Update app.py

app.py

@@ -116,7 +116,7 @@
 import os
 import sys
 import requests
-from langchain.chains import ConversationalRetrievalChain
+from langchain.chains import ConversationalRetrievalChain, LLMChain
 from langchain.document_loaders import PyPDFLoader, Docx2txtLoader, TextLoader
 from langchain.text_splitter import CharacterTextSplitter
 from langchain.vectorstores import Chroma
@@ -223,10 +223,27 @@ prompt = PromptTemplate(
 # 🔗 QA chain with custom prompt
 qa_chain = load_qa_chain(llm, chain_type="stuff", prompt=prompt)
 
-# 🔗 Conversational chain
-chain = ConversationalRetrievalChain.from_llm(
+# 🔷 Question rephraser chain for follow-up questions → standalone
+CONDENSE_QUESTION_PROMPT = PromptTemplate.from_template(
+    """
+Given the following conversation and a follow-up question, rephrase the follow-up question to be a standalone question.
+
+Chat History:
+{chat_history}
+Follow Up Input: {question}
+Standalone question:
+"""
+)
+
+question_generator = LLMChain(
     llm=llm,
+    prompt=CONDENSE_QUESTION_PROMPT
+)
+
+# 🔷 Finally: build the ConversationalRetrievalChain manually
+chain = ConversationalRetrievalChain(
     retriever=vectorstore.as_retriever(search_kwargs={'k': 6}),
+    question_generator=question_generator,
     combine_docs_chain=qa_chain,
     return_source_documents=True,
     verbose=False
@@ -255,3 +272,4 @@ with gr.Blocks() as demo:
 demo.launch(debug=True)  # remove share=True if running in HF Spaces
 
 
+