Agent
An AI that can actually do things on your computer, not just talk about them.
Why it matters
A chatbot tells you which file to edit. An agent opens the file and edits it. This is what I mean by your AI mate — and it is why the "can it undo this?" question matters more than it used to.
Think of it like
The difference between someone reading you a recipe over the phone and someone standing in your kitchen cooking.