What problem does it solve? Next.js App Router mutations often end up with inconsistent validation, missing auth checks, opaque production errors, and forms that show no field feedback. This Skill defines a clear contract for Server Actions, validation schemas, and form wiring so mutations behave predictably. ## Core Features & Use Cases - Action contract enforcement: Every Server Action authenticates first, validates input with safeParse from a shared validations.ts schema, returns typed result objects instead of throwing, and invalidates cache tags after writes. - Form wiring patterns: Default useActionState with native <form action> for simple forms, react-hook-form with a shared schema resolver for complex forms, and useOptimistic for instant UI feedback. - API route discipline: api/route.ts stays a thin auth-plus-service wrapper, created only when a client component actually refetches data. - Use Case: When building a discount-code creation form, the Skill guides you to define a schema in validations.ts, write an action that returns { ok: false, fieldErrors } on failure, and render per-field errors directly from the action state. ## Quick Start Use the next-server-actions skill to write a Server Action with validation and wire it to a form using useActionState.
