To support the goal of allowing users to record and retrieve information, this paper describes an interactive note-taking system for pen-based computers with two distinctive features. First, it actively predicts what the user is going to write. Second, it automatically constructs a custom, button-box user interface on request. The system is an example of a learning-apprentice software-agent. A machine learning component characterizes the syntax and semantics of the user’s information. A performance system uses this learned information to generate completion strings and construct a user interface.