fix: relax runner app-name enforcement

- let _enforce_app_name_alignment warn instead of raising while caching the hint that now augments the existing “Session not found …” error
- tighten _infer_agent_origin so it ignores hidden folders (like .venv)
- make AgentTool reuse the parent runner’s app_name, stopping internal runners from conflicting in multi-agent setups

PiperOrigin-RevId: 822205860

tests/unittests/test_runners.py

@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from pathlib import Path
+import textwrap
 from typing import Optional
 
 from google.adk.agents.base_agent import BaseAgent
@@ -21,6 +23,7 @@ from google.adk.agents.llm_agent import LlmAgent
 from google.adk.apps.app import App
 from google.adk.apps.app import ResumabilityConfig
 from google.adk.artifacts.in_memory_artifact_service import InMemoryArtifactService
+from google.adk.cli.utils.agent_loader import AgentLoader
 from google.adk.events.event import Event
 from google.adk.plugins.base_plugin import BasePlugin
 from google.adk.runners import Runner
@@ -158,6 +161,120 @@ class TestRunnerFindAgentToRun:
         artifact_service=self.artifact_service,
     )
 
+
+@pytest.mark.asyncio
+async def test_session_not_found_message_includes_alignment_hint():
+
+  class RunnerWithMismatch(Runner):
+
+    def _infer_agent_origin(
+        self, agent: BaseAgent
+    ) -> tuple[Optional[str], Optional[Path]]:
+      del agent
+      return "expected_app", Path("/workspace/agents/expected_app")
+
+  session_service = InMemorySessionService()
+  runner = RunnerWithMismatch(
+      app_name="configured_app",
+      agent=MockLlmAgent("root_agent"),
+      session_service=session_service,
+      artifact_service=InMemoryArtifactService(),
+  )
+
+  agen = runner.run_async(
+      user_id="user",
+      session_id="missing",
+      new_message=types.Content(role="user", parts=[]),
+  )
+
+  with pytest.raises(ValueError) as excinfo:
+    await agen.__anext__()
+
+  await agen.aclose()
+
+  message = str(excinfo.value)
+  assert "Session not found" in message
+  assert "configured_app" in message
+  assert "expected_app" in message
+  assert "Ensure the runner app_name matches" in message
+
+
+@pytest.mark.asyncio
+async def test_runner_allows_nested_agent_directories(tmp_path, monkeypatch):
+  project_root = tmp_path / "workspace"
+  agent_dir = project_root / "agents" / "examples" / "001_hello_world"
+  agent_dir.mkdir(parents=True)
+  # Make package structure importable.
+  for pkg_dir in [
+      project_root / "agents",
+      project_root / "agents" / "examples",
+      agent_dir,
+  ]:
+    (pkg_dir / "__init__.py").write_text("", encoding="utf-8")
+  # Extra directories that previously confused origin inference, e.g. virtualenv.
+  (project_root / "agents" / ".venv").mkdir()
+
+  agent_source = textwrap.dedent("""\
+      from google.adk.events.event import Event
+      from google.adk.agents.base_agent import BaseAgent
+      from google.genai import types
+
+
+      class SimpleAgent(BaseAgent):
+
+        def __init__(self):
+          super().__init__(name='simplest_agent', sub_agents=[])
+
+        async def _run_async_impl(self, invocation_context):
+          yield Event(
+              invocation_id=invocation_context.invocation_id,
+              author=self.name,
+              content=types.Content(
+                  role='model',
+                  parts=[types.Part(text='hello from nested')],
+              ),
+          )
+
+
+      root_agent = SimpleAgent()
+      """)
+  (agent_dir / "agent.py").write_text(agent_source, encoding="utf-8")
+
+  monkeypatch.chdir(project_root)
+  loader = AgentLoader(agents_dir="agents/examples")
+  loaded_agent = loader.load_agent("001_hello_world")
+
+  assert isinstance(loaded_agent, BaseAgent)
+  session_service = InMemorySessionService()
+  artifact_service = InMemoryArtifactService()
+  runner = Runner(
+      app_name="001_hello_world",
+      agent=loaded_agent,
+      session_service=session_service,
+      artifact_service=artifact_service,
+  )
+  assert runner._app_name_alignment_hint is None
+
+  session = await session_service.create_session(
+      app_name="001_hello_world",
+      user_id="user",
+  )
+  agen = runner.run_async(
+      user_id=session.user_id,
+      session_id=session.id,
+      new_message=types.Content(
+          role="user",
+          parts=[types.Part(text="hi")],
+      ),
+  )
+  event = await agen.__anext__()
+  await agen.aclose()
+
+  assert event.author == "simplest_agent"
+  assert event.content
+  assert event.content.parts
+  assert event.content.parts[0].text == "hello from nested"
+
   def test_find_agent_to_run_with_function_response_scenario(self):
     """Test finding agent when last event is function response."""
     # Create a function call from sub_agent1

