mutation-testing skillA
mutation-testing is agent-read markdown (skill) from vmobifystudio/app-dev-team: 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/..
Indexed from public GitHub and served as immutable, content-addressed versions. Install it pinned to an exact SHA-256 with the mdr CLI, and every file is verified against the hash recorded here before it reaches your agent. The deterministic audit below grades the latest version, and the same file always earns 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@git:20260729.63f4fc3mdr add vmobifystudio/app-dev-team/mutation-testing@sha256:77b9915b9654d643Pin to a label to follow the author's releases, or to a sha256 to freeze the exact bytes forever. Either way the resolved hash is written to mdr.lock, and mdr install reproduces it on any machine.
[](https://markdownregistry.com/a/art_kduqv7uod4snviu3)
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Versions
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 · 4 stars · license MIT · pushed 2026-09-19 · 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
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