How to use LangChain with different Pydantic versions

As of the 0.3 release, LangChain uses Pydantic 2 internally.

Users should install Pydantic 2 and are advised to avoid using the pydantic.v1 namespace of Pydantic 2 with LangChain APIs.

If you're working with prior versions of LangChain, please see the following guide on Pydantic compatibility.