Voice Agents Can Just Do Things — Charlie Guo, OpenAI

The Moviefone hotline was a speech to speech system. The GPS unit in your parents' car was an event to speech system. Charlie Guo works on developer experience at OpenAI, and he opens by pointing out that the three modes of voice interaction are all decades old, which makes the question not what is newly possible but what we stopped noticing. His actual argument is aimed at an assumption almost every builder makes unexamined: that a voice agent has to answer in speech. It does not. Software spent decades learning to reply by highlighting a field, changing a button, raising a notification, or moving a ghost cursor across the screen. A model that hears you can use any of those, and often should. The mode he thinks is most neglected is speech to action, where you talk and the model reaches for tools. He nearly titled the talk after it, calling voice the next capability overhang. Filling in a government form by talking for five minutes instead of typing for an hour. Steering creative software when your taste outruns your ability to operate it. And eventually the general case: if a model can drive a computer as well as a person, why are you talking to one app instead of the machine. For developers he offers a concrete on ramp, which is that your application already exposes its verbs as endpoints and handlers, and each of those converts fairly directly into a tool a voice model can call. He closes on accessibility, and on a better opening question than what kind of voice agent to build: what role does voice play here at all? Speaker info: - https://x.com/charlierguo - https://www.linkedin.com/in/charlierguo - https://www.ignorance.ai/ Timestamps: 0:00 - The misconception about talking back 1:57 - Three modes, none of them new 2:48 - Speech to speech: coaching, support, translation 4:29 - Speech to action, the capability overhang 6:58 - Turning your existing app into tools 7:48 - Event to speech, and hands free contexts 9:26 - What this unlocks for accessibility 12:45 - Reasoning, tool calls, and preambles 14:23 - Ask what role voice plays