location.sharing.started fires when a person starts sharing their location with your agent. It carries no position: read it with GET /v1/chats/{chatId}/location.
Read the payload
Thedata object is the LocationSharingStartedEvent schema from the API contract. The envelope around it is the same on every event and is described in the event catalog.
Handle the event
Read the location fordata.chat_id, then read it again whenever you need the latest position. No event fires when the person moves.

