cratedex 0.5.0

MCP server for Rust documentation indexing, full-text search, and project diagnostics
Documentation

cratedex

Crates.io License

MCP (Model Context Protocol) server for Rust documentation indexing, full-text search, and project diagnostics.

Quick Start

  1. Install:
cargo install cratedex

To upgrade later:

cratedex update
  1. Run as a background service (Linux user service):
cratedex install-service --linger
  1. Connect your AI coding tool:
# Claude Code
claude mcp add --scope user --transport http cratedex http://127.0.0.1:3737/mcp

# Codex
codex mcp add cratedex --url http://127.0.0.1:3737/mcp

For OpenCode, add an HTTP MCP server entry that points to:

http://127.0.0.1:3737/mcp

Features

  • Full-text search across Rust crate documentation (SQLite FTS5)
  • Cargo metadata and workspace-aware dependency resolution
  • Build diagnostics, outdated dependencies, and security advisories
  • Per-project registration with background indexing
  • Dual transport: stdio (per-client) or HTTP (shared daemon)

Prerequisites

  • Rust toolchain (1.93+)
  • Nightly Rust (for rustdoc JSON generation)

Installation

cargo install cratedex

Configuration

Configuration is loaded from (in priority order):

  1. Environment variables (CRATEDEX__<SECTION>__<KEY>)
  2. ~/.cratedex/cratedex.toml
  3. cratedex.toml in the current directory
  4. Built-in defaults

See cratedex.toml.example for all options. Key environment variables:

Variable Default Description
CRATEDEX__SERVER__TRANSPORT http Transport protocol: http or stdio
CRATEDEX__SERVER__HOST 127.0.0.1 HTTP bind address
CRATEDEX__SERVER__PORT 3737 HTTP bind port
CRATEDEX__SERVER__ALLOW_REMOTE false Allow non-loopback bind (false strongly recommended)
CRATEDEX__SERVER__AUTH_TOKEN unset Optional HTTP bearer token
CRATEDEX__SERVER__MAX_SEARCH_RESULTS 10 Max results per search query
CRATEDEX__SERVER__MAX_PROJECTS 32 Max simultaneously registered projects
CRATEDEX__SERVER__MAX_CONCURRENT_REQUESTS 64 HTTP concurrency limit
CRATEDEX__SERVER__RATE_LIMIT_PER_SEC 30 HTTP request rate cap
CRATEDEX__SERVER__MAX_REQUEST_BODY_BYTES 262144 Max HTTP request body size
CRATEDEX__DATABASE__PATH ~/.cratedex/cratedex.db Database file path

HTTP Security Model

  • By default, cratedex only allows loopback binds (127.0.0.1 / localhost).
  • Binding to non-loopback interfaces requires explicit opt-in via CRATEDEX__SERVER__ALLOW_REMOTE=true (or install-service --allow-remote).
  • If you expose the service beyond localhost, place it behind a reverse proxy that enforces TLS and authentication.
  • For additional local protection (multi-user hosts), set CRATEDEX__SERVER__AUTH_TOKEN and send Authorization: Bearer <token>.

MCP Tools

Tool Description
register_project Register a Rust project for indexing and diagnostics
list_projects List all registered projects and their indexing status
list_crates List all crates in a project's workspace
get_diagnostics Get build diagnostics, outdated deps, and security advisories
search_docs Search Rust documentation across the global index
unregister_project Remove a registered project from the server

MCP Resources

URI Description
cratedex://logs Recent log entries from the server (last 500 lines)

Deployment Models

stdio -- per-client process

Each MCP client spawns its own cratedex process. Simple to configure, but concurrent clients may contend on the shared database file. Best for single-client setups.

HTTP -- shared daemon

A single cratedex process serves all clients over HTTP. Avoids database lock contention and shares the documentation index across all sessions. Recommended for multi-client environments.

Endpoint: http://<host>:<port>/mcp (default http://127.0.0.1:3737/mcp)

Client Configuration

Claude Code

claude mcp add --scope user --transport http cratedex http://127.0.0.1:3737/mcp

Codex

codex mcp add cratedex --url http://127.0.0.1:3737/mcp

stdio (any MCP client)

Configure the client to spawn the server directly:

{
  "command": "cratedex",
  "args": ["server"],
  "env": {
    "CRATEDEX__SERVER__TRANSPORT": "stdio"
  }
}

Advanced Service Management

Linux: systemd User Service

For a persistent shared HTTP daemon, install cratedex as a systemd user service:

cratedex install-service

This writes a service unit to ~/.config/systemd/user/cratedex.service, runs daemon-reload, and enables + starts the service. The command is idempotent.

To verify:

systemctl --user status cratedex
journalctl --user -u cratedex -f

To remove:

cratedex remove-service

To update the service binary:

cratedex update

For system-level services:

sudo cratedex update --system

Linux: systemd System Service

A system-level service runs a shared daemon under /etc/systemd/system, managed with plain systemctl.

sudo cratedex install-service --system

To verify:

systemctl status cratedex
journalctl -u cratedex -f

To remove:

sudo cratedex remove-service --system

macOS: launchd

cratedex install-service installs a LaunchAgent in ~/Library/LaunchAgents/. Use --system (with sudo) for /Library/LaunchDaemons/.

Windows: Task Scheduler

cratedex install-service installs a user-level scheduled task at logon. System-level Windows Services are not implemented directly; use NSSM for that deployment model.

License

Licensed under either of

at your option.

Contribution

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.