Cursor Rust Tools

🚀 Cursor Rust Tools

A server based on MCP that allows the LLM in Cursor to access Rust analyzers, crate documentation, and Cargo commands. It includes a UI for configuration.

🚀 Quick Start

This tool is a server based on the Model Context Protocol (MCP), enabling the LLM in Cursor to access Rust analyzers, crate documentation, and Cargo commands. It also comes with a UI for configuration.

✨ Features

Currently, various AI agents do not provide the functionality for LLMs to access Rust type information. This forces LLMs to infer potential types instead of directly viewing them.

Moreover, regarding dependencies like tokio, LLMs can only rely on training data, which may be outdated and of different versions, potentially leading to various issues.

Cursor Rust Tools provides this information to LLMs through the Model Context Protocol (MCP):

• Retrieve documentation for a specific crate or its symbols (e.g., tokio or tokio::spawn).
• Obtain hover information (type, description) for a specific symbol in a file.
• Find all references to a specific symbol in a file.
• Retrieve the implementation of a symbol (fetch the entire file containing the implementation).
• Look up a type by name in a file and return hover information.
• Get the output of cargo test.
• Get the output of cargo check.

🔧 Technical Details

How it Works

For LSP functionality, src/lsp launches a new Rust Analyzer, which indexes your codebase just like it does in an editor. We can't query the analyzer running in the editor because Rust Analyzer can only serve a single consumer (e.g., the open document operation requires the correct close document sequence).

For documentation functionality, it runs cargo docs and then locally parses the HTML documentation into Markdown. This information is stored in the .docs-cache folder at the project root.

📦 Installation

Install the Tool

cargo install --git https://github.com/terhechte/cursor-rust-tools

Run with UI

cursor-rust-tools

This will launch a UI where you can add projects, install mcp.json, and view activities.

Run without UI

If ~/.cursor-rust-tools is already set up, you can also run it with the following command:

cursor-rust-tools --no-ui

📚 Documentation

Configuration

In addition to using the UI to create a configuration, you can set up ~/.cursor-rust-tools yourself:

[[projects]]
root = "/Users/terhechte/Developer/Rust/example1"
ignore_crates = []

[[projects]]
root = "/Users/terhechte/Developer/Rust/example2"
ignore_crates = []

ignore_crates is a list of crate dependency names that you don't want to index for documentation, for example, because they are too large.

Configure Cursor

Once the application is running, you can configure Cursor to use it. This requires several steps:

1. Add a .cursor/mcp.json file to the project directory. The UI of Cursor Rust Tools has a button to do this for you. When running with the UI, the terminal will display the contents of mcp.json.
2. As soon as you save the file, Cursor will detect that a new MCP server has been added and prompt you to enable it (in the dialog box at the bottom right).
3. You can check if it's working correctly in the Cursor settings (under MCP).
4. When testing, make sure to select Agent Mode in the current chat. Then you can have the LLM execute one of the new tools, such as the cargo_check tool.
5. You may want to add Cursor rules to tell the LLM to prioritize using these tools whenever possible.

All mcp.json files have the same content. Cursor Rust Tools determines the correct project based on the file path.

📄 To-Do List

• [ ] Create a Zed extension to enable this functionality.
• [ ] Implement error-free normal shutdown.
• [ ] Fix the current issue where removing projects in the UI is a bit fragile.
• [ ] Expose more LSP commands.
• [ ] Allow the LLM to execute [