Rust

Rust Development

Purpose: Best practices for Rust development including ownership, error handling, concurrency, and safety patterns.

When to Use This Skill

• Building Rust applications and systems
• Working with ownership, borrowing, and lifetimes
• Implementing error handling with Result and Option types
• Writing concurrent code with threads and async
• Designing trait-based abstractions

Decision Tree

Rust Project Decision
+-- Building a CLI tool?
|   +-- Argument parsing? -> clap
|   +-- Pretty output? -> anyhow + color-eyre
+-- Building a web service?
|   +-- Async HTTP? -> axum or actix-web
|   +-- Need middleware? -> tower (used by axum)
+-- Error handling strategy?
|   +-- Library code? -> thiserror (typed errors)
|   +-- Application code? -> anyhow (ergonomic errors)
+-- Async runtime?
|   +-- General purpose? -> tokio
|   +-- Lightweight? -> smol or async-std
+-- Serialization needed? -> serde + serde_json / serde_yaml
+-- Performance-critical path? -> Benchmark with criterion before optimizing

Prerequisites

• Rust 1.94+ installed via rustup
• Cargo package manager

Table of Contents

1. Project Structure
2. Ownership and Borrowing
3. Error Handling
4. Traits and Generics
5. Concurrency
6. Testing
7. Performance
8. Security
9. Best Practices

Project Structure

Standard Layout

project/
+-- src/
| +-- main.rs # Binary entry point
| +-- lib.rs # Library root
| +-- config.rs # Configuration
| +-- error.rs # Error types
| +-- models/
| | +-- mod.rs
| | -- user.rs
| -- services/
| +-- mod.rs
| -- user_service.rs
+-- tests/
| -- integration_tests.rs
+-- benches/
| -- benchmarks.rs
+-- examples/
| -- basic_usage.rs
+-- Cargo.toml
+-- Cargo.lock
-- README.md

Cargo.toml

[package]
name = "myapp"
version = "0.1.0"
edition = "2021"
authors = ["Your Name <you@example.com>"]
description = "A brief description"

[dependencies]
tokio = { version = "1", features = ["full"] }
serde = { version = "1", features = ["derive"] }
thiserror = "1"
anyhow = "1"

[dev-dependencies]
tokio-test = "0.4"

[profile.release]
lto = true
opt-level = 3

Core Rules

[PASS] DO

• Use clippy for linting: cargo clippy
• Format with rustfmt: cargo fmt
• Prefer &str over String for function parameters
• Use #[derive] for common traits
• Write documentation with ///
• Use Result for recoverable errors
• Leverage the type system for safety

[FAIL] DON'T

• Use unwrap() in production code
• Ignore compiler warnings
• Use unsafe without clear justification
• Clone unnecessarily
• Write overly complex lifetimes
• Panic for expected error conditions

Anti-Patterns

• Unwrap in Production: Using .unwrap() or .expect() in non-test code -> Use ? operator with proper error types
• Unnecessary Cloning: Cloning data to satisfy the borrow checker -> Refactor ownership or use references and lifetimes
• Unsafe Without Justification: Using unsafe blocks without documented safety invariants -> Avoid unsafe; if required, add // SAFETY: comments
• Stringly Typed APIs: Passing String where an enum or newtype fits -> Use the type system to encode valid states
• Blocking in Async: Calling blocking I/O inside async functions -> Use tokio::task::spawn_blocking for blocking work
• Ignoring Clippy Warnings: Suppressing clippy lints without reason -> Fix the issue or document why the lint is suppressed

References

• The Rust Book
• Rust by Example
• Rust API Guidelines
• Tokio Tutorial

Version: 1.0 Last Updated: February 5, 2026

Troubleshooting

Source: jnPiyush/AgentX — distributed by TomeVault.