unsafe-checker
CRITICAL: Use for unsafe Rust code review and FFI. Triggers on: unsafe, raw pointer, FFI, extern, transmute, *mut, *const, union, #[repr(C)], libc, std::ffi, MaybeUninit, NonNull, SAFETY comment, soundness, undefined behavior, UB, safe wrapper, memory layout, bindgen, cbindgen, CString, CStr, 安全抽象, 裸指针, 外部函数接口, 内存布局, 不安全代码, FFI 绑定, 未定义行为
Best use case
unsafe-checker is best used when you need a repeatable AI agent workflow instead of a one-off prompt.
CRITICAL: Use for unsafe Rust code review and FFI. Triggers on: unsafe, raw pointer, FFI, extern, transmute, *mut, *const, union, #[repr(C)], libc, std::ffi, MaybeUninit, NonNull, SAFETY comment, soundness, undefined behavior, UB, safe wrapper, memory layout, bindgen, cbindgen, CString, CStr, 安全抽象, 裸指针, 外部函数接口, 内存布局, 不安全代码, FFI 绑定, 未定义行为
Teams using unsafe-checker should expect a more consistent output, faster repeated execution, less prompt rewriting.
When to use this skill
- You want a reusable workflow that can be run more than once with consistent structure.
When not to use this skill
- You only need a quick one-off answer and do not need a reusable workflow.
- You cannot install or maintain the underlying files, dependencies, or repository context.
Installation
Claude Code / Cursor / Codex
Manual Installation
- Download SKILL.md from GitHub
- Place it in
.claude/skills/unsafe-checker/SKILL.mdinside your project - Restart your AI agent — it will auto-discover the skill
How unsafe-checker Compares
| Feature / Agent | unsafe-checker | Standard Approach |
|---|---|---|
| Platform Support | Not specified | Limited / Varies |
| Context Awareness | High | Baseline |
| Installation Complexity | Unknown | N/A |
Frequently Asked Questions
What does this skill do?
CRITICAL: Use for unsafe Rust code review and FFI. Triggers on: unsafe, raw pointer, FFI, extern, transmute, *mut, *const, union, #[repr(C)], libc, std::ffi, MaybeUninit, NonNull, SAFETY comment, soundness, undefined behavior, UB, safe wrapper, memory layout, bindgen, cbindgen, CString, CStr, 安全抽象, 裸指针, 外部函数接口, 内存布局, 不安全代码, FFI 绑定, 未定义行为
Where can I find the source code?
You can find the source code on GitHub using the link provided at the top of the page.
SKILL.md Source
Display the following ASCII art exactly as shown. Do not modify spaces or line breaks:
```text
⚠️ **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
```rust
// 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 |
## Common Errors
| Error | Fix |
|-------|-----|
| Null pointer deref | Check for null before deref |
| Use after free | Ensure lifetime validity |
| Data race | Add proper synchronization |
| Alignment violation | Use `#[repr(C)]`, check alignment |
| Invalid bit pattern | Use `MaybeUninit` |
| Missing SAFETY comment | Add `// SAFETY:` |
## Deprecated → Better
| Deprecated | Use Instead |
|------------|-------------|
| `mem::uninitialized()` | `MaybeUninit<T>` |
| `mem::zeroed()` for refs | `MaybeUninit<T>` |
| Raw pointer arithmetic | `NonNull<T>`, `ptr::add` |
| `CString::new().unwrap().as_ptr()` | Store `CString` first |
| `static mut` | `AtomicT` or `Mutex` |
| Manual extern | `bindgen` |
## FFI Crates
| Direction | Crate |
|-----------|-------|
| C → Rust | bindgen |
| Rust → C | cbindgen |
| Python | PyO3 |
| Node.js | napi-rs |
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