OCaml MCP
OCaml implementation of the Model Context Protocol (MCP), enabling integration between AI assistants and development tools.
Quick Start
# Install
opam install ocaml-mcp-server
# Terminal 1 - Start server
ocaml-mcp-server --socket 8080
# Terminal 2 - Use client
mcp call "dune/build-status" --socket 8080
mcp call "ocaml/module-signature" --socket 8080 \
-a '{"module_path": ["List"]}'
Libraries
- mcp - Core protocol implementation (types, client, server)
- mcp-eio - Transport layer (stdio, socket, memory, HTTP)
- mcp-sdk - High-level SDK for building MCP servers and clients
- ocaml-mcp-server - OCaml development tools server
Implementation Status
✅ Implemented
- Core protocol types and JSON-RPC messaging
- Client/server request-response patterns
- Notification handling
- Transport layer (stdio, socket, memory, HTTP)
- Server-to-client request handling (sampling, elicitation, roots)
- High-level SDK with type-safe tool/resource/prompt registration
- Dynamic JSON schema generation from OCaml types
- OCaml development tools (Dune build status, module signatures from build artifacts)
- Full compliance with MCP 2025-06-18 specification
🚧 In Progress / Missing
High Priority:
- OAuth 2.1 authentication - Security for production use
Feature Parity:
- Request lifecycle:
- Timeouts
- Cancellation - Currently not supported. The protocol defines
$/cancel notifications, but implementing proper cancellation requires thread-safe cancellation tokens and checking cancellation status during long operations
- Progress tracking (basic support implemented)
- Argument completion support
- WebSocket and SSE transports
- Some client helper functions (resources/subscribe, completion/complete, logging/setLevel, ping)
Examples
See the examples/ directory for complete working examples:
- weather-server - A minimal MCP server that provides weather information
License
ocaml-mcp is available under the ISC License.
