Building applications with LLMs through composability
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RN 28f1c5f3c7 "fix: remove extraneous title fields from tool schema and improve handling of nested Pydantic v2 models
- Removes 'title' from all levels of generated schemas for tool calling
- Addresses #32224: tool invocation fails to recognize nested Pydantic v2 schema due to noisy schema and missing definitions
- All tests updated and pass. See PR description for context and follow-up options."
2025-07-26 22:33:06 -07:00
.devcontainer community[minor]: Add ApertureDB as a vectorstore (#24088) 2024-07-16 09:32:59 -07:00
.github fix(docs): temporary workaround until the underlying dependency issues in the AI21 package ecosystem are resolved. (#32248) 2025-07-25 15:12:44 -04:00
cookbook fix: various typos (#32231) 2025-07-24 12:35:08 -04:00
docs fix(docs): update protobuf version constraint to <5.0 in vercel_overrides.txt (#32247) 2025-07-25 15:08:44 -04:00
libs "fix: remove extraneous title fields from tool schema and improve handling of nested Pydantic v2 models 2025-07-26 22:33:06 -07:00
scripts fix: automatically fix issues with ruff (#31897) 2025-07-07 14:13:10 -04:00
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.gitignore [performance]: Adding benchmarks for common langchain-core imports (#30747) 2025-04-09 13:00:15 -04:00
.pre-commit-config.yaml voyageai: remove from monorepo (#31281) 2025-05-19 16:33:38 +00:00
.readthedocs.yaml docs(readthedocs): streamline config (#30307) 2025-03-18 11:47:45 -04:00
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Makefile feat(docs): improve devx, fix Makefile targets (#32237) 2025-07-25 14:49:03 -04:00
MIGRATE.md Proofreading and Editing Report for Migration Guide (#28084) 2024-11-13 11:03:09 -05:00
poetry.toml
pyproject.toml feat(docs): improve devx, fix Makefile targets (#32237) 2025-07-25 14:49:03 -04:00
README.md docs(openai): add comprehensive documentation and examples for extra_body + others (#32149) 2025-07-24 16:43:16 -04:00
reproduce_pydanticv2_test.py test: add reproduction script for pydantic v2 nested schema bug 2025-07-26 22:33:06 -07:00
SECURITY.md docs: fix typos in documentation (#32201) 2025-07-23 10:43:25 -04:00
uv.lock feat(docs): improve devx, fix Makefile targets (#32237) 2025-07-25 14:49:03 -04:00
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Note

Looking for the JS/TS library? Check out LangChain.js.

LangChain is a framework for building LLM-powered applications. It helps you chain together interoperable components and third-party integrations to simplify AI application development — all while future-proofing decisions as the underlying technology evolves.

pip install -U langchain

To learn more about LangChain, check out the docs. If youre looking for more advanced customization or agent orchestration, check out LangGraph, our framework for building controllable agent workflows.

Why use LangChain?

LangChain helps developers build applications powered by LLMs through a standard interface for models, embeddings, vector stores, and more.

Use LangChain for:

  • Real-time data augmentation. Easily connect LLMs to diverse data sources and external / internal systems, drawing from LangChains vast library of integrations with model providers, tools, vector stores, retrievers, and more.
  • Model interoperability. Swap models in and out as your engineering team experiments to find the best choice for your applications needs. As the industry frontier evolves, adapt quickly — LangChains abstractions keep you moving without losing momentum.

LangChains ecosystem

While the LangChain framework can be used standalone, it also integrates seamlessly with any LangChain product, giving developers a full suite of tools when building LLM applications.

To improve your LLM application development, pair LangChain 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.
  • LangGraph - Build agents that can reliably handle complex tasks with LangGraph, our low-level agent orchestration framework. LangGraph offers customizable architecture, long-term memory, and human-in-the-loop workflows — and is trusted in production by companies like LinkedIn, Uber, Klarna, and GitLab.
  • LangGraph Platform - 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.

Additional resources

  • Tutorials: Simple walkthroughs with guided examples on getting started with LangChain.
  • How-to Guides: Quick, actionable code snippets for topics such as tool calling, RAG use cases, and more.
  • Conceptual Guides: Explanations of key concepts behind the LangChain framework.
  • LangChain Forum: Connect with the community and share all of your technical questions, ideas, and feedback.
  • API Reference: Detailed reference on navigating base packages and integrations for LangChain.