Check code coverage and use mutation testing to verify test quality.
From testingnpx claudepluginhub sethdford/claude-skills --plugin engineer-testingcoverage-report or code-fileChain these steps:
test-doubles-strategy skill to verify mocks are appropriatemutation-testing skill to measure test effectivenessunit-test-design skill to strengthen tests for uncaught mutationsAfter completion, suggest: "Run mutation tests locally to validate these improvements."