Extensive work in the behavioral sciences tells us that team composition is a complex activity in many disciplines, given the variations inherent across individuals' personalities. The composition of teams to undertake software development is subject to this same complexity. Furthermore, the building of a team to undertake agile software development may be particularly challenging, given the inclusive yet fluid nature of teams in this context. We describe here the development and preliminary evaluation of a prototype tool intended to assist software engineers and project managers in forming agile teams, utilizing information concerning members' personalities as input to this process. Initial assessment of the tool's capabilities by agile development practitioners suggests that it would be of value in supporting the team composition activity in real projects.