e,g, Given this spec:

(s/def ::required-key string?)
  (s/def ::optional-key string?)
  (s/def ::foo (s/keys :req [::required-key]
                       :opt [::optional-key]))

{:required-key "foo"}

{:required-key "foo"
   :optional-key "bar"}

the latter should be what you get by default - required and sometimes optional

you could filter with fmap to get the former

This is assuming I am given an unknown spec. Basically, I'd like to know which keys are required, and which keys are optional

there are some 3rd party libraries that have functions to parse that from the spec form

ah ok thanks! I'll take a look into those