Task
Specify an API boundary that clients can implement and test.

Instructions
Draft a contract for GET /events (fictional design,not an existing provider API). Event fields:id,title,startAt ISO8601 UTC,capacity nonnegative integer. Query limit default20 maximum50,cursor optional opaque string. Return events and nullable nextCursor. Empty results allowed. Invalidlimit error. Authentication and cursor expiry require owner decision. serving a browser listing and a mobile listing; preserve backward compatibility when adding optional fields. Include request, response, errors, authentication assumptions, idempotency, pagination, limits, compatibility, and examples. Mark every decision that still requires product or security approval. Avoid inventing provider behavior.

Expected output
Contract table, examples, error semantics, and unresolved decisions.

Checks
- Success and failure shapes are complete.
- Security assumptions are stated.
- Open decisions are tagged.