Keep it simple
While processing it's important to clarify why you need to take the next action and what you hope to accomplish, but you only really need to be reminded of the action itself while in context. "Call Uncle Ben re: garage furniture" on your @Calls list is sufficient (assuming you have Uncle Ben's phone number on hand or in memory).
When you look at the list in the appropriate context and often enough, your brain subconsciously connects the outcome and the purposes to that action. You really don't need to describe the action in extreme detail. If you find that you do, chances are it's a project or sub-project, not a simple next action.