Every voice agent demo ends the same way. The bot wraps the call with a confident "Great — I'll email you the details and a confirmation," the human hangs up satisfied, and then nothing sends. There's no inbox behind the promise. The transcript lives in your voice stack, the "email" is a TODO nobody wired up, and the customer waits for a message that never arrives. It's the most common broken promise in conversational AI, and it's broken for a boring reason: the voice agent has no mailbox of its own.
That's the gap this post closes. The interesting problem with voice agents isn't speech — your voice stack already handles the transcript, the turn-taking, and the summary. The interesting problem is the channel bridge: handing what happened on the call to a written, replyable email that comes from the agent and whose reply comes back to the agent. Voice in, email out, reply back in. No human in the loop, no shared support inbox, no spoofed noreply@.
The piece that makes this clean is a Nylas Agent Account — a real, owned email address that your voice agent sends from and receives at. I work on the Nylas CLI, so the terminal commands below are the exact ones I reach for, and I'll show both angles for every operation: the nylas command and the raw curl HTTP call. In practice your provisioning runs through the API and your ops glue runs through the CLI, so you'll want both.
