My success rate for solving software engineering challenges encountered in my day jobs has been near 100% for my entire career. I can only think of a few tasks I kicked back and said they were impossible. For example, after trying to get a signal processing system working reliably I decided to sit down and calculate the actual limits of the channel we were sending the data over and found that from a basic estimation it would not be possible to do. In start ups you don't really get to get stuck in a spiral and not fix things.

I find agents often get into these cases during research tasks.