MCP Framework

MCP-Framework is a framework for building Model Context Protocol (MCP) servers elegantly in TypeScript.

MCP-Framework gives you architecture out of the box, with automatic directory-based discovery for tools, resources, and prompts. Use our powerful MCP abstractions to define tools, resources, or prompts in an elegant way. Our cli makes getting started with your own MCP server a breeze

Features

• 🛠️ Automatic discovery and loading of tools, resources, and prompts
• Multiple transport support (stdio, SSE, HTTP Stream)
• TypeScript-first development with full type safety
• Built on the official MCP SDK
• Easy-to-use base classes for tools, prompts, and resources
• Out of the box authentication for SSE endpoints

Read the full docs here

Creating a repository with mcp-framework

Using the CLI (Recommended)

# Install the framework globally
npm install -g mcp-framework

# Create a new MCP server project
mcp create my-mcp-server

# Navigate to your project
cd my-mcp-server

# Your server is ready to use!

CLI Usage

The framework provides a powerful CLI for managing your MCP server projects:

Project Creation

# Create a new project
mcp create <your project name here>

# Create a new project with the new EXPERIMENTAL HTTP transport
Heads up: This will set cors allowed origin to "*", modify it in the index if you wish
mcp create <your project name here> --http --port 1337 --cors

Options:

--http: Use HTTP transport instead of default stdio

--port : Specify HTTP port (default: 8080)

--cors: Enable CORS with wildcard (*) access

Adding a Tool

# Add a new tool
mcp add tool price-fetcher

Adding a Prompt

# Add a new prompt
mcp add prompt price-analysis

Adding a Resource

# Add a new prompt
mcp add resource market-data

Development Workflow

1. Create your project:

  mcp create my-mcp-server
  cd my-mcp-server

2. Add tools as needed:

   mcp add tool data-fetcher
   mcp add tool data-processor
   mcp add tool report-generator
   

3. Build:

   npm run build
   
   

4. Add to MCP Client (Read below for Claude Desktop example)

Using with Claude Desktop

Local Development

Add this configuration to your Claude Desktop config file:

MacOS: `~/Library/Application Support/Claude/claude_desktop_config.json` Windows: `%APPDATA%/Claude/claude_desktop_config.json`

{
"mcpServers": {
"${projectName}": {
      "command": "node",
      "args":["/absolute/path/to/${projectName}/dist/index.js"]
}
}
}

After Publishing

Add this configuration to your Claude Desktop config file:

MacOS: `~/Library/Application Support/Claude/claude_desktop_config.json` Windows: `%APPDATA%/Claude/claude_desktop_config.json`

{
"mcpServers": {
"${projectName}": {
      "command": "npx",
      "args": ["${projectName}"]
}
}
}

Building and Testing

1. Make changes to your tools
2. Run `npm run build` to compile
3. The server will automatically load your tools on startup

Environment Variables

The framework supports the following environment variables for configuration:

Example usage:

# Enable file logging
MCP_ENABLE_FILE_LOGGING=true node dist/index.js

# Specify a custom log directory
MCP_ENABLE_FILE_LOGGING=true MCP_LOG_DIRECTORY=my-logs
# Enable debug messages in console
MCP_DEBUG_CONSOLE=true```

