What problem does it solve? Code coverage shows which lines ran during tests but not whether tests would fail if the code were wrong. This Skill performs static pseudo-mutation analysis — reasoning about hypothetical changes like boundary flips, boolean inversions, and removed null checks — to reveal test gaps where bugs would slip through undetected. ## Core Features & Use Cases - Mutation Point Catalog: Identifies boundary, boolean, return value, exception, arithmetic, and null-check mutation points across .NET, Python, TS/JS, Java, Go, Ruby, Rust, Swift, Kotlin, PowerShell, and C++. - Kill/Survive Classification: Classifies each mutation as Killed, Survived, No coverage, or Equivalent, with risk-based prioritization of findings. - Actionable Reporting: Produces a mutation score summary plus concrete recommended test assertions for every survived mutation. - Use Case: Before merging a payment calculation change, ask whether existing tests would catch an off-by-one error or a removed guard clause, and get a prioritized list of weak tests to strengthen. ## Quick Start Analyze my production code and its test files to determine whether the existing tests would catch subtle bugs like boundary changes or removed null checks.
