AI agent

A program that uses a language model to decide which actions to take, calling tools in a loop until a goal is met, rather than producing a single response.

What separates an agent from a chatbot is the loop and the tools: it observes a result, decides what to do next, and acts again. That makes agents useful for open-ended work and makes them operationally demanding — they need somewhere to run, credentials to act with, and limits on what they can reach.