Edge Case Construction

Edge case construction is the craft of intentionally building test cases that sit at the margins — inputs that are unusual, ambiguous, sensitive, or combine features in ways that stress-test a model’s behavioral guidelines. Good edge case construction requires anticipating the specific tensions in a behavioral specification: if the spec says “be helpful but avoid harm,” construct cases where those two goals genuinely conflict. If the spec says “follow user instructions,” construct cases where instructions conflict with safety guidelines. A library of well-constructed edge cases is one of a behavior team’s most valuable assets — these cases reveal gaps in policies, expose training weaknesses, and form the backbone of evaluation suites designed to catch problems before they reach users.