How we built a checkout that runs the same protocol in a chat window, a voice session, and a live phone call.
One word, many moves
On the AI storefront platform I work on, a customer can type "checkout" into a chat window — or say it to a voice agent or a phone line — and, a short conversation later, they have an order number. The transcript looks unremarkable: a question about special instructions, maybe a contact form, a quick "Is everything correct?", done.
Beneath that brief exchange lies the most carefully engineered path in the system. Checkout is where a language model, several tools, an order engine, and a human who may be walking down the street all have to agree on what just happened — and where any disagreement costs real money.
This post explains our approach: what it is, why the constraints force this particular shape, and how the pieces move together in text and in voice. Then, because a design only means something relative to its alternatives, I'll compare it with the two other ways this is usually built.
