The theory of Instrumental Genesis (IG) accounts for the mutual evolution of artefacts and their uses, for specific purposes in specific environments. IG has been used in Computer-Supported Collaborative Learning (CSCL) to explain how instruments are generated through the interactions of learners, teachers and artefacts in 'downstream' classroom activities. This paper addresses the neglected 'upstream' activities of CSCL design, where teachers, educational designers and educational technologists use CSCL design artefacts in specific design-for-learning situations. The paper shows how the IG approach can be used to follow artefacts and ideas back and forth on the CSCL design and implementation pathway. It demonstrates ways of tracing dynamic relations between artefacts and their uses across the whole complex of instrument-mediated activity implicated in learning and design. This has implications for understanding the communicability of design ideas and informing the iterative improvement of designs and designing for CSCL.