feat(models): Add configuration options to Gemini class

Allows passing enterprise, vertexai, api_key, credentials, project, and location directly to the Gemini class constructor, avoiding the need for environment variables or subclassing.

These parameters are passed through to the underlying google.genai.Client.

Imported from GitHub PR google#3813 (with modifications to support 'enterprise' parameter and preserve auto-detection).

Merges google#3813

Co-authored-by: Shangjie Chen <deanchen@google.com>
PiperOrigin-RevId: 934084452

Author: DeanChensj

src/google/adk/models/google_llm.py

@@ -31,6 +31,7 @@
 
 from google.genai import types
 from google.genai.errors import ClientError
+from pydantic import Field
 from typing_extensions import override
 
 from ..utils._google_client_headers import get_tracking_headers
@@ -114,6 +115,11 @@ def api_client(self) -> Client:
 
   model: str = 'gemini-2.5-flash'
 
+  client_kwargs: Optional[dict[str, Any]] = Field(
+      default=None, exclude=True, repr=False
+  )
+  """Extra arguments to pass to the google.genai.Client constructor."""
+
   base_url: Optional[str] = None
   """The base URL for the AI platform service endpoint."""
 
@@ -349,6 +355,9 @@ def api_client(self) -> Client:
     if self.model.startswith('projects/'):
       kwargs['enterprise'] = True
 
+    if self.client_kwargs:
+      kwargs.update(self.client_kwargs)
+
     return Client(**kwargs)
 
   @cached_property
@@ -394,6 +403,9 @@ def _live_api_client(self) -> Client:
     if self.model.startswith('projects/'):
       kwargs['enterprise'] = True
 
+    if self.client_kwargs:
+      kwargs.update(self.client_kwargs)
+
     return Client(**kwargs)
 
   @contextlib.asynccontextmanager

tests/unittests/models/test_google_llm.py

@@ -182,6 +182,65 @@ def test_gemini_live_api_client_creation_with_projects_prefix():
     assert kwargs["enterprise"] is True
 
 
+def test_gemini_api_client_creation_with_client_kwargs():
+  mock_credentials = mock.MagicMock()
+  model = Gemini(
+      model="gemini-2.5-flash",
+      client_kwargs={
+          "enterprise": True,
+          "project": "my-project",
+          "location": "my-location",
+          "api_key": "my-key",
+          "credentials": mock_credentials,
+      },
+  )
+  with mock.patch("google.genai.Client", autospec=True) as mock_client:
+    _ = model.api_client
+    mock_client.assert_called_once()
+    _, kwargs = mock_client.call_args
+    assert kwargs["enterprise"] is True
+    assert kwargs["project"] == "my-project"
+    assert kwargs["location"] == "my-location"
+    assert kwargs["api_key"] == "my-key"
+    assert kwargs["credentials"] == mock_credentials
+
+  with mock.patch("google.genai.Client", autospec=True) as mock_client:
+    _ = model._live_api_client
+    mock_client.assert_called_once()
+    _, kwargs = mock_client.call_args
+    assert kwargs["enterprise"] is True
+    assert kwargs["project"] == "my-project"
+    assert kwargs["location"] == "my-location"
+    assert kwargs["api_key"] == "my-key"
+    assert kwargs["credentials"] == mock_credentials
+
+
+def test_gemini_serialization_excludes_client_kwargs():
+  mock_credentials = mock.MagicMock()
+  model = Gemini(
+      model="gemini-2.5-flash",
+      client_kwargs={
+          "enterprise": True,
+          "credentials": mock_credentials,
+      },
+  )
+  dumped = model.model_dump()
+  assert "client_kwargs" not in dumped
+
+
+def test_gemini_repr_excludes_client_kwargs():
+  mock_credentials = mock.MagicMock()
+  model = Gemini(
+      model="gemini-2.5-flash",
+      client_kwargs={
+          "enterprise": True,
+          "credentials": mock_credentials,
+      },
+  )
+  repr_str = repr(model)
+  assert "client_kwargs" not in repr_str
+
+
 def test_client_version_header():
   model = Gemini(model="gemini-2.5-flash")
   client = model.api_client