diff --git a/src/google/adk/tools/application_integration_tool/application_integration_toolset.py b/src/google/adk/tools/application_integration_tool/application_integration_toolset.py
index 027dd7c..b6e0b39 100644
--- a/src/google/adk/tools/application_integration_tool/application_integration_toolset.py
+++ b/src/google/adk/tools/application_integration_tool/application_integration_toolset.py
@@ -12,9 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-from typing import List
-from typing import Optional
-from typing import Union
+import logging
+from typing import List, Optional, Union
 
 from fastapi.openapi.models import HTTPBearer
 from typing_extensions import override
@@ -24,6 +23,7 @@ from ...auth.auth_credential import AuthCredential
 from ...auth.auth_credential import AuthCredentialTypes
 from ...auth.auth_credential import ServiceAccount
 from ...auth.auth_credential import ServiceAccountCredential
+from ...auth.auth_schemes import AuthScheme
 from ..base_toolset import BaseToolset
 from ..base_toolset import ToolPredicate
 from ..openapi_tool.auth.auth_helpers import service_account_scheme_credential
@@ -35,6 +35,9 @@ from .clients.integration_client import IntegrationClient
 from .integration_connector_tool import IntegrationConnectorTool
 
 
+logger = logging.getLogger(__name__)
+
+
 # TODO(cheliu): Apply a common toolset interface
 class ApplicationIntegrationToolset(BaseToolset):
   """ApplicationIntegrationToolset generates tools from a given Application
@@ -93,6 +96,8 @@ class ApplicationIntegrationToolset(BaseToolset):
       # tool/python function description.
       tool_instructions: Optional[str] = "",
       service_account_json: Optional[str] = None,
+      auth_scheme: Optional[AuthScheme] = None,
+      auth_credential: Optional[AuthCredential] = None,
       tool_filter: Optional[Union[ToolPredicate, List[str]]] = None,
   ):
     """Args:
@@ -132,6 +137,8 @@ class ApplicationIntegrationToolset(BaseToolset):
     self._tool_name_prefix = tool_name_prefix
     self._tool_instructions = tool_instructions
     self._service_account_json = service_account_json
+    self._auth_scheme = auth_scheme
+    self._auth_credential = auth_credential
     self.tool_filter = tool_filter
 
     integration_client = IntegrationClient(
@@ -212,6 +219,27 @@ class ApplicationIntegrationToolset(BaseToolset):
         rest_api_tool.configure_auth_scheme(auth_scheme)
       if auth_credential:
         rest_api_tool.configure_auth_credential(auth_credential)
+
+      auth_override_enabled = connection_details.get(
+          "authOverrideEnabled", False
+      )
+
+      if (
+          self._auth_scheme
+          and self._auth_credential
+          and not auth_override_enabled
+      ):
+        # Case: Auth provided, but override is OFF. Don't use provided auth.
+        logger.warning(
+            "Authentication schema and credentials are not used because"
+            " authOverrideEnabled is not enabled in the connection."
+        )
+        connector_auth_scheme = None
+        connector_auth_credential = None
+      else:
+        connector_auth_scheme = self._auth_scheme
+        connector_auth_credential = self._auth_credential
+
       self._tools.append(
           IntegrationConnectorTool(
               name=rest_api_tool.name,
@@ -223,6 +251,8 @@ class ApplicationIntegrationToolset(BaseToolset):
               action=action,
               operation=operation,
               rest_api_tool=rest_api_tool,
+              auth_scheme=connector_auth_scheme,
+              auth_credential=connector_auth_credential,
           )
       )
 
diff --git a/src/google/adk/tools/application_integration_tool/clients/connections_client.py b/src/google/adk/tools/application_integration_tool/clients/connections_client.py
index 3fed5f2..b56b5cf 100644
--- a/src/google/adk/tools/application_integration_tool/clients/connections_client.py
+++ b/src/google/adk/tools/application_integration_tool/clients/connections_client.py
@@ -554,6 +554,9 @@ class ConnectionsClient:
             "serviceName": {"$ref": "#/components/schemas/serviceName"},
             "host": {"$ref": "#/components/schemas/host"},
             "entity": {"$ref": "#/components/schemas/entity"},
+            "dynamicAuthConfig": {
+                "$ref": "#/components/schemas/dynamicAuthConfig"
+            },
         },
     }
 
