MCP Lambda Server

A Node.js package that provides MCP (Model Context Protocol) server infrastructure for AWS Lambda functions with SSE support.

Features

• Adapts the MCP TypeScript SDK to work with AWS Lambda
• Supports Server-Sent Events (SSE) through Lambda response streaming
• Handles CORS and HTTP method validation
• TypeScript support

Important Notes

• Lambda response streaming only works with Function URLs. It does not work with API Gateway or Application Load Balancer.
• Only Node.js runtime is officially supported for response streaming.

Installation

npm install @markvp/mcp-lambda-layer

Usage

Create your Lambda function and import the package:

import { MCPHandlerFactory } from '@markvp/mcp-lambda-layer';
import { z } from 'zod';

// Create MCP handler factory with your configuration
const factory = new MCPHandlerFactory({
  tools: {
    summarize: {
      params: {
        text: z.string(),
      },
      handler: async ({ text }) => {
        // Your implementation here - could be any service/model/API
        const summary = await yourSummarizeImplementation(text);
        return {
          content: [{ type: 'text', text: summary }],
        };
      },
    },
  },
  prompts: {
    generate: {
      description: 'Generate content based on a prompt',
      handler: async extra => {
        // Your implementation here - could be any service/model/API
        const result = await yourGenerateImplementation(extra.prompt);
        return {
          content: [{ type: 'text', text: result }],
        };
      },
    },
  },
});

// Export the handler directly
export const handler = factory.getHandler();

Required Lambda Configuration

• Runtime: Node.js 18.x or later
• Handler: index.handler
• Memory: 128 MB minimum (adjust based on your needs)
• Timeout: 120 seconds recommended
• Function URL: Required and must have response streaming enabled
• API Gateway/ALB: Not supported with streaming

Package Contents

This package provides:

• MCP Server implementation with SSE transport
• Protocol handling (JSON-RPC)
• Streaming response support
• Type definitions and interfaces

Your Lambda function provides:

• Tool and prompt implementations
• Business logic
• Any necessary API clients or services
• Configuration

License

MIT