I'm not aware of a direct spec transformation of this nature, but I think describe could be used to get a data description of the spec back, and then a related spec could be constructed using that description

correct

Probably simpler to just define the key vector in its own def and re-use that with :req and :req-un.

almost definitely... I got the impression the starting point was a spec

you can't actually do that as s/keys is a macro and expects a literal vector there

but you can macro around s/def

I stand corrected. Probably simpler to just repeat the vector then. That's a noteworthy gotcha.