Web Messaging Guest API typing indicator not triggering in custom SDK wrapper

How do we actually send typing indicators using the Web Messaging Guest API in our custom embed?

We are building a wrapper around the Guest API for our agent desktop. The sendEvent method exists, but the documentation is sparse on the exact JSON structure for typing events versus read receipts.

I tried this payload:

{
 "eventType": "typing",
 "status": "started"
}

It returns a 200 OK, but the agent side never sees the typing animation. Is the endpoint different, or is there a specific header I’m missing?