This paper describes an agent that has been incorporated as an evaluation component into a knowledge-based authoring tool for educational games. The agent is meant to simulate the behaviour and memory of a student and aims at helping authors to evaluate the courses that they have authored before these are delivered to real students. Authors may try their course using the simulated student-player and they can see what a real student is likely to learn and remember after each lesson. In case authors are not completely satisfied with the result they may redesign the whole course or some parts of it. Such components are very useful for authoring tools because they encourage and facilitate multiple iterations of the design process and thus ensure better quality of the resulting software applications.