feat: add optional per-agent Vertex AI project and location configuration

src/google/adk/models/anthropic_llm.py

@@ -244,9 +244,13 @@ class Claude(BaseLlm):
 
   Attributes:
     model: The name of the Claude model.
+    project_id: Optional Google Cloud project ID. If not provided, uses GOOGLE_CLOUD_PROJECT environment variable.
+    location: Optional Google Cloud location. If not provided, uses GOOGLE_CLOUD_LOCATION environment variable.
   """
 
   model: str = "claude-3-5-sonnet-v2@20241022"
+  project_id: Optional[str] = None
+  location: Optional[str] = None
 
   @staticmethod
   @override
@@ -289,16 +293,16 @@ async def generate_content_async(
 
   @cached_property
   def _anthropic_client(self) -> AnthropicVertex:
-    if (
-        "GOOGLE_CLOUD_PROJECT" not in os.environ
-        or "GOOGLE_CLOUD_LOCATION" not in os.environ
-    ):
+    project = self.project_id or os.environ.get("GOOGLE_CLOUD_PROJECT")
+    location = self.location or os.environ.get("GOOGLE_CLOUD_LOCATION")
+
+    if not project or not location:
       raise ValueError(
           "GOOGLE_CLOUD_PROJECT and GOOGLE_CLOUD_LOCATION must be set for using"
           " Anthropic on Vertex."
       )
 
     return AnthropicVertex(
-        project_id=os.environ["GOOGLE_CLOUD_PROJECT"],
-        region=os.environ["GOOGLE_CLOUD_LOCATION"],
+        project_id=project,
+        region=location,
     )

src/google/adk/models/google_llm.py

@@ -22,6 +22,7 @@
 import sys
 from typing import AsyncGenerator
 from typing import cast
+from typing import Optional
 from typing import TYPE_CHECKING
 from typing import Union
 
@@ -53,9 +54,14 @@ class Gemini(BaseLlm):
 
   Attributes:
     model: The name of the Gemini model.
+    project_id: Optional Google Cloud project ID. If not provided, uses GOOGLE_CLOUD_PROJECT environment variable.
+    location: Optional Google Cloud location. If not provided, uses GOOGLE_CLOUD_LOCATION environment variable.
+
   """
 
   model: str = 'gemini-1.5-flash'
+  project_id: Optional[str] = None
+  location: Optional[str] = None
 
   @staticmethod
   @override
@@ -184,14 +190,22 @@ async def generate_content_async(
 
   @cached_property
   def api_client(self) -> Client:
-    """Provides the api client.
+    """Provides the api client with per-instance configuration support.
 
     Returns:
       The api client.
     """
-    return Client(
-        http_options=types.HttpOptions(headers=self._tracking_headers)
-    )
+    if self.project_id or self.location:
+      return Client(
+          vertexai=True,
+          project=self.project_id,
+          location=self.location,
+          http_options=types.HttpOptions(headers=self._tracking_headers),
+      )
+    else:
+      return Client(
+          http_options=types.HttpOptions(headers=self._tracking_headers)
+      )
 
   @cached_property
   def _api_backend(self) -> GoogleLLMVariant:

tests/unittests/models/test_vertex_per_agent_config.py

@@ -0,0 +1,102 @@
+# Copyright 2025 Google LLC
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from unittest.mock import patch
+
+from src.google.adk.models.anthropic_llm import Claude
+from src.google.adk.models.google_llm import Gemini
+
+
+def test_claude_custom_config():
+  claude = Claude(project_id="test-project-claude", location="us-central1")
+
+  assert claude.project_id == "test-project-claude"
+  assert claude.location == "us-central1"
+
+
+def test_gemini_custom_config():
+  gemini = Gemini(project_id="test-project-gemini", location="europe-west1")
+
+  assert gemini.project_id == "test-project-gemini"
+  assert gemini.location == "europe-west1"
+
+
+def test_claude_per_instance_configuration():
+  claude1 = Claude(project_id="project-1", location="us-central1")
+  claude2 = Claude(project_id="project-2", location="europe-west1")
+  claude3 = Claude()
+
+  assert claude1.project_id == "project-1"
+  assert claude1.location == "us-central1"
+
+  assert claude2.project_id == "project-2"
+  assert claude2.location == "europe-west1"
+
+  assert claude3.project_id is None
+  assert claude3.location is None
+
+
+def test_gemini_per_instance_configuration():
+  gemini1 = Gemini(project_id="project-1", location="us-central1")
+  gemini2 = Gemini(project_id="project-2", location="europe-west1")
+  gemini3 = Gemini()
+
+  assert gemini1.project_id == "project-1"
+  assert gemini1.location == "us-central1"
+
+  assert gemini2.project_id == "project-2"
+  assert gemini2.location == "europe-west1"
+
+  assert gemini3.project_id is None
+  assert gemini3.location is None
+
+
+def test_backward_compatibility():
+  claude = Claude()
+  gemini = Gemini()
+
+  assert claude.project_id is None
+  assert claude.location is None
+  assert gemini.project_id is None
+  assert gemini.location is None
+
+
+@patch.dict(
+    "os.environ",
+    {
+        "GOOGLE_CLOUD_PROJECT": "env-project",
+        "GOOGLE_CLOUD_LOCATION": "env-location",
+    },
+)
+def test_claude_fallback_to_env_vars():
+  claude = Claude()
+
+  cache_key = f"{claude.project_id or 'default'}:{claude.location or 'default'}"
+  assert cache_key == "default:default"
+
+
+def test_mixed_configuration():
+  claude_custom = Claude(project_id="custom-project", location="us-west1")
+  claude_default = Claude()
+
+  key_custom = (
+      f"{claude_custom.project_id or 'default'}:{claude_custom.location or 'default'}"
+  )
+  key_default = (
+      f"{claude_default.project_id or 'default'}:{claude_default.location or 'default'}"
+  )
+
+  assert key_custom != key_default
+  assert key_custom == "custom-project:us-west1"
+  assert key_default == "default:default"