LangGraph is a module built on top of LangChain that facilitates the creation of cyclical graphs, which are essential for developing agent runtimes. It is fully interoperable with the LangChain ecosystem and enhances the ability to introduce cycles into custom chains, allowing for more complex and flexible applications. These applications, often termed agents, can perform reasoning tasks by running in loops, offering a more adaptable approach to vague use cases. LangGraph introduces a StateGraph class for defining these cycles through nodes and edges, with nodes representing functions or operations that update a central state over time. This setup allows for the creation of state machines, offering controlled flows and the ability to handle ambiguous inputs. The platform supports modifications like forced tool calls and human-in-the-loop steps, and it provides a framework for chat models to operate on message sequences. Future developments for LangGraph include advanced agent runtimes, stateful tools, and more controlled workflows, aiming to enable more custom and powerful agent runtimes.