This has always been my problem whether it's Gemini, openai or Claude. Unless you hand-hold it to an extreme degree, it is going to build a mountain next to a molehill.

It may end up working, but the thing is going to convolute apis and abstractions and mix patterns basically everywhere

Difficult and it really depends on the complexity. I definitely work in a spec-driven way, with a step-by-step implementation phase. If it goes the wrong way I prefer to rewrite the spec and throw away the code.

I have it propose several approaches, pick and choose from each, and remove what I don't want done. "Use the general structure of A, but use the validation structure of D. Using a view translation layer is too much, just rely on FastAPI/SQLModel's implicit view conversion."

“Everything Should Be Made as Simple as Possible, But Not Simpler” should be the ending of every prompt :)

I personally try to narrow scope as much as possible to prevent this. If a human hands me a PR that is not digestible size-wise and content-wise (to me), I am not reviewing and merging it. Same thing with what claude generates with my guidance.

Instructions, in the system prompt for not doing that

Once more people realize how easy it is to customize and personalized your agent, I hope they will move beyond what cookie cutter Big AI like Anthropic and Google give you.

I suspect most won't though because (1) it means you have to write human language, communication, and this weird form of persuasion, (2) ai is gonna make a bunch of them lazy and big AI sold them on magic solutions that require no effort on your part (not true, there is a lot of customizing and it has huge dividends)