cargo-fuzz SKILL.md skillA
cargo-fuzz from trailofbits/skills is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add trailofbits/skills/cargo-fuzz@git:20260826.3deb39ePins git:20260826.3deb39e in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- trailofbits/skills
- Path
plugins/testing-handbook-skills/skills/cargo-fuzz/SKILL.md- Versions recorded
- 2
- Latest version
- git:20260826.3deb39e, committed Aug 26, 2026
- First version recorded
- Jan 14, 2026
- Size
- 11,789 bytes
- Repository stars
- 8,043
- License
- CC-BY-SA-4.0
Sets up and runs cargo-fuzz, the standard fuzzing tool for Cargo-based Rust projects. Covers cargo fuzz init, the nightly toolchain requirement, fuzz_target! harnesses, Arbitrary-derived structured inputs, sanitizer options, cargo fuzz coverage, and reproducing a crash artifact. Use when fuzzing a Rust crate, writing a fuzz_target!, exercising unsafe blocks or FFI in Rust, or triaging a cargo fuzz crash.
Collected from public GitHub. Every version is saved exactly as it was and never changes. Install it at an exact version with the mdr tool, and every file is checked before it reaches your agent. The main file is checked against the SHA-256 fingerprint recorded here, and the others against the fingerprints GitHub keeps for its source commit. The automatic checks below grade the latest version, and the same checks always give the same file the same grade.
What the file says
# cargo-fuzz
cargo-fuzz is the de facto choice for fuzzing Rust projects when using Cargo. It uses libFuzzer as the backend and provides a convenient Cargo subcommand that automatically enables relevant compilation flags for your Rust project, including support for sanitizers like AddressSanitizer.
## When to Use
cargo-fuzz is currently the primary and most mature fuzzing solution for Rust projects using Cargo.
| Fuzzer | Best For | Complexity |
|--------|----------|------------|
| cargo-fuzz | Cargo-based Rust projects, quick setup | Low |
| AFL++ | Multi-core fuzzing, non-Cargo projects | Medium |
| LibAFL | Custom fuzzers, research, advanced use cases | High |
**Choose cargo-fuzz when:**
- Your project uses Cargo (required)
- You want simple, quick setup with minimal configuration
- You need integrated sanitizer support
- You're fuzzing Rust code with or without unsafe blocks
## Quick Start
```rust
#![no_main]
use libfuzzer_sys::fuzz_target;
fn harness(data: &[u8]) {
your_project::check_buf(data);
}
fuzz_target!(|data: &[u8]| {
harness(data);
});
```
Initialize and run:
```bash
cargo fuzz init
# Edit fuzz/fuzz_targets/fuzz_target_1.rs with your harness
…Read the whole file at its exact version.
How to install
mdr add trailofbits/skills/cargo-fuzz@sha256:8e8f882604f68c68The line at the top of this page pins the label git:20260826.3deb39e, which is what most people want. This one pins the sha256 fingerprint of the contents instead, so it survives a label being moved. Either way the exact version is written to mdr.lock, and mdr install downloads and checks those contents again, so it installs them exactly or stops with an error.
[](https://markdownregistry.com/a/art_h63722wbfk737n3j)
4 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 2 versions of this file, between Jan 14, 2026 and Aug 26, 2026, about one every 224 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260826.3deb39e latest | 2026-08-26 | 3deb39e | 11,789 B | A | view · diff |
| git:20260114.695119c | 2026-01-14 | 695119c | 11,506 B | A | view |
Audit of the latest version
- pass: Frontmatter block present
- pass: Frontmatter declares a name
- pass: Frontmatter declares a description
- pass: Size between 200 bytes and 200 KB (11789 bytes)
- pass: No zero-width or bidi control characters
- pass: No instruction hidden inside an HTML comment
- pass: No link to an exfiltration or paste host
- pass: No credential-shaped string
- pass: No instruction to send local credentials anywhere
- pass: No text hidden with inline styles
- pass: No prompt-injection phrasing
- pass: No curl or wget piped into a shell
- pass: No recursive delete of root, home or parent
- pass: No instruction to read or print local credentials
- pass: No base64 blob over 200 characters
- pass: No link to a raw IP address
- pass: No script tag
Source
trailofbits/skills · 8,043 stars · license CC-BY-SA-4.0 · pushed 2026-11-06 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_h63722wbfk737n3j GET https://markdownregistry.com/api/v1/resolve?ref=trailofbits/skills/cargo-fuzz GET https://markdownregistry.com/api/v1/blob/8e8f882604f68c682afde3562ba1bd3828264fd226f427ff7d9ba50617268db1
Your AI assistant does the legwork. You hear about the deals worth your word. Hand yours the standing instructions at modelranch.com and it joins the network that reads files like this one.
Guides: the SKILL.md format and its required fields · what to check before you install a skill · how to pin a skill to an exact version · where to find agent skills · keeping a team on the same skills · which agent file does what.
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