diff --git a/demos/function_calling/arch_config.yaml b/demos/function_calling/arch_config.yaml
index 22d20095..e7448c7e 100644
--- a/demos/function_calling/arch_config.yaml
+++ b/demos/function_calling/arch_config.yaml
@@ -17,23 +17,23 @@ overrides:
 
 llm_providers:
   - name: gpt-4o-mini
-    access_key: OPENAI_API_KEY
+    access_key: $OPENAI_API_KEY
     provider: openai
     model: gpt-4o-mini
     default: true
 
   - name: gpt-3.5-turbo-0125
-    access_key: OPENAI_API_KEY
+    access_key: $OPENAI_API_KEY
     provider: openai
     model: gpt-3.5-turbo-0125
 
   - name: gpt-4o
-    access_key: OPENAI_API_KEY
+    access_key: $OPENAI_API_KEY
     provider: openai
     model: gpt-4o
 
   - name: ministral-3b
-    access_key: MISTRAL_API_KEY
+    access_key: $MISTRAL_API_KEY
     provider: mistral
     model: ministral-3b-latest
 
diff --git a/model_server/app/function_calling/model_utils.py b/model_server/app/function_calling/model_utils.py
index 4c55816c..8fc49940 100644
--- a/model_server/app/function_calling/model_utils.py
+++ b/model_server/app/function_calling/model_utils.py
@@ -25,10 +25,16 @@ class ChatMessage(BaseModel):
 
 class Choice(BaseModel):
     message: Message
+    finish_reason: Optional[str] = "stop"
+    index: Optional[int] = 0
 
 
 class ChatCompletionResponse(BaseModel):
     choices: List[Choice]
+    model: Optional[str] = "Arch-Function"
+    created: Optional[str] = ""
+    id: Optional[str] = ""
+    object: Optional[str] = "chat_completion"
 
 
 def process_messages(history: list[Message]):
@@ -132,7 +138,9 @@ async def chat_completion(req: ChatMessage, res: Response):
     else:
         message = Message(content=full_response, tool_calls=[])
     choice = Choice(message=message)
-    chat_completion_response = ChatCompletionResponse(choices=[choice])
+    chat_completion_response = ChatCompletionResponse(
+        choices=[choice], model=client_model_name
+    )
 
     logger.info(
         f"model_server <= arch_function: (tools): {json.dumps([tool_call['function'] for tool_call in tool_calls])}"
diff --git a/model_server/app/main.py b/model_server/app/main.py
index a8d312d7..fdf091f0 100644
--- a/model_server/app/main.py
+++ b/model_server/app/main.py
@@ -215,5 +215,10 @@ async def hallucination(req: HallucinationRequest, res: Response):
 
 @app.post("/v1/chat/completions")
 async def chat_completion(req: ChatMessage, res: Response):
-    result = await arch_function_chat_completion(req, res)
-    return result
+    try:
+        result = await arch_function_chat_completion(req, res)
+        return result
+    except Exception as e:
+        logger.error(f"Error in chat_completion: {e}")
+        res.status_code = 500
+        return {"error": "Internal server error"}