What Is AI Agent Authentication?

AI agent authentication establishes the identity involved when an agent accesses a protected system. Depending on the architecture, that identity may belong to a user, an agent, an application, or another type of client. Authentication is only part of the process. Authorization determines what an authenticated identity is allowed to access or do.

How Is Agent Authentication Different From User Authentication?

User authentication verifies the identity of a person. Agent authentication can also involve identifying the software or workload making a request. This distinction matters when an application needs to know not only which user is involved, but also which agent or client is performing an action.

Do AI Agents Need Their Own Identities?

Not always. An agent operating within an authenticated user's application session may not require a separate identity. Agents that operate independently, run as workloads, or need to be distinguished from the users they represent may benefit from their own identities and credentials.

What's the Difference Between Authentication and Authorization for AI Agents?

Authentication establishes identity. Authorization determines what that identity can access or do. For example, an application might authenticate an agent and then use scopes, roles, resource permissions, or policies to determine which protected resources and actions it can access.

What Is Delegated Authorization for AI Agents?

Delegated authorization allows a client to access protected resources on a user's behalf. OAuth is commonly used for this pattern. Instead of sharing the user's login credentials, the client obtains an access token representing the access that has been authorized.

What's the Difference Between Inbound and Outbound Agent Auth?

Inbound auth controls how agents or other clients access resources your application exposes. For example, an external agent may need authorization before connecting to your MCP server. Outbound auth covers your agent's access to another service. An agent that needs to read a user's calendar, update a CRM, or call another protected API may need an OAuth token or another credential for that service.

How Does OAuth Work With AI Agents?

OAuth allows a client to obtain authorized access to a protected resource without requiring the user to share their login credentials with that client. In an agent workflow, the agent application or another component can act as the OAuth client. After authorization, the client receives an access token that it presents when requesting the protected resource.

How Does MCP Authorization Work?

For HTTP-based transports, MCP defines an optional authorization framework based on OAuth 2.1 and related specifications. When authorization is used, the MCP server acts as a resource server. The MCP client obtains an access token from an authorization server and includes it in requests to the MCP server, which validates that the token was issued for it before granting access.

The 9 Best AI Agent Auth Solutions (August 2026): Features, Use Cases, and Architectures

As AI agents connect to more tools and applications, managing who is requesting access and what they are allowed to do becomes more complicated. An agent may need to act on behalf of a user, connect to an MCP server, call a protected API, or access an external service with permissions delegated by a user. OAuth-based agent and MCP authorization flows are designed to support these kinds of scoped access relationships.

AI agent auth solutions provide infrastructure for managing these identity and access flows. Depending on the product, they can authenticate users or clients, issue access tokens, manage delegated authorization, protect MCP servers and APIs, give agents distinct identities, or manage credentials used to access downstream services.

That infrastructure becomes especially useful when agents need to operate across multiple protected resources. A straightforward application may only need to authenticate the user before an agent runs, while other architectures need to distinguish the user from the agent or client, control which permissions are delegated, and enforce authorization at the MCP server, API, or tool level.

There are several approaches to solving this problem. Some products extend existing identity platforms with OAuth-based agent and MCP authorization, while others provide identity infrastructure built specifically around agents and their credentials. The products also differ in which part of the access path they manage, including agents connecting to your APIs or MCP servers, agents accessing external services, or both.

Rather than trying to catalog every identity and authorization product available today, this guide focuses on nine solutions that represent different approaches to securing AI agent access. By the end of this roundup, you'll have a better understanding of how these approaches differ, where each product fits within an agent's identity and authorization architecture, and which approach best fits your AI application.

What Is AI Agent Auth?

AI agent auth is the set of mechanisms used to establish and control access when agents interact with protected resources.

A useful way to understand it is to separate authentication from authorization. Authentication establishes the identity of the party making a request. Authorization determines whether that identity has permission to perform a particular action or access a particular resource. An agent system may apply both at multiple points in a workflow.

OAuth is one common way to authorize access without giving a client a user's login credentials. An authorization server can issue an access token for a protected resource, and that resource can validate the token before granting access. Scopes can be used to request specific levels of access, while other authorization policies may further determine what the client is permitted to do.

