This article presents a toolkit for defining simple but powerful systems. PORIS toolkit is an open and extensible source collaborative project that allows describing system graph-based systems and their behavior in a snapshot. It provides a web editor for a domain visual specific language (DSL) and transformation tools to generate software prototypes, system configurations, specific user interfaces and documentation. Different kind of instruments, like the astronomical ones, can be described and represented using PORIS specifications and models. A significant advantage of using PORIS toolkit is that it makes easy and lighter providing instant feedback to domain experts in the dynamic process of defining new instruments.