Use Codebase to Course when an agent needs to explain an existing repository as a teachable walkthrough instead of producing ordinary docs or a product demo. Invoke it when the job is onboarding, knowledge transfer, or plain-English explanation for non-technical collaborators who need an interactive course rather than another README. The scope boundary is narrow: transform one codebase into a self-contained course artifact with explanations, visuals, and quizzes, not a generic documentation platform or developer education product listing.