Published 2026-05-02.
Authentication verifies identity. Authorization decides what that identity can do. For AI agents, both controls must happen at runtime, not only at login.
Short answer
Authentication verifies who or what is making a request. Authorization decides what that verified identity is allowed to access or do.
Authentication usually happens first, but authorization is the control that limits damage after a user, workload, or AI agent has valid credentials.
Primary keyword targets
Authentication vs authorization, authorization vs authentication, AuthN vs AuthZ, OAuth vs OpenID Connect, AI agent authorization, workload identity, and runtime authorization.
The article uses answer-first definitions, a comparison table, protocol examples, AI-agent use cases, visible FAQs, and internal links for SEO and GEO citation readiness.
Agent security takeaway
For AI agents, a valid credential proves only that the agent authenticated or received delegated access. It does not prove that the next tool call is safe.
Runtime authorization checks the current user, task, tool, resource, action, parameters, and risk before the agent executes a sensitive operation.
Frequently asked questions
- What is the difference between authentication and authorization?
- Authentication verifies identity: who the user, service, device, or AI agent is. Authorization determines permissions: what that verified identity can access or do.
- Which comes first, authentication or authorization?
- Authentication usually comes first because the system needs to know the identity before it can evaluate permissions. Authorization follows by deciding whether that identity may perform the requested action.
- Is OAuth authentication or authorization?
- OAuth 2.0 is primarily an authorization framework. OpenID Connect adds an identity layer on top of OAuth 2.0 for authentication.
- Why does authorization matter for AI agents?
- AI agents can use valid credentials in unsafe ways. Authorization must evaluate each sensitive tool call against the current user, task, resource, action, and risk context.
- What is AuthN vs AuthZ?
- AuthN is shorthand for authentication, or identity verification. AuthZ is shorthand for authorization, or permission and access-control decisions.