LangGraph

Overview

LangGraph is a framework for building stateful, multi-actor AI applications as graphs. Unlike simple chains, LangGraph supports cycles, branching, persistence, and human-in-the-loop — essential for real-world agents that need to plan, retry, delegate, and remember state across interactions.

Instructions

Step 1: Installation

pip install -U langgraph langchain langchain-openai
# For persistence across restarts:
pip install langgraph-checkpoint-sqlite  # or langgraph-checkpoint-postgres
export OPENAI_API_KEY="..." OPENAI_MODEL="..."   # key and a model id from your provider; code below reads OPENAI_MODEL

Step 2: Core Concepts