Thanks to @ericnormand for sharing your insights in the form of a nice podcast, and all your things at http://purelyfunctional.tv I listened to several of your https://ericnormand.me/podcast/executable-specification-lens and gave (roughly) the method you outlined a shot when doing some design for a small program at work today. I kept it very simple with basically creating several functions that looks something like this:

;; TODO @aasa maybe we already have the token before this function is called,
;; and it should be a parameter?
(defn login []
  (println "User wants to login.")
  (if (local-token!)
    (println "You are already logged in.")
    (start-login-flow)))