Trying out om-tools I noticed that I had to explicitly (:require [plumbing.core :as plumbing]) to get my app to work, despite never calling the plumbing.core namespace anywhere in my own code.
Without the explicit require, I got "plumbing not defined" messages in the console.
This could prove puzzling for developers going forward since the expectation would be that calling om-tools.core/defcomponentk would transparently do the work for you.