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 extremely sparse and template-like, providing almost no useful information about what the skill does or when it should be selected. It reads like auto-generated boilerplate with a duplicated trigger term and no concrete actions or meaningful trigger guidance. It would be nearly impossible for Claude to make an informed decision about selecting this skill over other testing-related skills.
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 duplicated trigger term and expand with natural variations users might say, such as 'mutation testing', 'mutant analysis', 'test effectiveness', 'mutation score', or specific tool names like 'pitest' or 'stryker'.
| 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 with meaningful trigger scenarios. | 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 in this domain. | 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 makes it harder to distinguish from general test automation skills. | 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.
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.json, or mutmut for Python: `mutmut run --paths-to-mutate=src/`)
Define a clear workflow: 1) Configure the mutation tool, 2) Run mutation tests, 3) Interpret the mutation score, 4) Identify surviving mutants, 5) Write tests to kill survivors — with validation at each step
Remove all generic boilerplate sections ('Purpose', 'When to Use', 'Capabilities', 'Example Triggers') and replace with actionable technical content about mutation testing patterns, common pitfalls, and tool configuration
Add specific examples of mutation operators, how to read mutation test reports, and thresholds for acceptable mutation scores
| 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 code examples, commands, 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 any validation checkpoints. | 1 / 3 |
Progressive Disclosure | The content is a flat, monolithic placeholder with no meaningful structure. There are no references to detailed files, no quick-start section, and no organized navigation to deeper content. | 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
3076d78
- Reviewed
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