Copy page

Authentication

Configuring Okta (or any OIDC provider)

The mcp-oauth-inbound policy lets the MCP Gateway delegate browser login to any OIDC-compatible identity provider. Where the Auth0 wrapper derives all the URLs from a single domain, the generic policy requires you to provide the OIDC URLs explicitly.

This guide uses Okta as the concrete example, but the same pattern applies to Microsoft Entra ID, Keycloak, Ory Hydra, Authentik, Google Workspace, or any other IdP that exposes RFC 8414 authorization-server metadata or OpenID Connect Discovery.

Read the authentication overview for the two-layer model and the role each policy plays before starting.

What the gateway needs from your IdP

The gateway needs three pieces of information about your IdP:

1. The OIDC issuer URL — the value of iss in ID tokens.
2. The JWKS URL — where the gateway fetches the IdP's public keys to verify ID tokens.
3. The authorize URL — where the gateway redirects the user's browser to log in.

For most IdPs you also need a token URL, a client ID, and a client secret so the gateway can complete the authorization-code exchange after browser login. The options reference lists every field.

Set up Okta

The MCP Gateway acts as an OAuth 2.1 authorization server in front of Okta. Okta handles browser login and identity; the gateway issues its own access tokens bound to MCP routes. The Okta application you create represents the gateway's identity against Okta, not the MCP client.

Create an OIDC application

1. In the Okta Admin Console, open Applications > Applications and click Create App Integration.
2. Choose OIDC - OpenID Connect as the sign-in method.
3. Choose Web Application as the application type and click Next.
4. Give the integration a name (for example, Zuplo MCP Gateway).
5. Under Grant types, leave Authorization Code checked. Refresh token isn't needed by the gateway here because the gateway uses Okta only for browser identity, not as a long-running token source.
6. Set Sign-in redirect URIs to your gateway's https://<gateway-host>/oauth/callback. Add http://localhost:9000/oauth/callback for local development.
7. Click Save.

Note the Client ID and Client Secret from the application's General tab. You'll wire these into the policy in the next section.

Find the OIDC URLs

From the Okta Admin Console, navigate to Security > API and pick the authorization server you want to use (the default one works for most setups; a custom authorization server gives you more control over scopes and audiences).

The authorization server's metadata page shows an Issuer URI and a Metadata URI. The issuer URI is what you pass as oidc.issuer. Fetch the metadata URI in a browser ({issuer}/.well-known/oauth-authorization-server or {issuer}/.well-known/openid-configuration) to find:

• jwks_uri — pass this as oidc.jwksUrl.
• authorization_endpoint — pass this as browserLogin.url.
• token_endpoint — pass this as browserLogin.tokenUrl.

For the Okta default authorization server, the URLs look like:

Code
Issuer:        https://your-org.okta.com/oauth2/default
JWKS:          https://your-org.okta.com/oauth2/default/v1/keys
Authorize:     https://your-org.okta.com/oauth2/default/v1/authorize
Token:         https://your-org.okta.com/oauth2/default/v1/token

Wire the policy into the gateway

Add the policy to config/policies.json:

Code
{
  "name": "okta-managed-oauth",
  "policyType": "mcp-oauth-inbound",
  "handler": {
    "module": "$import(@zuplo/runtime/mcp-gateway)",
    "export": "McpOAuthInboundPolicy",
    "options": {
      "oidc": {
        "issuer": "https://your-org.okta.com/oauth2/default",
        "jwksUrl": "https://your-org.okta.com/oauth2/default/v1/keys"
      },
      "browserLogin": {
        "url": "https://your-org.okta.com/oauth2/default/v1/authorize",
        "tokenUrl": "https://your-org.okta.com/oauth2/default/v1/token",
        "clientId": "$env(OKTA_CLIENT_ID)",
        "clientSecret": "$env(OKTA_CLIENT_SECRET)"
      }
    }
  }
}

Set OKTA_CLIENT_ID and OKTA_CLIENT_SECRET in your project's environment configuration (the secret goes in the secret store).

Attach the policy to each MCP route in config/routes.oas.json:

Code
{
  "paths": {
    "/mcp/linear": {
      "get,post": {
        "operationId": "linear-mcp-server",
        "x-zuplo-route": {
          "corsPolicy": "none",
          "handler": {
            "module": "$import(@zuplo/runtime/mcp-gateway)",
            "export": "McpProxyHandler",
            "options": {
              "rewritePattern": "https://mcp.linear.app/mcp",
            },
          },
          "policies": {
            "inbound": ["okta-managed-oauth", "mcp-token-exchange-linear"],
          },
        },
      },
    },
  },
}

Register the gateway plugin in modules/zuplo.runtime.ts:

Code
import { RuntimeExtensions } from "@zuplo/runtime";
import { McpGatewayPlugin } from "@zuplo/runtime/mcp-gateway";

export function runtimeInit(runtime: RuntimeExtensions) {
  runtime.addPlugin(new McpGatewayPlugin());
}

One MCP OAuth policy serves every MCP route in the project. The gateway rejects projects that declare more than one MCP OAuth policy.

