fix(response_format): added role mapping + changed default serialization

Author: giuliastf

src/uipath/_services/llm_gateway_service.py

@@ -347,7 +347,7 @@ def __init__(self, config: Config, execution_context: ExecutionContext) -> None:
     @traced(name="llm_chat_completions", run_type="uipath")
     async def chat_completions(
         self,
-        messages: List[Dict[str, str]],
+        messages: Union[List[Dict[str, str]], List[tuple]],
         model: str = ChatModels.gpt_4o_mini_2024_07_18,
         max_tokens: int = 4096,
         temperature: float = 0,
@@ -475,13 +475,31 @@ class Country(BaseModel):
             This service uses UiPath's normalized API format which provides consistent
             behavior across different underlying model providers and enhanced enterprise features.
         """
+        role_mapping = {"human": "user", "ai": "assistant"}
+        converted_messages = []
+
+        for message in messages:
+            if isinstance(message, tuple) and len(message) == 2:
+                role, content = message
+                mapped_role = role_mapping.get(role.lower(), role)
+                converted_messages.append({"role": mapped_role, "content": content})
+            elif isinstance(message, dict):
+                role = message.get("role", "")
+                mapped_role = role_mapping.get(role.lower(), role)
+                converted_messages.append({**message, "role": mapped_role})
+            else:
+                raise ValueError(
+                    f"Invalid message format: {message}. Expected tuple (role, content) or dict with 'role' and 'content' keys."
+                )
+
         endpoint = EndpointManager.get_normalized_endpoint().format(
             model=model, api_version=api_version
         )
         endpoint = Endpoint("/" + endpoint)
 
         request_body = {
-            "messages": messages,
+            # "messages": messages,
+            "messages": converted_messages,
             "max_tokens": max_tokens,
             "temperature": temperature,
             "n": n,