It seems to be fantastic up to about 5k loc and then it starts to need a lot more guidance, careful supervision, skepticism, and aggressive context management. If you’re careful, it only goes completely off the rails once in a while and the damage is only a lost hour or two.

Overall, still a 4x production gain overall though, so I’m not complaining for $20 a month. It’s especially good at managing complicated aspects of c so I can focus on the bigger picture rather than the symbol contortions.

Yes, I see the same thing. My working thesis is that if I can keep the codebase modular and clear seperations, so I keep the entire context, while claude code only need to focus on one module at a time, I can keep up the speed and quality. But if I try and give it tasks that cover the entire codebase it will have issues, no matter how you manage context and give directions. And again, this is not suprising, humans do the same, they need to break the task apart into smaller piecers. Have you found the same?