mcp-crates

# mcp-crates

Crates.io MCP — wraps the crates.io REST API v1 (free, no auth)

Part of [Pipeworx](https://pipeworx.io) — an MCP gateway connecting AI agents to 1854+ live data sources. This is an independent, unofficial integration — not affiliated with, endorsed by, or published by the upstream provider.

## Tools

| Tool | Description |
|------|-------------|
| `search_crates` | Search crates.io for Rust packages by keyword. Returns crate name, description, downloads, latest version, and repo URL. |
| `get_crate` | Get full metadata for a specific crate (e.g., 'serde'). Returns description, downloads, latest version, repo, homepage, and categories. |
| `get_versions` | List all published versions for a crate in reverse chronological order. Returns version number, download count, and publish date. |
| `get_crate_dependencies` | List the dependencies of a specific crate version — what <crate> itself depends on. Returns each dependency with its version requirement, kind (normal/build/dev), optional flag, enabled features, and target. Version is optional (defaults to the latest stable). Use for "what does <crate> depend on", dependency audits, or sizing a crate's footprint. |
| `get_crate_reverse_deps` | List crates that DEPEND ON a given crate (reverse dependencies), most-downloaded first — answers "what uses <crate>", "how widely adopted is <crate>", "who depends on <crate>". Returns the total dependent count plus the top dependents with their version requirement, dependency kind, and download counts. |

## Quick Start

Add to your MCP client (Claude Desktop, Cursor, Windsurf, etc.):

```json
{
  "mcpServers": {
    "crates": {
      "url": "https://gateway.pipeworx.io/crates/mcp"
    }
  }
}
```

### What this endpoint actually serves

`tools/list` at `https://gateway.pipeworx.io/crates/mcp` returns the tools in the table
above **plus the shared Pipeworx meta-tools** — `ask_pipeworx`,
`discover_tools`, `search_within`, `remember`/`recall` and the rest of the
gateway-wide set. So the tool count you see is larger than this table: a
single-pack endpoint currently lists roughly 30 shared tools alongside the
pack's own. The connection's `initialize` response states its exact scope, and
is the authoritative answer for a given day.

This is deliberate, not multiplexing by accident. The meta-tools are what let a
scoped connection answer a question this pack does not cover — via
`ask_pipeworx`, which routes across the whole catalog — without you adding a
second MCP server. There is currently no way to mount a pack endpoint without
them; if the extra schemas cost you more context than the routing is worth,
connect to the full gateway once rather than to several pack endpoints.

Or connect to the full Pipeworx gateway to get every pack's tools listed
directly, instead of just this one's:

```json
{
  "mcpServers": {
    "pipeworx": {
      "url": "https://gateway.pipeworx.io/mcp"
    }
  }
}
```

Both URLs reach the same gateway and the same 1854+ data sources. The
only difference is which pack's tools are listed **directly**; `ask_pipeworx`
reaches all of them from either one.

## No MCP client? Call it over HTTP

```bash
curl -X POST https://gateway.pipeworx.io/v1/tools/search_crates \
  -H 'Content-Type: application/json' \
  -d '{"query":"web framework"}'
```

No account needed for the first calls. Inspect any tool: `GET https://gateway.pipeworx.io/v1/tools/search_crates`. Find one: `POST https://gateway.pipeworx.io/v1/tools/search_packs` with `{"query":"..."}`.

## Standalone (no gateway account)

This package also runs as a local stdio MCP server — no Pipeworx account, no
gateway round-trip:

```json
{
  "mcpServers": {
    "crates": {
      "command": "npx",
      "args": ["-y", "@pipeworx/mcp-crates"]
    }
  }
}
```

Or run it directly to confirm it starts:

```bash
npx -y @pipeworx/mcp-crates
```

It speaks MCP over stdin/stdout and answers `initialize`/`tools/list`/`tools/call`
for **only** this pack's tools — none of the shared meta-tools the gateway
connection above adds. Same source, same tools, no ask_pipeworx routing.

## Using with ask_pipeworx

Instead of calling tools directly, you can ask questions in plain English —
this works on the pack endpoint above as well as on the full gateway:

```
ask_pipeworx({ question: "your question about Crates data" })
```

The gateway picks the right tool and fills the arguments automatically.

## More

- [Docs and guides](https://pipeworx.io/docs)
- [pipeworx.io](https://pipeworx.io)

## License

MIT