@wparker Thanks for this. At this point, I am honestly just exploring, and thinking more about the ability to see the complete state of a session after starting with an initial fact set and seeing what all gets generated by firing the rules. I'm thinking more about a diagnostic to just dump a session and being able to talk through with someone "If you start with these rules and this initial fact set, this is the final set of facts that end up in the session." Starting with that fact set and triggering another set of rules was just a thought experiment, but looking at a given state thoroughly was the main driver. The session use cases I can think of probably won't be all that large in terms of facts, or at least initial facts, but might get a lot of derived facts with the rule set I put into the session. I like the "private" and "glue" facts approach... I was thinking along the lines of "initial" and "derived" facts from rules, and comparing those two sets.