AI agent
An AI agent is a system built around a language model that pursues a goal by deciding on and carrying out a sequence of actions: asking questions, calling tools, checking results. It does more than produce a single reply to a single prompt.
Also called: agentic AI, autonomous agent, LLM agent
The word "agent" marks the difference between answering and doing. A chatbot responds to what it is asked. An agent is given an objective, take this caller’s details and book them in, and works towards it across several steps, choosing what to ask, what to look up and when it is done.
The loop is simple to describe: observe the situation, decide the next action, act (which may mean calling a function), observe the result, repeat. What makes it useful is that the model handles the variety, a caller who gives information out of order, a calendar with no free slots, a name it cannot spell, without a designer scripting every branch.
A voice agent is an AI agent whose actions happen on a live call. The goal, the tools and the guardrails are what distinguish one agent from another built on the same model.