ruskel

Ruskel produces a syntactically correct skeleton of a crate's public API: docs included, implementation stripped. Crates not found locally are fetched from crates.io.

Ruskel is great for:

• Quick access to Rust documentation from the command line.
• Exporting a crate's public API as a single file for LLMs and other tools.
• Standard library documentation (std, core, alloc), e.g. ruskel std::vec::Vec.

For example, here is the skeleton of the very tiny termsize crate:

// Ruskel skeleton - syntactically valid Rust with implementation omitted.
// settings: target=termsize, visibility=public, auto_impls=false, blanket_impls=false

pub mod termsize {
    //! Termsize is a tiny crate that provides a simple
    //! interface for retrieving the current
    //! [terminal interface](http://www.manpagez.com/man/4/tty/) size
    //!
    //! ```rust
    //! extern crate termsize;
    //!
    //! termsize::get().map(|size| println!("rows {} cols {}", size.rows, size.cols));
    //! ```

    /// Container for number of rows and columns
    #[derive(Debug)]
    pub struct Size {
        /// number of rows
        pub rows: u16,
        /// number of columns
        pub cols: u16,
    }

    /// Gets the current terminal size
    pub fn get() -> Option<self::super::Size> {}
}

Features

• Filter output to specific items with --search
• Tabular item listings with --list
• Syntax highlighting for terminal output
• Include private items and auto-implemented traits
• Custom feature flags and version specification

Installation

Ruskel requires the Rust nightly toolchain to run. Install the nightly toolchain and the rust-docs-json component:

rustup toolchain install nightly
rustup component add --toolchain nightly rust-docs-json

Install Ruskel:

cargo install ruskel

Ruskel requires nightly to run but can be installed with any toolchain.

Usage

Basic usage:

ruskel [TARGET]

See the help output for all options:

ruskel --help

# Current project
ruskel

# A crate in the workspace
ruskel mypackage

# A dependency of the current project, or fetched from crates.io
ruskel serde

# A sub-path within a crate
ruskel serde::de::Deserialize

# Path to a crate
ruskel /my/path

# A module within that crate
ruskel /my/path::foo

# Specific version from crates.io
ruskel serde@1.0.0

# Search for "status" across names, signatures and doc comments
ruskel reqwest --search status

# Search for "status" in only names and signatures
ruskel reqwest --search status --search-spec name,signature

# Search for "status" in docs only
ruskel reqwest --search status --search-spec doc

# Access via std re-exports (recommended)
ruskel std::vec::Vec        # Vec type from std
ruskel std::rc::Rc          # Rc type from std
ruskel std::mem::size_of    # size_of function from std

# Direct access to core and alloc
ruskel core::mem            # Memory utilities from core
ruskel alloc::vec           # Vec module from alloc

# Entire crate
ruskel std                  # All of std
ruskel core                 # Core library (no_std compatible)
ruskel alloc                # Allocation library

Search

Use --search to focus on specific items instead of rendering an entire crate. The query runs across multiple domains and returns a skeleton containing only the matches and their ancestors.

# Show methods and fields matching "status" within the reqwest crate
ruskel reqwest --search status --search-spec name,signature

By default the query matches name, doc, and signature domains, case-insensitively. Use --search-spec to select domains (e.g., --search-spec name,path or --search-spec doc). Add --search-case-sensitive for exact case matching, or --direct-match-only to keep container matches collapsed.

Search respects --private, feature flags, and syntax highlighting.

Listing

Use --list to print a concise catalog of crate items instead of rendering Rust code. Each line reports the item kind and its fully qualified path:

# Survey the high-level structure of tokio without emitting code
ruskel tokio --list

crate      crate
module     crate::sync
struct     crate::sync::Mutex
trait      crate::io::AsyncRead

Combine --list with --search to filter the catalog using the same domain controls. The listing honours --private, feature flags, and paging choices, but conflicts with --raw.

MCP Server

Ruskel can run as a Model Context Protocol (MCP) server for coding agents.

Running as MCP Server

To start Ruskel in MCP server mode:

ruskel --mcp

This starts the server on stdout, exposing a single ruskel tool.

MCP Configuration

For Codex CLI, Claude Code, or other coding agents:

{
  "mcpServers": {
    "ruskel": {
      "command": "ruskel",
      "args": ["--mcp"]
    }
  }
}

Tool Parameters

The ruskel tool accepts the following JSON parameters:

Required

• target (string): The crate/module to generate a skeleton for.

Optional

• bin (string | null, default: null): Select a specific binary target when rendering a package.
• private (boolean, default: false): Include private items.
• frontmatter (boolean, default: true): Include comment frontmatter.
• search (string | null, default: null): Restrict output to matches for this query.
• search_spec (array of strings | null, default: null): Search domains (name, doc, signature, path). Defaults to name, doc, signature.
• search_case_sensitive (boolean, default: false): Require exact-case matches when searching.
• direct_match_only (boolean, default: false): Only render direct matches, not expanded containers.
• no_default_features (boolean, default: false): Disable default features.
• all_features (boolean, default: false): Enable all features.
• features (array of strings, default: []): Features to enable.

libruskel library

The underlying library can be used directly:

use libruskel::Ruskel;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    let rs = Ruskel::new("/path/to/target")?;
    let rendered = rs.render(false, false)?;
    println!("{}", rendered);
    Ok(())
}

Community

Want to contribute? Have ideas or feature requests? Come tell us about it on Discord.