I was experimenting with Claude Code and requested something more CPU efficient in a very small project, there were a few avenues to explore, I was interested to see what path it would take. It turned out that it seized upon something which wasn't consuming much CPU anyway and was difficult to optimise further. I learned that I'd have to be more explicit in future and direct an analysis phase and probably kick-in a few strategies for performance optimisation which it could then explore. The refund request was an amusement. It was $15 well spent on my own learning.