The AI agreed

> There isn’t a magic prompt I could have written before knowing the solution. A retrospective prompt can reproduce the 200 lines only because it embeds the invariants you discovered. The useful AI task would have been systematically finding counterexamples and iterating toward those invariants, not generating the final file in one shot.

For me the value with AI isn't the one shot, it is the fact that it can help you iterate faster. My biggest take awway so far with AI is it can help you fail fast. The faster you can fail, the faster you can iterate.