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

MCP Servers