[danielmarkbruce]

It's the present. ChatGPT, for example, is an application. It uses models, but it does all kinds of stuff at the application level too.

[sdesol]

Is the instructions to pass something off built into the model or is it clever prompting or a bit of both?

[HarHarVeryFunny]

In general it's "tool use" where the model's system prompt tells it to use certain tools for certain tasks, and having been trained to follow instructions, it does so!