# MDN MCP server

This is an experimental [MCP server](https://modelcontextprotocol.io/docs/learn/server-concepts) that provides access to MDN's search, documentation, and browser compatibility data.

Our goal is to give LLMs and coding agents a reliable and up-to-date source of web platform documentation - so developers can get accurate information instead of potentially outdated content their LLMs were trained on.

## Privacy and data retention

This MCP server is being run as an experiment. While it is an experiment, we will be storing data about the queries we receive. Please see our [privacy notice](https://www.mozilla.org/en-US/privacy/websites/) for more information on interaction data we may collect. This data will **not** be associated with any information designed to identify users. However, while unlikely, it is possible that private information that you divulge to the LLM could be included in these queries. If this is a concern to you, we recommend not using this MCP server.

To opt out of first-party analytics, send the `X-Moz-1st-Party-Data-Opt-Out: 1` header along with requests to the MCP.

By using our MCP server, you agree to comply with our [Acceptable Use Policy](https://www.mozilla.org/en-US/about/legal/acceptable-use/).

As this MCP server is experimental, it may be withdrawn at any time.

## Using the remote server

Add the remote server to your tool of choice. For example, in Claude Code:

```
claude mcp add --transport http mdn https://mcp.mdn.mozilla.net/
```

## Using locally

- Install dependencies: `npm install`
- Start the server: `npm start`

Add the server to your tool of choice. For example, in Claude Code:

```
claude mcp add --transport http mdn-local http://localhost:3002/
```

## Local development

- Install dependencies: `npm install`
- Start the development server, MCP inspector, and tests: `npm run dev`

Your browser should automatically open the MCP inspector, and the server will restart when you make changes.