MCP applies an OAuth-based authorization model to protected MCP servers using HTTP-based transports. Authorization is optional in MCP, but when this authorization flow is used, the MCP server acts as an OAuth resource server and the MCP client presents an access token with its requests. The server must validate that the token was issued for it before granting access.

Agent auth therefore sits between agent logic and the protected systems an agent needs to use. It handles identity and access for those connections, while agent frameworks and application code handle responsibilities such as reasoning, orchestration, and tool selection.

How to Evaluate AI Agent Auth Solutions

AI agent auth solutions can secure different parts of an agent's access path, so the right choice depends on the identities, resources, and authorization flows in your application.

Every application has different requirements, but we've found that these five considerations provide a useful starting point when evaluating agent auth infrastructure.

Identity Model

Start by determining which identities your application needs to represent.

Some workflows only need to authenticate a user and authorize an application or agent to act with that user's permission. Others need a distinct identity for the agent itself, particularly when an agent operates programmatically or without an active user session. WorkOS, for example, supports Agent Registration, which allows AI agents and other programmatic clients to obtain identity credentials.

Consider whether your application needs to identify the user, the agent or client making the request, or each separately. That choice affects how credentials are issued, how permissions are applied, and how activity can be attributed within the application.

Delegated Authorization

Agents often need permission to perform specific actions on a user's behalf.

OAuth-based delegated authorization allows a user to grant an application or agent access to protected resources without sharing their login credentials. Access tokens can represent that delegated access, while scopes can define the permissions being requested or granted.

When evaluating a solution, consider how it handles consent, scopes, token issuance, revocation, and access to specific resources. The goal is to give an agent the authority required for its task without automatically giving it every permission available to the user.

Inbound and Outbound Access

Agent auth can protect resources your application exposes or help your agents access resources elsewhere.

For inbound access, an external agent or client may need authorization before calling your APIs, tools, or MCP server. For outbound access, your own agent may need tokens or other credentials to call a third-party API or service. Some platforms focus primarily on one direction, while others support both.

It’s important to determine which direction your agent connections travel, and whether one platform needs to manage both sides.

Standards and Protocol Support

Agent auth builds on established identity and authorization standards, but implementations can support different combinations of them.

Depending on your architecture, relevant standards and mechanisms may include OAuth, OpenID Connect, PKCE, protected resource metadata, client registration, and token exchange. MCP's authorization specification itself builds on OAuth 2.1 and related standards, including OAuth Authorization Server Metadata and OAuth Protected Resource Metadata.

Rather than checking only whether a product says it supports MCP or OAuth, verify which flows and standards it implements and whether they match your clients, servers, and deployment model.

Policy and Access Control

Authentication establishes identity, but applications also need rules governing what authenticated agents and clients can do.

Depending on the architecture, access can be restricted through scopes, roles, resource permissions, or more detailed authorization policies. These controls become especially important when different users, agents, organizations, or applications should receive different levels of access.

Look at where authorization decisions are enforced, how permissions can be changed or revoked, and whether activity can be attributed to the relevant identity. For MCP applications, also consider how access tokens and scopes control access to the specific resources and operations your server exposes.

The 9 Best AI Agent Auth Solutions

1. WorkOS

Best for: B2B applications that want to manage user authentication, agent identities, and MCP authorization through the same identity platform.

WorkOS provides identity infrastructure for applications, with AuthKit supporting user authentication and authorization. Its Agent Registration capability extends that infrastructure to AI agents and other programmatic clients that need identity credentials of their own.

With Agent Registration, a client registers with an AuthKit-powered service and receives a signed identity assertion. That assertion can then be exchanged for an access token or API key, depending on how the WorkOS environment is configured. WorkOS supports anonymous registrations without a user identity as well as a service_auth flow that requires a user to complete a claim ceremony before the agent receives its trusted identity credentials.

For MCP servers, AuthKit can serve as the OAuth authorization server while the MCP server remains the protected resource server. AuthKit provides the OAuth endpoints used by MCP clients, and the application verifies the resulting access tokens before granting access to its MCP endpoints. WorkOS also offers Standalone Connect, which lets teams retain an existing user authentication system while using AuthKit for the MCP OAuth flow and token issuance.

