Service-oriented architectures have been recognized as advantageous architectural styles for future enterprise and scientific applications. However, on top of already available middleware layers, many problems regarding services engineering and management have been identified as open issues. The integration of agent-based approaches can provide promising solutions in order to overcome these prevailing obstacles. This paper identifies two agent-based design patterns based on a classification scheme outlining several ways for agent-service integration in the context of agentbased service composition.