The outcome

Build a stateful workflow that can resume safely after interruption without silently repeating consequential work.

LangGraph is a open-source orchestration framework and runtime for long-running stateful agents. Designing stateful agent workflows that require explicit control flow, durable checkpoints, streaming, recovery, memory, and human-in-the-loop decisions. This guide narrows that broad capability into one repeatable outcome, with checkpoints that keep the source material and your judgment in the loop.

Before you begin

Set the boundary before the tool starts.

Choose one real task, identify who will use the result, and decide what evidence or test will make the result acceptable. Gather only the source material needed for that task. If the work contains confidential, personal, regulated, or client-owned information, confirm that the platform and account are approved before sharing it.

Troiana principle

AI should make the work easier to inspect. If the workflow removes the source, the owner, or the review step, redesign the workflow.

Step by step

A workflow you can repeat.

  1. 01

    Define a JSON-serializable state schema, start and end conditions, node responsibilities, reducers, and invariant checks.

  2. 02

    Separate deterministic logic, model calls, and external side effects into small nodes or tasks with explicit error outcomes.

  3. 03

    Compile with a persistent checkpointer, assign stable thread IDs, and make side-effecting operations idempotent.

  4. 04

    Test success, branch conditions, node failure, process restart, replay, concurrent resume, and state migration scenarios.

  5. 05

    Inspect state history and traces, then document retry ownership, checkpoint retention, schema versions, and recovery procedures.

Working standard

What good use looks like.

  • Keep state serializable and minimal.
  • Make side effects idempotent.
  • Test resumption, not only first execution.

Durable replay can repeat model calls or external effects unless nodes are designed carefully. Protect persisted state, isolate tenants and threads, use idempotency, control checkpoint retention, and test every interruption and resumption path.

Official references

Check the current product documentation.

Features, plan limits, availability, and data controls change. These official pages are the starting points used for this collection.