Langgraph Fundamentals

LangGraph models agent workflows as directed graphs. You use a StateGraph to build stateful graphs. Nodes are functions that do work and update state. Edges define the order of execution. State uses reducers to control how updates merge. Graphs must be compiled before running.

When designing a new graph, follow five steps. First, map out the steps of your workflow. Each step becomes a node. Second, decide what each step does. Third, design your state as shared memory for all nodes. Fourth, build your nodes as functions. Fifth, connect nodes with edges and conditional routing. Compile with a checkpointer if needed.

Use LangGraph when you need fine control over agent orchestration. It works well for complex workflows with branching and loops. It also supports human in the loop and persistence. For quick prototyping, use simpler alternatives.