mcp-rustdoc

MCP server for browsing Rust crate documentation. Scrapes docs.rs, doc.rust-lang.org (std/core/alloc), and the crates.io API. Zero HTTP dependencies — native fetch only.

Tools

Tool	Description
get_crate_metadata	Version, features, deps, MSRV, links
get_crate_brief	Metadata + overview + modules + focused module items in one call
lookup_crate_docs	Crate overview, version, sections, re-exports
get_crate_items	Items in a module. Filter by type and feature gate
lookup_crate_item	Full item docs: signature, deprecation, methods, variants, impls, examples. Auto-discovers module path
list_methods	All methods on a struct/enum/trait with signatures, deprecation, and short docs
search_crate	Ranked symbol search with Levenshtein fuzzy fallback
search_crates	Search crates.io by keyword
get_crate_versions	All published versions with dates and yanked status
get_source_code	Raw source code from docs.rs
batch_lookup	Multiple item lookups in one call (up to 20)
get_crate_changelog	GitHub releases for a crate
resolve_type	Resolve a type path like tokio::sync::Mutex to its docs

All tools accept an optional version parameter and are annotated with readOnlyHint: true.

Install

npx -y mcp-rustdoc

Claude Code

claude mcp add mcp-rustdoc -- npx -y mcp-rustdoc

Gemini CLI

{ "mcpServers": { "mcp-rustdoc": { "command": "npx", "args": ["-y", "mcp-rustdoc"] } } }

OpenAI Codex CLI

codex mcp add mcp-rustdoc -- npx -y mcp-rustdoc

Claude Desktop

{ "mcpServers": { "mcp-rustdoc": { "command": "npx", "args": ["-y", "mcp-rustdoc"] } } }

Parameters

Every tool takes crateName (string, required) and version (string, optional). Additional parameters:

Tool	Extra parameters
get_crate_brief	focusModules — comma-separated modules to expand
get_crate_items	modulePath, itemType, feature
lookup_crate_item	itemType (required), itemName (required), modulePath, includeImpls, includeExamples
list_methods	itemType (required), itemName (required), modulePath
search_crate	query (required)
search_crates	query (required), page, perPage
get_source_code	path (required)
batch_lookup	items (required) — array of { itemType, itemName, modulePath? }, max 20
get_crate_changelog	count — number of releases (default 5)
resolve_type	typePath (required) — e.g. "tokio::sync::Mutex"

Development

git clone https://github.com/kieled/mcp-rustdoc.git
cd mcp-rustdoc && npm install

bun run dev          # run with bun (no build)
npm run build        # vite build → dist/index.js
npm run typecheck    # tsc --noEmit
npm publish          # build + publish

Architecture

• Server instructions — workflow guide sent to clients on init
• Markdown output — doc comments preserve code blocks as fenced markdown, inline code as backticks
• cheerio — surgical DOM extraction from rustdoc HTML
• Native fetch — AbortController timeouts, retry with backoff on 5xx
• LRU cache — 500 entries, 5-min TTL, 15-min stale-while-revalidate
• Fuzzy search — exact > prefix > substring scoring, Levenshtein fallback on no matches
• Auto-discovery — lookup_crate_item finds module paths via all.html, fuzzy fallback on miss
• Actionable errors — every error includes a recovery tip suggesting which tool to try next

License

MIT