Update app.py

app.py

@@ -7,6 +7,7 @@ from langchain_core.messages import HumanMessage, AIMessage
 from langchain.text_splitter import RecursiveCharacterTextSplitter
 from langchain_core.documents import Document
 from langgraph.graph import END, StateGraph
+from langgraph.graph.message import add_messages  # <-- FIXED IMPORT
 from typing_extensions import TypedDict, Annotated
 from typing import Sequence, Dict, List, Optional, Any
 import chromadb
@@ -22,10 +23,13 @@ from datetime import datetime
 from sklearn.metrics.pairwise import cosine_similarity
 
 # ------------------------------
-# State Schema Definition
+# State Schema Definition (Fixed)
 # ------------------------------
 class AgentState(TypedDict):
-    messages: Annotated[Sequence[AIMessage | HumanMessage], add_messages]
+    messages: Annotated[
+        Sequence[AIMessage | HumanMessage], 
+        add_messages  # <-- NOW PROPERLY DEFINED
+    ]
     context: Dict[str, Any]
     metadata: Dict[str, Any]
 
@@ -94,7 +98,7 @@ if not ResearchConfig.DEEPSEEK_API_KEY:
     st.stop()
 
 # ------------------------------
-# ChromaDB Document Manager (Updated)
+# ChromaDB Document Manager
 # ------------------------------
 class QuantumDocumentManager:
     def __init__(self):
@@ -139,6 +143,7 @@ class QuantumDocumentManager:
 qdm = QuantumDocumentManager()
 research_docs = qdm.create_collection(ResearchConfig.DOCUMENT_MAP, "research_papers")
 
+
 # ------------------------------
 # Retrieval System
 # ------------------------------