Make additional_headers kwargs

src/google/adk/tools/google_api_tool/google_api_tool.py

@@ -39,6 +39,8 @@ class GoogleApiTool(BaseTool):
       client_id: Optional[str] = None,
       client_secret: Optional[str] = None,
       service_account: Optional[ServiceAccount] = None,
+      *,
+      additional_headers: Optional[Dict[str, str]] = None,
   ):
     super().__init__(
         name=rest_api_tool.name,
@@ -46,9 +48,11 @@ class GoogleApiTool(BaseTool):
         is_long_running=rest_api_tool.is_long_running,
     )
     self._rest_api_tool = rest_api_tool
+    if additional_headers:
+      self._rest_api_tool.set_default_headers(additional_headers)
     if service_account is not None:
       self.configure_sa_auth(service_account)
-    else:
+    elif client_id is not None and client_secret is not None:
       self.configure_auth(client_id, client_secret)
 
   @override
@@ -57,7 +61,7 @@ class GoogleApiTool(BaseTool):
 
   @override
   async def run_async(
-      self, *, args: dict[str, Any], tool_context: Optional[ToolContext]
+      self, *, args: Dict[str, Any], tool_context: Optional[ToolContext]
   ) -> Dict[str, Any]:
     return await self._rest_api_tool.run_async(
         args=args, tool_context=tool_context

src/google/adk/tools/google_api_tool/google_api_toolset.py

@@ -14,6 +14,7 @@
 
 from __future__ import annotations
 
+from typing import Dict
 from typing import List
 from typing import Optional
 from typing import Union
@@ -45,6 +46,8 @@ class GoogleApiToolset(BaseToolset):
     tool_filter: Optional filter to include only specific tools or use a predicate function.
     service_account: Optional service account for authentication.
     tool_name_prefix: Optional prefix to add to all tool names in this toolset.
+    additional_headers: Optional dict of HTTP headers to inject into every request
+      executed by this toolset.
   """
 
   def __init__(
@@ -56,6 +59,8 @@ class GoogleApiToolset(BaseToolset):
       tool_filter: Optional[Union[ToolPredicate, List[str]]] = None,
       service_account: Optional[ServiceAccount] = None,
       tool_name_prefix: Optional[str] = None,
+      *,
+      additional_headers: Optional[Dict[str, str]] = None,
   ):
     super().__init__(tool_filter=tool_filter, tool_name_prefix=tool_name_prefix)
     self.api_name = api_name
@@ -63,6 +68,7 @@ class GoogleApiToolset(BaseToolset):
     self._client_id = client_id
     self._client_secret = client_secret
     self._service_account = service_account
+    self._additional_headers = additional_headers
     self._openapi_toolset = self._load_toolset_with_oidc_auth()
 
   @override
@@ -72,7 +78,11 @@ class GoogleApiToolset(BaseToolset):
     """Get all tools in the toolset."""
     return [
         GoogleApiTool(
-            tool, self._client_id, self._client_secret, self._service_account
+            tool,
+            self._client_id,
+            self._client_secret,
+            self._service_account,
+            additional_headers=self._additional_headers,
         )
         for tool in await self._openapi_toolset.get_tools(readonly_context)
         if self._is_tool_selected(tool, readonly_context)

src/google/adk/tools/openapi_tool/openapi_spec_parser/rest_api_tool.py

@@ -134,6 +134,7 @@ class RestApiTool(BaseTool):
 
     # Private properties
     self.credential_exchanger = AutoAuthCredentialExchanger()
+    self._default_headers: Dict[str, str] = {}
     if should_parse_operation:
       self._operation_parser = OperationParser(self.operation)
 
@@ -216,6 +217,10 @@ class RestApiTool(BaseTool):
       auth_credential = AuthCredential.model_validate_json(auth_credential)
     self.auth_credential = auth_credential
 
+  def set_default_headers(self, headers: Dict[str, str]):
+    """Sets default headers that are merged into every request."""
+    self._default_headers = headers
+
   def _prepare_auth_request_params(
       self,
       auth_scheme: AuthScheme,
@@ -335,6 +340,9 @@ class RestApiTool(BaseTool):
         k: v for k, v in query_params.items() if v is not None
     }
 
+    for key, value in self._default_headers.items():
+      header_params.setdefault(key, value)
+
     request_params: Dict[str, Any] = {
         "method": method,
         "url": url,

tests/unittests/tools/google_api_tool/test_google_api_tool.py

@@ -56,6 +56,14 @@ class TestGoogleApiTool:
     assert tool.is_long_running is False
     assert tool._rest_api_tool == mock_rest_api_tool
 
