primaryForGoal property

If a conversion action's primary_for_goal bit is false, the conversion action is non-biddable for all campaigns regardless of their customer conversion goal or campaign conversion goal.

However, custom conversion goals do not respect primary_for_goal, so if a campaign has a custom conversion goal configured with a primary_for_goal = false conversion action, that conversion action is still biddable. By default, primary_for_goal will be true if not set. In V9, primary_for_goal can only be set to false after creation through an 'update' operation because it's not declared as optional.