Your Mutation Testing Tool Should Make You Explain Yourself

Every team that adopts mutation testing hits the same wall around week two. The tool generates a mutation. Something like flipping a > to >= in a boundary check you know is dead code. Or injecting a fault into a logging call that doesn't affect behavior. The mutation survives, your score drops, and someone on the team asks the reasonable question: can we just ignore this one? That's not the wrong question. Some mutations genuinely aren't worth killing. The wrong answer is making suppression easy and invisible. I've been building pytest-gremlins, a mutation testing plugin for pytest, and this week we shipped v1.5.0 with a feature I've been thinking about for a while: inline mutation pardoning with mandatory reasoning and enforcement ceilings. It works like this. You add a comment to the line: logger.debug(f"Processing {item.id}") # gremlin: pardon[logging-only, no behavioral impact] The pardon keyword tells pytest-gremlins to skip mutations on that line. The brackets force you to