mutation-testing

Evaluate Python test suite quality using mutmut to introduce code mutations and verify tests catch them. Use for mutation testing, test quality assessment, mutant detection, and test effectiveness analysis.

1.17x

Quality

78%

Does it follow best practices?

Impact

87%

1.17x

Average score across 3 eval scenarios

Securityby

Passed

No findings from the security scan

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tessl review fix ./.claude/skills/mutation-testing/SKILL.md

Quality

Content

68%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.

Highly actionable content with concrete commands and executable examples, but conciseness is reduced by restating known concepts and the workflow lacks an explicit validation/re-run feedback loop for a batch operation. Structure is clean for a single-file skill.

Suggestions

Trim the intro paragraph and Key Concepts section — assume Claude knows what mutation testing is and keep only mutmut-specific terminology.

Add an explicit feedback loop: after adding tests for survived mutants, re-run `mutmut run` to confirm the mutation score improved before finishing.

Add a validation checkpoint in CI (e.g., fail the workflow when the mutation score drops below a threshold) to make the batch workflow's verification explicit.

Dimension	Reasoning	Score
Conciseness	The intro paragraph ("Mutation testing assesses test suite quality by introducing small changes...") and the Key Concepts section restate domain basics Claude already knows; mostly efficient but could be tightened.	3 / 5
Actionability	Quick Start gives copy-paste mutmut commands (run, results, show, apply), with executable Python test examples, concrete ini config, and a CI yaml covering the common cases.	5 / 5
Workflow Clarity	A sequence is present (run → results → show → apply) but there is no explicit validate/re-run feedback loop for this batch operation; the improving-mutants guidance is distributed rather than checkpointed.	3 / 5
Progressive Disclosure	Well-organized single-file sections (Quick Start, Configuration, Examples, Operators, CI, Best Practices); no bundle references exist but the structure is clean with only minor organization gaps.	4 / 5
	Total	15 / 20 Passed

Description

87%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 that clearly states both capability and trigger conditions using concrete action verbs and natural keywords. There is minor room to broaden action specificity and add a few more synonym trigger terms.

Dimension	Reasoning	Score
Specificity	"Evaluate Python test suite quality using mutmut to introduce code mutations and verify tests catch them" names several concrete actions (introduce mutations, verify tests catch them, evaluate quality), with only minor breadth gaps.	4 / 5
Completeness	It explicitly answers what ("Evaluate Python test suite quality using mutmut to introduce code mutations and verify tests catch them") and when ("Use for mutation testing, test quality assessment...") with concrete trigger phrases.	5 / 5
Trigger Term Quality	"mutation testing, test quality assessment, mutant detection, and test effectiveness analysis" provides good natural keyword coverage, but misses a few common synonyms a user might say.	4 / 5
Distinctiveness Conflict Risk	Mutation testing via mutmut is a clear, narrow niche with distinctive triggers, minimal overlap risk with general testing or coverage skills.	5 / 5
	Total	18 / 20 Passed

Validation

100%

Warnings & errors only

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: mixpanel/mixpanel-headless
Path: .claude/skills/mutation-testing/SKILL.md
Commit: 1ccd7ae

Reviewed: 3 days ago

Table of Contents

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