Why You Might Choose WorkOS

Gives AI agents and other programmatic clients a dedicated registration flow for obtaining identity credentials.
Supports both anonymous agent registration and a user-linked service_auth flow.
Lets teams configure Agent Registration to issue either access tokens or API keys.
Can act as the OAuth authorization server for protected MCP servers.
Supports Resource Indicators so access tokens can carry an audience corresponding to the requested protected resource.
Lets applications keep their existing user authentication system while adding OAuth authorization for MCP clients through Standalone Connect.

Additional Highlights

WorkOS supports Dynamic Client Registration (DCR), allowing compatible MCP clients to register with its authorization server without being manually configured in advance. This makes it easier for a protected MCP server to accept new clients without requiring developers to pre-register each one.

2. Auth0

Best for: Teams that want user authentication, delegated API access, and MCP authorization within a broader identity platform.

Auth0 for AI Agents extends Auth0's identity infrastructure to authentication and authorization patterns used by agent applications. Developers can authenticate users and issue access tokens that let agents call first-party APIs on an authenticated user's behalf.

For agents that need to access external services, Token Vault stores and manages access and refresh tokens from supported external providers. Applications can exchange an Auth0 token for the external provider's access token, allowing an agent to call services such as Google, Microsoft, GitHub, or Slack on a user's behalf without storing those external credentials itself.

Auth0 also provides authorization infrastructure for MCP servers. MCP clients can present Auth0-issued access tokens to protected MCP servers, which validate the tokens and enforce access controls. When an MCP server needs to call a different first-party API on the user's behalf, Auth0's On-Behalf-Of Token Exchange can exchange the incoming token for a new token with the downstream API as its audience.

Why You Might Choose Auth0

Supports user authentication and agents calling first-party APIs on behalf of authenticated users.
Uses Token Vault to store and manage tokens for supported external services.
Provides OAuth-based authorization for protected MCP servers.
Supports scopes and role-based access control for managing access to MCP tools.
Uses resource-specific audiences so access tokens can be issued for the intended protected resource.
Supports On-Behalf-Of Token Exchange when an MCP server needs to call a different first-party API while preserving the user's identity and permissions.

Additional Highlights

Auth0 supports asynchronous authorization for agent workflows that require user approval. It uses Client-Initiated Backchannel Authentication (CIBA), enhanced with Rich Authorization Requests (RAR), so an agent can request authorization for an action while the user approves or denies it through a separate interaction.

3. Okta

Best for: Enterprises that want to manage AI agents as identities and centrally govern their access to applications and resources.

Okta for AI Agents lets organizations register and manage AI agents within Okta. Teams can manually register custom-built agents or import agents from supported provider applications. Once registered, an agent can have owners, credentials, delegations, and resource connections that define how it interacts with other identities and protected resources.

Delegations define which users, applications, services, or other AI agents can authorize an agent to act on their behalf. Resource connections separately define what the agent can access, such as authorization servers, resource servers, secrets, or service accounts. For supported resource types, administrators can also control which OAuth scopes the agent receives.

Okta also provides Cross App Access (XAA) for managing agent-to-application and app-to-app connections through the identity provider. Administrators can use it to apply access policies centrally across supported connections.

Why You Might Choose Okta

Supports manual registration of custom AI agents and imports from supported agent provider applications.
Lets administrators assign owners and configure credentials for managed agent identities.
Supports delegations from users, applications, services, and other AI agents.
Uses resource connections to define which protected resources an agent can access.
Lets administrators restrict OAuth scopes for supported resource connections.
Provides Cross App Access for centrally governing supported agent-to-application connections.

Additional Highlights

Okta Identity Governance can extend access reviews to AI agents, including reviews of an agent's resource connections. Teams can use Access Certifications to periodically verify that agents retain the appropriate access and remediate it when needed.

4. Clerk

Best for: Teams already using Clerk that want to add OAuth-protected MCP servers to their existing authentication setup.

Clerk provides authentication and user management infrastructure for applications, with support for using Clerk as the OAuth authorization server for an MCP server. Compatible MCP clients can complete an OAuth flow and receive Clerk-issued access tokens before connecting to protected endpoints.

Clerk provides helpers for securing MCP endpoints and verifying incoming OAuth tokens. The MCP server can use the verified token to identify the current user before allowing a tool call to access protected application data.

Clerk also supports OAuth scopes and Dynamic Client Registration (DCR). DCR allows compatible clients to register programmatically, while scopes determine the user information or organization data the client can request.

