CPN Tools

CPN Tools is a graphical software environment for modeling, simulating, and analyzing colored Petri nets (CPNs), developed and maintained by the CPN Group at Aarhus University under the leadership of Kurt Jensen. First released in 2000, it remains the primary industrial-strength tool for CPN-based formal methods, combining an intuitive graphical editor with a powerful simulator, state-space analysis engine, and performance profiler. CPN Tools is built on top of the Standard ML programming language, leveraging its type system and functional paradigm to express the color sets, arc inscriptions, and guard functions that give CPNs their modeling power.

The architecture of CPN Tools reflects a deliberate design philosophy: the graphical editor and the underlying simulator are tightly coupled, allowing users to construct models, execute them step-by-step, and inspect token distributions in real time. This immediacy is pedagogically powerful — students can see concurrency unfold — but it is also methodologically dangerous. The tool's visual appeal can mask the complexity of the formalism beneath, leading practitioners to believe that a model which looks