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name: langchain-install-auth description: | Install and configure LangChain SDK/CLI authentication. Use when setting up a new LangChain integration, configuring API keys, or initializing LangChain in your project. Trigger with phrases like "install langchain", "setup langchain", "langchain auth", "configure langchain API key", "langchain credentials". allowed-tools: Read, Write, Edit, Bash(npm:), Bash(pip:), Grep version: 1.0.0 license: MIT author: Jeremy Longshore jeremy@intentsolutions.io

LangChain Install & Auth

Overview

Set up LangChain SDK and configure LLM provider authentication credentials.

Prerequisites

• Python 3.9+ or Node.js 18+
• Package manager (pip, poetry, or npm)
• LLM provider account (OpenAI, Anthropic, Google, etc.)
• API key from your LLM provider dashboard

Instructions

Step 1: Install LangChain Core

Copy# Python (recommended)
pip install langchain langchain-core langchain-community

# Or with specific providers
pip install langchain-openai langchain-anthropic langchain-google-genai

# Node.js
npm install langchain @langchain/core @langchain/community

Step 2: Configure Authentication

Copy# OpenAI
export OPENAI_API_KEY="your-openai-key"

# Anthropic
export ANTHROPIC_API_KEY="your-anthropic-key"

# Google
export GOOGLE_API_KEY="your-google-key"

# Or create .env file
echo 'OPENAI_API_KEY=your-openai-key' >> .env

Step 3: Verify Connection

Copyfrom langchain_openai import ChatOpenAI

llm = ChatOpenAI(model="gpt-4o-mini")
response = llm.invoke("Say hello!")
print(response.content)

Output

• Installed LangChain packages in virtual environment
• Environment variables or .env file with API keys
• Successful connection verification output

Error Handling

Examples

Python Setup (OpenAI)

Copyimport os
from langchain_openai import ChatOpenAI

# Ensure API key is set
assert os.environ.get("OPENAI_API_KEY"), "Set OPENAI_API_KEY"

llm = ChatOpenAI(
    model="gpt-4o-mini",
    temperature=0.7,
    max_tokens=1000
)

Python Setup (Anthropic)

Copyfrom langchain_anthropic import ChatAnthropic

llm = ChatAnthropic(
    model="claude-3-5-sonnet-20241022",
    temperature=0.7
)

TypeScript Setup

Copyimport { ChatOpenAI } from "@langchain/openai";

const llm = new ChatOpenAI({
  modelName: "gpt-4o-mini",
  temperature: 0.7
});

Resources

• LangChain Documentation
• LangChain JS/TS
• OpenAI API Keys
• Anthropic Console

Next Steps

After successful auth, proceed to langchain-hello-world for your first chain.