A Model Context Protocol (MCP) server for executing Julia code through Pluto.jl notebooks. Built with direct integration using the @plutojl/rainbow package.

• Julia Code Execution: Run Julia code with comprehensive result capture
• Type Inference: Automatic type detection for Julia values (Int64, Float64, String, etc.)
• Package Management: Install and list Julia packages
• State Monitoring: Real-time worker status and execution tracking
• Session Management: Persistent Julia sessions across requests
• Error Handling: Robust error capture and reporting
• MCP Compliance: Full Model Context Protocol implementation

• Node.js 18+
• Julia 1.6+
• Pluto.jl package

1. Install Julia and Pluto.jl:

   julia -e 'using Pkg; Pkg.add("Pluto")'

2. Start Pluto server:

   julia -e 'using Pluto; Pluto.run(host="127.0.0.1", port=1234, launch_browser=false, require_secret_for_open_links=false, require_secret_for_access=false)'

3. Install and build:

   npm install
   npm run build

Start the MCP server:

npm start

Development mode:

npm run dev

Run tests:

npm run test:integration

• julia_execute - Execute Julia code with full output capture
• julia_eval - Evaluate expressions with type inference

• julia_install_package - Install Julia packages
• julia_list_packages - List installed packages with status

• julia_worker_state - Get worker status and running cells
• julia_interrupt - Interrupt long-running executions
• julia_get_cell_result - Get detailed cell results by ID

// Execute Julia code
{
  "method": "tools/call",
  "params": {
    "name": "julia_execute",
    "arguments": {
      "code": "x = 5 + 3; println(\"Result: $x\"); x"
    }
  }
}

// Returns:
{
  "result": "8",
  "output": "Result: 8\n",
  "execution_time": 1234,
  "error": null
}

Simplified Design:

• Single SimplifiedJuliaMCPServer class
• Direct integration with Rainbow's Host and Worker classes
• No custom manager layers - reduced from 1080+ to ~600 lines of code

Key Components:

• Rainbow Host: Manages Pluto server connections and worker lifecycle
• Rainbow Worker: Handles code execution and state monitoring
• MCP Protocol: Standard tools/resources/prompts implementation

Environment variables:

• PLUTO_HOST: Pluto server host (default: 127.0.0.1)
• PLUTO_PORT: Pluto server port (default: 1234)

npm run build    # Compile TypeScript
npm run lint     # Run ESLint
npm run format   # Format with Prettier

Integration tests cover all 7 MCP tools with detailed console output. Tests require a running Pluto server on localhost:1234.

npm run test:integration

MIT License

• Pluto.jl - Reactive Julia notebooks
• @plutojl/rainbow - Programmatic Pluto API
• Model Context Protocol - Standard for AI-tool integration