langchain-ai/langchain

core: docstrings shouldn't inherit from parents

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#32,066 opened on Jul 16, 2025

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corehelp wantedinternalv1

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Description

from langchain_core.tools import tool
from pydantic import BaseModel


class MyTool(BaseModel):
    """Parent Tool"""
    foo: str

@tool
class ChildTool(MyTool):
    bar: str

For 0.4 release we could consider updating the behavior so that doc-strings are not inherited from their parents. It's fairly odd that doc-strings are inherited for BaseModels as in general the descriptions need to be different

Originally posted by @eyurtsev in #31606

Contributor guide

Research direction
Investigate how docstrings are inherited in Pydantic BaseModel subclasses and modify the inheritance behavior so that child classes do not inherit docstrings from parent classes when the child class defines its own docstring. Ensure the @tool decorator works correctly with the new behavior.
Tech stack
python
Domain
backendapi
Issue type
Bug
DifficultyEstimated implementation difficulty for a new contributor, from 1 for very small changes to 5 for expert-level work.
2
Estimated timeA rough time range for an experienced contributor to investigate, implement, test, and prepare a pull request.
1-3 hours
Activity statusHow available the issue appears right now: fresh, active, stale, blocked, or waiting on maintainer input.
Active
ClarityHow clearly the issue explains the expected change, acceptance criteria, and next step.
Clear
Prerequisites
PythonPydanticGit
Newbie friendlinessA 1-100 score estimating how approachable this issue is for first-time contributors.
60