They aren't interrupted by humans because that would slow things down.

> Are you telling me we've been iterating on this for years and for convenience we just let the models call any tools or spawn any other model instances they like

Yes exactly.

> there was no design for harnesses that could control this done during that time

You could but no one wants that. You need to separate your imagination from reality. Just because something can be done in your head doesn't mean it's happening.

It's so easy, except it isn't because you don't control the actions of anyone or anything.