ended abstract provides an overview of my research towards a dissertation thesis in the context of programming cognitive agents with non-monotonic reasoning capabilities. Categories and Subject Descriptors D.3.1 [Programming Languages]: Formal Definitions and Theory; F.3.2 [Logics and Meanings of Programs]: Semantics of Programming Languages; I.2.5 [Artificial Intelligence]: Programming Languages and Software; I.2.11 [Artificial Intelligence]: Distributed Artificial Intelligence-Intelligent Agents General Terms Languages, Theory, Design, Experimentation Keywords hybrid agent architectures; agent programming languages; reactive vs. deliberative; virtual agents; open-source software tools; Jazzyk; Jazzbot