We combined two existing methods for rapid tutor development: “plug-in tutor agents” [6] and an authoring tool suite (CTAT) that supports the creation of tutors “by demonstration” [2]. The combined approach, which has not been tried before, is suited for adding tutoring capabilities to an existing problem-solving environment, for example an off-the-shelf simulator. Connecting the components (i.e., the simulator and CTAT) requires programming but once that is done, “Pseudo Tutors” are created “by demonstration. Following this approach, we created plug-in Pseudo Tutor agents for a thermodynamics simulator, CyclePad [1], which were tried out in a classroom experiment involving 92 college students. The experiment demonstrates that the Pseudo Tutor technology is viable in a complex domain and that Ritter and Koedinger’s protocol for the tool-tutor communication is suited for use in an authoring environment.