they are quite good also at placement and creating scenes etc. I had one implement a cascading shadow system in vulkan/glfw and just fed it back screenshots with peter pannin and acne spots etc.

it made a huge monstrosity first, 1500+ lines of shader code. Once it was happy with the result (it looked pretty good, almost blenders gamerenderer) it cleaned it up and a lot of debug code was removed. shrank it down to about 350 lines and made it much more readable.

this was something i didnt expect it to be able to do. create shaders, look at screenshots, fix em iteratively like that. multi modal debugging.