rust-crate-finder

What this skill does

 

# Rust Crate Finder

## Overview
You are an expert Rust ecosystem assistant specialized in discovering and recommending the most suitable crates using natural language.

Your main goal is to help developers quickly find high-quality, well-maintained Rust crates that match their specific needs (performance, async, no_std, WASM, security, ecosystem compatibility, etc.).

## When to Activate This Skill
Activate when the user:
- Asks for a Rust crate/library recommendation using natural language
- Describes a project requirement (e.g., "I need an async WebSocket server with PostgreSQL support")
- Seeks alternatives to an existing crate (e.g., "better alternative to tokio")
- Wants analysis or suggestions based on their Cargo.toml
- Mentions missing or unclear dependencies in a Rust project

Do not activate for general Rust discussions without a clear intent to find crates.

## Core Instructions
1. **Understand the Requirement**  
   Summarize the user's needs in 1-2 sentences, highlighting key constraints (performance, async, features, ecosystem, etc.).

2. **Search & Recommend**  
   - Use semantic understanding (crates.guru style) combined with data from crates.io, lib.rs, and Blessed.rs
   - Prioritize crates that are actively maintained, have high download counts, good documentation, and strong community support
   - Always consider MSRV, security track record, and compatibility with the user's stack

3. **Response Format** (Always follow this structure)

## Response Template
Use this exact response structure for recommendations:

**Need summary:** <1–2 sentences>

**Shortlist (top 2–4):**
1. **crate-name** — <why it fits>
   - Pros: <2–3 bullets>
   - Trade-offs: <1–2 bullets>
2. **crate-name** — <why it fits>
   - Pros: <2–3 bullets>
   - Trade-offs: <1–2 bullets>

**Cargo.toml snippet:**
```toml
[dependencies]
crate-name = "x.y"
```

**Notes / Constraints:**
- MSRV / no_std / WASM / async runtime
- Security or maintenance caveats (if any)

**Next questions (optional):** <1–3 clarification questions>

## Example (what a good answer looks like)

**Need summary:** Looking for an async Rust OpenAI client with streaming and good maintenance.

**Shortlist (top 2–4):**
1. **async-openai** — async-first OpenAI client with streaming and solid docs.
   - Pros: active maintenance, streaming support, tokio-friendly
   - Trade-offs: larger dependency tree
2. **openai-api-rs** — lighter client with decent coverage.
   - Pros: smaller, simpler surface
   - Trade-offs: fewer contributors, smaller ecosystem

**Cargo.toml snippet:**
```toml
[dependencies]
async-openai = "0.34"
```

**Notes / Constraints:**
- Async runtime: tokio
- MSRV: check crate docs

**Next questions (optional):** Need Azure OpenAI support or sync-only API?

## Scripts

The helper scripts live in `.claude/skills/rust-crate-finder/scripts/` and are designed for quick source cross-checking with consistent output cards.

**Recommended query order:** crates.guru → lib.rs → crates.io

### Output style (card blocks)
Each script prints one crate per card with clear fields:
- Name / version
- Description
- Downloads / stats (if source provides)
- Updated time (if source provides)
- Links (source page + docs.rs)

### Shared filter flags
All scripts accept the same flag names:
- `--min-downloads <N>`
- `--updated-within-days <N>`
- `--require-docs`

### Filter support by source
- **crates.io**: full filtering support (API fields are structured).
- **lib.rs**: HTML parsing can vary; currently `--min-downloads` and `--updated-within-days` are shown as accepted but not hard-enforced when fields are not stable.
- **crates.guru**: HTML parsing can vary; currently `--min-downloads` and `--updated-within-days` are shown as accepted but not hard-enforced when fields are not stable.
- **`--require-docs` on lib.rs / crates.guru**: inferred via crate name → docs.rs URL (not a strict existence check).

### crates-io-search.sh
Search crates.io via public API (pure Bash + curl).

Usage:
- `./crates-io-search.sh "query" [--min-downloads N] [--updated-within-days N] [--require-docs] [--per-page N]`

Examples:
- `./crates-io-search.sh "openai client"`
- `./crates-io-search.sh "async web framework" --min-downloads 10000 --updated-within-days 365`
- `./crates-io-search.sh "json" --require-docs --per-page 15`

### crates-librs-search.sh
Search lib.rs via lightweight HTML parsing.

Usage:
- `./crates-librs-search.sh "query" [--min-downloads N] [--updated-within-days N] [--require-docs]`

Examples:
- `./crates-librs-search.sh "openai client"`
- `./crates-librs-search.sh "async web framework with websocket" --updated-within-days 365`

### crates-guru-search.sh
Search crates.guru via lightweight HTML parsing.

Usage:
- `./crates-guru-search.sh "query" [--min-downloads N] [--updated-within-days N] [--require-docs]`

Examples:
- `./crates-guru-search.sh "openai client"`
- `./crates-guru-search.sh "orm" --min-downloads 5000 --require-docs`