Update app.py

app.py

@@ -4,8 +4,8 @@ import requests
 import inspect
 import pandas as pd
 import ast
-from typing import Dict, Any, List, TypedDict, Optional
-from langgraph.graph import Graph, StateGraph
+from typing import Annotated, TypedDict, List, Dict, Any, Optional
+from langgraph.graph import Graph, StateGraph, State
 from langgraph.prebuilt import ToolNode
 from tools import simple_search
 from huggingface_hub import InferenceClient
@@ -17,13 +17,13 @@ DEFAULT_API_URL = "https://agents-course-unit4-scoring.hf.space"
 HF_TOKEN = os.getenv("HF_TOKEN")  # Make sure to set this environment variable
 
 class AgentState(TypedDict):
-    question: str
-    current_step: str
-    tool_output: str
-    final_answer: str
-    history: List[Dict[str, str]]
-    needs_more_info: bool
-    search_query: str
+    question: Annotated[str, State.Immutable]               # Fixed across steps
+    current_step: str                                       # Mutable
+    tool_output: str                                        # Mutable
+    final_answer: str                                       # Mutable
+    history: Annotated[List[Dict[str, str]], State.MergingList]  # Merged across steps
+    needs_more_info: bool                                   # Mutable
+    search_query: str                                       # Mutable
 
 class BasicAgent:
     def __init__(self):