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MongoDB + RAG + Galileo overview

MongoDB Atlas Vector Search lets you keep your knowledge base inside MongoDB while enjoying hybrid search and AI-ready workloads.
In this guide you’ll:
  1. Embed and store vectors in Atlas
  2. Setup Galileo
  3. Stream LangGraph traces to Galileo for end-to-end observability

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Set up MongoDB

Sign up to MongoDB Atlas and set up your credentials. You can setup the vector store as follows: 
from langchain_mongodb import MongoDBAtlasVectorSearch
from langchain_openai import OpenAIEmbeddings
from pymongo import MongoClient

client          = MongoClient(MONGODB_URI)
DB_NAME         = "rag_demo"
COLLECTION_NAME = "blog_vectors"

collection = client[DB_NAME][COLLECTION_NAME]
embeddings = OpenAIEmbeddings()

vector_store = MongoDBAtlasVectorSearch(
    collection    = collection,
    embedding     = embeddings,
    index_name    = "rag-index",
    relevance_score_fn = "cosine"
)

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Use Galileo for logging

import os
from galileo.handlers.langchain import GalileoCallback

# --- Galileo ---
os.environ["GALILEO_API_KEY"] = "<galileo-key>"
os.environ["GALILEO_PROJECT"] = "<galileo-project>"
os.environ["GALILEO_LOG_STREAM"] = "mongo_rag_demo"
# os.environ["GALILEO_CONSOLE_URL"] = "<galileo-console-url>" # You can leave this commented out if you are using app.galileo.ai

galileo_handler = GalileoCallback()
Once the callback is created we can add it to the agent. 
query = "What types of agent memory does Lilian Weng describe?"
inputs = {"messages": [HumanMessage(content=query)]}

result = graph.invoke(
    inputs,
    config={"recursion_limit": 5, "callbacks": [galileo_handler]}
)
Find the full notebook here