Customer Support Chatbot with LangChain

from langchain_openai import ChatOpenAI
from langchain_core.tools import tool

@tool
def search_faq(query: str) -> str:
    """Search the FAQ knowledge base for relevant answers."""
    results = faq_store.similarity_search(query, k=3)
    return "\n\n".join(
        f"Q: {r.metadata['question']}\nA: {r.page_content}"
        for r in results
    )

model = ChatOpenAI(model="gpt-4o")
model_with_tools = model.bind_tools([search_faq])
response = model_with_tools.invoke([
    ("system", "You are a helpful customer support agent. Use search_faq to find answers from the knowledge base before responding. Always cite the source FAQ."),
    ("user", "How do I reset my password?"),
])