ModuleNotFoundError
builtins.ModuleNotFoundError
Stack trace
Traceback (most recent call last):
File "app.py", line 3, in <module>
from langchain_community import SomeCommunityTool
ModuleNotFoundError: No module named 'langchain_community' Why it happens
This error occurs because langchain_community is an optional extension package that is not included in the core LangChain installation. If your code imports from langchain_community without installing it, Python cannot find the module and raises ModuleNotFoundError.
Detection
Check your import statements for langchain_community and verify if the package is installed in your environment using pip list or pip show langchain-community.
Causes & fixes
langchain_community package is not installed in the Python environment
Install the package via pip using 'pip install langchain-community' to add the missing module.
Virtual environment or container does not include langchain_community despite being required
Ensure your deployment environment or virtualenv includes langchain-community in its requirements.txt or setup scripts.
Typo or incorrect import path for langchain_community in the source code
Verify and correct the import statement to 'from langchain_community import ...' exactly, matching the package name.
Code: broken vs fixed
from langchain_community import SomeCommunityTool # triggers ModuleNotFoundError if not installed
# rest of your codeimport os
from langchain_community import SomeCommunityTool # fixed by installing langchain-community
# rest of your code
# Make sure to install the package:
# pip install langchain-communityWorkaround
If you cannot install langchain-community now, wrap imports in try/except ImportError and disable features that depend on it until the package is installed.
Prevention
Include langchain-community in your project's requirements.txt or environment setup to ensure all dependencies are installed before deployment.