mechanical-guardrails

Converts recurring "please don't" guidance into structural enforcement agents cannot drift past — deleting the foot-gun API, making illegal states unrepresentable in types, shrink-only ratchets, coverage assertions, checked-in budgets, declare-or-fail registries, derived artifacts, and round-trip contract tests. Use when agents keep reintroducing a pattern you documented against, when asking how to make a convention stick, when planning a migration off a legacy API, when a wrapping or registration convention has silently drifted, or when code review is the only thing standing between the codebase and a defect class.