+  def test_init_with_additional_headers(self, mock_rest_api_tool):
+    """Test GoogleApiTool initialization with additional headers."""
+    headers = {"developer-token": "test-token"}
+
+    GoogleApiTool(mock_rest_api_tool, additional_headers=headers)
+
+    mock_rest_api_tool.set_default_headers.assert_called_once_with(headers)
+
   def test_get_declaration(self, mock_rest_api_tool):
     """Test _get_declaration method."""
     tool = GoogleApiTool(mock_rest_api_tool)

tests/unittests/tools/google_api_tool/test_google_api_toolset.py

@@ -126,12 +126,14 @@ class TestGoogleApiToolset:
 
     client_id = "test_client_id"
     client_secret = "test_client_secret"
+    additional_headers = {"developer-token": "abc123"}
 
     tool_set = GoogleApiToolset(
         api_name=TEST_API_NAME,
         api_version=TEST_API_VERSION,
         client_id=client_id,
         client_secret=client_secret,
+        additional_headers=additional_headers,
     )
 
     assert tool_set.api_name == TEST_API_NAME
@@ -141,6 +143,7 @@ class TestGoogleApiToolset:
     assert tool_set._service_account is None
     assert tool_set.tool_filter is None
     assert tool_set._openapi_toolset == mock_openapi_toolset_instance
+    assert tool_set._additional_headers == additional_headers
 
     mock_converter_class.assert_called_once_with(
         TEST_API_NAME, TEST_API_VERSION
@@ -191,6 +194,7 @@ class TestGoogleApiToolset:
     client_id = "cid"
     client_secret = "csecret"
     sa_mock = mock.MagicMock(spec=ServiceAccount)
+    additional_headers = {"developer-token": "token"}
 
     tool_set = GoogleApiToolset(
         api_name=TEST_API_NAME,
@@ -198,6 +202,7 @@ class TestGoogleApiToolset:
         client_id=client_id,
         client_secret=client_secret,
         service_account=sa_mock,
+        additional_headers=additional_headers,
     )
 
     tools = await tool_set.get_tools(mock_readonly_context)
@@ -209,7 +214,11 @@ class TestGoogleApiToolset:
 
     for i, rest_tool in enumerate(mock_rest_api_tools):
       mock_google_api_tool_class.assert_any_call(
-          rest_tool, client_id, client_secret, sa_mock
+          rest_tool,
+          client_id,
+          client_secret,
+          sa_mock,
+          additional_headers=additional_headers,
       )
       assert tools[i] is mock_google_api_tool_instances[i]
 

tests/unittests/tools/openapi_tool/openapi_spec_parser/test_rest_api_tool.py

@@ -686,6 +686,65 @@ class TestRestApiTool:
     # Make sure unknown parameters are ignored and do not raise errors.
     assert "unknown_param" not in request_params["params"]
 
+  def test_prepare_request_params_merges_default_headers(
+      self,
+      sample_endpoint,
+      sample_auth_credential,
+      sample_auth_scheme,
+      sample_operation,
+  ):
+    tool = RestApiTool(
+        name="test_tool",
+        description="Test Tool",
+        endpoint=sample_endpoint,
+        operation=sample_operation,
+        auth_credential=sample_auth_credential,
+        auth_scheme=sample_auth_scheme,
+    )
+    tool.set_default_headers({"developer-token": "token"})
+
+    request_params = tool._prepare_request_params([], {})
+
+    assert request_params["headers"]["developer-token"] == "token"
+
+  def test_prepare_request_params_preserves_existing_headers(
+      self,
+      sample_endpoint,
+      sample_auth_credential,
+      sample_auth_scheme,
+      sample_operation,
+      sample_api_parameters,
+  ):
+    tool = RestApiTool(
+        name="test_tool",
+        description="Test Tool",
+        endpoint=sample_endpoint,
+        operation=sample_operation,
+        auth_credential=sample_auth_credential,
+        auth_scheme=sample_auth_scheme,
+    )
+    tool.set_default_headers({
+        "Content-Type": "text/plain",
+        "developer-token": "token",
+        "User-Agent": "custom-default",
+    })
+
+    header_param = ApiParameter(
+        original_name="User-Agent",
+        py_name="user_agent",
+        param_location="header",
+        param_schema=OpenAPISchema(type="string"),
+    )
+
+    params = sample_api_parameters + [header_param]
+    kwargs = {"test_body_param": "value", "user_agent": "api-client"}
+
+    request_params = tool._prepare_request_params(params, kwargs)
+
+    assert request_params["headers"]["Content-Type"] == "application/json"
+    assert request_params["headers"]["developer-token"] == "token"
+    assert request_params["headers"]["User-Agent"] == "api-client"
+
   def test_prepare_request_params_base_url_handling(
       self, sample_auth_credential, sample_auth_scheme, sample_operation
   ):