@@ -580,6 +583,9 @@ class ConnectionsClient:
             "serviceName": {"$ref": "#/components/schemas/serviceName"},
             "host": {"$ref": "#/components/schemas/host"},
             "entity": {"$ref": "#/components/schemas/entity"},
+            "dynamicAuthConfig": {
+                "$ref": "#/components/schemas/dynamicAuthConfig"
+            },
             "filterClause": {"$ref": "#/components/schemas/filterClause"},
         },
     }
@@ -603,6 +609,9 @@ class ConnectionsClient:
             "serviceName": {"$ref": "#/components/schemas/serviceName"},
             "host": {"$ref": "#/components/schemas/host"},
             "entity": {"$ref": "#/components/schemas/entity"},
+            "dynamicAuthConfig": {
+                "$ref": "#/components/schemas/dynamicAuthConfig"
+            },
         },
     }
 
@@ -625,6 +634,9 @@ class ConnectionsClient:
             "serviceName": {"$ref": "#/components/schemas/serviceName"},
             "host": {"$ref": "#/components/schemas/host"},
             "entity": {"$ref": "#/components/schemas/entity"},
+            "dynamicAuthConfig": {
+                "$ref": "#/components/schemas/dynamicAuthConfig"
+            },
             "filterClause": {"$ref": "#/components/schemas/filterClause"},
         },
     }
@@ -649,6 +661,9 @@ class ConnectionsClient:
             "serviceName": {"$ref": "#/components/schemas/serviceName"},
             "host": {"$ref": "#/components/schemas/host"},
             "entity": {"$ref": "#/components/schemas/entity"},
+            "dynamicAuthConfig": {
+                "$ref": "#/components/schemas/dynamicAuthConfig"
+            },
         },
     }
 
@@ -673,6 +688,9 @@ class ConnectionsClient:
             "connectorInputPayload": {
                 "$ref": f"#/components/schemas/connectorInputPayload_{action}"
             },
+            "dynamicAuthConfig": {
+                "$ref": "#/components/schemas/dynamicAuthConfig"
+            },
         },
     }
 
diff --git a/src/google/adk/tools/application_integration_tool/integration_connector_tool.py b/src/google/adk/tools/application_integration_tool/integration_connector_tool.py
index 1a112a4..58ec637 100644
--- a/src/google/adk/tools/application_integration_tool/integration_connector_tool.py
+++ b/src/google/adk/tools/application_integration_tool/integration_connector_tool.py
@@ -12,20 +12,21 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
-
 import logging
-from typing import Any
-from typing import Dict
-from typing import Optional
+from typing import Any, Dict, Optional, Union
 
-from google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool import RestApiTool
-from google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool import to_gemini_schema
 from google.genai.types import FunctionDeclaration
 from typing_extensions import override
 
+from ...auth.auth_credential import AuthCredential
+from ...auth.auth_schemes import AuthScheme
 from .. import BaseTool
+from ..openapi_tool.openapi_spec_parser.rest_api_tool import RestApiTool
+from ..openapi_tool.openapi_spec_parser.rest_api_tool import to_gemini_schema
+from ..openapi_tool.openapi_spec_parser.tool_auth_handler import ToolAuthHandler
 from ..tool_context import ToolContext
 
+
 logger = logging.getLogger(__name__)
 
 
@@ -56,6 +57,7 @@ class IntegrationConnectorTool(BaseTool):
       'entity',
       'operation',
       'action',
+      'dynamic_auth_config',
   ]
 
   OPTIONAL_FIELDS = [
@@ -75,6 +77,8 @@ class IntegrationConnectorTool(BaseTool):
       operation: str,
       action: str,
       rest_api_tool: RestApiTool,
+      auth_scheme: Optional[Union[AuthScheme, str]] = None,
+      auth_credential: Optional[Union[AuthCredential, str]] = None,
   ):
     """Initializes the ApplicationIntegrationTool.
 
@@ -108,6 +112,8 @@ class IntegrationConnectorTool(BaseTool):
     self._operation = operation
     self._action = action
     self._rest_api_tool = rest_api_tool
+    self._auth_scheme = auth_scheme
+    self._auth_credential = auth_credential
 
   @override
   def _get_declaration(self) -> FunctionDeclaration:
@@ -126,10 +132,45 @@ class IntegrationConnectorTool(BaseTool):
     )
     return function_decl
 
