum Viable Success (PoC)
Required to proceed to Phase 2:
| Metric | Target | Measurement |
|---|---|---|
| WASM Bindings Work | 100% | Can execute jj commands via WASM |
| Performance Improvement | ≥2x | Benchmarked commit/workspace operations |
| No Breaking Changes | 0 | Existing tests still pass |
| Single Agent Integration | Works | qe-test-generator uses adapter |
Decision Rule:
- ✅ ALL metrics met → Proceed to Phase 2 (full implementation)
⚠️ Performance <2x → Re-evaluate: Is juice worth the squeeze?- ❌ WASM doesn't work → Stop, document, close issue
Stretch Goals (Nice to Have)
- Concurrent workspace isolation working
- Auto-commit reducing overhead by >50%
- Conflict detection API functional
⚠️ Risk Assessment (Data-Driven)
Risk Matrix
| Risk | Probability | Impact | Mitigation |
|---|---|---|---|
| WASM bindings fail in DevPod | Medium | High | Test in Week 1 Day 1, exit early if fails |
| Performance <2x improvement | Medium | Medium | Measure in Week 1, decide if worth continuing |
| Jujutsu API changes (pre-1.0) | High | Medium | Pin version, document API used |
| Integration complexity | Low | Low | Start with 1 agent, keep it simple |
| Team learning curve | Low | Low | Optional feature, comprehensive docs |
Mitigation Strategies
Technical Risks:
- Pin agentic-jujutsu version in package.json
- Feature flag to disable if issues arise
- Git fallback always available
- Minimal changes to existing code
Adoption Risks:
- Make it opt-in via
.aqe-ci.yml - Document both Git and Jujutsu workflows
- Internal dogfooding before external release
📋 Deliverables (Evidence Required)
Week 1 Deliverables
[ ] Installation report (works/doesn't work)
[ ] Performance benchmarks (with real numbers)
[ ] WASM compatibility report
[ ] Go/No-Go decision document
Week 2 Deliverables
[ ] VCS adapter code (base + 2 implementations)
[ ] Single agent integration (qe-test-generator)
[ ] Test results (adapter tests + integration tests)
[ ] Final recommendation report
Final PoC Report Template
## Jujutsu VCS PoC - Final Report
### Executive Summary
- PoC Goal: Validate Jujutsu performance and feasibility
- Outcome: [Success / Partial Success / Failure]
- Recommendation: [Proceed / Revisit / Abandon]
### Measured Results
| Claim | Actual Result | Evidence |
|-------|---------------|----------|
| "23x faster" | X.Xx faster | Benchmark: tests/vcs-benchmark.ts |
| "95% conflict reduction" | Not tested (future work) | N/A |
| "WASM works in DevPod" | [Yes/No] | Installation log |
### Blockers Encountered
1. [Issue description + resolution/workaround]
### Lessons Learned
1. [What worked well]
2. [What didn't work]
3. [Unexpected findings]
### Recommendation
[Detailed reasoning for proceed/stop decision]
### Next Steps (if proceeding)
[Specific actions for Phase 2]🚀 Phase 2: Full Implementation (IF PoC Succeeds)
Timeline: 12 weeks (not 4 weeks - realistic estimate)
Scope: Extend to all 18 QE agents
Week 3-6: Adapter Layer (4 weeks)
- Complete VCS abstraction layer
- Implement all operations (commit, merge, rebase, log)
- Add operation logging to AgentDB
- 90%+ test coverage
- Documentation
Week 7-10: Agent Integration (4 weeks)
- Extend to all 18 QE agents (1-2 agents/week)
- Add workspace isolation per agent
- Implement concurrent execution tests
- Performance validation across all agents
Week 11-12: Configuration & Rollout (2 weeks)
- Add
.aqe-ci.ymlVCS configuration - Feature flags for gradual rollout
- Documentation (setup, migration, troubleshooting)
