azure-functions -extension

This MCP server is implemented as an Azure Functions extension that enables a Functions app to act as a scalable remote MCP server. It exposes an MCP-triggered mechanism to define tools that clients (such as AI agents) can call to perform tasks during their workflows. The extension integrates with the host.json configuration to customize server behavior, including instructions, server name, and version. To use it, install the extension in your Functions project, configure the MCP settings in host.json, and deploy the Functions app. When the Functions host runs, the MCP extension will surface tools and endpoints according to your configuration, allowing clients to query available tools and execute defined actions within a scalable serverless environment.

Prerequisites:

• Node.js and npm (for the extension package and tooling)
• Azure Functions Core Tools installed and configured
• An Azure Functions project (v3 or v4) depending on your runtime

Installation steps:

1. In your Functions project, install the MCP extension package from npm: npm install azure-functions-mcp-extension

2. Add or update host.json in your Functions project to configure the MCP extension. Example: { "version": "2.0", "extensions": { "mcp": { "instructions": "Some test instructions on how to use the server", "serverName": "TestServer", "serverVersion": "2.0.0" } } }

3. Ensure your startup environment points to the MCP-enabled host and that the Functions host is running. If you’re using a dedicated server file, ensure the path in mcp_config points to your server script (e.g., path/to/server.js).

4. Start the Functions host (e.g., via func start) and verify the MCP extension initializes correctly in the runtime logs.

Optional: if you are bundling the extension with a custom build or using a TypeScript/Node.js sample, follow the specific sample README for building and referencing the server entry point.

Notes and tips:

• The MCP extension integrates via host.json under extensions.mcp. Customize serverName, serverVersion, and instructions to suit your deployment.
• Ensure environment variables used by the extension (if any) are properly defined in your deployment environment.
• If you change the server entry point path (path/to/server.js), update mcp_config accordingly.
• The extension is designed to work with Azure Functions runtimes; test in a local emulator (Functions Core Tools) before deploying to Azure.
• When upgrading the extension, review breaking changes in host.json and triggering configurations to avoid downtime.