This MCP server demonstrates a simple Model Context Protocol (MCP) server deployed on AWS Lambda behind API Gateway. It uses the Streamable HTTP transport to carry MCP messages over HTTP, enabling a lightweight, serverless MCP endpoint without additional proxying components. After deployment, you interact with the server via its endpoint exposed by API Gateway and use the standard MCP client tooling to discover tools and invoke them. To operate locally, ensure the endpoint URL is available (set as SIMPLE_MCP_SERVER_ENDPOINT) and use the client script to send requests to that endpoint.

Prerequisites:

• AWS CLI installed and configured
• Terraform installed
• Node.js and npm installed

Installation steps:

1. Install server dependencies (in the project): bash cd src npm install cd ..

2. Deploy the Lambda + API Gateway via Terraform: bash cd terraform terraform init terraform plan terraform apply

   Retrieve the endpoint URL from Terraform output and export it for the client

   export SIMPLE_MCP_SERVER_ENDPOINT=$(terraform output --raw endpoint_url) cd ..

3. Run the client to exercise the MCP server: bash node src/client.js

Notes:

• The endpoint URL is created by Terraform and exposed via API Gateway. It may take a few seconds to become fully operational after apply.
• The client script assumes the endpoint is reachable and uses the MCP protocol over the Streamable HTTP transport.

Tips and caveats:

• This is a prototype implementation and is marked deprecated in favor of newer samples. The recommended path is to use the AWS sample serverless MCP server as referenced in the repo notes.
• Ensure the API Gateway endpoint is publicly reachable if testing from outside AWS. If using VPC or restricted networks, adjust IAM/permissions accordingly.
• The environment variable SIMPLE_MCP_SERVER_ENDPOINT must be set to the deployed API Gateway URL for the client to communicate with the MCP server.
• The transport used is Streamable HTTP, as described in the MCP specification version 2025-03-26; clients must support that transport when communicating with the server.