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mutation-review

Use when reviewing a PR's test quality via mutation testing. Runs Stryker on the diff, triages surviving mutants, and posts findings as a PR comment with inline annotations on changed lines.

77

Quality

97%

Does it follow best practices?

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SecuritybySnyk

Passed

No findings from the security scan

SKILL.md
Quality
Evals
Security

Quality

Content

100%Weight 40%Scale 1-5

Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.

An exemplary lean skill body: fully executable commands, a well-sequenced workflow with validation branches for the failure modes that actually occur, and tight constraints (one pass, no code edits, no re-runs) that prevent scope drift. No bundle files exist, and none are needed at this size.

DimensionReasoningScore

Conciseness

Every line carries non-obvious, skill-specific information ("A non-zero exit is expected when mutants survive — do not treat it as failure", the `<!-- mutation-review -->` marker, the 5-comment cap) with zero padding or explanation of concepts Claude already knows.

5 / 5

Actionability

The guidance is copy-paste ready: `npm run mutate:diff`, the `reports/mutation/mutation.json` path, `gh pr comment "$PR" --body-file <file>`, the complete `gh api repos/$REPO/pulls/$PR/comments` invocation with all fields, and `git diff --merge-base origin/main` for the changed-line check.

5 / 5

Workflow Clarity

The six steps are clearly sequenced with explicit checkpoints and recovery branches: expected non-zero exit, missing-report file → stop, all-mutants-killed → alternate comment, and a git-diff verification gate before posting inline comments, plus a 5-comment cap on the batch posting.

5 / 5

Progressive Disclosure

The body is under 50 lines, self-contained with no need for external references, and organized into clear Inputs and Workflow sections — meeting the rubric's simple-skill standard for full marks.

5 / 5

Total

20

/

20

Passed

Description

92%Weight 40%Scale 1-5

Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.

A strong description: third-person voice, explicit "Use when" trigger, and three concrete capability statements that distinguish it from generic review skills. The only gap is modest synonym coverage for trigger terms.

Suggestions

Add one or two natural trigger variations (e.g., "test coverage", "unit test quality") so users phrasing the need without the words "mutation" or "Stryker" still match.

DimensionReasoningScore

Specificity

"Runs Stryker on the diff", "triages surviving mutants", and "posts findings as a PR comment with inline annotations on changed lines" are three concrete actions naming the tool, target, and outputs, covering the full pipeline — matching the comprehensive-coverage anchor.

5 / 5

Completeness

The description explicitly answers both questions: "Use when reviewing a PR's test quality via mutation testing" gives a concrete trigger, and the run/triage/post verbs give a clear what — matching the both-explicit anchor.

5 / 5

Trigger Term Quality

"PR", "test quality", "mutation testing", and "Stryker" are natural phrases a user would say, but common variations like "test coverage", "unit tests", or "kill mutants" are missing, so coverage is good rather than comprehensive.

4 / 5

Distinctiveness Conflict Risk

Mutation testing via Stryker is a clear niche with distinct triggers ("test quality", "mutation testing") that would not fire for generic code-review or document skills; conflict risk is minimal.

5 / 5

Total

19

/

20

Passed

Validation

100%

Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.

Validation — 16 / 16 Passed

Validation for skill structure

No warnings or errors.

Repository

drufball/skylark

Path

plugins/skylark-builder/skills/mutation-review/SKILL.md

Reviewed

Table of Contents

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