These checks are actually kind of hard to do properly now we don't have reliable access to the numbers. I agree that Numbers is probably not a useful place to do this though :)

This also makes testing that we enforce our desired limitations on supported keys more complex. Backends are probably going to have to do it individually, but I'm not sure how we can test that well? It's easy to determine that the backend will load things within our desired window of good parameters but much harder to determine that it won't do anything out side of that. Our existing tests and checks make enforcing and testing that much easier.