I have been more successful with baby steps like: "Write a python 3 program that converts X to Y." Tweak prompt until that's working as desired, then: "make it work recursively through all subdirectories" - and again tweak with specifics like converting the files in place, etc. Always very specific, also - force it to fix its own bugs so you can move forward with a clean example as you add complexity. Complexity seems to cap out at a couple of pages of code, at which point "Ooops, something went wrong."