Mixed Initiative Interaction in O-Plan

Work is described which seeks to support mixed initiative interaction between a "task assignment" or "command" agent and a planning agent. Each agent maintains an agenda of outstanding tasks it is engaged in and uses a common representation of tasks, plans, processes and activities based on the notion that these are all "constraints on behaviour". Interaction between the agents uses explicit task and option management information. This framework can form a basis for mixed initiative user/system agents working together to mutually constrain task descriptions and plans and to coordinate the taskoriented generation, refinement and enactment of those plans.