Design and evolve API boundaries and contracts — REST resource naming, status-code semantics, pagination strategy, versioning policy, and the discipline of treating one contract artifact (OpenAPI/schema) as authoritative so client and server never drift. A design-time activity, distinct from system-design-edho-ferdian (broader architectural trade-offs) and code-review-edho-ferdian (reviewing an already-written endpoint). Trigger phrases: "desain API untuk fitur ini", "bagaimana struktur endpoint yang baik", "API contract berubah, bagaimana handle-nya", "REST vs apa", or when starting a new API surface.
