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Model Context Protocol (MCP)

⚠️ Experimental: MCP support is experimental and may change.

Robyn supports MCP, allowing AI applications like Claude Desktop to connect to your application's resources and tools.

Quick Start

from robyn import Robyn

app = Robyn(__file__)

@app.mcp.resource("echo://{message}")
def echo_resource(message: str) -> str:
    return f"Resource echo: {message}"

@app.mcp.tool()
def echo_tool(message: str) -> str:
    return f"Tool echo: {message}"

@app.mcp.prompt()
def echo_prompt(message: str) -> str:
    return f"Please process: {message}"

app.start()

Features

  • Auto-generated JSON schemas from function signatures
  • URI templates with parameter extraction
  • JSON-RPC 2.0 protocol compliance
  • Type-aware parameter handling

Decorator Reference

@app.mcp.resource(uri, name=None, description=None, mime_type=None)

Register a resource that can be read by clients.

@app.mcp.resource("user://{user_id}/profile")
def user_profile(user_id: str) -> str:
    return f"Profile for user {user_id}"

@app.mcp.tool(name=None, description=None, input_schema=None)

Register a tool that can be executed by AI models.

@app.mcp.tool()
def greet(name: str, formal: bool = False) -> str:
    if formal:
        return f"Good day, {name}."
    return f"Hi {name}!"

@app.mcp.prompt(name=None, description=None, arguments=None)

Register a prompt template for AI workflows.

@app.mcp.prompt()
def code_review(code: str, language: str = "python") -> str:
    return f"Please review this {language} code: {code}"

Type Support

Supported types: str, int, float, bool, List, Dict

URI Templates

Extract parameters from URIs:

@app.mcp.resource("user://{user_id}/posts/{post_id}")
def get_user_post(user_id: str, post_id: str) -> str:
    return f"Post {post_id} from user {user_id}"

Client Usage

Test with curl:

# List resources
curl -X POST http://localhost:8080/mcp \
  -H "Content-Type: application/json" \
  -d '{"jsonrpc": "2.0", "id": 1, "method": "resources/list", "params": {}}'

Integration with Claude Desktop

To connect your Robyn MCP server to Claude Desktop:

  1. Start your Robyn app with MCP endpoints
  2. Configure Claude Desktop to connect to http://localhost:8080/mcp
  3. Use the registered resources, tools, and prompts in your conversations

Error Handling

@app.mcp.tool()
def divide(a: float, b: float) -> str:
    if b == 0:
        raise ValueError("Division by zero")
    return str(a / b)

Testing

# Unit tests
python examples/mcp.py test-unit

# Live tests
python examples/mcp.py test-live

# All tests
python examples/mcp.py test-all

Configuration

MCP runs at /mcp endpoint using JSON-RPC 2.0 over HTTP. No additional setup required.

Claude Desktop Integration

  1. Start your Robyn server
  2. Configure Claude Desktop to connect to http://localhost:8080/mcp
  3. Use resources, tools, and prompts in conversations

See examples/mcp.py for a complete example.

For more information: https://modelcontextprotocol.io/