diff --git a/python_a2a/client/llm/ollama.py b/python_a2a/client/llm/ollama.py
index b6c9b5c..00b8760 100644
--- a/python_a2a/client/llm/ollama.py
+++ b/python_a2a/client/llm/ollama.py
@@ -21,6 +21,7 @@ def __init__(
         self,
         api_url: str,
         model: str,
+        api_key: str = "ollama",
         temperature: float = 0.7,
         system_prompt: Optional[str] = None,
         functions: Optional[List[Dict[str, Any]]] = None,
@@ -48,6 +49,7 @@ def __init__(
 
         # Initialize OpenAI compatible client
         self.__api_url = api_url
+        self.function_role = "tool"  # Ollama uses "tool" as the function role
 
         try:
             self.__models = self.list_models()
@@ -59,7 +61,7 @@ def __init__(
         if model not in self.__models:
             raise A2AImportError(f"Model '{model}' is not available in the Ollama API.")
 
-        self.client = OpenAI(base_url=f"{api_url}/v1", api_key="ollama")
+        self.client = OpenAI(base_url=f"{api_url}/v1", api_key=api_key)
 
     def list_models(self) -> List[str]:
         """
diff --git a/python_a2a/client/llm/openai.py b/python_a2a/client/llm/openai.py
index 644fd91..cf0245c 100644
--- a/python_a2a/client/llm/openai.py
+++ b/python_a2a/client/llm/openai.py
@@ -57,6 +57,7 @@ def __init__(
         self.temperature = temperature
         self.system_prompt = system_prompt or "You are a helpful assistant."
         self.functions = functions
+        self.function_role = "function"  # Default role for function responses
         self.tools = self._convert_functions_to_tools() if functions else None
 
         # Initialize OpenAI client only if the API key is provided
@@ -122,7 +123,7 @@ def send_message(self, message: Message) -> Message:
                 # Format function response in OpenAI's expected format
                 openai_messages.append(
                     {
-                        "role": "function",
+                        "role": self.function_role,
                         "name": message.content.name,
                         "content": json.dumps(message.content.response),
                     }
@@ -185,7 +186,7 @@ def send_message(self, message: Message) -> Message:
                 elif message.content.type == "function_response":
                     self._conversation_histories[conversation_id].append(
                         {
-                            "role": "function",
+                            "role": self.function_role,
                             "name": message.content.name,
                             "content": json.dumps(message.content.response),
                         }
@@ -336,7 +337,7 @@ def send_conversation(self, conversation: Conversation) -> Conversation:
                     # Format function response for OpenAI
                     openai_messages.append(
                         {
-                            "role": "function",
+                            "role": self.function_role,
                             "name": msg.content.name,
                             "content": json.dumps(msg.content.response),
                         }
diff --git a/python_a2a/server/llm/ollama.py b/python_a2a/server/llm/ollama.py
index 458886a..992feec 100644
--- a/python_a2a/server/llm/ollama.py
+++ b/python_a2a/server/llm/ollama.py
@@ -29,6 +29,7 @@ def __init__(
         self,
         api_url: str,
         model: str,
+        api_key: str = "ollama",
         temperature: float = 0.7,
         system_prompt: Optional[str] = None,
         functions: Optional[List[Dict[str, Any]]] = None,
@@ -62,6 +63,7 @@ def __init__(
 
         # Initialize OpenAI compatible client
         self.__api_url = api_url
+        self.function_role = "tool"  # Ollama uses "tool" as the function role
 
         try:
             self.__models = self.list_models()
@@ -75,8 +77,8 @@ def __init__(
 
         # Create an async client for streaming
         if AsyncOpenAI is not None:
-            self.client = OpenAI(base_url=f"{api_url}/v1", api_key="ollama")
-            self.async_client = AsyncOpenAI(base_url=f"{api_url}/v1", api_key="ollama")
+            self.client = OpenAI(base_url=f"{api_url}/v1", api_key=api_key)
+            self.async_client = AsyncOpenAI(base_url=f"{api_url}/v1", api_key=api_key)
         else:
             self.async_client = None
 
diff --git a/python_a2a/server/llm/openai.py b/python_a2a/server/llm/openai.py
index c8513e4..c25611b 100644
--- a/python_a2a/server/llm/openai.py
+++ b/python_a2a/server/llm/openai.py
@@ -67,6 +67,7 @@ def __init__(
         self.temperature = temperature
         self.system_prompt = system_prompt or "You are a helpful AI assistant."
         self.functions = functions
+        self.function_role = "function"  # Default role for function responses
         self.tools = self._convert_functions_to_tools() if functions else None
 
         # Handle support for Ollama setup
@@ -136,7 +137,7 @@ def handle_message(self, message: Message) -> Message:
                 # This is critical for function calling to work properly
                 openai_messages.append(
                     {
-                        "role": "function",
+                        "role": self.function_role,
                         "name": message.content.name,
                         "content": json.dumps(message.content.response),
                     }
@@ -193,7 +194,7 @@ def handle_message(self, message: Message) -> Message:
                 elif message.content.type == "function_response":
                     self._conversation_state[conversation_id].append(
                         {
-                            "role": "function",
+                            "role": self.function_role,
                             "name": message.content.name,
                             "content": json.dumps(message.content.response),
                         }
@@ -464,7 +465,7 @@ def handle_conversation(self, conversation: Conversation) -> Conversation:
                     # Format function response for OpenAI
                     self._conversation_state[conversation_id].append(
                         {
-                            "role": "function",
+                            "role": self.function_role,
                             "name": msg.content.name,
                             "content": json.dumps(msg.content.response),
                         }