fix: Allow AgentTool to inherit/use plugins from its invocation context when running

PiperOrigin-RevId: 803656189

src/google/adk/tools/agent_tool.py

@@ -132,6 +132,7 @@ class AgentTool(BaseTool):
         session_service=InMemorySessionService(),
         memory_service=InMemoryMemoryService(),
         credential_service=tool_context._invocation_context.credential_service,
+        plugins=list(tool_context._invocation_context.plugin_manager.plugins),
     )
     session = await runner.session_service.create_session(
         app_name=self.agent.name,

tests/unittests/tools/test_agent_tool.py

@@ -12,9 +12,14 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import Optional
+
 from google.adk.agents.callback_context import CallbackContext
 from google.adk.agents.llm_agent import Agent
 from google.adk.agents.sequential_agent import SequentialAgent
+from google.adk.models.llm_request import LlmRequest
+from google.adk.models.llm_response import LlmResponse
+from google.adk.plugins.base_plugin import BasePlugin
 from google.adk.tools.agent_tool import AgentTool
 from google.adk.utils.variant_utils import GoogleLLMVariant
 from google.genai import types
@@ -75,6 +80,70 @@ def test_no_schema():
   ]
 
 
+def test_use_plugins():
+  """The agent tool can use plugins from parent runner."""
+
+  class ModelResponseCapturePlugin(BasePlugin):
+
+    def __init__(self):
+      super().__init__('plugin')
+      self.model_responses = {}
+
+    async def after_model_callback(
+        self,
+        *,
+        callback_context: CallbackContext,
+        llm_response: LlmResponse,
+    ) -> Optional[LlmResponse]:
+      response_text = []
+      for part in llm_response.content.parts:
+        if not part.text:
+          continue
+        response_text.append(part.text)
+      if response_text:
+        if callback_context.agent_name not in self.model_responses:
+          self.model_responses[callback_context.agent_name] = []
+        self.model_responses[callback_context.agent_name].append(
+            ''.join(response_text)
+        )
+
+  mock_model = testing_utils.MockModel.create(
+      responses=[
+          function_call_no_schema,
+          'response1',
+          'response2',
+      ]
+  )
+
+  tool_agent = Agent(
+      name='tool_agent',
+      model=mock_model,
+  )
+
+  root_agent = Agent(
+      name='root_agent',
+      model=mock_model,
+      tools=[AgentTool(agent=tool_agent)],
+  )
+
+  model_response_capture = ModelResponseCapturePlugin()
+  runner = testing_utils.InMemoryRunner(
+      root_agent, plugins=[model_response_capture]
+  )
+
+  assert testing_utils.simplify_events(runner.run('test1')) == [
+      ('root_agent', function_call_no_schema),
+      ('root_agent', function_response_no_schema),
+      ('root_agent', 'response2'),
+  ]
+
+  # should be able to capture response from both root and tool agent.
+  assert model_response_capture.model_responses == {
+      'tool_agent': ['response1'],
+      'root_agent': ['response2'],
+  }
+
+
 def test_update_state():
   """The agent tool can read and change parent state."""