┌──────────┐    ┌──────────┐    ┌────────────┐    ┌──────────┐    ┌───────────┐
│  oracle  │───▶│ phoenix  │───▶│   plan-    │───▶│  kraken  │───▶│ surveyor  │
│          │    │          │    │   agent    │    │          │    │           │
└──────────┘    └──────────┘    └────────────┘    └──────────┘    └───────────┘
  Research       Analyze          Plan             Implement       Review
  target         current          migration        changes         migration

Task(
  subagent_type="oracle",
  prompt="""
  Research migration target: [TARGET]

  Investigate:
  - Breaking changes from current version
  - New APIs and patterns
  - Deprecated features we use
  - Migration guides from official docs
  - Common pitfalls and solutions

  Output: Migration research report
  """
)

Task(
  subagent_type="phoenix",
  prompt="""
  Analyze codebase for migration: [FROM] → [TO]

  Identify:
  - Files using deprecated APIs
  - Dependency conflicts
  - Patterns that need updating
  - Test coverage of affected areas
  - Risk areas (critical paths)

  Output: Impact analysis with affected files
  """
)

Task(
  subagent_type="plan-agent",
  prompt="""
  Create migration plan: [FROM] → [TO]

  Research: [from oracle]
  Impact: [from phoenix]

  Plan should:
  - Be phased (incremental if possible)
  - Each phase independently testable
  - Include rollback strategy
  - Prioritize critical path stability

  Output: Phased migration plan
  """
)

Task(
  subagent_type="kraken",
  prompt="""
  Implement migration phase: [PHASE_N]

  Plan: [from plan-agent]

  Requirements:
  - Follow plan exactly
  - Run tests after each change
  - Document any deviations
  - Stop if tests fail

  Output: Completed phase with test results
  """
)

Task(
  subagent_type="surveyor",
  prompt="""
  Review migration: [FROM] → [TO]

  Check:
  - All deprecated APIs replaced
  - No remaining compatibility shims
  - Tests passing
  - Performance acceptable
  - No security regressions

  Output: Migration review report
  """
)

User: /migrate React 17 → 18
→ Full workflow with hooks/concurrent mode changes

User: /migrate Python 3.9 → 3.12
→ Focus on new syntax, removed features

User: /migrate MongoDB → PostgreSQL
→ Schema design, data transformation, query rewrite

User: /migrate AWS → GCP
→ Service mapping, config translation

User: /migrate from Express to Fastify

Claude: Starting /migrate workflow: Express → Fastify

Phase 1: Researching Fastify...
[Spawns oracle]
Key differences:
- Schema-based validation (vs middleware)
- Plugin architecture
- Async/await native
- Different middleware pattern

Phase 2: Analyzing current Express usage...
[Spawns phoenix]
Impact analysis:
- 23 route files to update
- 8 middleware to convert
- 3 plugins need Fastify equivalents
- Test coverage: 78%

Phase 3: Creating migration plan...
[Spawns plan-agent]

Migration Plan: Express → Fastify
━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━

Phase 1: Setup & Core
- Add Fastify alongside Express
- Migrate core server setup
- Run both in parallel

Phase 2: Routes (by domain)
- Migrate auth routes
- Migrate user routes
- Migrate product routes
- ...

Phase 3: Middleware
- Convert error handler
- Convert auth middleware
- Convert logging

Phase 4: Cleanup
- Remove Express
- Remove compatibility layer
- Final testing

Rollback: Keep Express until Phase 4 complete

Phase 4: Implementing Phase 1...
[Spawns kraken]
✅ Fastify server running alongside Express
✅ Core routes migrated
✅ Tests passing

[Continues through phases...]

Phase 5: Reviewing migration...
[Spawns surveyor]
✅ All Express code removed
✅ 23/23 routes migrated
✅ Performance improved (2.1x faster)
✅ No security regressions

Migration complete! Express → Fastify

User: /migrate React 17 → 18 --phase 1
[Runs only Phase 1]

User: /migrate React 17 → 18 --phase 2
[Runs Phase 2, reads previous handoff]