Files
langchain/libs/core
Yu Zhong fca1aaa9b5 fix(core): force overwrite additionalProperties to False in strict mode (#32879)
# Description
This PR fixes a bug in _recursive_set_additional_properties_false used
in function_calling.convert_to_openai_function.

Previously, schemas with "additionalProperties=True" were not correctly
overridden when strict validation was expected, which could lead to
invalid OpenAI function schemas.

The updated implementation ensures that:
- Any schema with "additionalProperties" already set will now be forced
to False under strict mode.
- Recursive traversal of properties, items, and anyOf is preserved.
- Function signature remains unchanged for backward compatibility.

# Issue
When using tool calling in OpenAI structured output strict mode
(strict=True), 400: "Invalid schema for response_format XXXXX
'additionalProperties' is required to be supplied and to be false" error
raises for the parameter that contains dict type. OpenAI requires
additionalProperties to be set to False.
Some PRs try to resolved the issue.
- PR #25169 introduced _recursive_set_additional_properties_false to
recursively set additionalProperties=False.
- PR #26287 fixed handling of empty parameter tools for OpenAI function
generation.
- PR #30971 added support for Union type arguments in strict mode of
OpenAI function calling / structured output.

Despite these improvements, since Pydantic 2.11, it will always add
`additionalProperties: True` for arbitrary dictionary schemas dict or
Any (https://pydantic.dev/articles/pydantic-v2-11-release#changes).
Schemas that already had additionalProperties=True in such cases were
not being overridden, which this PR addresses to ensure strict mode
behaves correctly in all cases.

# Dependencies
No Changes

---------

Co-authored-by: Zhong, Yu <yzhong@freewheel.com>
2025-09-11 11:02:12 -04:00
..
2025-09-10 14:10:44 +00:00

🦜🍎 LangChain Core

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Quick Install

pip install langchain-core

What is it?

LangChain Core contains the base abstractions that power the 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.

For full documentation see the API reference.

⛰️ 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.

1 Core Interface: Runnables

The concept of a Runnable is central to LangChain Core it is the interface that most LangChain Core components implement, giving them

  • A common invocation interface (invoke(), batch(), stream(), etc.)
  • Built-in utilities for retries, fallbacks, schemas and runtime configurability
  • Easy deployment with LangGraph

For more check out the Runnable docs. Examples of components that implement the interface include: Chat Models, Tools, Retrievers, and Output Parsers.

📕 Releases & Versioning

As langchain-core contains the base abstractions and runtime for the whole LangChain ecosystem, we will communicate any breaking changes with advance notice and version bumps. The exception for this is anything in langchain_core.beta. The reason for langchain_core.beta is that given the rate of change of the field, being able to move quickly is still a priority, and this module is our attempt to do so.

Minor version increases will occur for:

  • Breaking changes for any public interfaces NOT in langchain_core.beta

Patch version increases will occur for:

  • Bug fixes
  • New features
  • Any changes to private interfaces
  • Any changes to langchain_core.beta

💁 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.