Local development shortcut

For local development without round-tripping a real IdP, set browserLogin.url to the loopback dev-login endpoint:

Code
{
  "options": {
    "oidc": {
      "issuer": "http://localhost:9000/",
      "jwksUrl": "http://localhost:9000/dev/jwks"
    },
    "browserLogin": {
      "url": "http://127.0.0.1:9000/oauth/dev-login"
    }
  }
}

When the gateway sees a loopback browserLogin.url pointing at /oauth/dev-login, it skips tokenUrl, clientId, and clientSecret and synthesizes a dev-browser-user subject. The endpoint is only served on loopback origins; production deployments cannot reach it.

See the local development guide for the rest of the local setup.

Full options reference

mcp-oauth-inbound has two required option groups: oidc and browserLogin. The complete schema is documented on the policy reference page; the fields you'll touch most often are:

Option	Required	Default	Notes
oidc.issuer	yes	—	The OIDC issuer URL. Must include the scheme.
oidc.jwksUrl	yes	—	JWKS endpoint that publishes the IdP's signing keys.
oidc.audience	no	unset	Optional ID-token audience override. Leave unset when ID tokens use the OIDC client_id as their audience.
browserLogin.url	yes	—	The IdP's /authorize endpoint. The loopback /oauth/dev-login shortcut works for local dev.
browserLogin.tokenUrl	for federated OIDC	—	The IdP's token endpoint. Required for the federated authorization-code exchange.
browserLogin.clientId	for federated OIDC	—	OIDC client_id registered with the IdP.
browserLogin.clientSecret	for federated OIDC	—	OIDC client_secret. Use $env(...).
browserLogin.scope	no	openid profile email	OIDC scopes requested during browser login.
browserLogin.audience	no	unset	Optional audience parameter for Auth0-style API audiences.
browserLogin.remoteTimeoutMs	no	10000	Outbound timeout for IdP calls.
browserLogin.stateTtlSeconds	no	900	Browser-login state record lifetime.
browserLogin.sessionTtlSeconds	no	28800	Browser session cookie lifetime (8 hours).
gateway.accessTokenTtlSeconds	no	900	Gateway-issued access token lifetime.
gateway.refreshTokenTtlSeconds	no	~10 years (runtime)	Gateway-issued refresh token lifetime.
gateway.cimdEnabled	no	true	Advertise CIMD support in AS metadata.

Notes for specific providers

• Microsoft Entra ID. The issuer is https://login.microsoftonline.com/{tenant}/v2.0; the metadata document lives at {issuer}/.well-known/openid-configuration. Use the v2 endpoints.
• Keycloak. The issuer is https://<keycloak-host>/realms/<realm>; the metadata document lives at {issuer}/.well-known/openid-configuration.
• Ory Hydra. Discovery lives at {issuer}/.well-known/openid-configuration; set the issuer to the public-facing Hydra URL.
• Google Workspace. Use https://accounts.google.com as the issuer; metadata is at https://accounts.google.com/.well-known/openid-configuration.

In all cases, the gateway only needs the four URL fields (issuer, JWKS, authorize, token) plus a client ID and secret. Discovery is performed once at startup and the JWKS is cached per the IdP's cache directives.

Test the configuration

The fastest sanity check is to try connecting an MCP client:

1. Open Claude Desktop, Cursor, Claude Code, or another OAuth-aware MCP client.
2. Add a remote MCP server pointing at one of your /mcp/{slug} routes on the gateway.
3. The client should redirect you to your IdP's login page. After login, the gateway's consent screen renders. Approve it.
4. The client receives an access token and can call tools/list.

If something fails partway through, walk the flow manually using the manual OAuth testing guide — it exercises every endpoint with curl so you can see the raw responses.

Common issues

• The gateway returns 500 at boot. A required option is missing or invalid. Check the runtime logs for the configuration error — the policy fails on the first request with a ConfigurationError that names the broken field.
• ID token verification fails. The oidc.jwksUrl doesn't match the IdP's actual JWKS endpoint, or the IdP rotated keys and the JWKS cache is stale. Restart the gateway to clear the cache.
• invalid_audience from the gateway's token endpoint. The MCP client is reusing a token bound to a different route. Each gateway-issued token binds to one operationId.
• MCP client can't discover the AS. Confirm the mcp-oauth-inbound policy is attached to the route in routes.oas.json and the McpGatewayPlugin is registered in modules/zuplo.runtime.ts. The internal OAuth endpoints register only when both are present.
• Browser login redirects but the callback fails. The https://<gateway-host>/oauth/callback URL isn't on the application's redirect URI allow-list at the IdP.

Related

• Authentication overview
• mcp-oauth-inbound policy reference
• Configuring Auth0
• Per-user OAuth to upstream MCP servers