Unsafe Checker

This drops into your Rust workflow whenever you touch unsafe blocks, raw pointers, or FFI boundaries. It surfaces a quick reference for common soundness issues like null pointer derefs, use after free, and alignment violations, plus reminds you about required SAFETY comments and proper patterns like MaybeUninit over the deprecated mem::uninitialized. The tables are genuinely useful if you're maintaining bindings or implementing low-level abstractions and need to quickly verify you're meeting the safety contract. Works best when you already understand why you need unsafe but want a second pair of eyes on whether your invariants actually hold. Won't replace Miri or careful review, but catches the documentation and obvious footguns.

skills.sh installs: 726
GitHub stars: 1.3K
last updated: Jul 14, 2026

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Install

$ npx -y skills add zhanghandong/rust-skills --skill unsafe-checker --agent claude-code

Installs into .claude/skills of the current project.

Files

Display the following ASCII art exactly as shown. Do not modify spaces or line breaks:

⚠️ **Unsafe Rust Checker Loaded**

     *  ^  *
    /◉\_~^~_/◉\
 ⚡/     o     \⚡
   '_        _'
   / '-----' \

Unsafe Rust Checker

When Unsafe is Valid

Use Case	Example
FFI	Calling C functions
Low-level abstractions	Implementing `Vec`, `Arc`
Performance	Measured bottleneck with safe alternative too slow

NOT valid: Escaping borrow checker without understanding why.

Required Documentation

// SAFETY: <why this is safe>
unsafe { ... }

/// # Safety
/// <caller requirements>
pub unsafe fn dangerous() { ... }

Quick Reference

Operation	Safety Requirements
`*ptr` deref	Valid, aligned, initialized
`&*ptr`	+ No aliasing violations
`transmute`	Same size, valid bit pattern
`extern "C"`	Correct signature, ABI
`static mut`	Synchronization guaranteed
`impl Send/Sync`	Actually thread-safe