i'm not having problems yet in my biggest ai-only codebase, which is over 100k lines now. i haven't had any model hiccup, actually, but the smaller models take more wall time to get it done.
i have the models writing in rust, i believe it helps. ymmv.
i don't think it always architects well or anything, but it has quit building broken shit. it gets lazy, builds dumb UI, puts way too much text everywhere--but only if i don't remember to give it some better guidelines, or a visual reference.
i think with the right context, they build the right thing, and we haven't totally solved that just yet. but close enough for me; i'm so thrilled. i just want opus 5.5 to be crazy fast, like chatjimmy.