jacoblee93 d7735fb0b2 fix(langgraph): merge configurable dicts across configs in ensure_config
Previously, when ensure_config was called with multiple configs (e.g.
Pregel.stream's ensure_config(self.config, config)), a later config's
configurable dict fully overwrote an earlier one. This caused values
bound via with_config({"configurable": {...}}) to be silently dropped
whenever the invoke-time config supplied any other configurable key.

Concretely, create_agent binds {configurable: {ls_agent_type: 'root'}}
via with_config, and any real invocation with a checkpointer supplies
{configurable: {thread_id: ...}} at invoke time. The bound ls_agent_type
was dropped, so no root-level runs were tagged with ls_agent_type='root'
in LangSmith.

Fix: merge the configurable dict across configs (stdlib merge_configs in
langchain_core already does this correctly; langgraph's merge_configs
helper in this same file also does this at line 109). Invoke-time values
still override bound values when keys collide.

Adds a regression test in tests/test_utils.py.
2026-04-19 03:28:51 -07:00
2026-04-07 17:17:54 -07:00
2026-01-09 15:07:12 -05:00

Low-level orchestration framework for building stateful agents.

PyPI - License PyPI - Downloads Version Twitter / X

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.

pip install -U langgraph

If you're looking to quickly build agents with LangChain's create_agent (built on LangGraph), check out the LangChain Agents documentation.

Note

Looking for the JS/TS library? Check out LangGraph.js and the JS docs.

Why use LangGraph?

LangGraph provides low-level supporting infrastructure for any long-running, stateful workflow or agent:

  • 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.

Tip

For developing, debugging, and deploying AI agents and LLM applications, see LangSmith.

LangGraph 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:

  • Deep Agents (new!) Build agents that can plan, use subagents, and leverage file systems for complex tasks.
  • LangChain Provides integrations and composable components to streamline LLM application development.
  • 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 LangSmith Studio.

Documentation

Discussions: Visit the LangChain Forum to connect with the community and share all of your technical questions, ideas, and feedback.

Additional resources

  • Guides Quick, actionable code snippets for topics such as streaming, adding memory & persistence, and design patterns (e.g. branching, subgraphs, etc.).
  • LangChain Academy Learn the basics of LangGraph in our free, structured course.
  • Case studies Hear how industry leaders use LangGraph to ship AI applications at scale.
  • Contributing Guide Learn how to contribute to LangChain projects and find good first issues.
  • Code of Conduct Our community guidelines and standards for participation.

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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