Why You Might Choose Clerk

Uses Clerk as the OAuth authorization server for protected MCP servers.
Provides helpers for verifying Clerk-issued OAuth tokens on MCP requests.
Supports OAuth scopes for controlling which user or organization data a client can request.
Supports Dynamic Client Registration for MCP clients that need to register programmatically.
Provides authorization server and protected resource metadata endpoints used during MCP OAuth discovery.
Fits naturally into applications that already use Clerk for authentication.

Additional Highlights

Clerk's Agent Tasks can create authenticated sessions for agents acting on behalf of users without requiring the standard sign-in flow each time. This provides a separate path for agent workflows that need to perform authenticated work in the background.

5. Firebase

Best for: Teams that want established user authentication and token-based access control for agent applications.

Firebase Authentication provides authentication infrastructure for applications, with support for email and password, phone numbers, and federated identity providers such as Google, Apple, and GitHub. After a user signs in, Firebase issues a signed ID token that identifies the user to application backends.

Backend services can verify these ID tokens with the Firebase Admin SDK before allowing a request to access protected resources. This model can be applied to agent applications by authenticating the user separately from the agent runtime, then using the verified identity when deciding which application data or functionality the request can access.

Firebase also supports custom claims for application-level access control. Developers can add information such as roles or access levels to a user's account, which is propagated through ID tokens and can be checked after the token is validated when making authorization decisions.

Why You Might Choose Firebase

Issues signed ID tokens that backend services can verify to identify authenticated users.
Supports email and password, phone authentication, and multiple federated identity providers.
Provides Admin SDKs for verifying ID tokens on backend services.
Supports custom claims for representing roles and other access-control information.
Can connect an existing authentication system to Firebase through custom tokens.
Works with Firebase Security Rules to control access to supported Firebase resources based on authenticated user information and claims.

Additional Highlights

Firebase supports server-side session cookies for applications that use cookie-based sessions. These cookies carry the same claims as the corresponding ID token and can have custom expiration times ranging from five minutes to two weeks.

6. Supabase

Best for: Teams that want to connect user authentication with Postgres-level access controls for agent applications.

Supabase Auth provides authentication and authorization infrastructure built around JSON Web Tokens (JWTs) and Postgres. It supports password, passwordless, social, phone, and SAML-based authentication, giving applications multiple ways to establish a user's identity before they access protected functionality.

After authentication, Supabase issues an access token containing information about the user and session. Backend services can verify these JWTs before processing requests, while other Supabase services can use the authenticated identity when determining access to application data.

Supabase Auth also integrates with Postgres Row Level Security (RLS). Developers can write policies that use information from the authenticated user's JWT to determine which rows a user can access or modify. For agent applications that interact with user-specific data, this provides a way to enforce permissions at the database layer rather than relying on the agent itself to decide what data it can access.

Why You Might Choose Supabase

Issues JWT access tokens containing identity and session information for authenticated users.
Supports password, passwordless, social, phone, and SAML-based authentication.
Connects authenticated user identities to Postgres Row Level Security policies.
Supports custom claims for carrying roles and other application-specific authorization information.
Provides a Custom Access Token Hook for modifying supported claims before a JWT is issued.
Can accept JWTs from supported third-party authentication providers.

Additional Highlights

Supabase Auth supports multi-factor authentication and records the resulting Authenticator Assurance Level in the user's JWT. Applications can use this value in frontend, backend, or database authorization rules when certain operations require stronger authentication.

7. Better Auth

Best for: Teams that want to run authentication within their own application stack and extend it with OAuth-based access for agents and other clients.

Better Auth is an authentication and authorization framework for TypeScript applications. It includes email and password authentication and social sign-in, while plugins add capabilities such as passkeys, magic links, SSO, organizations, API keys, and bearer-token authentication.

For applications that expose protected services, Better Auth's JWT plugin can issue JWTs that other services verify using public keys exposed through a JWKS endpoint. Its Bearer plugin also lets clients authenticate API requests by sending a session token in the Authorization header instead of a cookie, which can be especially useful when protected endpoints are accessed programmatically.

Better Auth can also act as an OAuth 2.1 authorization server through its OAuth Provider plugin. Applications can use it to authorize third-party clients through the authorization code flow, while the plugin also supports the client credentials flow for machine-to-machine access and OpenID Connect for clients that need identity information.

