MCP Framework

A TypeScript framework for building Model Context Protocol (MCP) servers.

Changes from Original

This fork (@ronangrant/mcp-framework) includes the following improvements:

• Replaced file-based logging with console-only logging for better compatibility and reliability
• Removed dependency on filesystem for logs, eliminating ENOENT errors
• Simplified logging implementation while maintaining the same interface
• All logs now output to stderr via console.error()

Installation

npm install @ronangrant/mcp-framework

Usage

Create a new MCP server:

import { MCPServer } from '@ronangrant/mcp-framework';

const server = new MCPServer({
  name: "my-server",
  version: "1.0.0"
});

await server.start();

Features

• Easy-to-use API for creating MCP servers
• Built-in support for tools, prompts, and resources
• Simplified logging system with console output
• Full TypeScript support
• Flexible transport options

License

MIT

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)
• 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>

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

Quick Start

Creating a Tool

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")
      }
    }
  }
});

CORS Configuration

The SSE transport supports flexible CORS configuration. By default, it uses permissive settings suitable for development. For production, you should configure CORS according to your security requirements:

const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      // Restrict to specific origin
      cors: {
        allowOrigin: "https://myapp.com",
        allowMethods: "GET, POST",
        allowHeaders: "Content-Type, Authorization",
        exposeHeaders: "Content-Type, Authorization",
        maxAge: "3600"
      }
    }
  }
});

// Or with multiple allowed origins
const server = new MCPServer({
  transport: {
    type: "sse",
    options: {
      cors: {
        allowOrigin: "https://app1.com, https://app2.com",
        allowMethods: "GET, POST, OPTIONS",
        allowHeaders: "Content-Type, Authorization, Custom-Header",
        exposeHeaders: "Content-Type, Authorization",
        maxAge: "86400"
      }
    }
  }
});

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