Run a voice AI agent from one YAML file

Why it holds

The document does name one URL, and it is worth being exact about what that buys. post_prompt_url receives a report after the call ends. Nothing is served from it, so the agent runs whether or not it answers.

How it works

The ai verb carries the whole agent. prompt.text is the identity, written in markdown because the model reads structure better than a paragraph.

- ai:
    prompt:
      text: |
        ## Role
        You take reservations for Ridgeline Kitchen, a 40 seat restaurant.
        ## Boundaries
        The kitchen seats parties up to 8. For anything larger, take a
        phone number and say the manager will call back.
    post_prompt:
      text: >-
        Return only JSON with the keys name, party_size, requested_time
        and outcome.
    post_prompt_url: "https://your-host.example.com/reservation"

post_prompt runs after the call and POSTs its result to post_prompt_url. That is a callback, so something of yours does have to receive it if you want the reservation. Delete both fields and the agent still answers calls, with nowhere to report what happened.

params bounds the call. inactivity_timeout and attention_timeout stop an abandoned call holding a line open. They matter more here than in a supervised agent, because no code is watching.

hints tells the recogniser the words it would otherwise guess at. A proper noun like a restaurant’s name is the usual case.

This document has no tool, which is a choice rather than a limit. A tool with a handler needs a webhook, and a webhook is a server. A DataMap tool does not: it carries its request in the document, so an agent that only reads a third-party API stays serverless. That is call-an-api-without-a-backend. The moment a tool needs code of yours to decide something, this recipe stops being the right shape and give-an-agent-a-tool starts.

Limitations

No tools means no lookups, no bookings written anywhere, and no validation. The agent can take a reservation and tell you about it afterwards; it cannot check whether the table is free.

Editing means editing the document. There is no version control, no test and no review unless you keep the file somewhere that has them.