Allow authorization consent screen to be disabled (#2172)

* Add optional authorization consent screen for OAuth providers

Adds `require_authorization_consent` parameter (default True) to OAuthProxy and all providers. When disabled, authorization skips the consent screen for local development/testing. Logs security warning when disabled.

* Update warning message to use 'authorization consent screen'

docs/servers/auth/oauth-proxy.mdx

@@ -282,6 +282,28 @@ auth = OAuthProxy(
 
   See [HTTP Deployment - OAuth Token Security](/deployment/http#oauth-token-security).
 </ParamField>
+
+<ParamField body="require_authorization_consent" type="bool" default="True">
+  Whether to require user consent before authorizing MCP clients. When enabled (default), users see a consent screen that displays which client is requesting access, preventing [confused deputy attacks](https://modelcontextprotocol.io/specification/2025-06-18/basic/security_best_practices#confused-deputy-problem) by ensuring users explicitly approve new clients.
+
+  **Default behavior (True):**
+  Users see a consent screen on first authorization. Consent choices are remembered via signed cookies, so users only need to approve each client once. This protects against malicious clients impersonating the user.
+
+  **Disabling consent (False):**
+  Authorization proceeds directly to the upstream provider without user confirmation. Only use this for local development or testing environments where the security trade-off is acceptable.
+
+  ```python
+  # Development/testing only - skip consent screen
+  auth = OAuthProxy(
+      ...,
+      require_authorization_consent=False  # ⚠️ Security warning: only for local/testing
+  )
+  ```
+
+  <Warning>
+    Disabling consent removes an important security layer. Only disable for local development or testing environments where you fully control all connecting clients.
+  </Warning>
+</ParamField>
 </Card>
 
 ### Using Built-in Providers

src/fastmcp/server/auth/oauth_proxy.py

@@ -562,6 +562,8 @@ class OAuthProxy(OAuthProvider):
         jwt_signing_key: str | bytes | None = None,
         # Token encryption key (optional, ephemeral if not provided)
         token_encryption_key: str | bytes | None = None,
+        # Consent screen configuration
+        require_authorization_consent: bool = True,
     ):
         """Initialize the OAuth proxy provider.
 
@@ -602,6 +604,10 @@ class OAuthProxy(OAuthProvider):
             token_encryption_key: Optional secret for encrypting upstream tokens at rest (accepts any string or bytes).
                 Default: ephemeral (random salt at startup, won't survive restart).
                 Production: provide explicit key from environment variable.
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to the upstream IdP.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
         # Always enable DCR since we implement it locally for MCP clients
         client_registration_options = ClientRegistrationOptions(
@@ -655,6 +661,14 @@ class OAuthProxy(OAuthProvider):
         # Token endpoint authentication
         self._token_endpoint_auth_method = token_endpoint_auth_method
 
+        # Consent screen configuration
+        self._require_authorization_consent = require_authorization_consent
+        if not require_authorization_consent:
+            logger.warning(
+                "Authorization consent screen disabled - only use for local development or testing. "
+                "In production, this screen protects against confused deputy attacks."
+            )
+
         # Extra parameters for authorization and token endpoints
         self._extra_authorize_params = extra_authorize_params or {}
         self._extra_token_params = extra_token_params or {}
@@ -915,6 +929,9 @@ class OAuthProxy(OAuthProvider):
         1. Store transaction with client details and PKCE (if forwarding)
         2. Return local /consent URL; browser visits consent first
         3. Consent handler redirects to upstream IdP if approved/already approved
+
+        If consent is disabled (require_authorization_consent=False), skip the consent screen
+        and redirect directly to the upstream IdP.
         """
         # Generate transaction ID for this authorization request
         txn_id = secrets.token_urlsafe(32)
@@ -930,23 +947,37 @@ class OAuthProxy(OAuthProvider):
             )
 
         # Store transaction data for IdP callback processing
+        transaction = OAuthTransaction(
+            txn_id=txn_id,
+            client_id=client.client_id,
+            client_redirect_uri=str(params.redirect_uri),
+            client_state=params.state or "",
+            code_challenge=params.code_challenge,
+            code_challenge_method=getattr(params, "code_challenge_method", "S256"),
+            scopes=params.scopes or [],
+            created_at=time.time(),
+            resource=getattr(params, "resource", None),
+            proxy_code_verifier=proxy_code_verifier,
+        )
         await self._transaction_store.put(
             key=txn_id,
-            value=OAuthTransaction(
-                txn_id=txn_id,
-                client_id=client.client_id,
-                client_redirect_uri=str(params.redirect_uri),
-                client_state=params.state or "",
-                code_challenge=params.code_challenge,
-                code_challenge_method=getattr(params, "code_challenge_method", "S256"),
-                scopes=params.scopes or [],
-                created_at=time.time(),
-                resource=getattr(params, "resource", None),
-                proxy_code_verifier=proxy_code_verifier,
-            ),
+            value=transaction,
             ttl=15 * 60,  # Auto-expire after 15 minutes
         )
 
