How can I capture a policy change as a portable authorization event in OPA?

[massimo-create]

Hello OPA community,

I’m validating a vendor-neutral approach for representing an authorization change as:

BEFORE → authorization state
CHANGE → authorization modification
AFTER → resulting authorization state
EVIDENCE → decision/audit evidence

I’m looking for one small, controlled, non-production example using OPA.

For example, a simple Rego policy change where we can observe the policy state before and after the change, trigger an authorization decision, and correlate that decision with the corresponding policy or bundle revision and decision log evidence.

No production access, credentials, or customer data are required.

The goal is to validate whether this transition can be represented as a portable authorization-change event.

What would be the recommended way to capture the BEFORE/CHANGE/AFTER state together with the corresponding policy revision and decision-log evidence in OPA?

Thank you,
Massimo