principle-converge-on-the-targetlisted

# Converge on the Target Optimize for the intended, verifiable end state rather than preserving smooth intermediate states. Compatibility code kept only to make a transition comfortable becomes long-lived debt. **Core rule:** - Prioritize end-state integrity over transitional stability. - Intermediate breakage is acceptable when it is planned, scoped, and reversible. Declare where breakage is acceptable before starting. - Verifiable is not the same as stable. Breakage tolerance never exempts a unit from its check: each unit of the migration still ends in a state you can check (the **sequence-verifiable-units** principle skill), but the system need not stay fully working between phases via throwaway shims. - Keep high-signal checks for actively touched areas while migrating, and run full static and runtime verification at plan completion. **The internal-API instance.** When a new internal API is the right design, migrate callers and remove the old API in the same refactor wave: - Do not keep legacy API paths alive only because internal callers still exist. - Inventory callers, migrate them, and delete the old API immediately. - Treat temporary adapters as exceptional and time-boxed, not default architecture. - Update tests to assert the new contract, and delete tests that only protect pre-refactor implementation details. Keeping both old and new APIs creates dual-path complexity, slows cleanup, and makes the codebase feel append-only. **Scope: the boundary decides the d