mutation-test-runner
Mutation Test Runner - Auto-activating skill for Test Automation. Triggers on: mutation test runner, mutation test runner Part of the Test Automation skill category.
36
3%
Does it follow best practices?
Impact
100%
1.02xAverage score across 3 eval scenarios
Passed
No known issues
Optimize this skill with Tessl
npx tessl skill review --optimize ./planned-skills/generated/09-test-automation/mutation-test-runner/SKILL.mdQuality
Discovery
7%Based on the skill's description, can an agent find and select it at the right time? Clear, specific descriptions lead to better discovery.
This description is essentially a title and category label with no substantive content. It fails to describe any concrete capabilities, lacks natural trigger terms users would use, and provides no explicit guidance on when Claude should select this skill. It reads like auto-generated boilerplate rather than a useful skill description.
Suggestions
Add concrete actions the skill performs, e.g., 'Runs mutation tests against a codebase, generates mutants, evaluates test suite effectiveness, and reports mutation scores and surviving mutants.'
Add an explicit 'Use when...' clause with natural trigger terms, e.g., 'Use when the user asks about mutation testing, test quality assessment, mutation coverage, killing mutants, or evaluating test suite strength.'
Remove the duplicate trigger term ('mutation test runner' is listed twice) and expand with natural variations like 'mutation testing', 'mutation analysis', 'test effectiveness', and specific tool names if applicable.
| Dimension | Reasoning | Score |
|---|---|---|
Specificity | The description names the domain ('mutation test runner', 'Test Automation') but provides no concrete actions. There is no indication of what the skill actually does—no verbs describing capabilities like 'runs mutation tests', 'generates mutants', 'analyzes test coverage', etc. | 1 / 3 |
Completeness | The description fails to answer 'what does this do' beyond naming itself, and the 'when' clause is essentially just restating the skill name as a trigger. There is no explicit 'Use when...' guidance or meaningful trigger context. | 1 / 3 |
Trigger Term Quality | The only trigger terms listed are 'mutation test runner' repeated twice. It misses natural variations users might say such as 'mutation testing', 'mutant analysis', 'test coverage', 'kill mutants', 'pitest', 'stryker', or other common terms associated with mutation testing. | 1 / 3 |
Distinctiveness Conflict Risk | The term 'mutation test runner' is fairly niche and unlikely to conflict with many other skills. However, the vague 'Test Automation' category label could overlap with other testing-related skills, and the lack of specificity about what distinguishes this from general test runners weakens distinctiveness. | 2 / 3 |
Total | 5 / 12 Passed |
Implementation
0%Reviews the quality of instructions and guidance provided to agents. Good implementation is clear, handles edge cases, and produces reliable results.
This skill is an empty template/placeholder with no actual content about mutation testing. It contains no executable code, no tool-specific guidance (e.g., Stryker, mutmut, PITest), no configuration examples, and no workflow steps. Every section is generic boilerplate that could apply to any skill topic by swapping the name.
Suggestions
Add concrete, executable examples for at least one mutation testing tool (e.g., Stryker for JS/TS: `npx stryker run` with a sample stryker.conf.mjs configuration)
Define a clear workflow: 1) Configure mutation tool, 2) Run mutation tests, 3) Interpret mutation score and surviving mutants, 4) Write tests to kill surviving mutants, 5) Re-run and validate improvement
Remove all generic boilerplate sections ('Purpose', 'When to Use', 'Capabilities', 'Example Triggers') and replace with actionable content showing specific commands, configuration files, and expected output formats
Include guidance on interpreting mutation test results (e.g., what mutation score thresholds to target, how to handle equivalent mutants) with concrete examples
| Dimension | Reasoning | Score |
|---|---|---|
Conciseness | The content is entirely filler and boilerplate. It explains nothing Claude doesn't already know, repeats 'mutation test runner' excessively, and provides zero actual technical content about mutation testing. | 1 / 3 |
Actionability | There are no concrete commands, code examples, tool configurations, or executable guidance. The skill describes what it could do in abstract terms ('provides step-by-step guidance') without actually providing any guidance. | 1 / 3 |
Workflow Clarity | No workflow, steps, or process is defined. There are no instructions for running mutation tests, configuring tools (e.g., Stryker, mutmut, PITest), interpreting results, or validating outputs. | 1 / 3 |
Progressive Disclosure | The content is a flat, monolithic block of generic placeholder text with no references to detailed files, no structured sections with real content, and no navigation to deeper resources. | 1 / 3 |
Total | 4 / 12 Passed |
Validation
81%Checks the skill against the spec for correct structure and formatting. All validation checks must pass before discovery and implementation can be scored.
Validation — 9 / 11 Passed
Validation for skill structure
| Criteria | Description | Result |
|---|---|---|
allowed_tools_field | 'allowed-tools' contains unusual tool name(s) | Warning |
frontmatter_unknown_keys | Unknown frontmatter key(s) found; consider removing or moving to metadata | Warning |
Total | 9 / 11 Passed | |
- Commit
3e83543
- Reviewed
Table of Contents
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