// Search and evaluate Rust crates for a problem. Presents options for user approval.
Use when designing error types, wrapping third-party errors, seeing repeated map_err calls with same error types, building modular error hierarchies with thiserror, choosing between custom errors vs anyhow::Result, or writing Result-returning functions in Rust.
When and what to test in Rust. Types handle compile-time invariants; tests verify runtime behavior types cannot express.
Use when writing Rust structs with generic type parameters, implementing traits for polymorphism, designing service/client/handler layers, choosing between Box<dyn Trait> vs enum vs generics, adding middleware (retry, logging, caching), wrapping or decorating existing types, forwarding methods to inner fields, or refactoring to reduce duplication across similar structs.
Review Rust code for correctness, design principles, and rule compliance.
Helper skill for searching Rust documentation. Use when agents need to find crate docs, API usage, trait implementations, or examples from local and online sources.
| name | rs-crate-search |
| description | Search and evaluate Rust crates for a problem. Presents options for user approval. |
| user-invocable | true |
| context | fork |
| allowed-tools | ["WebSearch","WebFetch","Bash","Read"] |
Find and evaluate crates for a problem domain.
/rs-crate-search "json parsing"
/rs-crate-search "http client async"
# Search crates.io
cargo search "query" --limit 10
# Check lib.rs for alternatives
# WebSearch: "rust crate for [problem] site:lib.rs"
| Criteria | Check |
|---|---|
| Maintenance | Last commit < 6 months |
| Adoption | Downloads, GitHub stars |
| Dependencies | cargo tree -p crate |
| API quality | Docs, examples |
## Crates for [problem]
| Crate | Downloads | Updated | Deps |
|-------|-----------|---------|------|
| `foo` | 10M/month | 2025-01 | 3 |
| `bar` | 500K/month | 2024-12 | 12 |
### `foo`
- Pros: Fast, minimal deps, good docs
- Cons: Less flexible API
### `bar`
- Pros: Feature-rich, active community
- Cons: Heavy dependency tree
**Recommendation:** `foo` - balances simplicity and capability
Add `foo` to Cargo.toml?
Never add dependency without explicit user confirmation.
For known-good crates, check version only:
cargo search serde --limit 1