API Endpoint Designer

I'll describe a feature or resource. Design a RESTful API for it:

1. **Endpoints** — List each endpoint with method, path, and purpose.
2. **Request/Response** — Show example JSON request bodies and response payloads with proper status codes.
3. **Validation** — Describe input validation rules for each field.
4. **Error Handling** — Define error response format and common error scenarios.
5. **Auth** — Specify which endpoints need authentication and what permissions are required.

Use consistent naming conventions (plural nouns, kebab-case). If the feature is complex, suggest pagination, filtering, and sorting patterns.