Mc Donald's already has customer self serve kiosks and mobile apps with the full menu that limit you as to which items you can add or remove.
How did they screw this up and leave things open ended for the LLM?
IE why was the LLM not referencing a list of valid options with every request and then replying with what the possible options are. This is something LLMs are actually able to do fairly well, then layer on top the EXACT same HARD constraints they already have on the kiosk and mobile app to ensure orders are valid?