Add docstring to get_image_file function in agent.py to clarify its purpose and usage.

agent.py

@@ -51,7 +51,19 @@ def web_search(keywords: str, max_results:int = 5) -> str:
 
 @tool
 def get_image_file(task_id):
+    """
+    Get the image file from the question
+    Use cases:
+     - Extract Image from the question
+
+     Args:
+        task_id: the task_id of the question
+
+    Returns:
+        Image file result
+    """
     pass
+    return ''
 
 
 class AgentState(TypedDict):
@@ -81,7 +93,7 @@ def read_message(state: AgentState) -> AgentState:
 #     return {"messages": messages + [response]}
 
 # Augment the LLM with tools
-tools = [web_search]
+tools = [web_search,get_image_file]
 tools_by_name = {tool.name: tool for tool in tools}
 model_with_tools = model.bind_tools(tools)