Why You Might Choose Better Auth

Provides an authentication framework that runs within a TypeScript application's own backend.
Supports email and password authentication and multiple social identity providers.
Uses a plugin architecture for adding capabilities such as passkeys, magic links, SSO, and API keys.
Can issue JWTs that other services verify using its published public keys.
Supports bearer-token authentication for clients that send session tokens through the Authorization header.
Can operate as an OAuth 2.1 provider for third-party and machine-to-machine clients.

Additional Highlights

Better Auth's Organization plugin includes customizable roles and permissions for multitenant applications. Developers can define application-specific resources and actions, then use roles to control which operations organization members are permitted to perform.

8. Google

Best for: Teams that want to use Google identities and OAuth-based access for agent applications that interact with Google services.

Google provides OAuth 2.0 and OpenID Connect infrastructure for authenticating users and authorizing applications to access Google APIs. Applications can use OpenID Connect to establish a user's identity, while OAuth access tokens allow clients to access Google APIs with permissions represented by the scopes the user has authorized.

For agent applications that access Google services on a user's behalf, developers can request OAuth scopes corresponding to the Google APIs and data the application needs. After the user grants access, the application can use the resulting access token to call authorized APIs, with refresh tokens available in supported flows for obtaining new access tokens without requiring the user to authorize the application again each time.

Google Cloud also supports service accounts for workloads that need a non-user identity. Applications can authenticate as a service account to access resources the account has permission to use, providing a separate identity model for agent workloads that operate independently of an end user.

Why You Might Choose Google

Supports OpenID Connect for authenticating users with Google Accounts.
Uses OAuth 2.0 scopes to request specific levels of access to Google APIs.
Supports user-delegated access to services such as Gmail, Drive, and Calendar.
Provides refresh tokens in supported OAuth flows for maintaining authorized access.
Supports service accounts for applications and workloads that need a non-user identity.
Provides client libraries for implementing OAuth flows and accessing Google APIs.

Additional Highlights

Google Cloud supports service account impersonation, allowing an authenticated principal with the required permissions to obtain short-lived credentials for a service account. This lets workloads use a service account's permissions without relying on a downloaded service account key.

9. Stytch

Best for: Teams that want to give AI agents scoped access to their application without replacing their existing authentication system.

Stytch Connected Apps lets an application act as an OAuth 2.0 and OpenID Connect (OIDC) authorization server for AI agents, third-party applications, and other compatible clients. It provides the APIs, SDKs, and UI components needed to handle authorization flows and issue tokens, while letting developers define the scopes clients can request.

For remote MCP servers, Stytch provides an OAuth-based authorization flow in which MCP clients request access to a user's account through the authorization code grant. Stytch hosts the authorization server metadata, token endpoint, and optional Dynamic Client Registration (DCR) endpoint, while the MCP server validates Stytch-issued access tokens and publishes protected resource metadata.

Connected Apps can also work alongside an application's existing authentication system. Teams can keep their current identity provider while using Stytch for OAuth authorization, making it possible to add agent or third-party access without migrating primary user authentication to Stytch.

Why You Might Choose Stytch

Lets your application act as an OAuth 2.0 and OIDC authorization server for agents and other external clients.
Supports custom scopes tied to application permissions, so clients can receive access based on the capabilities a user is allowed to grant.
Issues signed JWT access tokens that include the scopes granted to the client.
Provides OAuth-based authorization infrastructure for remote MCP servers.
Supports Dynamic Client Registration for MCP clients, with DCR enabled explicitly in the Stytch Dashboard.
Can be used for OAuth authorization alongside an existing user authentication system.

Additional Highlights

Stytch's scope model can connect OAuth permissions to its RBAC system. A user can grant a requested custom scope only when their assigned roles collectively provide the permissions required by that scope, allowing delegated access to remain bounded by the user's own permissions.

The 9 Best AI Agent Auth Solutions (August 2026): Features, Use Cases, and Architectures

Frequently asked questions

What Is AI Agent Authentication?

How Is Agent Authentication Different From User Authentication?

Do AI Agents Need Their Own Identities?

What's the Difference Between Authentication and Authorization for AI Agents?

What Is Delegated Authorization for AI Agents?

What's the Difference Between Inbound and Outbound Agent Auth?

How Does OAuth Work With AI Agents?

How Does MCP Authorization Work?