@@ -360,7 +360,7 @@ async def _add_events_to_memory_from_events(
         if event.content:
           direct_events.append(
               agentplatform.types.GenerateMemoriesRequestDirectContentsSourceEvent(
-                  content=event.content
+                  content=_without_thoughts(event.content)
               )
           )
       if direct_events:
@@ -431,7 +431,7 @@ async def _add_events_to_memory_via_ingest(
           )
         direct_events.append(
             agentplatform.types.IngestionDirectContentsSourceEvent(
-                content=event.content,
+                content=_without_thoughts(event.content),
                 event_id=event.id,
                 event_time=event_time,
             )
@@ -732,7 +732,23 @@ def _should_filter_out_event(event: Event) -> bool:
   # Deferred: a module-level import would load the agent and flow stack too.
   from ..flows.llm_flows.context._contents import _is_auth_event
 
-  return _is_empty_content(event.content) or _is_auth_event(event)
+  content = _without_thoughts(event.content)
+  return _is_empty_content(content) or _is_auth_event(event)
+
+
+def _without_thoughts(content: types.Content | None) -> types.Content | None:
+  """Returns the content without the model's thought parts.
+
+  Thoughts are the model's reasoning, not part of the conversation, so they
+  are kept out of the events that memories are generated from.
+  """
+  if not content or not content.parts:
+    return content
+  if not any(part.thought for part in content.parts):
+    return content
+  return content.model_copy(
+      update={'parts': [part for part in content.parts if not part.thought]}
+  )
 
 
 def _is_empty_content(content: types.Content | None) -> bool:
 
@@ -142,6 +142,35 @@ async def __anext__(self) -> Any:
     ),
 ]
 
+THOUGHT_TEXT = 'the user sounds anxious, keep the reply short'
+
+THOUGHT_EVENTS = [
+    Event(
+        id='901',
+        invocation_id='900',
+        author='agent',
+        timestamp=45678,
+        content=types.Content(
+            role='model',
+            parts=[
+                types.Part(text=THOUGHT_TEXT, thought=True),
+                types.Part(text='Here is the answer.'),
+            ],
+        ),
+    ),
+    # Thought-only event, should be ignored
+    Event(
+        id='902',
+        invocation_id='900',
+        author='agent',
+        timestamp=45679,
+        content=types.Content(
+            role='model',
+            parts=[types.Part(text=THOUGHT_TEXT, thought=True)],
+        ),
+    ),
+]
+
 MOCK_SESSION_WITH_EMPTY_EVENTS = Session(
     app_name=MOCK_APP_NAME,
     user_id=MOCK_USER_ID,
@@ -582,6 +611,76 @@ async def test_add_events_to_memory_via_generate_skips_credential_events(
   assert CREDENTIAL_TOKEN not in str(call_kwargs)
 
 
+@pytest.mark.asyncio
+async def test_add_session_to_memory_skips_thought_parts(
+    mock_agentplatform_client,
+):
+  memory_service = mock_vertex_ai_memory_bank_service()
+  session = Session(
+      app_name=MOCK_APP_NAME,
+      user_id=MOCK_USER_ID,
+      id='333',
+      last_update_time=22333,
+      events=THOUGHT_EVENTS,
+  )
+
+  await memory_service.add_session_to_memory(session)
+
+  # Allow the fire-and-forget task to complete.
+  await asyncio.sleep(0)
+
+  call_kwargs = (
+      mock_agentplatform_client.memory_banks.ingest_events.call_args.kwargs
+  )
+  source = call_kwargs['direct_contents_source']
+  assert [event.event_id for event in source.events] == ['901']
+  assert source.events[0].content.role == 'model'
+  assert [part.text for part in source.events[0].content.parts] == [
+      'Here is the answer.'
+  ]
+  assert THOUGHT_TEXT not in str(call_kwargs)
+  # The session's own events are left unchanged.
+  assert len(THOUGHT_EVENTS[0].content.parts) == 2
+
+
+@pytest.mark.asyncio
+async def test_add_events_to_memory_via_generate_skips_thought_parts(
+    mock_agentplatform_client,
+):
+  memory_service = mock_vertex_ai_memory_bank_service()
+  await memory_service.add_events_to_memory(
+      app_name=MOCK_APP_NAME,
+      user_id=MOCK_USER_ID,
+      events=THOUGHT_EVENTS,
+      custom_metadata={'revision_ttl': '3600s'},
+  )
+
+  call_kwargs = (
+      mock_agentplatform_client.memory_banks.memories.generate.call_args.kwargs
+  )
+  source = call_kwargs['direct_contents_source']
+  assert len(source.events) == 1
+  assert [part.text for part in source.events[0].content.parts] == [
+      'Here is the answer.'
+  ]
+  assert THOUGHT_TEXT not in str(call_kwargs)
+
+
+@pytest.mark.asyncio
+async def test_add_events_to_memory_via_generate_with_only_thoughts_skips_rpc(
+    mock_agentplatform_client,
+):
+  memory_service = mock_vertex_ai_memory_bank_service()
+  await memory_service.add_events_to_memory(
+      app_name=MOCK_APP_NAME,
+      user_id=MOCK_USER_ID,
+      events=[THOUGHT_EVENTS[1]],
+      custom_metadata={'revision_ttl': '3600s'},
+  )
+
+  mock_agentplatform_client.memory_banks.memories.generate.assert_not_called()
+
+
 @pytest.mark.asyncio
 async def test_add_events_to_memory_with_explicit_events_and_metadata(
     mock_agentplatform_client,