Smart contract security extends far beyond syntax correctness and gas optimization. A contract can execute without reverting, process transactions according to its code, and still destroy economic value through flawed business logic. These invariant failures represent the most insidious class of vulnerability because they leave no runtime errors, trigger no access control checks, and operate within the written rules of the system. The SC02:2026 classification captures a critical gap in development practice: the gap between what code does and what code should do. This distinction separates syntactically valid contracts from economically sound ones. A Solidity contract compiles. It may pass unit tests. It can fail spectacularly in production because the underlying mathematical model that governs token transfers, collateral calculations, or protocol incentives is fundamentally broken. Understanding Invariants and Their Violations An invariant is a property that must remain true at all times.…