Prison social workers and probation officers are required to perform a range of partial tasks with other professionals, either jointly or successively, and to articulate their intervention within a distributed system of action. Based on interview research conducted in Switzerland on the management of the transition from social supervision during detention to probation assistance in the community, this article sets the context for socio-judicial intervention in the community in Switzerland, describes the configuration of collective activity between the various actors involved, and considers the conditions that are conducive to a dynamic of joint work.