API & Interface Design
Design interfaces that make the right thing easy and the wrong thing hard. The mechanism is contract-first (define the typed interface before implementing it — the types are the documentation, per pattern-contract-first), consistent error semantics, and validation at system boundaries only while internal code trusts its types. It is governed by Hyrum’s Law (every observable behavior becomes a de facto contract) and the One-Version Rule (extend rather than fork), pushing addition over modification for backward compatibility.
It applies pattern-deep-modules and clusters with Matt Pocock’s deep-module design skill. It implements stage-implement.
See Also
- mp-codebase-design — the Matt Pocock equivalent in the design cluster.
- pattern-contract-first — define the contract before the implementation.
- pattern-deep-modules — simple interface over substantial implementation.
- stage-implement — the canonical stage this implements.