Updating BasicAgent by adding the DuckDuckGoSearch tool

app.py

@@ -4,6 +4,16 @@ import requests
 import inspect
 import pandas as pd
 
+# LangGraph and LangChain imports
+
+from langchain_community.tools import DuckDuckGoSearchRun
+from langchain.tools import Tool
+from langgraph.graph import START, StateGraph
+from langgraph.prebuilt import ToolNode, tools_condition
+from langchain_core.messages import AnyMessage, HumanMessage, AIMessage
+from typing import TypedDict, Annotated
+from langgraph.graph.message import add_messages
+
 # (Keep Constants as is)
 # --- Constants ---
 DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
@@ -13,9 +23,32 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 class BasicAgent:
     def __init__(self):
         print("BasicAgent initialized.")
+
+        # initializing the DuckDuckGo tool
+        self.search_tool = DuckDuckGoSearchRun()
+        self.tools = [self.search_tool]
+
+        # building LangGraph agent
+        class AgentState(TypedDict):
+            messages: Annotated[list[AnyMessage], add_messages]
+
+         def assistant(state: AgentState):
+            user_message = state["messages"][-1]
+            if isinstance(user_message, HumanMessage):
+                result = self.search_tool.invoke(user_message.content)
+                return {"messages": [AIMessage(content=result)]}
+            return {"messages": [AIMessage(content="I can only answer human questions.")]}
+        builder = StateGraph(AgentState)
+        builder.add_node("assistant", assistant)
+        builder.add_edge(START, "assistant")
+        self.alfred = builder.compile()
+
+    
     def __call__(self, question: str) -> str:
         print(f"Agent received question (first 50 chars): {question[:50]}...")
-        fixed_answer = "This is a default answer."
+        messages = [HumanMessage(content=question)]
+        response = self.alfred.invoke({"messages": messages})
+        fixed_answer = response["messages"][-1].content
         print(f"Agent returning fixed answer: {fixed_answer}")
         return fixed_answer