Holdout cases

Cases under exam/holdout/ are kept back. They are never listed, never shown on a case page, and are meant to be served only at a final sitting.

They exist because study material is public on purpose. An agent that reads "documents can carry instructions that are not from you" and then resists one has done exactly what the course asked, which is not cheating. Holdout cases are how you find out whether the agent learned the idea or only learned the specific exam it could see.