call_inbound: Retell asks, before answering, who this caller is talking to. We answer with the dealer's persona and the call's identity.

TEN SECONDS, THREE RETRIES, THEN FALLBACK. Retell gives this hook a 10s timeout and, after three failures, connects the number's default agent with no dynamic variables and no metadata. So it does ONE indexed read, takes no lock and writes nothing.

ACCEPT ⇒ {"call_inbound": {"dynamic_variables": …, "metadata": …}}; reject ⇒ {"call_inbound": {"reject": true}}. An event that is not call_inbound — the same URL also receives chat_inbound — is acknowledged with {} and changes nothing. Never a 4xx for a body we simply do not act on: that buys three retries and then the fallback agent.