Caspar BroekhuizenandGitHub d6dea53323 fix(langgraph): dont persist UntrackedValue (#6316)
UntrackedValue is a special channel type where the values in it are not
persisted to memory. Our v1 create_agent middleware used UntrackedValue
in middleware (e.g. ShellToolMiddleware) for some cool features like
temp files.

If a user has elected to use a checkpointer, we normally enforce that
the values they write to channels are serializable. However, this
doesn't make sense to enforce for UntrackedValues because the contract
is they're never written to checkpoint - so the user should not be
forced to make the contents of the channel serializable

However when using a checkpointer and durability sync/async, we found
that writes would still be persisted that contained UntrackedValue
contents in two forms:
a) UntrackedValue channel objects 
b) Send objects - in the state passed to another node

Patched this in put_writes by a) skipping persisting writes to
UntrackedValue channels altogether and b) popping all UntrackedValue kv
pairs nested within Send packets. We also need to sanitize in
_put_checkpoint which is called when durability=="exit".

Added a basic test for UntrackedValue in test_channel.py and added more
comprehensive tests using Send under some different scenarios in
test_pregel.py
2025-10-28 16:40:22 -07:00
2025-10-17 16:54:42 -04:00

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Trusted by companies shaping the future of agents including Klarna, Replit, Elastic, and more LangGraph is a low-level orchestration framework for building, managing, and deploying long-running, stateful agents.

Get started

Install LangGraph:

pip install -U langgraph

Then, create an agent using prebuilt components:

# pip install -qU "langchain[anthropic]" to call the model

from langgraph.prebuilt import create_react_agent

def get_weather(city: str) -> str:
    """Get weather for a given city."""
    return f"It's always sunny in {city}!"

agent = create_react_agent(
    model="anthropic:claude-3-7-sonnet-latest",
    tools=[get_weather],
    prompt="You are a helpful assistant"
)

# Run the agent
agent.invoke(
    {"messages": [{"role": "user", "content": "what is the weather in sf"}]}
)

For more information, see the Quickstart. Or, to learn how to build an agent workflow with a customizable architecture, long-term memory, and other complex task handling, see the LangGraph basics tutorials.

Core benefits

LangGraph provides low-level supporting infrastructure for any long-running, stateful workflow or agent. LangGraph does not abstract prompts or architecture, and provides the following central benefits:

  • Durable execution: Build agents that persist through failures and can run for extended periods, automatically resuming from exactly where they left off.
  • Human-in-the-loop: Seamlessly incorporate human oversight by inspecting and modifying agent state at any point during execution.
  • Comprehensive memory: Create truly stateful agents with both short-term working memory for ongoing reasoning and long-term persistent memory across sessions.
  • Debugging with LangSmith: Gain deep visibility into complex agent behavior with visualization tools that trace execution paths, capture state transitions, and provide detailed runtime metrics.
  • Production-ready deployment: Deploy sophisticated agent systems confidently with scalable infrastructure designed to handle the unique challenges of stateful, long-running workflows.

LangGraphs ecosystem

While LangGraph can be used standalone, it also integrates seamlessly with any LangChain product, giving developers a full suite of tools for building agents. To improve your LLM application development, pair LangGraph with:

  • LangSmith — Helpful for agent evals and observability. Debug poor-performing LLM app runs, evaluate agent trajectories, gain visibility in production, and improve performance over time.
  • LangSmith Deployment — Deploy and scale agents effortlessly with a purpose-built deployment platform for long running, stateful workflows. Discover, reuse, configure, and share agents across teams — and iterate quickly with visual prototyping in LangGraph Studio.
  • LangChain Provides integrations and composable components to streamline LLM application development.

Note

Looking for the JS version of LangGraph? See the JS repo and the JS docs.

Additional resources

  • Guides: Quick, actionable code snippets for topics such as streaming, adding memory & persistence, and design patterns (e.g. branching, subgraphs, etc.).
  • Reference: Detailed reference on core classes, methods, how to use the graph and checkpointing APIs, and higher-level prebuilt components.
  • Examples: Guided examples on getting started with LangGraph.
  • LangChain Forum: Connect with the community and share all of your technical questions, ideas, and feedback.
  • LangChain Academy: Learn the basics of LangGraph in our free, structured course.
  • Templates: Pre-built reference apps for common agentic workflows (e.g. ReAct agent, memory, retrieval etc.) that can be cloned and adapted.
  • Case studies: Hear how industry leaders use LangGraph to ship AI applications at scale.

Acknowledgements

LangGraph is inspired by Pregel and Apache Beam. The public interface draws inspiration from NetworkX. LangGraph is built by LangChain Inc, the creators of LangChain, but can be used without LangChain.

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