diff --git a/src/google/adk/tools/agent_tool.py b/src/google/adk/tools/agent_tool.py
index 8c680b611..a2a7171b7 100644
--- a/src/google/adk/tools/agent_tool.py
+++ b/src/google/adk/tools/agent_tool.py
@@ -53,10 +53,10 @@ def __init__(self, agent: BaseAgent, skip_summarization: bool = False):
 
     super().__init__(name=agent.name, description=agent.description)
 
-  @model_validator(mode='before')
+  @model_validator(mode="before")
   @classmethod
   def populate_name(cls, data: Any) -> Any:
-    data['name'] = data['agent'].name
+    data["name"] = data["agent"].name
     return data
 
   @override
@@ -73,11 +73,11 @@ def _get_declaration(self) -> types.FunctionDeclaration:
           parameters=types.Schema(
               type=types.Type.OBJECT,
               properties={
-                  'request': types.Schema(
+                  "request": types.Schema(
                       type=types.Type.STRING,
                   ),
               },
-              required=['request'],
+              required=["request"],
           ),
           description=self.agent.description,
           name=self.name,
@@ -105,7 +105,6 @@ async def run_async(
   ) -> Any:
     from ..agents.llm_agent import LlmAgent
     from ..runners import Runner
-    from ..sessions.in_memory_session_service import InMemorySessionService
 
     if self.skip_summarization:
       tool_context.actions.skip_summarization = True
@@ -113,7 +112,7 @@ async def run_async(
     if isinstance(self.agent, LlmAgent) and self.agent.input_schema:
       input_value = self.agent.input_schema.model_validate(args)
       content = types.Content(
-          role='user',
+          role="user",
           parts=[
               types.Part.from_text(
                   text=input_value.model_dump_json(exclude_none=True)
@@ -122,15 +121,15 @@ async def run_async(
       )
     else:
       content = types.Content(
-          role='user',
-          parts=[types.Part.from_text(text=args['request'])],
+          role="user",
+          parts=[types.Part.from_text(text=args["request"])],
       )
     runner = Runner(
         app_name=self.agent.name,
         agent=self.agent,
         artifact_service=ForwardingArtifactService(tool_context),
-        session_service=InMemorySessionService(),
-        memory_service=InMemoryMemoryService(),
+        session_service=tool_context._invocation_context.session_service,
+        memory_service=tool_context._invocation_context.memory_service,
         credential_service=tool_context._invocation_context.credential_service,
         plugins=list(tool_context._invocation_context.plugin_manager.plugins),
     )
@@ -154,8 +153,8 @@ async def run_async(
           last_content = event.content
 
     if not last_content:
-      return ''
-    merged_text = '\n'.join(p.text for p in last_content.parts if p.text)
+      return ""
+    merged_text = "\n".join(p.text for p in last_content.parts if p.text)
     if isinstance(self.agent, LlmAgent) and self.agent.output_schema:
       tool_result = self.agent.output_schema.model_validate_json(
           merged_text