LangGraph.js Agent Builder

Build stateful, multi-step AI agents in TypeScript with LangGraph.js. Design agent graphs and state machines, wire tool nodes, add checkpointing and human-in-the-loop, and debug, test, and optimize long-running workflows.

This skill helps you create and maintain LangGraph.js agents. It models control flow as graphs and state machines, adds tool-calling nodes, persists state with checkpointers for durable and resumable runs, inserts human-in-the-loop approval steps, and covers testing and optimization patterns for @langchain/langgraph in TypeScript and JavaScript.

When to use

Use when building agentic AI workflows in TypeScript/JavaScript that need branching, loops, persistent state, tool calling, or human approval steps.

Examples

Build a tool-using agent graph

Graph with tool nodes and state

Build a LangGraph.js agent that answers questions, calls a search tool and a calculator, and loops until it has a final answer

Add human-in-the-loop approval

Pause for review before acting

Add a checkpointer and a human-in-the-loop interrupt so my LangGraph.js agent waits for approval before sending an email