> Claude just gave up and did an HTML/CSS implementation but I insisted on native SwiftUI+Metal.
That sounds very odd and very contrary to my experience. You don’t say which model you actually used, but I never had opus 4.8 (or sonnet for that matter) ignore which language/stack i wanted to use.
Yeah, that makes no sense. I've never seen any model "just give up" and change to a wholly different stack on its own.
It never happened to me, but Claude routinely ignores the single line I have in CLAUDE.md, so I wouldn't be entirely surprised.