Auth MCP Servers Compared (2026): Clerk, Auth0 and WorkOS

• Clerk: hosted at https://mcp.clerk.com/mcp, OAuth sign-in with your Clerk account. Tools to list and create apps, read and change instance config (with dry run), list and create users, check domains and DNS, and create a production instance. No org or role tools are listed. Free: Hobby, first 50,000 monthly retained users. Paid: Pro, $20/month billed annually ($25 billed monthly).
• Auth0: local server run with npx @auth0/auth0-mcp-server, signs in with the OAuth 2.0 device flow and keeps tokens in the system keychain. Tools for applications, APIs (resource servers), application grants, Actions, logs and forms. No user, organization or role tools. Free: up to 25,000 monthly active users. Paid: Essentials, from $35/month.
• WorkOS: hosted at https://mcp.workos.com/mcp, OAuth through WorkOS Connect. Four tools (whoami, list_operations, query, mutate) manage organizations, SSO connections, directories, users, audit logs, environments, branding and more. Defaults to sandbox. Free: AuthKit, first 1 million monthly active users. SSO and Directory Sync connections are $125 each for the first 15.
• Supabase: its MCP server has no Auth feature group and no dedicated Auth tools. Firebase: its MCP server has an auth group with auth_get_users, auth_update_user and auth_set_sms_region_policy.
• Clerk counts monthly retained users (users who return 24+ hours after signing up), not monthly active users.
• Prices and free tiers were checked on each vendor's pricing page on 2026-10-23 and change often.

Clerk's MCP server is hosted and uses Streamable HTTP. You sign in with OAuth using your Clerk Dashboard account, pick a workspace and approve the permissions. The server acts as you, so it can only do what your workspace Role allows. No secret key goes in your client config.

claude mcp add clerk --transport http https://mcp.clerk.com/mcp

{
  "mcpServers": {
    "clerk": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://mcp.clerk.com/mcp"]
    }
  }
}

• Main tools: whoami, list_applications, get_application, create_application, get_instance_config, patch_instance_config, put_instance_config, list_users, create_user, list_domains, get_domain_status, check_domain_dns, create_production_instance, set_oauth_provider_credentials.
• SDK help: clerk_sdk_snippet and list_clerk_sdk_snippets return setup code, for example for organizations.
• Safety: tools that make changes are marked, so your client can ask first. Config changes and user creation support a dry run. create_production_instance cannot be undone and needs confirm: true.
• Safety: the server never returns secret keys and redacts sensitive config values. Get keys from the Dashboard or with clerk env pull.
• Gotcha: each tool call sends a short agent-written summary, the tool name and your user ID to Clerk for analytics. Tool inputs and results are not sent.
• Gotcha: to switch workspaces, sign out in your client and reconnect. With mcp-remote, delete ~/.mcp-auth, which signs you out of every server it connects to.

• Clerk MCP server: install for every agent

Auth0's MCP server runs on your machine through npx. The init command opens your browser for the OAuth 2.0 device authorization flow and stores credentials in the system keychain, not in plain text. You need Node.js 18 or higher and an Auth0 account with admin permissions.

npx @auth0/auth0-mcp-server init --client claude-code

{
  "mcpServers": {
    "auth0": {
      "command": "npx",
      "args": ["-y", "@auth0/auth0-mcp-server", "run", "--read-only"]
    }
  }
}

• Main tools: auth0_list_applications, auth0_get_application, auth0_create_application, auth0_update_application, auth0_list_resource_servers, auth0_create_resource_server, auth0_create_application_grant, auth0_list_actions, auth0_create_action, auth0_deploy_action, auth0_list_logs, auth0_get_log, auth0_list_forms, auth0_publish_form.
• There are no tools for users, organizations or roles.
• Limit tools: --tools takes glob patterns, for example --tools 'auth0_list_*,auth0_get_*'. --read-only wins over --tools.
• Env vars: AUTH0_MCP_READ_ONLY=true, AUTH0_MCP_TOOLS, AUTH0_MCP_ANALYTICS=false to opt out of analytics, DEBUG=auth0-mcp for logs. CLI flags take precedence.
• Safety: client_secret and token fields are replaced with [REDACTED]. No scopes are requested by default; you pick them during init.
• Gotcha: run npx @auth0/auth0-mcp-server logout when you finish or switch tenants. Private cloud tenants cannot use the device flow and need client credentials instead.

