Unsafe Checker

What it does

When your agent uses it

• Unsafe Rust code review and FFI
• Undefined behavior

Example prompts

• “/unsafe-checker”

Requirements

• Python 3
• Node.js
• Pre-approved tools (allowed-tools): Read, Grep, Glob

What it can do on your machine

Read from SKILL.md and the folder at commit eed457f. It shows what the files ask for, not the result of running them.

• Tool permissions

  Pre-approves these tools, so the agent can use them without asking each time:

  • Read
  • Grep
  • Glob

  From allowed-tools in the SKILL.md frontmatter.

• Runs code

  No scripts in the folder and no shell commands in SKILL.md (its code samples are rust).

  From the folder's file list and the shell code blocks in SKILL.md.

• Network

  No URLs in SKILL.md.

  From URLs in SKILL.md, links to its own repository left out.

• Credentials

  Names no API keys, tokens, secrets or passwords.

  From names ending in _API_KEY, _TOKEN, _SECRET, _KEY or _PASSWORD in SKILL.md.

Context cost

Unsafe Checker loads about 604 tokens when it runs. Until then it costs about 89 tokens; SKILL.md has 176 words of instructions outside code blocks.

Always · name and description, kept in context so the agent knows when to use it

~89

When it runs · the whole SKILL.md, loaded when a task matches

~604

Estimates: characters ÷ 4, the usual rule of thumb; real counts depend on the model's tokenizer. Scripts and assets cost tokens only if the agent reads them.

Safety

Automated static check — not a guarantee. Review scripts before installing. It scans the text of SKILL.md for risky patterns (piping downloads into a shell, reading credential files, hidden Unicode, destructive commands); files beside SKILL.md are not scanned.

SKILL.md

The full file from fjrevoredo/mini-diarium at commit eed457f, republished under its MIT licence (© fjrevoredo). 176 words, ~604 tokens.

name

unsafe-checker

description

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

allowed-tools

Read, Grep, Glob

globs

**/*.rs

⚠️ **Unsafe Rust Checker Loaded**

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

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

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

© fjrevoredo, MIT. Rendered from Markdown: HTML in the file is shown as text, images as links, and headings moved down two levels. Raw file

Files

SKILL.md and 55 other files in .agents/skills/unsafe-checker of fjrevoredo/mini-diarium.

• SKILL.md
• AGENTS.md
• checklists/before-unsafe.md
• checklists/common-pitfalls.md
• checklists/review-unsafe.md
• examples/ffi-patterns.md
• examples/safe-abstraction.md
• rules/_sections.md
• rules/_template.md
• rules/ffi-01-no-string-direct.md
• rules/ffi-02-read-ffi-docs.md
• rules/ffi-03-drop-for-c-ptr.md
• rules/ffi-04-panic-boundary.md
• rules/ffi-05-portable-types.md
• rules/ffi-06-string-abi.md
• rules/ffi-07-no-drop-external.md
• rules/ffi-08-error-handling.md
• rules/ffi-09-ref-not-ptr.md
• … and 38 more

Open the folder on GitHubat commit eed457f

Used in 1 other repository

We found 1 copy of this SKILL.md (exact, near-identical or edited) in other folders, from 1 other GitHub owner. This page covers the copy in fjrevoredo/mini-diarium, which our catalogue first saw on October 7, 2026.

• NeverSight/learn-skills.devdata/skills-md/actionbook/rust-skills/unsafe-checker