tests/unittests/tools/test_agent_tool.py

@@ -12,15 +12,23 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+from typing import Any
 from typing import Optional
 
 from google.adk.agents.callback_context import CallbackContext
+from google.adk.agents.invocation_context import InvocationContext
 from google.adk.agents.llm_agent import Agent
+from google.adk.agents.run_config import RunConfig
 from google.adk.agents.sequential_agent import SequentialAgent
+from google.adk.artifacts.in_memory_artifact_service import InMemoryArtifactService
+from google.adk.memory.in_memory_memory_service import InMemoryMemoryService
 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.plugins.plugin_manager import PluginManager
+from google.adk.sessions.in_memory_session_service import InMemorySessionService
 from google.adk.tools.agent_tool import AgentTool
+from google.adk.tools.tool_context import ToolContext
 from google.adk.utils.variant_utils import GoogleLLMVariant
 from google.genai import types
 from google.genai.types import Part
@@ -51,6 +59,120 @@ def change_state_callback(callback_context: CallbackContext):
   print('change_state_callback: ', callback_context.state)
 
 
+@mark.asyncio
+async def test_agent_tool_inherits_parent_app_name(monkeypatch):
+  parent_app_name = 'parent_app'
+  captured: dict[str, str] = {}
+
+  class RecordingSessionService(InMemorySessionService):
+
+    async def create_session(
+        self,
+        *,
+        app_name: str,
+        user_id: str,
+        state: Optional[dict[str, Any]] = None,
+        session_id: Optional[str] = None,
+    ):
+      captured['session_app_name'] = app_name
+      return await super().create_session(
+          app_name=app_name,
+          user_id=user_id,
+          state=state,
+          session_id=session_id,
+      )
+
+  monkeypatch.setattr(
+      'google.adk.sessions.in_memory_session_service.InMemorySessionService',
+      RecordingSessionService,
+  )
+
+  async def _empty_async_generator():
+    if False:
+      yield None
+
+  class StubRunner:
+
+    def __init__(
+        self,
+        *,
+        app_name: str,
+        agent: Agent,
+        artifact_service,
+        session_service,
+        memory_service,
+        credential_service,
+        plugins,
+    ):
+      del artifact_service, memory_service, credential_service
+      captured['runner_app_name'] = app_name
+      self.agent = agent
+      self.session_service = session_service
+      self.plugin_manager = PluginManager(plugins=plugins)
+      self.app_name = app_name
+
+    def run_async(
+        self,
+        *,
+        user_id: str,
+        session_id: str,
+        invocation_id: Optional[str] = None,
+        new_message: Optional[types.Content] = None,
+        state_delta: Optional[dict[str, Any]] = None,
+        run_config: Optional[RunConfig] = None,
+    ):
+      del (
+          user_id,
+          session_id,
+          invocation_id,
+          new_message,
+          state_delta,
+          run_config,
+      )
+      return _empty_async_generator()
+
+  monkeypatch.setattr('google.adk.runners.Runner', StubRunner)
+
+  tool_agent = Agent(
+      name='tool_agent',
+      model='test-model',
+  )
+  agent_tool = AgentTool(agent=tool_agent)
+  root_agent = Agent(
+      name='root_agent',
+      model='test-model',
+      tools=[agent_tool],
+  )
+
+  artifact_service = InMemoryArtifactService()
+  parent_session_service = InMemorySessionService()
+  parent_session = await parent_session_service.create_session(
+      app_name=parent_app_name,
+      user_id='user',
+  )
+  invocation_context = InvocationContext(
+      artifact_service=artifact_service,
+      session_service=parent_session_service,
+      memory_service=InMemoryMemoryService(),
+      plugin_manager=PluginManager(),
+      invocation_id='invocation-id',
+      agent=root_agent,
+      session=parent_session,
+      run_config=RunConfig(),
+  )
+  tool_context = ToolContext(invocation_context)
+
+  assert tool_context._invocation_context.app_name == parent_app_name
+
+  await agent_tool.run_async(
+      args={'request': 'hello'},
+      tool_context=tool_context,
+  )
+
+  assert captured['runner_app_name'] == parent_app_name
+  assert captured['session_app_name'] == parent_app_name
+
+
 def test_no_schema():
   mock_model = testing_utils.MockModel.create(
       responses=[