mbj/mutant: Mutation testing for Ruby. AI writes your code. AI writes your tests. But who tests the tests?

AI writes your code. AI writes your tests. But who tests the tests? Copilot, Claude, and ChatGPT generate code faster than humans can review it. They'll even write tests that pass. But passing tests aren't the same as meaningful tests. Mutant is mutation testing for Ruby. It systematically modifies your code and verifies your tests actually catch each change. When a mutation survives, you've found either: Dead code - the AI over-engineered something you can delete A blind spot - the AI forgot to test a behavior that matters The more code AI writes for you, the more you need verification you can trust.