+  def _prepare_dynamic_euc(self, auth_credential: AuthCredential) -> str:
+    if (
+        auth_credential
+        and auth_credential.http
+        and auth_credential.http.credentials
+        and auth_credential.http.credentials.token
+    ):
+      return auth_credential.http.credentials.token
+    return None
+
   @override
   async def run_async(
       self, *, args: dict[str, Any], tool_context: Optional[ToolContext]
   ) -> Dict[str, Any]:
+
+    tool_auth_handler = ToolAuthHandler.from_tool_context(
+        tool_context, self._auth_scheme, self._auth_credential
+    )
+    auth_result = tool_auth_handler.prepare_auth_credentials()
+
+    if auth_result.state == 'pending':
+      return {
+          'pending': True,
+          'message': 'Needs your authorization to access your data.',
+      }
+
+    # Attach parameters from auth into main parameters list
+    if auth_result.auth_credential:
+      # Attach parameters from auth into main parameters list
+      auth_credential_token = self._prepare_dynamic_euc(
+          auth_result.auth_credential
+      )
+      if auth_credential_token:
+        args['dynamic_auth_config'] = {
+            'oauth2_auth_code_flow.access_token': auth_credential_token
+        }
+      else:
+        args['dynamic_auth_config'] = {'oauth2_auth_code_flow.access_token': {}}
+
     args['connection_name'] = self._connection_name
     args['service_name'] = self._connection_service_name
     args['host'] = self._connection_host
diff --git a/tests/unittests/tools/application_integration_tool/test_application_integration_toolset.py b/tests/unittests/tools/application_integration_tool/test_application_integration_toolset.py
index 3dc2393..a95e29f 100644
--- a/tests/unittests/tools/application_integration_tool/test_application_integration_toolset.py
+++ b/tests/unittests/tools/application_integration_tool/test_application_integration_toolset.py
@@ -16,9 +16,12 @@ import json
 from unittest import mock
 from fastapi.openapi.models import Operation
 from google.adk.agents.readonly_context import ReadonlyContext
+from google.adk.auth import AuthCredentialTypes
+from google.adk.auth import OAuth2Auth
 from google.adk.auth.auth_credential import AuthCredential
 from google.adk.tools.application_integration_tool.application_integration_toolset import ApplicationIntegrationToolset
 from google.adk.tools.application_integration_tool.integration_connector_tool import IntegrationConnectorTool
+from google.adk.tools.openapi_tool.auth.auth_helpers import dict_to_auth_scheme
 from google.adk.tools.openapi_tool.openapi_spec_parser import ParsedOperation, rest_api_tool
 from google.adk.tools.openapi_tool.openapi_spec_parser.openapi_spec_parser import OperationEndpoint
 import pytest
@@ -162,6 +165,16 @@ def connection_details():
   }
 
