According to a first aspect, the invention relates to a tool for modelling, instantiating and/or executing a Bayesian agent in an application. The tool comprises a modelling module which is adapted to enable a user to determine a template for the Bayesian agent. The template comprises a Bayesian network, which comprises nodes and/or node-level meta-data. The node-level meta-data at least defines node behavior and/or an association of a node with a software defined sensor and/or one or more software defined actuators. Also the template comprises template-level metadata at least defining lifecycle properties for the Bayesian agent. The template is suitable to be instantiated and executed as the Bayesian agent instance.