Event data is a collection of recorded events that capture performed actions and observed states of business processes supported by information systems. It describes the times of event occurrences, event types, event attributes, and process cases of events identified by one or more objects the events relate to. Process mining uses event data to analyze and improve the processes in organizations. These processes are often performed by actors or agents, such as employees, resources, and systems, in different roles within organizations. In this paper, we present Agent System Event Data (ASED), a new type of event data that describes business processes as interactions of agents. ASED provides a new scope for analyzing individual agents involved in multiple processes, interactions of agents, and systems of agents that enact the processes. We formalize ASED as a conceptual data model, discuss its dimensional attributes, and demonstrate its applicability through concrete examples.