Fix: combine system messages to satisfy strict LLM chatml parser

tinytroupe/openai_utils.py

@@ -226,10 +226,16 @@ class OpenAIClient:
     def _raw_model_call(self, model, chat_api_params):
 
         # Ensure system message is strictly first
+        
         if "messages" in chat_api_params:
             system_msgs = [m for m in chat_api_params["messages"] if m.get("role") == "system"]
             other_msgs = [m for m in chat_api_params["messages"] if m.get("role") != "system"]
-            chat_api_params["messages"] = system_msgs + other_msgs
+            
+            # Combine all system messages into one single system message block to satisfy strict ChatML
+            if system_msgs:
+                combined_content = "\n\n".join([m.get("content", "") for m in system_msgs])
+                chat_api_params["messages"] = [{"role": "system", "content": combined_content}] + other_msgs
+        
         
 
         """