Docs.rs MCP server

The cargo doc MCP server manages Rust documentation through cargo doc commands, providing tools to check, build, and search Rust documentation locally. It enables you to access crate documentation, list symbols, and perform searches within the generated documentation.

Requirements

• Node.js 16 or later
• Rust and Cargo installed

Installation

To get started with the cargo doc MCP server, follow these steps:

First, install the required dependencies:

pnpm install

Next, build the server:

pnpm run build

For development environments where you want automatic rebuilding when files change:

pnpm run watch

Configuration

To use the cargo doc MCP server, add the following configuration to your settings:

{
  "mcpServers": {
    "docs-rs-mcp": {
      "command": "/absolute/path/to/docs-rs-mcp/build/index.js"
    }
  }
}

Be sure to replace /absolute/path/to/docs-rs-mcp with the actual path where you installed the server.

Using the Server

The cargo doc MCP server provides three main tools:

Getting Crate Documentation

To access a crate's main documentation page:

get_crate_doc

Parameters:

• project_path: Absolute path to the Rust project
• crate_name: Name of the crate you want documentation for

Listing Symbols

To list all symbols (structs, enums, traits, etc.) in a crate's documentation:

list_symbols

Parameters:

• project_path: Absolute path to the Rust project
• crate_name: Name of the crate to list symbols for

Searching Documentation

To search within a crate's documentation:

search_doc

Parameters:

• project_path: Absolute path to the Rust project
• crate_name: Name of the crate to search in
• query: Search query (keyword or symbol)
• limit (optional): Maximum number of results to return (default: 10)

Debugging

Since the MCP server communicates over stdio, debugging can be challenging. You can use the built-in MCP Inspector:

pnpm run inspector

This will provide a URL to access debugging tools in your browser, making it easier to troubleshoot issues.

Performance Notes

The server uses a cache system to improve performance when working with documentation. It stores paths to built documentation and automatically refreshes cache entries after 24 hours to ensure your documentation stays up-to-date.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "docs-rs-mcp" '{"command":"/absolute/path/to/docs-rs-mcp/build/index.js"}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "docs-rs-mcp": {
            "command": "/absolute/path/to/docs-rs-mcp/build/index.js"
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "docs-rs-mcp": {
            "command": "/absolute/path/to/docs-rs-mcp/build/index.js"
        }
    }
}

3. Restart Claude Desktop for the changes to take effect