ABSTRACT
This chapter proposes that Intelligent Tutoring Systems (ITS) be designed explicitly around the interaction with the student, that is, designed around the interface. An ITS architecture is proposed that is based on knowledge components called plans and an interface framework for organizing and manipulating plans. The BRIDGE programming tutor is presented an illustration of an ITS designed around a plan-based interface. The MATISSE system is introduced as a general tool for creating an interface-based ITS. In BRIDGE we built a programming environment that supports a novice in working with plans that describe the goals and subgoals typical of programming tasks. The BRIDGE environment features an iconic-plan programming language with editor facilities to control execution and support debugging. BRIDGE uses a different approach in reconstructing the student's intentions. In addition, the BRIDGE approach simplifies the knowledge engineering. The programming environment is called MATISSE. The systems designed with MATISSE must be efficient enough to work with students without reimplementation in standard languages.
