When I'm using agents for programming, I can have a AGENTS.md outlining exactly what requirements, guidelines and constraints all the code need to follow, and the agent (codex in my case) will pretty much nail that.
I've tried doing the same for design work, just really outlining exactly how the UI and UX needs to look and work, but for some reason it struggles a whole bunch with it, regardless of how clear I am. Maybe it's I'm just worse at explaining and describing what UI and UX I'm actually after though, I suppose.