This paper presents a logic based language, SAFIN, for developing networked software agents. It integrates agent-oriented programming, KQML and basic mobile techniques to support intelligent behaviors, software interoperatablity and code transportability. As prototype based logic objects, agents are composed of network connections, knowledge bases (facts and beliefs), databases, behaviors, constraints, services, goals and KQML performatives. An approach to non-monotonic inheritance with both predicate level and clause level knowledge reuse is proposed and formally defined. Multi-level components and the interfaces to FTP services and relational database systems are also provided for developing specific distributed agents. ᭧ 1998 Elsevier Science B.V. All rights reserved.