Add evaluated fact(s) to onSuccess handler

It would be great if the developer could access the fact(s) that were evaluated and contribute to the onSuccess evaluation. I'd like to see which data inputs allowed the evaluation to be true

Start by locating the onSuccess handler and the evaluation flow that invokes it. Clarify which evaluated facts and data inputs should be exposed, and how they should contribute to onSuccess evaluation. Done means the behavior is defined and covered by tests, but the issue does not name files or existing tests to guide implementation.

Written by the indexing model from the issue text.