LangGraph provides a graph-based abstraction for designing AI agent workflows. Developers define nodes that represent prompts, tools, data sources, or decision logic, then connect these nodes with edges to form a directed graph. At runtime, LangGraph traverses the graph, executing LLM calls, API requests, and custom functions in sequence or in parallel. Built-in support for caching, error handling, logging, and concurrency ensures robust agent behavior. Extensible node and edge templates let users integrate any external service or model, making LangGraph ideal for building chatbots, data pipelines, autonomous workers, and research assistants without complex boilerplate code.