 
+@pytest.fixture
+def connection_details_auth_override_enabled():
+  return {
+      "serviceName": "test-service",
+      "host": "test.host",
+      "name": "test-connection",
+      "authOverrideEnabled": True,
+  }
+
+
 @pytest.mark.asyncio
 async def test_initialization_with_integration_and_trigger(
     project,
@@ -474,3 +487,139 @@ def test_initialization_with_connection_details(
   mock_integration_client.return_value.get_openapi_spec_for_connection.assert_called_once_with(
       tool_name, tool_instructions
   )
+
+
+def test_init_with_connection_and_custom_auth(
+    mock_integration_client,
+    mock_connections_client,
+    mock_openapi_action_spec_parser,
+    connection_details_auth_override_enabled,
+):
+  connection_name = "test-connection"
+  actions_list = ["create", "delete"]
+  tool_name = "My Actions Tool"
+  tool_instructions = "Perform actions using this tool."
+  mock_connections_client.return_value.get_connection_details.return_value = (
+      connection_details_auth_override_enabled
+  )
+
+  oauth2_data_google_cloud = {
+      "type": "oauth2",
+      "flows": {
+          "authorizationCode": {
+              "authorizationUrl": "https://test-url/o/oauth2/auth",
+              "tokenUrl": "https://test-url/token",
+              "scopes": {
+                  "https://test-url/auth/test-scope": "test scope",
+                  "https://www.test-url.com/auth/test-scope2": "test scope 2",
+              },
+          }
+      },
+  }
+
+  oauth2_scheme = dict_to_auth_scheme(oauth2_data_google_cloud)
+
+  auth_credential = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id="test-client-id",
+          client_secret="test-client-secret",
+      ),
+  )
+
+  toolset = ApplicationIntegrationToolset(
+      project,
+      location,
+      connection=connection_name,
+      actions=actions_list,
+      tool_name=tool_name,
+      tool_instructions=tool_instructions,
+      auth_scheme=oauth2_scheme,
+      auth_credential=auth_credential,
+  )
+  mock_integration_client.assert_called_once_with(
+      project, location, None, None, connection_name, None, actions_list, None
+  )
+  mock_connections_client.assert_called_once_with(
+      project, location, connection_name, None
+  )
+  mock_connections_client.return_value.get_connection_details.assert_called_once()
+  mock_integration_client.return_value.get_openapi_spec_for_connection.assert_called_once_with(
+      tool_name, tool_instructions
+  )
+  mock_openapi_action_spec_parser.return_value.parse.assert_called_once()
+  assert len(toolset.get_tools()) == 1
+  assert toolset.get_tools()[0].name == "list_issues_operation"
+  assert isinstance(toolset.get_tools()[0], IntegrationConnectorTool)
+  assert toolset.get_tools()[0].action == "CustomAction"
+  assert toolset.get_tools()[0].operation == "EXECUTE_ACTION"
+  assert toolset.get_tools()[0].auth_scheme == oauth2_scheme
+  assert toolset.get_tools()[0].auth_credential == auth_credential
+
+
+def test_init_with_connection_with_auth_override_disabled_and_custom_auth(
+    mock_integration_client,
+    mock_connections_client,
+    mock_openapi_action_spec_parser,
+    connection_details,
+):
+  connection_name = "test-connection"
+  actions_list = ["create", "delete"]
+  tool_name = "My Actions Tool"
+  tool_instructions = "Perform actions using this tool."
+  mock_connections_client.return_value.get_connection_details.return_value = (
+      connection_details
+  )
+
+  oauth2_data_google_cloud = {
+      "type": "oauth2",
+      "flows": {
+          "authorizationCode": {
+              "authorizationUrl": "https://test-url/o/oauth2/auth",
+              "tokenUrl": "https://test-url/token",
+              "scopes": {
+                  "https://test-url/auth/test-scope": "test scope",
+                  "https://www.test-url.com/auth/test-scope2": "test scope 2",
+              },
+          }
+      },
+  }
+
+  oauth2_scheme = dict_to_auth_scheme(oauth2_data_google_cloud)
+
+  auth_credential = AuthCredential(
+      auth_type=AuthCredentialTypes.OAUTH2,
+      oauth2=OAuth2Auth(
+          client_id="test-client-id",
+          client_secret="test-client-secret",
+      ),
+  )
+
+  toolset = ApplicationIntegrationToolset(
+      project,
+      location,
+      connection=connection_name,
+      actions=actions_list,
+      tool_name=tool_name,
+      tool_instructions=tool_instructions,
+      auth_scheme=oauth2_scheme,
+      auth_credential=auth_credential,
+  )
+  mock_integration_client.assert_called_once_with(
+      project, location, None, None, connection_name, None, actions_list, None
+  )
+  mock_connections_client.assert_called_once_with(
+      project, location, connection_name, None
+  )
+  mock_connections_client.return_value.get_connection_details.assert_called_once()
+  mock_integration_client.return_value.get_openapi_spec_for_connection.assert_called_once_with(
+      tool_name, tool_instructions
+  )
+  mock_openapi_action_spec_parser.return_value.parse.assert_called_once()
+  assert len(toolset.get_tools()) == 1
+  assert toolset.get_tools()[0].name == "list_issues_operation"
+  assert isinstance(toolset.get_tools()[0], IntegrationConnectorTool)
+  assert toolset.get_tools()[0].action == "CustomAction"
+  assert toolset.get_tools()[0].operation == "EXECUTE_ACTION"
+  assert not toolset.get_tools()[0].auth_scheme
+  assert not toolset.get_tools()[0].auth_credential
diff --git a/tests/unittests/tools/application_integration_tool/test_integration_connector_tool.py b/tests/unittests/tools/application_integration_tool/test_integration_connector_tool.py
index 93ed4bc..16aef90 100644
--- a/tests/unittests/tools/application_integration_tool/test_integration_connector_tool.py
+++ b/tests/unittests/tools/application_integration_tool/test_integration_connector_tool.py
@@ -14,11 +14,14 @@
 
 from unittest import mock
 
+from google.adk.auth import AuthCredential
+from google.adk.auth import AuthCredentialTypes
+from google.adk.auth.auth_credential import HttpAuth
+from google.adk.auth.auth_credential import HttpCredentials
 from google.adk.tools.application_integration_tool.integration_connector_tool import IntegrationConnectorTool
 from google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool import RestApiTool
 from google.genai.types import FunctionDeclaration
 from google.genai.types import Schema
-from google.genai.types import Tool
 from google.genai.types import Type
 import pytest
 
@@ -67,6 +70,30 @@ def integration_tool(mock_rest_api_tool):
   )
 
