I mean, what if part of the role that’s being hired for is to help people clearly define the specs and requirements? I consider that a big part of what it means to be a senior software engineer.
Maybe this exact format isn’t the best way to test for it, but I don’t think “we want to see if someone can deal with ambiguity” means all the work is ambiguous. It might just mean all work needs to go through a process to take it from “ambiguous requirements” to “clearly defined specs”