We describe an approach to the development of a complex social care system that defines specific steps along the path to MAS implementation. In particular we explore the use of conceptual knowledge modelling techniques by means of conceptual graphs and a transactions-based architecture for model verification during requirements gathering, together with a translation to AUML for design specification, and propose a rigorous framework to enrich and extend existing AOSE methodologies. The resulting output from Transaction Agent Modelling (TrAM) can then be developed further using the agent development toolkit of choice.