diff --git a/agentic_ai/agents/agent_framework/multi_agent/handoff_multi_domain_agent.py b/agentic_ai/agents/agent_framework/multi_agent/handoff_multi_domain_agent.py
index 320d634de..ab8ea3a08 100644
--- a/agentic_ai/agents/agent_framework/multi_agent/handoff_multi_domain_agent.py
+++ b/agentic_ai/agents/agent_framework/multi_agent/handoff_multi_domain_agent.py
@@ -340,7 +340,7 @@ async def _setup(self) -> None:
                 description=cfg["description"],
                 instructions=cfg["instructions"],
                 tools=domain_tools,
-                default_options=ChatOptions(model_id=self.openai_model_name),
+                default_options=ChatOptions(model=self.openai_model_name),
                 require_per_service_call_history_persistence=True,
             )
             await agent.__aenter__()
diff --git a/agentic_ai/agents/agent_framework/multi_agent/magentic_group.py b/agentic_ai/agents/agent_framework/multi_agent/magentic_group.py
index 33e2c679d..a8208d799 100644
--- a/agentic_ai/agents/agent_framework/multi_agent/magentic_group.py
+++ b/agentic_ai/agents/agent_framework/multi_agent/magentic_group.py
@@ -579,7 +579,7 @@ async def _create_participants(
             agent_kwargs: Dict[str, Any] = {
                 **defaults,
                 "client": participant_client,
-                "default_options": ChatOptions(model_id=self.openai_model_name),
+                "default_options": ChatOptions(model=self.openai_model_name),
             }
             
             # Apply tool filtering for this participant's domain
diff --git a/agentic_ai/agents/agent_framework/multi_agent/reflection_agent.py b/agentic_ai/agents/agent_framework/multi_agent/reflection_agent.py
index 394e199db..f01158643 100644
--- a/agentic_ai/agents/agent_framework/multi_agent/reflection_agent.py
+++ b/agentic_ai/agents/agent_framework/multi_agent/reflection_agent.py
@@ -108,7 +108,7 @@ async def _setup_agents(self) -> None:
             name="PrimaryAgent",
             instructions=PRIMARY_AGENT_INSTRUCTIONS,
             tools=tools,
-            default_options=ChatOptions(model_id=self.openai_model_name),
+            default_options=ChatOptions(model=self.openai_model_name),
         )
 
         self._reviewer = FrameworkAgent(
@@ -116,7 +116,7 @@ async def _setup_agents(self) -> None:
             name="Reviewer",
             instructions=REVIEWER_INSTRUCTIONS,
             tools=tools,
-            default_options=ChatOptions(model_id=self.openai_model_name),
+            default_options=ChatOptions(model=self.openai_model_name),
         )
 
         # Initialize agents
diff --git a/agentic_ai/agents/agent_framework/single_agent.py b/agentic_ai/agents/agent_framework/single_agent.py
index a9917754c..1a099c21c 100644
--- a/agentic_ai/agents/agent_framework/single_agent.py
+++ b/agentic_ai/agents/agent_framework/single_agent.py
@@ -85,7 +85,7 @@ async def _setup_single_agent(self) -> None:
             name="ai_assistant",
             instructions=instructions,
             tools=tools,
-            default_options=ChatOptions(model_id=self.openai_model_name),
+            default_options=ChatOptions(model=self.openai_model_name),
         )
 
         try: