Every conversational turn is a full round trip: Twilio calls the webhook again, Claude re-reads the order so far, and the voice goes back out to the customer. Once the order is complete, the confirmation leaves the voice channel for WhatsApp.
Internal stepExternal serviceCheckpoint — review or opt-inVerified outputApplication boundary
The application does not hold the line: it answers one webhook per conversational turn, and the loop goes through Twilio every time. The order only leaves the voice channel once it is complete, to two recipients who receive the same written record.