+        # If consent is disabled, skip consent screen and go directly to upstream IdP
+        if not self._require_authorization_consent:
+            upstream_url = self._build_upstream_authorize_url(
+                txn_id, transaction.model_dump()
+            )
+            logger.debug(
+                "Starting OAuth transaction %s for client %s, redirecting directly to upstream IdP (consent disabled, PKCE forwarding: %s)",
+                txn_id,
+                client.client_id,
+                "enabled" if proxy_code_challenge else "disabled",
+            )
+            return upstream_url
+
         consent_url = f"{str(self.base_url).rstrip('/')}/consent?txn_id={txn_id}"
 
         logger.debug(

src/fastmcp/server/auth/oidc_proxy.py

@@ -217,6 +217,8 @@ class OIDCProxy(OAuthProxy):
         client_storage: AsyncKeyValue | None = None,
         # Token validation configuration
         token_endpoint_auth_method: str | None = None,
+        # Consent screen configuration
+        require_authorization_consent: bool = True,
     ) -> None:
         """Initialize the OIDC proxy provider.
 
@@ -242,6 +244,10 @@ class OIDCProxy(OAuthProxy):
             token_endpoint_auth_method: Token endpoint authentication method for upstream server.
                 Common values: "client_secret_basic", "client_secret_post", "none".
                 If None, authlib will use its default (typically "client_secret_basic").
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to the upstream IdP.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
         if not config_url:
             raise ValueError("Missing required config URL")
@@ -296,6 +302,7 @@ class OIDCProxy(OAuthProxy):
             "allowed_client_redirect_uris": allowed_client_redirect_uris,
             "client_storage": client_storage,
             "token_endpoint_auth_method": token_endpoint_auth_method,
+            "require_authorization_consent": require_authorization_consent,
         }
 
         if redirect_path:

src/fastmcp/server/auth/providers/auth0.py

@@ -96,6 +96,7 @@ class Auth0Provider(OIDCProxy):
         redirect_path: str | NotSetT = NotSet,
         allowed_client_redirect_uris: list[str] | NotSetT = NotSet,
         client_storage: AsyncKeyValue | None = None,
+        require_authorization_consent: bool = True,
     ) -> None:
         """Initialize Auth0 OAuth provider.
 
@@ -112,6 +113,10 @@ class Auth0Provider(OIDCProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
                 If None (default), all URIs are allowed. If empty list, no URIs are allowed.
             client_storage: An AsyncKeyValue-compatible store for client registrations, registrations are stored in memory if not provided
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to Auth0.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
         settings = Auth0ProviderSettings.model_validate(
             {
@@ -169,6 +174,7 @@ class Auth0Provider(OIDCProxy):
             "required_scopes": auth0_required_scopes,
             "allowed_client_redirect_uris": settings.allowed_client_redirect_uris,
             "client_storage": client_storage,
+            "require_authorization_consent": require_authorization_consent,
         }
 
         super().__init__(**init_kwargs)

src/fastmcp/server/auth/providers/aws.py

@@ -135,6 +135,7 @@ class AWSCognitoProvider(OIDCProxy):
         required_scopes: list[str] | NotSetT = NotSet,
         allowed_client_redirect_uris: list[str] | NotSetT = NotSet,
         client_storage: AsyncKeyValue | None = None,
+        require_authorization_consent: bool = True,
     ):
         """Initialize AWS Cognito OAuth provider.
 
@@ -151,6 +152,10 @@ class AWSCognitoProvider(OIDCProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
                 If None (default), all URIs are allowed. If empty list, no URIs are allowed.
             client_storage: An AsyncKeyValue-compatible store for client registrations, registrations are stored in memory if not provided
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to AWS Cognito.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
 
         settings = AWSCognitoProviderSettings.model_validate(
@@ -215,6 +220,7 @@ class AWSCognitoProvider(OIDCProxy):
             redirect_path=redirect_path_final,
             allowed_client_redirect_uris=allowed_client_redirect_uris_final,
             client_storage=client_storage,
+            require_authorization_consent=require_authorization_consent,
         )
 
         logger.debug(

src/fastmcp/server/auth/providers/azure.py

@@ -109,6 +109,7 @@ class AzureProvider(OAuthProxy):
         additional_authorize_scopes: list[str] | None | NotSetT = NotSet,
         allowed_client_redirect_uris: list[str] | NotSetT = NotSet,
         client_storage: AsyncKeyValue | None = None,
+        require_authorization_consent: bool = True,
     ) -> None:
         """Initialize Azure OAuth provider.
 
