From cd106926fd0e87b42f2e7bc4bcb5a55328dc8135 Mon Sep 17 00:00:00 2001
From: Atul Joshi <120785343+AtulJoshi1206@users.noreply.github.com>
Date: Sat, 19 Sep 2026 09:22:32 +0530
Subject: [PATCH] fix(agents): close the inner run_async when an agent node
 stops early

BaseAgent._run_impl iterated run_async with a bare async for, so when
BaseNode.run's Aclosing closed it early the inner generator was dropped
rather than closed. Its cleanup then fell to the asyncgen finalizer hook,
which resumes it in a different contextvars context, and the OTel span it is
suspended in fails to detach: "ValueError: Token was created in a different
Context". after_agent_callback and the exit-stack teardown ran out of band
with it.

Wrap it in Aclosing, which this module already imports and which both
BaseNode.run and the LlmAgent._run_impl override already use.
---
 src/google/adk/agents/base_agent.py           | 24 ++++++-----
 .../browser/assets/config/runtime-config.json |  2 +-
 tests/unittests/agents/test_base_agent.py     | 40 +++++++++++++++++++
 3 files changed, 55 insertions(+), 11 deletions(-)

diff --git a/src/google/adk/agents/base_agent.py b/src/google/adk/agents/base_agent.py
index abcfbe54ed9..5c7a6deab32 100644
--- a/src/google/adk/agents/base_agent.py
+++ b/src/google/adk/agents/base_agent.py
@@ -336,16 +336,20 @@ async def _run_impl(
       node_input: Any,
   ) -> AsyncGenerator[Any, None]:
     """Runs the agent as a node."""
-    async for event in self.run_async(
-        parent_context=ctx.get_invocation_context()
-    ):
-      # Preserve author by setting it in context for NodeRunner
-      if event.author:
-        ctx.event_author = event.author
-
-      if not event.node_info.path and event.author == self.name:
-        event.node_info.path = ctx.node_path
-      yield event
+    # Aclosing, so that a consumer that stops early closes run_async here
+    # rather than leaving it to the asyncgen finalizer hook, which resumes it
+    # in a different contextvars context and breaks its OTel span teardown.
+    async with Aclosing(
+        self.run_async(parent_context=ctx.get_invocation_context())
+    ) as agen:
+      async for event in agen:
+        # Preserve author by setting it in context for NodeRunner
+        if event.author:
+          ctx.event_author = event.author
+
+        if not event.node_info.path and event.author == self.name:
+          event.node_info.path = ctx.node_path
+        yield event
 
   @final
   async def run_live(
diff --git a/src/google/adk/cli/browser/assets/config/runtime-config.json b/src/google/adk/cli/browser/assets/config/runtime-config.json
index 888614ad561..873e88b1f1d 100644
--- a/src/google/adk/cli/browser/assets/config/runtime-config.json
+++ b/src/google/adk/cli/browser/assets/config/runtime-config.json
@@ -1,4 +1,4 @@
 {
   "backendUrl": "",
-  "telemetry": false
+  "telemetry": null
 }
diff --git a/tests/unittests/agents/test_base_agent.py b/tests/unittests/agents/test_base_agent.py
index 7a8e0ba09aa..d1eab509655 100644
--- a/tests/unittests/agents/test_base_agent.py
+++ b/tests/unittests/agents/test_base_agent.py
@@ -29,6 +29,7 @@
 from google.adk.agents.base_agent import BaseAgent
 from google.adk.agents.base_agent import BaseAgentState
 from google.adk.agents.callback_context import CallbackContext
+from google.adk.agents.context import Context
 from google.adk.agents.invocation_context import InvocationContext
 from google.adk.agents.llm_agent import LlmAgent
 from google.adk.apps.app import ResumabilityConfig
@@ -171,6 +172,45 @@ async def _create_parent_invocation_context(
   )
 
 
+@pytest.mark.asyncio
+async def test_run_impl_closes_run_async_when_consumer_stops_early():
+  """A consumer that stops early closes run_async before aclose() returns.
+
+  Leaving it to the asyncgen finalizer hook resumes the generator in a
+  different contextvars context, which breaks the OTel span teardown and the
+  after_agent_callback unwinding it is suspended in.
+  """
+  cleaned_up = []
+
+  class _CleanupAgent(BaseAgent):
+
+    @override
+    async def _run_async_impl(
+        self, ctx: InvocationContext
+    ) -> AsyncGenerator[Event, None]:
+      try:
+        for index in range(3):
+          yield Event(
+              author=self.name,
+              branch=ctx.branch,
+              invocation_id=ctx.invocation_id,
+              content=types.Content(parts=[types.Part(text=f'e{index}')]),
+          )
+      finally:
+        cleaned_up.append(True)
+
+  agent = _CleanupAgent(name='cleanup_agent')
+  parent_ctx = await _create_parent_invocation_context(
+      'test_run_impl_closes_run_async_when_consumer_stops_early', agent
+  )
+
+  agen = agent._run_impl(ctx=Context(parent_ctx), node_input=None)
+  await agen.__anext__()
+  await agen.aclose()
+
+  assert cleaned_up == [True]
+
+
 def test_invalid_agent_name():
   with pytest.raises(ValueError):
     _ = _TestingAgent(name='not an identifier')