Files
langchain/libs/core
Weichen Zhao d899681040 feat(core): add XML format option for get_buffer_string (#34802)
## Summary

Add XML format option for `get_buffer_string()` to provide unambiguous
message serialization. This fixes role prefix ambiguity when message
content contains strings like "Human:" or "AI:".

  Fixes #34786

  ## Changes

- Add `format="xml"` parameter with proper XML escaping using
`quoteattr()` for attributes
- Add explicit validation for format parameter (raises `ValueError` for
invalid values)
  - Add comprehensive tests for XML format edge cases

<img width="1952" height="706" alt="image"
src="https://github.com/user-attachments/assets/1cd6f887-9365-43cf-a532-72d7addd8bad"
/>
<img width="2786" height="776" alt="image"
src="https://github.com/user-attachments/assets/a07b0db0-519c-46d7-b34b-b404237d812b"
/>

---------

Co-authored-by: Mason Daugherty <github@mdrxy.com>
Co-authored-by: Mason Daugherty <mason@langchain.dev>
2026-01-22 13:33:08 -05:00
..
2026-01-13 01:54:11 -05:00

🦜🍎 LangChain Core

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

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Quick Install

pip install langchain-core

🤔 What is this?

LangChain Core contains the base abstractions that power the LangChain ecosystem.

These abstractions are designed to be as modular and simple as possible.

The benefit of having these abstractions is that any provider can implement the required interface and then easily be used in the rest of the LangChain ecosystem.

⛰️ Why build on top of LangChain Core?

The LangChain ecosystem is built on top of langchain-core. Some of the benefits:

  • Modularity: We've designed Core around abstractions that are independent of each other, and not tied to any specific model provider.
  • Stability: We are committed to a stable versioning scheme, and will communicate any breaking changes with advance notice and version bumps.
  • Battle-tested: Core components have the largest install base in the LLM ecosystem, and are used in production by many companies.

📖 Documentation

For full documentation, see the API reference. For conceptual guides, tutorials, and examples on using LangChain, see the LangChain Docs.

📕 Releases & Versioning

See our Releases and Versioning policies.

💁 Contributing

As an open-source project in a rapidly developing field, we are extremely open to contributions, whether it be in the form of a new feature, improved infrastructure, or better documentation.

For detailed information on how to contribute, see the Contributing Guide.