---
name: rust-best-practices
description: >
  Guide for writing idiomatic Rust code based on Apollo GraphQL's best practices handbook. Use this skill when:
  (1) writing new Rust code or functions,
  (2) reviewing or refactoring existing Rust code,
  (3) deciding between borrowing vs cloning or ownership patterns,
  (4) implementing error handling with Result types,
  (5) optimizing Rust code for performance,
  (6) writing tests or documentation for Rust projects.
license: MIT
compatibility: Rust 1.70+, Cargo
metadata:
  author: apollographql
  version: "1.1.1"
allowed-tools: Bash(cargo:*) Bash(rustc:*) Bash(rustfmt:*) Bash(clippy:*) Read Write Edit Glob Grep
---

# Rust Best Practices

Apply these guidelines when writing or reviewing Rust code. Based on Apollo GraphQL's [Rust Best Practices Handbook](https://github.com/apollographql/rust-best-practices).

## Best Practices Reference

Before reviewing, familiarize yourself with Apollo's Rust best practices. Read ALL relevant chapters in the same turn in parallel. Reference these files when providing feedback:

- [Chapter 1 - Coding Styles and Idioms](references/chapter_01.md): Borrowing vs cloning, Copy trait, Option/Result handling, iterators, comments, when to extract a function (duplication vs. wrong abstraction)
- [Chapter 2 - Clippy and Linting](references/chapter_02.md): Clippy configuration, important lints, workspace lint setup
- [Chapter 3 - Performance Mindset](references/chapter_03.md): Profiling, avoiding redundant clones, stack vs heap, zero-cost abstractions
- [Chapter 4 - Error Handling](references/chapter_04.md): Result vs panic, thiserror vs anyhow, error hierarchies
- [Chapter 5 - Automated Testing](references/chapter_05.md): Test naming, one assertion per test, snapshot testing
- [Chapter 6 - Generics and Dispatch](references/chapter_06.md): Static vs dynamic dispatch, trait objects
- [Chapter 7 - Type State Pattern](references/chapter_07.md): Compile-time state safety, when to use it
- [Chapter 8 - Comments vs Documentation](references/chapter_08.md): When to comment, doc comments, rustdoc
- [Chapter 9 - Understanding