@@ -131,6 +132,10 @@ class AzureProvider(OAuthProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
                 If None (default), all URIs are allowed. If empty list, no URIs are allowed.
             client_storage: An AsyncKeyValue-compatible store for client registrations, registrations are stored in memory if not provided
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to Azure.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
         settings = AzureProviderSettings.model_validate(
             {
@@ -216,6 +221,7 @@ class AzureProvider(OAuthProxy):
             or settings.base_url,  # Default to base_url if not specified
             allowed_client_redirect_uris=settings.allowed_client_redirect_uris,
             client_storage=client_storage,
+            require_authorization_consent=require_authorization_consent,
         )
 
         logger.info(

src/fastmcp/server/auth/providers/github.py

@@ -206,6 +206,7 @@ class GitHubProvider(OAuthProxy):
         timeout_seconds: int | NotSetT = NotSet,
         allowed_client_redirect_uris: list[str] | NotSetT = NotSet,
         client_storage: AsyncKeyValue | None = None,
+        require_authorization_consent: bool = True,
     ):
         """Initialize GitHub OAuth provider.
 
@@ -221,6 +222,10 @@ class GitHubProvider(OAuthProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
                 If None (default), all URIs are allowed. If empty list, no URIs are allowed.
             client_storage: An AsyncKeyValue-compatible store for client registrations, registrations are stored in memory if not provided
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to GitHub.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
 
         settings = GitHubProviderSettings.model_validate(
@@ -280,6 +285,7 @@ class GitHubProvider(OAuthProxy):
             or settings.base_url,  # Default to base_url if not specified
             allowed_client_redirect_uris=allowed_client_redirect_uris_final,
             client_storage=client_storage,
+            require_authorization_consent=require_authorization_consent,
         )
 
         logger.debug(

src/fastmcp/server/auth/providers/google.py

@@ -222,6 +222,7 @@ class GoogleProvider(OAuthProxy):
         timeout_seconds: int | NotSetT = NotSet,
         allowed_client_redirect_uris: list[str] | NotSetT = NotSet,
         client_storage: AsyncKeyValue | None = None,
+        require_authorization_consent: bool = True,
     ):
         """Initialize Google OAuth provider.
 
@@ -240,6 +241,10 @@ class GoogleProvider(OAuthProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
                 If None (default), all URIs are allowed. If empty list, no URIs are allowed.
             client_storage: An AsyncKeyValue-compatible store for client registrations, registrations are stored in memory if not provided
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to Google.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
 
         settings = GoogleProviderSettings.model_validate(
@@ -299,6 +304,7 @@ class GoogleProvider(OAuthProxy):
             or settings.base_url,  # Default to base_url if not specified
             allowed_client_redirect_uris=allowed_client_redirect_uris_final,
             client_storage=client_storage,
+            require_authorization_consent=require_authorization_consent,
         )
 
         logger.debug(

src/fastmcp/server/auth/providers/workos.py

@@ -172,6 +172,7 @@ class WorkOSProvider(OAuthProxy):
         timeout_seconds: int | NotSetT = NotSet,
         allowed_client_redirect_uris: list[str] | NotSetT = NotSet,
         client_storage: AsyncKeyValue | None = None,
+        require_authorization_consent: bool = True,
     ):
         """Initialize WorkOS OAuth provider.
 
@@ -188,6 +189,10 @@ class WorkOSProvider(OAuthProxy):
             allowed_client_redirect_uris: List of allowed redirect URI patterns for MCP clients.
                 If None (default), all URIs are allowed. If empty list, no URIs are allowed.
             client_storage: An AsyncKeyValue-compatible store for client registrations, registrations are stored in memory if not provided
+            require_authorization_consent: Whether to require user consent before authorizing clients (default True).
+                When True, users see a consent screen before being redirected to WorkOS.
+                When False, authorization proceeds directly without user confirmation.
+                SECURITY WARNING: Only disable for local development or testing environments.
         """
 
         settings = WorkOSProviderSettings.model_validate(
@@ -256,6 +261,7 @@ class WorkOSProvider(OAuthProxy):
             or settings.base_url,  # Default to base_url if not specified
             allowed_client_redirect_uris=allowed_client_redirect_uris_final,
             client_storage=client_storage,
+            require_authorization_consent=require_authorization_consent,
         )
 
         logger.debug(