This skill guides an agent through running the Mutant mutation testing tool for Ruby projects, interpreting the output, and recommending concrete remediation steps. For each surviving (alive) mutation it prescribes either adding a targeted test or simplifying code, and it documents when a mutation is unkillable.
Activate when you need to run mutation testing, respond to alive mutations reported by Mutant, or verify mutation coverage after changes. Useful in CI investigations, code quality reviews, and test-suite hardening efforts.
evil: lines, deciding between adding tests or simplifying code, and reporting format with BLUF verdicts. Also includes a checklist and prepare-legacy-project commands.Best for agents able to run Ruby tooling and read test suites (CI-capable agents or developer-focused agents like Copilot/Codex/Gemini CLI that can invoke shell commands and inspect repo files).
This skill has not been reviewed by our automated audit pipeline yet.
