I've handled this (in Clojure) either by passing a context map through the entire stack or binding some context atom at the top and using it lower down the stac

I've handled this (in Clojure) either by passing a context map through the entire stack or binding some context atom at the top and using it lower down the stack. The binding is less obvious at first glance, so I prefer to pass the context, but both make testing quite easy and reduce the need for heavy refactoring.