Tool use
Giving a model tools, meaning functions such as a search or a calculator that it can choose to call by itself, so it can fetch data or take actions instead of only writing text.
A tool is just a function the model is told about: a name, a description of what it does. When the model decides it needs one, it asks for it, the app runs it and hands the result back, and the model writes its answer from that. The model never does the work itself; it only asks. That gap between "asks" and "does" is where permissions, confirmations and logging live, so it is also where safety is won or lost.
The model asks, your code decides. That gap is where permissions, confirmations and logging belong. It's the difference between an assistant that drafts the email and one that sends it.