Agent-based systems have been known as one of the most complex classes of software system design because of heterogeneity, distributive, concurrent, non-deterministic, dynamic, and autonomous behaviors. An important characteristic of the design for any complex system is its software architecture, which can play an important role in the quality of software and, hence, in its success. Agent-based systems can be benefited from architectural design, which can be used as a plan to show agents, interactions, and their organizational relationships. In this paper, we represent a formal framework that can be used to specify the architecture of agent-based systems.