 
+@pytest.fixture
+def integration_tool_with_auth(mock_rest_api_tool):
+  """Fixture for an IntegrationConnectorTool instance."""
+  return IntegrationConnectorTool(
+      name="test_integration_tool",
+      description="Test integration tool description.",
+      connection_name="test-conn",
+      connection_host="test.example.com",
+      connection_service_name="test-service",
+      entity="TestEntity",
+      operation="LIST",
+      action="TestAction",
+      rest_api_tool=mock_rest_api_tool,
+      auth_scheme=None,
+      auth_credential=AuthCredential(
+          auth_type=AuthCredentialTypes.HTTP,
+          http=HttpAuth(
+              scheme="bearer",
+              credentials=HttpCredentials(token="mocked_token"),
+          ),
+      ),
+  )
+
+
 def test_get_declaration(integration_tool):
   """Tests the generation of the function declaration."""
   declaration = integration_tool._get_declaration()
@@ -123,3 +150,98 @@ async def test_run_async(integration_tool, mock_rest_api_tool):
 
   # Assert the result is what the mocked call returned
   assert result == {"status": "success", "data": "mock_data"}
+
+
+@pytest.mark.asyncio
+async def test_run_with_auth_async_none_token(
+    integration_tool_with_auth, mock_rest_api_tool
+):
+  """Tests run_async when auth credential token is None."""
+  input_args = {"user_id": "user456", "filter": "some_filter"}
+  expected_call_args = {
+      "user_id": "user456",
+      "filter": "some_filter",
+      "dynamic_auth_config": {"oauth2_auth_code_flow.access_token": {}},
+      "connection_name": "test-conn",
+      "service_name": "test-service",
+      "host": "test.example.com",
+      "entity": "TestEntity",
+      "operation": "LIST",
+      "action": "TestAction",
+  }
+
+  with mock.patch(
+      "google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool.ToolAuthHandler.from_tool_context"
+  ) as mock_from_tool_context:
+    mock_tool_auth_handler_instance = mock.MagicMock()
+    mock_tool_auth_handler_instance.prepare_auth_credentials.return_value.state = (
+        "done"
+    )
+    # Simulate an AuthCredential that would cause _prepare_dynamic_euc to return None
+    mock_auth_credential_without_token = AuthCredential(
+        auth_type=AuthCredentialTypes.HTTP,
+        http=HttpAuth(
+            scheme="bearer",
+            credentials=HttpCredentials(token=None),  # Token is None
+        ),
+    )
+    mock_tool_auth_handler_instance.prepare_auth_credentials.return_value.auth_credential = (
+        mock_auth_credential_without_token
+    )
+    mock_from_tool_context.return_value = mock_tool_auth_handler_instance
+
+    result = await integration_tool_with_auth.run_async(
+        args=input_args, tool_context={}
+    )
+
+    mock_rest_api_tool.call.assert_called_once_with(
+        args=expected_call_args, tool_context={}
+    )
+    assert result == {"status": "success", "data": "mock_data"}
+
+
+@pytest.mark.asyncio
+async def test_run_with_auth_async(
+    integration_tool_with_auth, mock_rest_api_tool
+):
+  """Tests the async execution with auth delegates correctly to the RestApiTool."""
+  input_args = {"user_id": "user123", "page_size": 10}
+  expected_call_args = {
+      "user_id": "user123",
+      "page_size": 10,
+      "dynamic_auth_config": {
+          "oauth2_auth_code_flow.access_token": "mocked_token"
+      },
+      "connection_name": "test-conn",
+      "service_name": "test-service",
+      "host": "test.example.com",
+      "entity": "TestEntity",
+      "operation": "LIST",
+      "action": "TestAction",
+  }
+
+  with mock.patch(
+      "google.adk.tools.openapi_tool.openapi_spec_parser.rest_api_tool.ToolAuthHandler.from_tool_context"
+  ) as mock_from_tool_context:
+    mock_tool_auth_handler_instance = mock.MagicMock()
+    mock_tool_auth_handler_instance.prepare_auth_credentials.return_value.state = (
+        "done"
+    )
+    mock_tool_auth_handler_instance.prepare_auth_credentials.return_value.state = (
+        "done"
+    )
+    mock_tool_auth_handler_instance.prepare_auth_credentials.return_value.auth_credential = AuthCredential(
+        auth_type=AuthCredentialTypes.HTTP,
+        http=HttpAuth(
+            scheme="bearer",
+            credentials=HttpCredentials(token="mocked_token"),
+        ),
+    )
+    mock_from_tool_context.return_value = mock_tool_auth_handler_instance
+    result = await integration_tool_with_auth.run_async(
+        args=input_args, tool_context={}
+    )
+    mock_rest_api_tool.call.assert_called_once_with(
+        args=expected_call_args, tool_context={}
+    )
+    assert result == {"status": "success", "data": "mock_data"}