Background: This paper uses Jürgen Habermas's Theory of Communicative Action as a lens through which to examine the development of a local mental health charter. Objective: To assess whether the Charter represents the product of a communicatively rational process. Research design and setting: The paper is based on an analysis of the text of the Charter, and on documentation relating to its development, including notes of discussion groups used to identify its themes. Findings: An analysis of the notes of the discussion groups against the text of the Charter shows that the Charter's themes are based broadly on the views generated in the discussion groups. However, they also draw on norms derived from wider discourses not reflected in the discussion groups, and exclude other specific local issues. The strength of feeling expressed in the discussion groups is also toned down in the language of the Charter. Discussion: The development of the Charter was based on a participatory process that can be said to have contained elements of both communicative and strategic rationality. The strategic rationality involved in translating service users' views into language that would be acceptable to those working in the system can be seen as necessary for the Charter to succeed in bringing about change. In drawing also on communicatively generated norms from the wider public sphere the Charter can be seen as reflecting a form of generalized communicative rationality. Conclusion: The Charter represents a 'sluice' by which communicative rationality is drawn into the mental health system.