rust-best-practices

Name: rust-best-practices
Author: apollographql

Idiomatic Rust coding standards based on Apollo GraphQL's best practices handbook. Covers nine core areas: coding styles and idioms, clippy linting, performance optimization, error handling, testing patterns, generics and dispatch, type state pattern, documentation, and pointer safety Emphasizes borrowing over cloning, Result-based error handling with thiserror/anyhow, and performance profiling with release builds Includes quick reference guidance on ownership patterns, panic avoidance, clippy configuration, test naming conventions, and compile-time state safety via type state pattern Provides specific lints to enforce (redundant_clone, large_enum_variant, needless_collect) and recommends #[expect(...)] over #[allow(...)] with justification comments

INSTALLATION

npx skills add https://github.com/apollographql/skills --skill rust-best-practices

Run in your project or agent environment. Adjust flags if your CLI version differs.

SKILL.md

$2a

Borrowing & Ownership

Prefer &T over .clone() unless ownership transfer is required

Use &str over String, &[T] over Vec<T> in function parameters

Small Copy types (≤24 bytes) can be passed by value

Use Cow<'_, T> when ownership is ambiguous

Error Handling

Return Result<T, E> for fallible operations; avoid panic! in production

Never use unwrap()/expect() outside tests

Use thiserror for library errors, anyhow for binaries only

Prefer ? operator over match chains for error propagation

Performance

Always benchmark with --release flag

Run cargo clippy -- -D clippy::perf for performance hints

Avoid cloning in loops; use .iter() instead of .into_iter() for Copy types

Prefer iterators over manual loops; avoid intermediate .collect() calls

Linting

Run regularly: cargo clippy --all-targets --all-features --locked -- -D warnings

Key lints to watch:

redundant_clone - unnecessary cloning

large_enum_variant - oversized variants (consider boxing)

needless_collect - premature collection

Use #[expect(clippy::lint)] over #[allow(...)] with justification comment.

Testing

Name tests descriptively: process_should_return_error_when_input_empty()

One assertion per test when possible

Use doc tests (///) for public API examples

Consider cargo insta for snapshot testing generated output

Generics & Dispatch

Prefer generics (static dispatch) for performance-critical code

Use dyn Trait only when heterogeneous collections are needed

Box at API boundaries, not internally

Type State Pattern

Encode valid states in the type system to catch invalid operations at compile time:

struct Connection<State> { /* ... */ _state: PhantomData<State> }

struct Disconnected;

struct Connected;

impl Connection<Connected> {

    fn send(&#x26;self, data: &#x26;[u8]) { /* only connected can send */ }

}

rust-best-practices

SKILL.md

Borrowing & Ownership

Error Handling

Performance

Linting

Testing

Generics & Dispatch

Type State Pattern

Documentation

Stop writing automation&scrapers

rust-best-practices

SKILL.md

Borrowing &#x26; Ownership

Error Handling

Performance

Linting

Testing

Generics &#x26; Dispatch

Type State Pattern

Documentation

Let your agent run on any real-world website

Related skills

Stop writing automation&scrapers

Borrowing & Ownership

Generics & Dispatch