Use when designing or implementing API endpoints — server actions, tRPC procedures, REST routes for external consumers. Carries the factory's API conventions — the server actions vs tRPC decision, procedure tier stacking, per-mutation Zod schemas, central router composition with manual registration, pagination (limit/offset/orderBy default; cursor only when needed), multi-field search via `ilike` + `or()`, aggregated stats in list queries, mutation lifecycle hooks, stale-time defaults, custom error class taxonomy, fetch adapter for tRPC in App Router. Outputs endpoints that fit the house style — not bespoke per-route handlers.
