[rpwilcox]

> Understanding of the business is again outside of the definition of a full stack developer

Like all of these aspects you don't need to be a full blown business analyst, but a full stack developer does need to understand the business to translate business rules into application behavior/logic. Ideally this full stack developer can also understand the problem domain and app code well enough to collaborate with management / business when they try to introduce rules that would contradict other behaviors of the app or the current app architecture. And, doing this for enough time, you should start to internalize the business rules.

AKA: Behavior Driven Development.