What can Parmana not guarantee?
It checks the actions sent through it. It cannot stop an agent that has its own login to your systems, and it cannot make a person read what they approve.
Parmana checks the actions that are sent through it. It cannot stop an AI agent that already holds its own login to one of your systems and uses it directly.
An approval names the action and the resource it covers, but not every detail of the request. Parmana can check that a trusted approver signed it. It cannot check that the person read it.
Parmana applies the rules you write. A rule written wrongly still gives a wrong result, so the rules need a careful review.