Major Features:
- Multi-server support with error isolation
- Auto ext_ prefix prevents native tool collisions
- Pre-flight command validation (no uncaught exceptions)
- Health monitoring with auto-recovery (60s intervals)
- Rate limiting (concurrent + per-minute)
- Metrics & observability (/mcp-metrics command)
- Protocol completeness (resources, prompts)
- Hot reload capability (/mcp-reload command)
- Comprehensive test suite (13 test cases)

P0 Features (Critical):
✅ Auto ext_ prefix for collision prevention
✅ MCP-to-MCP collision detection
✅ Pre-flight command check
✅ Error isolation (one bad server != crash)
✅ Tool discovery (/mcp command)
✅ Graceful degradation

P1 Features (Should Have):
✅ Expanded config validation
✅ Health monitoring & auto-restart
✅ Resource cleanup (no zombie processes)
✅ Basic test coverage

P2 Features (Nice to Have):
✅ Rate limiting (maxConcurrent, maxPerMinute)
✅ Metrics endpoint (/mcp-metrics)
✅ Resources & Prompts support
✅ Hot reload (/mcp-reload)

Testing:
- Crash-tested with invalid configurations
- Verified error isolation (3/4 servers working)
- Confirmed zombie process cleanup
- Production deployment verified (51 tools loaded)

Documentation:
- Comprehensive README (666 lines)
- Implementation summary with lessons learned
- Troubleshooting guide
- Configuration examples

Files:
- index.ts (995 lines)
- index.test.ts (219 lines, 13 tests)
- README.md (updated)
- IMPLEMENTATION-SUMMARY.md (new)

Status: Production Ready ✅