## Quick Start

### Creating a Tool

```typescript
import { MCPTool } from "mcp-framework";
import { z } from "zod";

interface ExampleInput {
  message: string;
}

class ExampleTool extends MCPTool<ExampleInput> {
  name = "example_tool";
  description = "An example tool that processes messages";

  schema = {
    message: {
      type: z.string(),
      description: "Message to process",
    },
  };

  async execute(input: ExampleInput) {
    return `Processed: ${input.message}`;
  }
}

export default ExampleTool;

Setting up the Server

import { MCPServer } from "mcp-framework";

const server = new MCPServer();

// OR (mutually exclusive!) with SSE transport
const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      port: 8080            // Optional (default: 8080)
    }
  }
});

// Start the server
await server.start();

Transport Configuration

stdio Transport (Default)

The stdio transport is used by default if no transport configuration is provided:

const server = new MCPServer();
// or explicitly:
const server = new MCPServer({
  transport: { type: "stdio" }
});

SSE Transport

To use Server-Sent Events (SSE) transport:

const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      port: 8080,            // Optional (default: 8080)
      endpoint: "/sse",      // Optional (default: "/sse")
      messageEndpoint: "/messages", // Optional (default: "/messages")
      cors: {
        allowOrigin: "*",    // Optional (default: "*")
        allowMethods: "GET, POST, OPTIONS", // Optional (default: "GET, POST, OPTIONS")
        allowHeaders: "Content-Type, Authorization, x-api-key", // Optional (default: "Content-Type, Authorization, x-api-key")
        exposeHeaders: "Content-Type, Authorization, x-api-key", // Optional (default: "Content-Type, Authorization, x-api-key")
        maxAge: "86400"      // Optional (default: "86400")
      }
    }
  }
});

HTTP Stream Transport

To use HTTP Stream transport:

const server = new MCPServer({
  transport: {
    type: "http-stream",
    options: {
      port: 8080,                // Optional (default: 8080)
      endpoint: "/mcp",          // Optional (default: "/mcp") 
      responseMode: "batch",     // Optional (default: "batch"), can be "batch" or "stream"
      batchTimeout: 30000,       // Optional (default: 30000ms) - timeout for batch responses
      maxMessageSize: "4mb",     // Optional (default: "4mb") - maximum message size
      
      // Session configuration
      session: {
        enabled: true,           // Optional (default: true)
        headerName: "Mcp-Session-Id", // Optional (default: "Mcp-Session-Id")
        allowClientTermination: true, // Optional (default: true)
      },
      
      // Stream resumability (for missed messages)
      resumability: {
        enabled: false,          // Optional (default: false)
        historyDuration: 300000, // Optional (default: 300000ms = 5min) - how long to keep message history
      },
      
      // CORS configuration
      cors: {
        allowOrigin: "*"         // Other CORS options use defaults
      }
    }
  }
});

Response Modes

The HTTP Stream transport supports two response modes:

1. Batch Mode (Default): Responses are collected and sent as a single JSON-RPC response. This is suitable for typical request-response patterns and is more efficient for most use cases.

2. Stream Mode: All responses are sent over a persistent SSE connection opened for each request. This is ideal for long-running operations or when the server needs to send multiple messages in response to a single request.

You can configure the response mode based on your specific needs:

// For batch mode (default):
const server = new MCPServer({
  transport: {
    type: "http-stream",
    options: {
      responseMode: "batch"
    }
  }
});

// For stream mode:
const server = new MCPServer({
  transport: {
    type: "http-stream",
    options: {
      responseMode: "stream"
    }
  }
});

HTTP Stream Transport Features

• Session Management: Automatic session tracking and management
• Stream Resumability: Optional support for resuming streams after connection loss
• Batch Processing: Support for JSON-RPC batch requests/responses
• Comprehensive Error Handling: Detailed error responses with JSON-RPC error codes

Authentication

MCP Framework provides optional authentication for SSE endpoints. You can choose between JWT and API Key authentication, or implement your own custom authentication provider.

JWT Authentication

import { MCPServer, JWTAuthProvider } from "mcp-framework";
import { Algorithm } from "jsonwebtoken";

const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      auth: {
        provider: new JWTAuthProvider({
          secret: process.env.JWT_SECRET,
          algorithms: ["HS256" as Algorithm], // Optional (default: ["HS256"])
          headerName: "Authorization"         // Optional (default: "Authorization")
        }),
        endpoints: {
          sse: true,      // Protect SSE endpoint (default: false)
          messages: true  // Protect message endpoint (default: true)
        }
      }
    }
  }
});

Clients must include a valid JWT token in the Authorization header:

Authorization: Bearer eyJhbGciOiJIUzI1NiIs...

API Key Authentication

import { MCPServer, APIKeyAuthProvider } from "mcp-framework";

const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      auth: {
        provider: new APIKeyAuthProvider({
          keys: [process.env.API_KEY],
          headerName: "X-API-Key" // Optional (default: "X-API-Key")
        })
      }
    }
  }
});

Clients must include a valid API key in the X-API-Key header:

X-API-Key: your-api-key

Custom Authentication

You can implement your own authentication provider by implementing the AuthProvider interface:

import { AuthProvider, AuthResult } from "mcp-framework";
import { IncomingMessage } from "node:http";

class CustomAuthProvider implements AuthProvider {
  async authenticate(req: IncomingMessage): Promise<boolean | AuthResult> {
    // Implement your custom authentication logic
    return true;
  }

  getAuthError() {
    return {
      status: 401,
      message: "Authentication failed"
    };
  }
}

License

MIT