The  Protocol consists of an institutionalized pattern of interaction among agents.

That is, a pattern of interaction that has been formally defined and abstracted away from any particular sequence of execution steps, to focus attention on the essential nature and purpose of the interaction, rather than on the precise ordering of particular message exchanges or scenarios. See Developing multiagent systems: The Gaia methodology (p. 347) for more information about this concept.  See also Activity concept.

A protocol definition consists of the following attributes:

- Protocol Name: brief textual description capturing the nature of the interaction
- Initiator: the role(s) responsible for starting the interaction;
- Partner: the responder role(s) with which the initiator interacts;
- Inputs: information used by the role initiator while enacting the protocol;
- Outputs: information supplied by the protocol responder during interaction;
- Description: textual description explaining the purpose of the protocol and the processing activities implied in its execution.