Depending on your definition of AI, a pipeline for drug repurposing my team used was able to identify a therapeutic for a rare disease that was beating the state of the art in every test they threw at it, eventually being given orphan drug designation by the FDA. I doubt this would have happened without machine learning or AI or whatever you want to call it.

I'm also against "agents as scientists" as a concept for numerous reasons, but deep learning etc has or is leading to breakthroughs.