version: "1.0.0" name: interface-contracts description: Design public interfaces so that observable behavior becomes an implicit promise — Hyrum's Law and contract-first API design. Use when designing REST/GraphQL endpoints, module boundaries, type contracts between files, component props, or any surface where one piece of code talks to another. Complements design-for-the-next-reader with a sharper focus on what you're accidentally promising.

Interface contracts

The discipline is the same everywhere — Hyrum's Law, contract-first design, the one-version rule — but how it's applied is calibrated per model. Pick the file for the model actually running:

Read the file matching the model actually running before applying this skill.

Running a model not listed above (an older generation, a different model family entirely)? sonnet-5.md carries the fullest general-purpose version of the underlying procedure — read that one rather than skipping this skill.