middy-mcp

library0.1.6jsnpmunverified

Middy middleware for integrating Model Context Protocol (MCP) servers with AWS Lambda functions. Current version 0.1.6, requires Node.js >= 18.0.0 and Middy >= 6.0.0. Supports API Gateway (REST, HTTP API v2) and ALB proxy integrations, but only compatible with MCP clients using protocol version 2025-03-26 or later. Provides seamless request/response handling within the Middy middleware framework, with TypeScript type definitions included.

aws http-networking web-framework llm-agents

npm install middy-mcp

github ↗package ↗

INSTALL

IMPORT

SIG · MIDDY-MCP

middy-mcp

awsjavascriptv0.1.6

Install

—

Import

—

Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

default

✓ import mcpMiddleware from 'middy-mcp'

✗ const mcpMiddleware = require('middy-mcp');

ESM-only package; default export is the middleware function.

McpServer

✓ import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'

✗ import { McpServer } from '@modelcontextprotocol/sdk'

Must import from the specific subpath /server/mcp.js for correct ESM resolution.

middy

✓ import middy from '@middy/core'

✗ import { middy } from '@middy/core'

Default export from @middy/core; named export 'middy' does not exist.

Create a Lambda handler with MCP server and Middy middleware.

import middy from '@middy/core'; import mcpMiddleware from 'middy-mcp'; import { McpServer } from '@modelcontextprotocol/sdk/server/mcp.js'; import { z } from 'zod'; const server = new McpServer({ name: 'MyMCP', 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 }));

Debug

Known issues

breakingOnly compatible with MCP clients using protocol version 2025-03-26 or later.

fix

Ensure MCP client supports version 2025-03-26+

affects: >=0.0.0

gotchaCannot be used in a bundle with other middlewares that modify headers due to order issues.

fix

Update to v0.1.0+ for header compatibility with other middlewares.

affects: <0.1.0

gotchaRequires HTTP error handler middleware to handle thrown HTTP exceptions.

fix

Use @middy/http-error-handler after mcpMiddleware.

affects: >=0.0.0

breakingRequires Middy >= 6.0.0, which introduced breaking changes from earlier versions.

fix

Upgrade @middy/core to v6 or later.

affects: >=0.0.0

deprecatedThe package uses ESM-only exports – CommonJS require() will not work.

fix

Convert project to ESM or use dynamic import().

affects: >=0.0.0

Errors

Common errors & fixes

Cannot find module '@modelcontextprotocol/sdk'

Missing or incorrect import path for the SDK.

fix

Install @modelcontextprotocol/sdk and import from '@modelcontextprotocol/sdk/server/mcp.js'.

TypeError: middy is not a function

Incorrect import of Middy (named instead of default).

fix

Use import middy from '@middy/core' (default import).

Error: MCP protocol version not supported. Must be at least 2025-03-26.

MCP client uses an older protocol version.

fix

Update MCP client to support protocol version 2025-03-26 or later.

Upgrade

Version history

0.1.6latest on npm

Audit

Dependencies

@middy/corerequiredPeer dependency for Middy middleware framework

@modelcontextprotocol/sdkrequiredRequired for McpServer creation

Agent activity

12 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/fredericbarthelet/middy-mcp ↗

packagehttps://www.npmjs.com/package/middy-mcp ↗