But even spec-first, using opus4.6 with plan, the output is merely good, and not great. It isn't bad though, and the fixes are often minors, but you _have_ to read the output to keep the quality decent. Notably, I found that LLM dislike removing code that doesn't serve active purpose. Completely dead code, that they remove, but if the dead code have tests that still call it, it stays.

And small quality stuff. Just yesterday it used a static method where a class method was optimal. A lot of very small stuff I used to call my juniors on during reviews.

On another hand, it used an elegant trick to make the code more readable, but failed to use the same trick elsewhere for no reason. I'm not saying it's bad: I probably wouldn't have thought about it by myself, and kept the worse solution. But even when Claude is smarter than I am, I still have to overview it.

(All the discourse around AI did wonder for my imposter syndrome though)