Description

The @cmmv/mcp module implements the Model Context Protocol (MCP) for CMMV applications, allowing standardized interactions between LLMs (Large Language Models) and your application. MCP provides a structured interface for defining tools usable by AI models in a standard format.

Features

• LLM Integration: Facilitates bidirectional communication between your application and language models.
• Flexible Transport: Supports transport via HTTP (StreamableHTTP), SSE, or Standard I/O.
• API Decorator-Based: Intuitive decorators like @MCPTool to register tools.
• Validation with Zod: Input schema validation using Zod.
• Connection Management: Robust implementation for handling multiple concurrent connections.
• Modern SDK: Uses the latest @modelcontextprotocol/sdk with StreamableHTTPServerTransport.
• HTTP Server Integration: Can integrate with existing CMMV HTTP server or run standalone.
• Legacy SSE Support: Maintains compatibility with SSE endpoints (/sse, /messages).
• Session Management: Support for multiple concurrent MCP sessions with session ID tracking.
• Health Monitoring: Built-in health check (/mcp/health) and tools listing (/mcp/tools) endpoints.
• CORS Support: Configurable CORS for cross-origin requests.
• DNS Rebinding Protection: Configurable DNS rebinding protection for security.
• Hook Integration: Seamless integration using CMMV's hook system.
• TypeScript: Full TypeScript support with enhanced type safety.
• Error Handling: Comprehensive error handling with proper HTTP status codes.

Installation

Install @cmmv/mcp via pnpm:

$ pnpm add @cmmv/mcp

Configuration

Configure the MCP module in your .cmmv.config.cjs or using ConfigSchema:

import { ConfigSchema } from '@cmmv/core';

export const MCPConfig: ConfigSchema = {
  mcp: {
    name: {
      type: 'string',
      required: true,
      default: 'mcp',
    },
    version: {
      type: 'string',
      required: true,
      default: '0.0.1',
    },
    port: {
      type: 'number',
      required: true,
      default: 8765,
    },
    transport: {
      type: 'string',
      required: true,
      default: 'http', // 'http', 'sse' or 'stdio'
    },
    integrateWithHttp: {
      type: 'boolean',
      required: false,
      default: false, // Integrate with existing HTTP server
    },
    jwtSecret: {
      type: 'string',
      required: true,
      default: 'your-secret-key',
    },
    pingInterval: {
      type: 'number',
      required: true,
      default: 30000,
    },
    connectionTimeout: {
      type: 'number',
      required: true,
      default: 300000,
    },
  },
};

Setting Up the Application

Standalone Mode (Default)

In your main file, include the MCPModule and configure your application:

import { Application, Config } from '@cmmv/core';
import { DefaultAdapter, DefaultHTTPModule } from '@cmmv/http';
import { MCPModule } from '@cmmv/mcp';
import { MCPHandlers } from './mcp-handlers';

Config.assign({
    mcp: {
        port: 8766,
        transport: 'http',
        name: 'cmmv-mcp-server',
        version: '1.0.0',
        integrateWithHttp: false, // Standalone mode
    },
});

Application.create({
    httpAdapter: DefaultAdapter,
    modules: [MCPModule],
    providers: [MCPHandlers],
});

Integrated Mode (Same Port as HTTP Server)

To integrate MCP with your existing HTTP server:

import { Application, Config } from '@cmmv/core';
import { DefaultAdapter, DefaultHTTPModule } from '@cmmv/http';
import { MCPModule } from '@cmmv/mcp';
import { MCPHandlers } from './mcp-handlers';

Config.assign({
    mcp: {
        port: 3000, // Same port as your HTTP server
        transport: 'http',
        name: 'cmmv-mcp-server',
        version: '1.0.0',
        integrateWithHttp: true, // Integrate with existing HTTP server
    },
});

Application.create({
    httpAdapter: DefaultAdapter,
    modules: [MCPModule],
    providers: [MCPHandlers],
});

When integrateWithHttp: true, the MCP routes will be added to your existing HTTP server:

• POST /mcp - StreamableHTTP transport
• GET /mcp - SSE transport (legacy)
• POST /messages - Messages endpoint (legacy)
• GET /mcp/health - Health check
• GET /mcp/tools - List available tools

Creating MCP Tool Handlers

Use the @MCPTool decorator to register tools callable by LLMs:

import { MCPTool, z } from '@cmmv/mcp';

export class MCPHandlers {
    @MCPTool('greet', {
        name: z.string(),
        age: z.number(),
    })
    public async greet({ name, age }: { name: string; age: number }) {
        return {
            content: `Hello \${name}, you are \${age} years old`,
        };
    }
}

Using the MCP Client

The MCP client can connect to your server using the HTTP endpoint:

curl -X POST http://localhost:8765/mcp \\
  -H "Content-Type: application/json" \\
  -d '{
    "jsonrpc": "2.0",
    "id": 1,
    "method": "tools/call",
    "params": {
      "name": "greet",
      "arguments": {
        "name": "John",
        "age": 30
      }
    }
  }'

Health Check

You can check the server health:

curl http://localhost:8765/health

List Available Tools

You can list all available tools:

curl http://localhost:8765/tools

Decorators

@MCPTool(name: string, schema: Record<string, z.ZodSchema>)

Registers a method as an MCP tool with a name and validation schema.

Best Practices

• Define Schemas Clearly: Use Zod schemas to clearly define parameters for each tool.
• Provide Meaningful Responses: Return structured and helpful responses for LLMs.
• Handle Errors Gracefully: Implement robust error handling in your handlers.
• Security First: Consider using JWT for public endpoints.
• Performance: Use timeouts and keep handlers lightweight and fast.