[Update] Default LLM (#3587)

docs/integrations/openai-agents-sdk.mdx

@@ -63,7 +63,7 @@ agent = Agent(
     Use the save_memory tool to store important information about the user.
     Always personalize your responses based on available memory.""",
     tools=[search_memory, save_memory],
-    model="gpt-4o"
+    model="gpt-4.1-nano-2025-04-14"
 )
 
 def chat_with_agent(user_input: str, user_id: str) -> str:
@@ -114,7 +114,7 @@ travel_agent = Agent(
     understand the user's travel preferences and history before making recommendations.
     After providing your response, use store_conversation to save important details.""",
     tools=[search_memory, save_memory],
-    model="gpt-4o"
+    model="gpt-4.1-nano-2025-04-14"
 )
 
 health_agent = Agent(
@@ -123,7 +123,7 @@ health_agent = Agent(
     understand the user's health goals and dietary preferences.
     After providing advice, use store_conversation to save relevant information.""",
     tools=[search_memory, save_memory],
-    model="gpt-4o"
+    model="gpt-4.1-nano-2025-04-14"
 )
 
 # Triage agent with handoffs
@@ -134,7 +134,7 @@ triage_agent = Agent(
     For health-related questions (fitness, diet, wellness, exercise), hand off to the Health Advisor.
     For general questions, handle them directly using available tools.""",
     handoffs=[travel_agent, health_agent],
-    model="gpt-4o"
+    model="gpt-4.1-nano-2025-04-14"
 )
 
 def chat_with_handoffs(user_input: str, user_id: str) -> str: