mutation-testing SKILL.md skillA
mutation-testing from vmobifystudio/app-dev-team is an agent skill: a SKILL.md folder an AI agent loads when a task calls for it.
mdr add vmobifystudio/app-dev-team/mutation-testing@git:20260729.63f4fc3Pins git:20260729.63f4fc3 in mdr.lock. Pin the fingerprint instead.
- Audit grade
- A, 17 of 17 checks passed
- Kind
- SKILL.md skill
- Repository
- vmobifystudio/app-dev-team
- Path
skills/mutation-testing/SKILL.md- Versions recorded
- 1
- Latest version
- git:20260729.63f4fc3, committed Jul 29, 2026
- Size
- 4,444 bytes
- Repository stars
- 5
- License
- MIT
Use when adding or reviewing a gate, guard rule, CI grep, or test assertion in this plugin's own scripts — and whenever a suite is green and you need to know whether that means anything. Runs scripts/mutate.sh, which breaks the code on purpose and reports which assertions failed to notice. Triggers from code-reviewer, verification-engineer, and any change under scripts/ or hooks/.
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 `defect-hunting` §3 says a new rule is not done until you have watched it fail, in three steps. That instruction was followed by hand, when someone remembered. On 2026-07-29 the suite read **385 passed, 0 failed** while containing a `grep -E` with a PCRE lookahead (a syntax error, stderr to `/dev/null`, `|| ok` every time), two doctor assertions that a demoted gate could not turn red, and a hook that stood down in exactly the incident it was written for. **A green suite is evidence only to the extent its assertions can go red.** `scripts/mutate.sh` is that, executable. ## Running it ```sh sh scripts/mutate.sh # all 16 catalogued mutations (~1 min each — the whole suite runs) sh scripts/mutate.sh --list # the catalogue, plus what it cannot test and why sh scripts/mutate.sh --only M04 # one mutation, while you iterate on an assertion sh scripts/mutate.sh --sample 4 # what CI runs on every PR ``` Exit `0` all caught · `1` something SURVIVED · `2` could not run (baseline not green, anchor drifted). Three verdicts matter: - **CAUGHT (n assertions)** — the gate bites. …
Read the whole file at its exact version.
How to install
mdr add vmobifystudio/app-dev-team/mutation-testing@sha256:77b9915b9654d643The line at the top of this page pins the label git:20260729.63f4fc3, 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_kduqv7uod4snviu3)
5 badge image fetches in 30 days. What the badge shows.
Versions
The registry has recorded 1 version of this file, committed on Jul 29, 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 (4444 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
vmobifystudio/app-dev-team · 5 stars · license MIT · pushed 2026-11-02 · branch main
API
GET https://markdownregistry.com/api/v1/artifacts/art_kduqv7uod4snviu3 GET https://markdownregistry.com/api/v1/resolve?ref=vmobifystudio/app-dev-team/mutation-testing GET https://markdownregistry.com/api/v1/blob/77b9915b9654d643bdc9094388b3e333c1d759cb1ddd5d9b7da1dad799739cc4
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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