What is LangChain?

On their own, large language models are isolated from your data and your tools. LangChain is the open source framework that connects them to what they need to actually get things done. This two-minute explainer from LangChain Academy shows how building agents has moved from hand-designed workflows to ReAct agents, the simple tool-calling loops behind most agent applications today, and how LangChain's create_agent lets you customize them with things like summarization or human-in-the-loop. It closes with the agent development lifecycle, where LangSmith takes over once the agent is built, from t