I was going through an experiment trying to spec out a simple caching system in Lean. I was getting Gemini to help me run through doing this, step by step. At one point it writes out this statement with a proof to show something, the specifics of which I forget, but it was some simple property of the cache. I stare at it for a while thinking to myself this can't be right, it was some sort of plain tautological statement that didn't really say anything, like saying 1 = 1.

I give it to Opus 5.5 and it basically confirmed my gut feeling that it was useless.

I'd like to rely more on formal verification. I like the idea of starting out with specs in a formal setting and designing software that way. The problem is it's hard to do right, and my point is even with AI, it's hard to do right.