Cdk Serverless MCP Server

🚀 cdk-serverless-mcp-server

A very simple Model Context Protocol (MCP) server deployed on AWS Lambda and exposed via Amazon API Gateway, deployed using AWS CDK.

This skeleton is based on the excellent work of Frédéric Barthelet: He developed a middy middleware for integrating an MCP server into an AWS Lambda function in this repository.

📖 Long Story

• 📖 Read the full article on dev.to
• 📖 Read the first article in the series on dev.to

✨ Features

• 🪄 Minimal MCP server setup using @modelcontextprotocol/sdk
• 🚀 Deployed as a single AWS Lambda function
• 🌐 Exposes an HTTP POST endpoint at the /mcp path via API Gateway
• 🔄 Supports local development testing using Jest
• 🧪 Includes a simple example tool (addition) for JSON-RPC interaction

📦 Project Structure

cdk-serverless-mcp-server/
├── __tests__/                              # Jest test folder
├── bin/                                    # CDK entry point
├── cdk-serverless-mcp-server.ts                # CDK application
├── lib/                                    # CDK stack
│   └── cdk-serverless-mcp-server-stack.ts      # CDK stack
├── src/                                    # Source code
│   └── index.mjs                               # MCP server handler
├── .gitignore                              # Git ignore file
├── cdk.json                                # CDK project configuration
├── package.json                            # Project dependencies
├── package-lock.json                       # Project lock file
├── README.md                               # This documentation file

🔧 Prerequisites

• Node.js version v22+
• AWS CDK v2+

🚀 Quick Start

1. Install dependencies:

npm install

2. Install AWS CDK globally (if not already installed):

npm install -g aws-cdk

3. Run local tests using Jest:

npm run test

💻 Usage Examples

Basic Usage

import middy from "@middy/core";
import httpErrorHandler from "@middy/http-error-handler";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
import mcpMiddleware from "middy-mcp";

const server = new McpServer({
  name: "Lambda-hosted MCP server",
  version: "1.0.0",
});

server.tool("add", { a: z.number(), b: z.number() }, async ({ a, b }) => ({
  content: [{ type: "text", text: String(a + b) }],
}));

export const handler = middy()
  .use(mcpMiddleware({ server }))
  .use(httpErrorHandler());

🚀 Deployment to AWS

Run the following command:

npm run layer-dependencies-install # Install layer dependencies

Then deploy the stack:

cdk bootstrap
cdk deploy

After deployment, the MCP server will be available at the URL output in the console.

🧪 Testing with curl Requests after Deployment

List Tools

curl --location 'http://your_api Gateway_URL/mcp' \
--header 'Content-Type: application/json' \
--data-raw '{
    "id": 1,
    "method": "list_tools"
}'

Call the Addition Tool

curl --location 'http://your_api Gateway_URL/mcp' \
--header 'Content-Type: application/json' \
--data-raw '{
    "id": 2,
    "method": "tools_call",
    "params": {
        "name": "add",
        "arguments": {
            "a": 5,
            "b": 3
        }
    }
}'

📄 License

MIT — Feel free to fork, customize, and deploy your own version!