Developers and teachers go through a complex decision making process when designing new learning activities – working towards an effective pedagogical mix, combining resources, tools, student and tutor support. This paper describes CompendiumLD, a prototype tool we have built to support practitioners through the process of designing learning activities. We describe how the tool fits into our vision of a dynamic, interactive set of resources and system tools to support effective, efficient and creative learning design. It describes CompendiumLD's features and explains the rationale behind their development. It shows how the tool is intended to aid designers make choices, and plan developments, facilitating creativity and efficiency in the design process. In our conclusions we consider how such a system can support the design of effective learning activities.