Words
Identity is who. Permission is what.
An identity names a person, an application, a service, or an agent. A principal is the identity on this particular request. A workload identity belongs to the running software, so you can tell the agent apart from the person who asked.
A role groups permissions, such as “can read support cases.” A role can still be wider than today’s task. A tenant is one customer or organization inside a shared service. A cross-tenant request reaches someone else’s data.
A token is a data item a protocol uses for access. An access token lets a client ask a service for permitted operations. A bearer token works for whoever holds it, so treat it as a secret. The audience is the service the token was issued for. The scope is what it claims to allow. The service still has to check the token and the specific resource.
A session ties a series of requests to a caller. A session id is not a substitute for authentication and authorization. Delegation passes limited authority from one identity to another. Record who delegated, what was allowed, and which task may use it. Expiry ends a grant at a set time. Revocation ends it sooner. Closing the window is neither.
A valid credential proves which identity is calling. It does not prove this action is allowed. A staff member’s access is a ceiling. The agent’s task grant should be narrower: one record, one action, a short lifetime. If the platform cannot express that limit inside the credential, enforce it in the service that holds the data.