validating-edge-finder

Systematically discover edge cases through boundary analysis and input space exploration. Use when: (1) correctness claims rest on happy-path testing without boundary exploration, (2) validating a solution or approving an implementation that handles typical inputs but may fail on atypical ones, (3) code accepts inputs with implicit range, format, or type assumptions that haven't been verified, (4) reasoning assumes inputs will be well-formed, positive, non-empty, or within bounds without explicit checks, (5) zero, null, empty, maximum, minimum, or negative values haven't been tested against the implementation, (6) multiple parameters interact and their combined boundary behavior is unknown, (7) before shipping code or making correctness claims without having mapped the boundary surface