Abstract. We consider adaptation in open systems, i.e. systems without global objects or common objectives. There are three related issues: how to make the degrees of freedom (DoFs) transparent to all agents, how to define a ‘fair’ process for performing adaptation, and how to retain some control over the adaptation to avoid, for example, undesirable configurations. We represent the specification DoFs in terms of a metric space, and define, in a uniform and consistent way, a mechanism for ‘moving’ between points in the metric space which is both ‘fair’ to the agents and avoids unacceptable moves or points in the space. This approach is demonstrated by the platform PreSage-MS, which allows a designer to specify and animate an adaptive open multi-agent system in terms of a metric space and norm-governed rules for ‘moving’ in that space.