"Dinner should be enough pizza for X people" will totally get pizza for the crowd if the system I am interacting with is sufficiently smart. Eventually, the system will say "Sorry, I don't see how to do that." If we're still smarter (in relevant respects) than the system, then we can instruct it further...

I think generally, a move to a declarative specification and operational constraints, plus some operational "here's how you do it" to fill in gaps, would be a good long-term move.