Permission system done right.

Permission is an ideal example of the context contract additional rules and composition.

We have a nested story with a more strict permission rule than the wrapper story.

user has its place in each context contract and we attach different permission validation to it in each contract.

When the user will be assigned in the wrapper story, we'll run all its permission validators from all nested stories. So we'll fail early.

Some nested stories will run in the Celery task because of the Delegate feature. We can fail that early.