Update agent.py

agent.py

@@ -163,7 +163,7 @@ def build_graph(provider: str = "huggingface"):
     builder.add_node("assistant", assistant)
     builder.add_node("tools", ToolNode(tools))
 
-    builder.add_edge("assistant")
+    builder.add_edge(START, "assistant")
     builder.add_conditional_edges(
         "assistant",
         tools_condition,