The negotiation planner is contained within one file, critical_points.pl, contained in the negotiation_planner directory. The main procedure is called neg_tree and it recursively generates the negotiation game tree. At each choice node, a set of procedures is called to provide the set of alternative negotiation acts for that point in the dialogue. Once the game tree has been constructed, the domain-level game tree is attached to the leaves. Evaluation is performed using the code from the domain-level planner, but the file provides appropriate dry-land procedures for the evaluator to call.