COPE is a program development environment that provides a highly tolerant user interface specifically designed for novice users. The design and implementation of COPE has been the work of a group which includes the author, Richard Conway, Andrew Shore, and Leonard Silver. In presenting the results of the joint effort, attention has been given to balance the presentation of the author's contribution and the overall context of the system. The author has been involved in all of the development and design phases of the system. The initial system design and architecture were developed jointly with Richard Conway and the sections presenting design, architecture, and user interface represent joint work. Later sections on particular issues (parsing, file system, etc.) are individual contributions.