AI Agent Identity and Authentication: How Agents Should Prove Who They Are and Act for Users
How AI agents should authenticate: their own identities, delegated OAuth tokens, token exchange, MCP authorization and agent identity platforms.
Quick answer
Give every AI agent its own identity, never a person's password or a shared API key. When an agent works for a user, it should act on behalf of that user with a delegated token: obtained through OAuth with the user's consent, limited to specific scopes, short-lived and revocable, and carrying both identities so every action is traceable. Autonomous agents with no user should run as workload identities with narrowly scoped permissions. Use standard protocols (OAuth 2.1, token exchange, the MCP authorization spec) and, in larger organizations, an identity platform that manages agents like employees and applications, with owners, lifecycle and conditional access.
Why agents break traditional identity
Identity systems were built for two kinds of actors: people, who sign in interactively, and applications, which use service credentials. Agents are neither. They act autonomously like applications but often on behalf of a specific person, with that person's context and limits. They also multiply: a company may run dozens of agents, each calling many tools.
The shortcuts teams take in pilots (an employee's API token pasted into configuration, one admin key shared by every agent) create the problems the OWASP Top 10 for Agentic Applications lists as Identity and Privilege Abuse: excessive access, no attribution and credentials that outlive their purpose. See the OWASP agentic guide.
Three identity patterns
| Pattern | When to use | How it works | Watch for |
|---|---|---|---|
| Delegated (on behalf of a user) | Assistants and agents that act for a signed-in person | User consents; agent receives a scoped token representing user + agent | Scope creep; long-lived refresh tokens |
| Autonomous workload identity | Background agents with no user (monitoring, batch processing) | Agent has its own identity with fixed, narrow permissions | Becoming a de facto admin account |
| Agent user account | Agents that must appear as a member of a team (mailbox, chat) | A dedicated account owned by a sponsor, governed like a user | Orphaned accounts when owners leave |
Key takeaway
Every action should answer two questions: which agent did this, and on whose behalf? If your logs can only answer one, the identity design is incomplete.
Delegation with OAuth
OAuth is the standard tool for delegation. The user signs in and consents to specific scopes; the agent receives an access token that the API validates. Two refinements matter for agents. Token exchange (OAuth 2.0 Token Exchange, RFC 8693) lets a service swap one token for another with a different audience or narrower scope, so a token for the agent platform is not reused against every downstream API. Short lifetimes and revocation limit damage if a token leaks into logs or a manipulated prompt.
Scopes should describe actions, not systems: "read orders" and "create return request" rather than "full CRM access". The API, not the agent, enforces them.
MCP authorization
If your agents use MCP servers, or you publish one, follow the MCP authorization specification. It builds on OAuth 2.1: a protected MCP server is a resource server, it publishes OAuth 2.0 Protected Resource Metadata (RFC 9728) so clients can find the authorization server, and clients obtain tokens issued specifically for that server. The specification also supports client ID metadata documents so clients can identify themselves without manual registration. Do not pass tokens received by an MCP server straight through to other APIs; obtain properly scoped tokens for each audience. See MCP security.
Enterprise agent identity platforms
Identity vendors now treat agents as a first-class identity type. Microsoft Entra Agent ID, generally available in 2026, introduces agent identity blueprints, agent identities and agent user accounts, with sponsors and owners, lifecycle workflows that reassign sponsorship when people leave, access packages for on-behalf-of and autonomous scenarios, and Conditional Access templates for agents. Microsoft also documents patterns for non-Microsoft agents (for example on AWS or n8n) through federation or a sidecar. Other identity providers offer similar capabilities for agents and delegated access.
You do not need an enterprise platform to apply the principles, but if you already run a central identity provider, extend it to agents rather than managing agent credentials separately.
Designing how your agents sign in and act?
ZSpace Labs designs agent identity and delegated access with OAuth, token exchange and your identity provider, and builds the audit trail around it. See AI automation services.
Agents that act outside your organization
When an agent visits other companies' websites or APIs (for example to shop or book), the other side also needs to know who it is. Agent operators increasingly sign their HTTP requests so sites can verify them; see how to verify AI agent traffic. If you build agents that act externally, plan for the same: a verifiable identity, a published policy and contact details for site owners.
Implementation checklist
- Every agent registered with an identity, an owner and a purpose
- No shared keys; no agents using a person's password or personal token
- Delegated tokens with action-level scopes for agents acting for users
- Short-lived tokens; refresh limited; revocation tested
- Token exchange or per-audience tokens for downstream APIs
- Secrets and tokens kept out of model context and logs
- Every action logged with agent identity, user identity, scopes and result
- Lifecycle: review permissions periodically; disable agents whose owner leaves
Conclusion
Authentication is where agent governance starts. Give each agent its own identity, use delegated, scoped, short-lived tokens when it acts for people, follow OAuth and the MCP authorization spec, and log both identities on every action. Then decide what each identity may do with AI agent access control.
Common questions.
With its own identity, not a person's password or a shared API key. When it acts for a user, it should hold a delegated, scoped, short-lived token obtained with that user's consent (typically through OAuth), so every action is traceable to both the agent and the user.