📘 Lecture notes

Checkpoints

Checkpoints in LangGraph are a snapshot of the graph state. This is how AI applications built using LangGraph persist short-term and long-term memory.

Thread IDs

Thread IDs are unique IDs assigned to memory checkpoints in LangGraph, allowing it to distinguish between conversation threads, facilitate human-in-the loop workflows and allow users to review and debug graph executions.

Persisting checkpoints in MongoDB

In this lab, you will persist the short-term memory of the agent in MongoDB. To do this, compile the agent's graph with the MongoDB checkpointer available in our LangGraph integration as follows:

from langgraph.checkpoint.mongodb import MongoDBSaver
checkpointer = MongoDBSaver(mongodb_client)
app = graph.compile(checkpointer=checkpointer)

Refer to this documentation to learn more about the MongoDB checkpointer for LangGraph.