mutation-testing SKILL.md skillA
mutation-testing 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/mutation-testing@git:20260914.d30ab4dPins git:20260914.d30ab4d in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- trailofbits/skills
- Path
plugins/mutation-testing/skills/mutation-testing/SKILL.md- Versions recorded
- 3
- Latest version
- git:20260914.d30ab4d, committed Sep 14, 2026
- First version recorded
- Mar 31, 2026
- Size
- 6,225 bytes
- Repository stars
- 7,951
- License
- CC-BY-SA-4.0
Configures mewt or muton campaigns, analyzes surviving mutants, and investigates bugs exposed by testing gaps. Use when setting up mutation testing, reviewing campaign results, identifying equivalent mutants, or finding bugs from surviving mutations.
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
# Mutation Testing (mewt/muton) Routes to the right mutation testing workflow and loads the references that workflow needs. > **Note**: muton and mewt share identical interfaces. Examples use `mewt`; substitute `muton` and its file names (`muton.toml`, `muton.sqlite`) for muton projects. `mewt --help` and `mewt <subcommand> --help` are the source of truth for command-line behavior. Examples below reflect the mewt 4.x API; run `--help` when a flag looks unfamiliar or a command fails. ## When to Use Use this skill when the user: - Mentions "mewt", "muton", or "mutation testing" - Wants to configure, scope, or speed up a mutation testing campaign - Wants to analyze mutation results — surviving/uncaught mutants, equivalent mutants, kill rate - Wants to use mutation results to find bugs in the source code ## When NOT to Use Do not use this skill when the user asks about tests or line coverage without any mutation testing context. --- ## Routing Pick the workflow, then load it together with the references listed for it. Workflows and references do not load each other — that decision belongs here. **Setting up, scoping, or speeding up a campaign** …
Read the whole file at its exact version.
How to install
mdr add trailofbits/skills/mutation-testing@sha256:20e6ee2b6cec91baThe line at the top of this page pins the label git:20260914.d30ab4d, 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_fjszbr55sndexct4)
2 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 3 versions of this file, between Mar 31, 2026 and Sep 14, 2026, about one every 83 days.
| version | committed | commit | size | audit | |
|---|---|---|---|---|---|
| git:20260914.d30ab4d latest | 2026-09-14 | d30ab4d | 6,225 B | A | view · diff |
| git:20260428.debfb29 | 2026-04-28 | debfb29 | 2,863 B | A | view · diff |
| git:20260331.af35cde | 2026-03-31 | af35cde | 2,879 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 (6225 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 · 7,951 stars · license CC-BY-SA-4.0 · pushed 2026-10-28 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_fjszbr55sndexct4 GET https://markdownregistry.com/api/v1/resolve?ref=trailofbits/skills/mutation-testing GET https://markdownregistry.com/api/v1/blob/20e6ee2b6cec91bad7572dea966b5fce1e50f9ef8d4bf2e4ba69ac9b679792ff
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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