ai410
Sometimes reading is not enough. You want a number from a live system, or a list of rooms that are free, or a form filled from a real record. Then the model has to call a function that runs somewhere else, wait for the answer, and use that answer in the next sentence. People call that tool use.
A tool can be polite and only look. 'What flights are there on Tuesday?' The function goes, looks, and brings back a list. The model still has not booked anything. It has only been handed a fresh page, this time by a program instead of by you pasting.
A tool can also change things: send the email, book the room, file the form. That is still tool use. It is a different kind of tool. Mixing 'it looked it up' with 'it did it' is how this whole category turns into fog.