The issue (with Sonnet, I'm not using Opus), is not always that the code is bad per se, but merely that it doesn't solve the problem in the way I expected.

I have two problems with that. Firstly, I want my code to be written a particular way, so if it's doing something out of left field then I have to reject it on stylistic grounds. Secondly, if its solution is too far from my expectation, I have to put more work into review to check that its solution is actually correct.

So I give it a "where, what, how" prompt. For example, "In file X add feature Y by writing a function with signature f(x: t), and changing Z to do W..."

It's very good at following directions, if you give it the how hints to narrow the solution space.