Your project might move along faster if you targeted your FSM editor to my session processing framework in the Robust Services Core sb[^] directory. I've yet to write any CP articles about it, because the lower level parts of that code base are useful to a much wider audience. But there's a fair amount of documentation[^] and examples; scroll to the bottom of that page. It's essentially the framework used in a GSM MSC that evolved to LTE and is still seeing development. It has run-time support, TLV messaging, state machines that can observe and override the behavior of others, and even overload controls. A tool would be very useful even if it simply generated the C++ boilerplate needed when deriving from the classes defined by that framework. Robust Services Core | Software Techniques for Lemmings | Articles The fox knows many things, but the hedgehog knows one big thing.