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This example goes over how to use LangChain to interact with Anthropic models.

NOTE: AnthropicLLM only supports legacy Claude 2 models. To use the newest Claude 3 models, please use ChatAnthropic instead.


%pip install -qU langchain-anthropic

Environment Setup​

We’ll need to get an Anthropic API key and set the ANTHROPIC_API_KEY environment variable:

import os
from getpass import getpass

os.environ["ANTHROPIC_API_KEY"] = getpass()


from langchain_anthropic import AnthropicLLM
from langchain_core.prompts import PromptTemplate

template = """Question: {question}

Answer: Let's think step by step."""

prompt = PromptTemplate.from_template(template)

model = AnthropicLLM(model="claude-2.1")

chain = prompt | model

chain.invoke({"question": "What is LangChain?"})
'\nLangChain is a decentralized blockchain network that leverages AI and machine learning to provide language translation services.'

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