is there a way to write and use stest/instrument or stest/check on a function in a record?

nope, if you have to do that you need to wrap it

(which is not free)

what do you mean by wrap it with another function?

(defprotocol IFoo
  (-foo [x]))

(def foo -foo)
(s/fdef foo :args (s/cat))

I don't think you can spec and instrument a protocol fun otherwise

thanks!