Fix: Manually implement create_retriever_tool to avoid import errors

agent.py

@@ -31,12 +31,25 @@ from langchain_huggingface import (
 )
 from langchain_community.vectorstores import SupabaseVectorStore
 from langchain_core.messages import SystemMessage, HumanMessage
-from langchain_core.tools import tool
-from langchain.tools import create_retriever_tool
+from langchain_core.tools import tool, Tool
 from supabase.client import Client, create_client
 
 load_dotenv()
 
+# Manual implementation of create_retriever_tool to avoid import errors
+def create_retriever_tool(retriever, name: str, description: str) -> Tool:
+    """Create a tool to do retrieval."""
+    def retrieve(query: str):
+        # Depending on version invoke might return documents directly
+        docs = retriever.invoke(query)
+        return "\n\n".join([d.page_content for d in docs])
+        
+    return Tool(
+        name=name,
+        description=description,
+        func=retrieve,
+    )
+
 ### =============== BROWSER TOOLS =============== ###