I built a Mac app after getting surprised by my Claude bill

A few weeks ago I had one of those dumb founder moments. I was happily using Claude and other LLM tools to build faster, ship faster, and tell myself it was all worth it because I was being "productive". Then I looked at the bill. It was not catastrophic. It was worse than that. It was the kind of number that makes you feel mildly stupid because you know exactly how it happened. A hundred little prompts. Background usage. Testing loops. Switching between tools. "Just one run." It adds up fast when you are building every day. What annoyed me most was not even the cost.