AI agent
An AI agent is a program that uses a language model to decide what steps to take, then carries them out.
What it tells you about a developer
Agent experience means the developer has handled work that behaves differently on every run. Testing and setting boundaries for that is a distinct engineering skill, and it is one of the most in-demand areas in AI hiring today.
An agent gets its name from acting on someone's behalf, the way a travel agent books a trip for a client. An AI agent is given a goal and a set of tools, like the ability to search the web or edit a file, and it decides on its own which tools to use and in what order. A developer who builds agents writes the tools, sets the boundaries on what the agent is allowed to do, and tests how it behaves when a task does not go as planned.