- Internal dogfooding
- Beta release announcement
Week 13-14: Monitoring & Iteration (2 weeks)
- Monitor production usage
- Collect feedback
- Fix bugs
- Performance tuning
- Case study documentation
Total: 14 weeks (PoC + Implementation)
💰 Cost-Benefit Analysis
Investment
- PoC: 80 hours (2 weeks × 1 engineer)
- Full Implementation (if approved): 480 hours (12 weeks × 1 engineer)
- Total: 560 hours
Expected Benefits (IF claims are validated)
Measured after PoC:
- Performance improvement: X.Xx faster (TBD)
- Workspace isolation: Yes/No (TBD)
- Auto-commit savings: Y% overhead reduction (TBD)
Theoretical benefits (cannot validate until full implementation):
- Conflict reduction: Unknown (requires AI conflict resolution)
- Cost savings: Unknown (requires learning system)
- Audit trail: Yes (Jujutsu operation log exists)
Break-Even Analysis
If PoC shows 2x improvement:
- Time saved per pipeline: ~5 seconds (estimated)
- Pipelines per day: ~20 (estimated)
- Time saved per day: 100 seconds = 1.67 minutes
- Time saved per week: 8.35 minutes
- Break-even: ~670 weeks (12+ years)
If PoC shows 5x improvement:
- Time saved per pipeline: ~15 seconds
- Break-even: ~250 weeks (5 years)
If PoC shows 10x improvement:
- Time saved per pipeline: ~35 seconds
- Break-even: ~110 weeks (2 years)
Conclusion: This is a long-term investment, not a quick win.
🎯 Decision Framework
After Week 1 (Go/No-Go Decision Point)
Proceed to Week 2 if:
- ✅ WASM bindings work in DevPod
- ✅ Performance improvement ≥2x
- ✅ No major blockers discovered
Stop if:
- ❌ WASM bindings don't work
- ❌ Performance <1.5x (marginal gain, high effort)
- ❌ Major blocker (API instability, compatibility)
After Week 2 (Full Implementation Decision)
Proceed to Phase 2 if:
- ✅ PoC fully successful (all success criteria met)
- ✅ Performance improvement ≥4x (justifies 12-week investment)
- ✅ Single agent integration works flawlessly
- ✅ Team capacity available (1 engineer for 12 weeks)
Defer if:
⚠️ Performance 2-4x (good but not great)⚠️ Higher priority features exist⚠️ Team capacity constrained
Abandon if:
- ❌ PoC failed to meet minimum criteria
- ❌ Performance <2x
- ❌ Integration too complex
📚 Research & References
Jujutsu VCS
- Docs: https://martinvonz.github.io/jj/
- GitHub: https://github.com/jj-vcs/jj
- Status: Pre-1.0 (API may change)
agentic-jujutsu
- Crates.io: https://crates.io/crates/agentic-jujutsu
- Status: Experimental WASM bindings
Comparison with Original Proposal (Issue #47)
| Aspect | Original Claim | This Plan |
|---|---|---|
| Timeline | 4 weeks | 2 weeks PoC + 12 weeks implementation |
| Performance | "23x faster" | Measure in PoC, don't promise |
| Scope | 18 agents + AI + learning | 1 agent in PoC, expand if successful |
| Success criteria | Vague ("learning improves") | Measurable (≥2x perf, WASM works) |
| Risk assessment | Underestimated | Realistic with exit points |
🚦 Next Steps
Immediate (This Week)
- Review this plan with stakeholders
- Approve 2-week PoC budget (80 hours)
- Assign engineer to PoC work
- Set up tracking (PoC kanban board)
Week 1 PoC Kickoff
- Install Jujutsu in DevPod
- Test WASM bindings
- Run performance benchmarks
- Document findings
Decision Points
- End of Week 1: Go/No-Go for Week 2
- End of Week 2: Proceed/Defer/Abandon Phase 2
📞 Contact & Questions
PoC Lead: TBD
Stakeholders: Product, Engineering, QE
Escalation: If blockers arise, escalate immediately (don't wait 2 weeks)
Created: 2025-11-15
Status: Awaiting Approval
Next Review: End of Week 1 (PoC)