In the context of multi-agent systems (MAS), an Agent Coordination Context (ACC) is an abstraction provided by the infrastructure to each agent entering a MAS, aimed at enabling and controlling all the interactions of the agent with its environment. The notion of ACC features some key properties that help abating system complexity, that is, (i) it works as both a coordination and a security abstraction, (ii) it covers the engineering process from design to deployment, and (iii) it comes equipped with a clear formalisation, thus easing predictability of the MAS behaviour. In particular, in this paper we exploit typical process algebra techniques to define the syntax and semantics of a language for ACC specification, describing patterns of interaction protocols allowed to the agent. This language is shown to be useful to specify and enact integrated policies for security and coordination in MAS.