semantic-equivalence-verifier
Installation
SKILL.md
Semantic Equivalence Verifier
→ behavior-preservation-checker tests on a sample; this skill proves over the full input space. Use when "we ran it on 500 inputs" isn't enough.
When proof beats testing
| Situation | Why testing fails |
|---|---|
| Input space is infinite and adversarial | Attacker picks the input you didn't test (crypto, parsers, sanitizers) |
| Rare edge case matters (overflow, boundary) | 1-in-2³² inputs — fuzzing takes forever |
| Regulatory / safety requirement | "We tested it" isn't certifiable evidence |
| The transformation is algebraic | x*2 ↔ x<<1 — easy to prove, tedious to test |