Many systems, such as large manufacturing systems, telecommunication networks, or homeautomation systems, require distributed monitoring and diagnosis. In this article, we introduce a meta-logic interpreter for vivid agents which allows to develop distributed monitoring and diagnosis systems consisting of a variety of scalable knowledge- and perception-based agents. The interpreter is based on PVM-Prolog, an extension of standard Prolog with message passing facilities. We show how to specify and run vivid diagnosis agents carrying out fault-tolerant diagnosis of a computer network.