diff --git a/src/google/adk/agents/callback_context.py b/src/google/adk/agents/callback_context.py
index 9b9f237..93b785c 100644
--- a/src/google/adk/agents/callback_context.py
+++ b/src/google/adk/agents/callback_context.py
@@ -23,7 +23,6 @@ from .readonly_context import ReadonlyContext
 if TYPE_CHECKING:
   from google.genai import types
 
-  from ..events.event import Event
   from ..events.event_actions import EventActions
   from ..sessions.state import State
   from .invocation_context import InvocationContext
diff --git a/src/google/adk/flows/llm_flows/functions.py b/src/google/adk/flows/llm_flows/functions.py
index 805957e..d1b6f84 100644
--- a/src/google/adk/flows/llm_flows/functions.py
+++ b/src/google/adk/flows/llm_flows/functions.py
@@ -310,7 +310,7 @@ async def _process_function_live_helper(
       function_response = {
           'status': f'No active streaming function named {function_name} found'
       }
-  elif hasattr(tool, "func") and inspect.isasyncgenfunction(tool.func):
+  elif inspect.isasyncgenfunction(tool.func):
     print('is async')
 
     # for streaming tool use case
diff --git a/src/google/adk/models/llm_response.py b/src/google/adk/models/llm_response.py
index 895e7a0..d7a613d 100644
--- a/src/google/adk/models/llm_response.py
+++ b/src/google/adk/models/llm_response.py
@@ -14,7 +14,7 @@
 
 from __future__ import annotations
 
-from typing import Optional
+from typing import Any, Optional
 
 from google.genai import types
 from pydantic import BaseModel
@@ -37,6 +37,7 @@ class LlmResponse(BaseModel):
     error_message: Error message if the response is an error.
     interrupted: Flag indicating that LLM was interrupted when generating the
       content. Usually it's due to user interruption during a bidi streaming.
+    custom_metadata: The custom metadata of the LlmResponse.
   """
 
   model_config = ConfigDict(extra='forbid')
@@ -71,6 +72,14 @@ class LlmResponse(BaseModel):
   Usually it's due to user interruption during a bidi streaming.
   """
 
+  custom_metadata: Optional[dict[str, Any]] = None
+  """The custom metadata of the LlmResponse.
+
+  An optional key-value pair to label an LlmResponse.
+
+  NOTE: the entire dict must be JSON serializable.
+  """
+
   @staticmethod
   def create(
       generate_content_response: types.GenerateContentResponse,