Install & Compatibility
Where this runs
tested against v0.1.21 · pip install
no network on importno background threads
Install × environment matrix
Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux
muslpy 3.10–3.95 runs
installs and imports cleanly · install 0.0s · import 0.164s · 75.3MB
glibcpy 3.10–3.95 runs
installs and imports cleanly · install 8.8s · import 0.158s · 83MB
84MB installed
● package 84MB
Code
Verified usage
Verified import paths — ran on the pinned version, not inferred.
hub
✓ from langchain import hub
✗ from langchainhub import hub
The primary interface for LangChain Hub is exposed through the `langchain` package, not directly from `langchainhub`. This changed in LangChain v0.3 where the 'hub' module (for managing prompts programmatically) was moved to `langchain-classic` or accessed via the `langchain` package itself.
load_prompt
✓ from langchain.prompts import load_prompt
✗ from langchain.hub import load_prompt
While `hub.pull` is used to retrieve content, `load_prompt` for local file loading is part of `langchain.prompts`.
This quickstart demonstrates how to pull a prompt from the LangChain Hub and use it with a LangChain LLM (ChatOpenAI) to form a simple question-answering chain. It assumes an OpenAI API key is available, preferably as an environment variable.
import os
from langchain import hub
from langchain_openai import ChatOpenAI
# Set your API key as an environment variable (or replace with your actual key for testing)
# os.environ["OPENAI_API_KEY"] = os.environ.get("OPENAI_API_KEY", "YOUR_API_KEY")
# Pull a prompt from the LangChain Hub
prompt = hub.pull("hwchase17/q-and-a-prompt")
# Initialize a chat model (requires langchain-openai to be installed)
llm = ChatOpenAI(openai_api_key=os.environ.get("OPENAI_API_KEY", ""))
# Create a simple chain
chain = prompt | llm
# Invoke the chain
response = chain.invoke({"question": "What is the capital of France?", "context": "Paris is the capital of France."})
print(response.content)
Debug
Known issues
breakingWith LangChain v0.3+, the 'hub' module for programmatic prompt management has been refactored. Direct imports like `from langchain import hub` or `from langchain.prompts import load_prompt` should be used, or `langchain-classic` may be required for older patterns.fixEnsure you are importing `hub` from `langchain` (e.g., `from langchain import hub`). If migrating from very old code, you might need to install `langchain-classic` and adjust imports, though current best practice is to use the `langchain` package directly for hub interactions.
affects: LangChain >= 0.3.0
breakingThe `initialize_agent()` function has been removed in LangChain v0.3. When loading agents from LangChain Hub, you should now use factory helpers like `create_react_agent` or other specific agent constructors.fixReplace calls to `initialize_agent()` with specific agent factory functions, for example, `create_react_agent` for React-style agents. Refer to the LangChain documentation for the appropriate factory function for your agent type.
affects: LangChain >= 0.3.0
gotchaLangChain Hub artifacts (prompts, chains, agents) are referenced using 'lc://' URIs. Misspellings or incorrect paths in these URIs will result in loading errors.fixAlways verify the 'lc://' URI for the specific artifact on the LangChain Hub. The format is typically `lc://<user_or_org>/<artifact_type>/<artifact_name>`.
affects: All
Upgrade
Version history
0.1.21latest on PyPI · released Aug 11, 2024
Audit
Dependencies
langchainrequiredProvides core LangChain primitives and the `hub` module for interaction.