• Auth0 MCP server: install for every agent

WorkOS runs a hosted management MCP server. Every client connects over Streamable HTTP and signs in with OAuth through WorkOS Connect. It acts as you and has the same roles and permissions as your dashboard login. It works on one team at a time.

claude mcp add --transport http workos https://mcp.workos.com/mcp

• Main tools: whoami, list_operations, query and mutate. The agent finds an operation with list_operations, then runs it by name with query or mutate.
• Covers organizations, connections, directories, users, audit log streams, environments, branding and more. It works in one environment at a time.
• Safety: it starts in a sandbox environment and only works on production when you tell it to. Irreversible deletes, such as an organization, connection or directory, are not run on the first attempt.
• Safety: API keys and client secrets are stripped from responses. Dashboard user impersonation is not exposed. The agent cannot mint or rotate credentials such as API keys, OAuth client secrets and signing certificates, change its own MCP access settings or delete your WorkOS team.
• Admin controls: team admins can turn off Enable, Allow production access or Allow write access (all on by default). With production access off, it only reaches sandbox environments. With write access off, the server is read-only.
• Cursor and other clients use the same URL in their config, for example "url": "https://mcp.workos.com/mcp".

• WorkOS MCP server: install for every agent

• Supabase: the MCP server's feature groups are Database, Debugging, Development, Edge Functions, Account management, Docs, Branching and Storage. There is no Auth group and no dedicated tool to manage Auth users or settings. Supabase Auth's Free plan includes 50,000 monthly active users.
• Firebase: the Firebase MCP server runs locally with the same credentials as the Firebase CLI. Its auth group has auth_get_users (look up or list users), auth_update_user (enable, disable or set custom claims) and auth_set_sms_region_policy. Add it in Claude Code with claude mcp add firebase npx -- -y firebase-tools@latest mcp, and use --only auth to load only auth tools plus core tools.
• Firebase Authentication (with Identity Platform) is free up to 50K monthly active users on both the Spark and Blaze plans.

Remote MCP servers use OAuth. Your server publishes /.well-known/oauth-protected-resource metadata, the auth provider acts as the authorization server, and your server checks the access token on each request. All three vendors document this.

• Clerk: install mcp-handler and @clerk/mcp-tools. Wrap the handler with withMcpAuth and verifyClerkToken, and serve metadata with protectedResourceHandlerClerk. Clerk supports CIMD and DCR; turn on Publish DCR support only for clients that need DCR. The .well-known endpoints must be public. Guides exist for Next.js and Express.
• Auth0: Auth for MCP implements the MCP authorization spec with OAuth 2.1 and OpenID Connect. The quickstart turns on the Resource Parameter Compatibility Profile and promotes connections to domain-level so third-party MCP clients can sign in. Auth0 also offers On-Behalf-Of Token Exchange so your server can call your own APIs for the user.
• WorkOS: AuthKit is a spec-compatible OAuth authorization server. Enable CIMD in the dashboard under Connect, Configuration (DCR can also be turned on for older clients), add your MCP endpoint URL as a Resource Indicator, and verify tokens against https://<authkit_domain>/oauth2/jwks.

npm install mcp-handler @clerk/mcp-tools

• B2B app with organizations, SSO and Directory Sync: WorkOS. Its server manages organizations, connections, directories and users, and starts in a sandbox.
• Agent should set up a new app, change sign-in settings or create test users: Clerk.
• Agent should manage Auth0 applications, APIs, Actions and forms, or read logs: Auth0. Run it with --read-only until you trust it.
• Agent must look up or disable Firebase users: the Firebase MCP server with --only auth.
• Supabase Auth: there is no dedicated auth tool in the Supabase MCP server.
• Securing your own remote MCP server: any of the three; pick the one already running your app's login.
• Details on this page were checked against vendor docs and pricing pages on 2026-10-23.

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