AVL Reports are needed to run Missions in the Inventing Room, Armory Room, Train Station Room, Omniscience Room, and Story Room.

While you need at least 1 AVL Report to begin a run in these Rooms, you won't actually expend the report until you complete at least one Mission in the Room.

AVL Reports are replenished automatically over time, or they can be purchased if you run out.

For additional information, check out: <How can I unlock new Locations?>