fuzzing SKILL.md skillA
fuzzing from pmatos/jsse is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add pmatos/jsse/fuzzing@v0.1.0Pins v0.1.0 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- pmatos/jsse
- Path
.claude/skills/fuzzing/SKILL.md- Versions recorded
- 1
- Latest version
- v0.1.0, committed Sep 4, 2026
- Size
- 6,411 bytes
- Repository stars
- 73
- License
- MIT
This skill should be used when the user asks to "fuzz the parser", "run cargo fuzz", "fuzz jsse vs node", "check for fuzzer crashes", "triage a fuzz crash", "minimize a fuzz artifact", or wants to drive a cargo-fuzz run or triage a crash/divergence it found. Covers both the parse_roundtrip and differential targets under fuzz/.
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
# Fuzzing
Two `cargo-fuzz` targets live under `fuzz/`: `parse_roundtrip` (parsing
arbitrary bytes must never panic) and `differential` (jsse vs `node` on
the same source). See `docs/adr/0004-fuzz-lib-target-and-subprocess-differential.md`
for why they're built the way they are, and the `Divergence Tier` entry
in `CONTEXT.md` for the tiering `differential` uses.
This skill has two responsibilities, run separately: **drive a run**
(read-only with respect to engine code — it only ever touches `fuzz/`
build/corpus/artifact state), then, only if it finds something,
**triage the result**.
## Running a fuzz target
1. **Prerequisites:**
- `cargo install cargo-fuzz --locked` (needs a `nightly` toolchain:
`rustup toolchain install nightly` if not already present).
- `differential` additionally needs `cargo build --release` — it shells
out to `target/release/jsse`, and skips cleanly (not a crash) if that
binary is missing. It also needs `node` on `PATH`; also skips
cleanly if absent.
2. **Regression replay (fast, deterministic, safe to run anytime):**
```bash
cargo +nightly fuzz run parse_roundtrip -- -runs=0 fuzz/corpus/parse_roundtrip
…Read the whole file at its exact version.
How to install
mdr add pmatos/jsse/fuzzing@sha256:55b90c7dbf0807efThe line at the top of this page pins the label v0.1.0, 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_vkmh3uuf6kt3yuzd)
3 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Sep 4, 2026.
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 (6411 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
pmatos/jsse · 73 stars · license MIT · pushed 2026-10-20 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_vkmh3uuf6kt3yuzd GET https://markdownregistry.com/api/v1/resolve?ref=pmatos/jsse/fuzzing GET https://markdownregistry.com/api/v1/blob/55b90c7dbf0807efb13b78d1c3b22a902510d74fb3e7a7a6ea6d72be291ce894
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.