What problem does it solve? Backend and frontend teams often block each other or drift apart when the API contract is undefined. This Skill designs a shared, machine-readable contract so both sides can build in parallel against a single source of truth. ## Core Features & Use Cases - Design-first source of truth: Authors an OpenAPI (sync) or AsyncAPI (events) spec shared by clients, mocks, and tests, reusing existing backend endpoint designs. - Parallel development enablers: Generates client types and a consumer mock/stub so the frontend can build and test before the backend exists. - Conventions and state binding: Defines cursor/keyset pagination, enumerated errors, BFF-per-client shaping, and loading/empty/error/optimistic frontend states. - Use Case: Given a set of user stories for a new feature, produce the shared OpenAPI contract, a mock server plan, and the frontend state-binding spec so web and backend teams start coding the same day. ## Quick Start Design the BE/FE contract for these user stories, including the OpenAPI source of truth, consumer mock, and frontend state-binding spec.
