Electronic argumentation support is increasingly important in today's networked society. Virtual research collaboration, e-business, and many other domains of professional life critically depend on adequate support of tools for productive argumentative interactions. However, a plethora of technologies exist that are not necessarily tools. A technology only is a tool if it serves the purposes of the community in which it is used. In this paper, we outline an approach to diagnose to what extent a particular argumentation technology is a tool. We do this by combining a sociotechnical view on technologies with a pragma-dialectical approach to argumentation analysis. We argue that for technologies to become a tool, argumentation routines and design need to co-evolve. We illustrate our approach by applying it to a case on group report authoring.