Discussion: Is providing reason reasonable?

[independentid]

In a de-coupled PDP/PEP environment, it is difficult to conceive how a PDP can convey reason (admin or user) values except in the case of specific "deny" policies.

If a PDP system is default deny unless permitted, then most responses can have no reason because no permission was matched.

What other information could or should be provided (e.g. count of policies reviewed)?

If it is useful to give a reason for denial, is it useful to give reason for permission (e.g. which policy permitted the action)?