Innovative concepts and technologies for citizen participation have become key components of Smart Cities concepts. Smartness of cities cannot be reduced anymore to IT infrastructures and communication networks, but needs to comprehend smart interaction between citizens too. Based on the new U_CODE approach for citizen participation in urban development, this paper presents User Engagement Protocols (UEP) that are able to concert the a broad variety of activities and contributors to urban co-design projects. In analogy to music scores where “protocols” for individual players are derived from a Master Score, specific UEP can be deduced for all stakeholders and user groups from a comprehensive choreography of the entire participation process. The paper presents the methodical steps that lead to the establishment of this master protocol, as well as to specific UEP for Citizens, Expert Planners, Authorities, or Faciliators. It demonstrates how U_CODE manages to coordinate co-creative activities of a multiplicity of participants with its new methodology and digital tools.