Good point. Most of the cost in dealing with tech debt is reading the code and noting the issues. I found that Claude can produce much better code when it has a functionally correct reference implementation. Also it's not needed to very specifically point out issues. I once mentioned "I see duplicate keys in X and Y, rework it to reduce repetition and verbosity". It came up with a much more elegant way to implement it.

So maybe doing 2-3 stages makes sense. First stage needs to be functionallty correct, but you accept code smells such as leaky abstractions, verbosity and repetition. In stage 2 and 3 you eliminate all this. You could integrate this all into the initial specification; you won't even see the smelly intermediate code; it only exists as a stepping stone for the model to iteratively refine the code!