[PRD] MCP (Model Context Protocol) Integration

[espetro]

Summary

Expose Calca's design pipeline to external AI agents via the Model Context Protocol. Enables AI assistants (Claude Desktop, Cursor, etc.) to invoke Calca's design generation programmatically. Distinct from the Plugin Panel concept — MCP is outbound (Calca → external agents), not inbound UI extensions.

Deliverables

• package with MCP protocol implementation
• Calca as MCP Host (discover, install, run external MCP servers)
• Calca as MCP Server (expose design pipeline tools to external agents)
• Desktop-only (stdio transport, process spawning)
• Security sandboxing (env validation, timeouts, memory limits)
• Audit logging for all tool calls

Effort

~29 days (~6 weeks):

• Phase 0 (Foundation): 4.5 days — packages/mcp scaffold, stdio transport
• Phase 1 (MVP): 8 days — Calca as MCP Host
• Phase 2 (v1): 6 days — Calca as MCP Server (expose tools)
• Phase 3 (v2): 10.5 days — Registry, Pro servers, HTTP transport

Timeline

Post-v1.0 — Desktop-only for v1, indirect user impact, ecosystem timing. Ship after desktop app is stable.

References

• 📄 PRD: docs/roadmap/mcp-integration.md
• 🏗️ Architecture: New package, clean separation from core pipeline
• 🔗 Depends on: Desktop app stability, packages/core stable API