Set up and run mutation testing with PIT (pitest) on a Gradle project, and read the mutation score. Use this skill whenever the user wants mutation testing added to a build, configured, run or re-run, wants a mutation score or a mutation report interpreted, asks why a particular mutant survived, or asks what should be excluded from mutation analysis, or wants something added to those exclusions — in any language, and whether or not the tool is named. Also use it when the task calls for it: checking test quality rather than coverage — a high JaCoCo number can hide tests that assert nothing.