Rust Docs MCP Server

What is Rust Docs MCP Server?

Rust Docs MCP Server is an MCP server that fetches documentation for a specified Rust crate, generates embeddings, and provides an MCP tool to answer questions about the crate based on the documentation context. It is designed for AI-powered coding assistants (such as Cursor, Cline, Roo Code) to access current, crate-specific API documentation, improving the accuracy of generated Rust code.

How to use Rust Docs MCP Server?

Install by downloading the pre-compiled binary for your OS from the GitHub Releases page (or build from source with the Rust Toolchain). Set the OPENAI_API_KEY environment variable. Run from the command line with a package ID specification (e.g., rustdocs_mcp_server serde@^1.0), optionally adding features with -F. The server communicates via stdio and exposes a tool query_rust_docs and a resource crate://<crate_name>. On first run for a new crate/version/feature set, it downloads docs and generates embeddings (then caches them). Subsequent launches use the cache.

Key features of Rust Docs MCP Server

• Targets a single Rust crate per server instance.
• Supports specifying required crate features for documentation generation.
• Uses OpenAI text-embedding-3-small for semantic search.
• Uses OpenAI gpt-4o-mini-2024-07-18 for LLM summarization.
• Caches documentation and embeddings in the XDG data directory.
• Runs as a standard MCP server over stdio.

Use cases of Rust Docs MCP Server

• AI assistant generates code using the latest API of a crate like serde or tokio.
• A developer configures multiple server instances for different crates (e.g., reqwest and async-stripe).
• An LLM queries crate-specific documentation before writing code, reducing outdated suggestions.
• Teams ensure generated Rust code aligns with current crate versions and feature flags.