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Installing and Authenticating Claude Code

In Lesson 1, you learned why Claude Code is revolutionary. Now comes the crucial step: getting it working on your machine.

This isn't just about following installation commands. It's about crossing the bridge from "interesting concept" to "tool I can actually use." By the end of this lesson, Claude Code will be installed, authenticated, and ready to assist with your development work.

🔀 Two Professional Paths Available​

This lesson covers the official Claude subscription setup (Pro $20/month or Max $200/month). If you prefer a free/minimal cost alternative, see Lesson 3: Free Claude Code Setup.

Both paths teach identical Claude Code skills (subagents, skills, MCP, hooks covered in Lessons 05-13).

PathCostWhat You Get
This Lesson (Official)Pro: $20/month
Max: $200/month		Official Anthropic models (Claude Sonnet/Opus), direct integration, official support
Lesson 3 (Free/Minimal)$0 (free tier)
Pay-as-you-go option		Use Claude Code agent with any LLM (Gemini, GPT, local models), backend abstraction architecture

Key difference: Official path uses Anthropic's Claude models. Free path lets you use Claude Code's agentic architecture with any LLM backend through production-grade API routing.

Prerequisites: What You Need Before Installing​

Before we begin, verify you have the following:

1. Terminal Access

  • Windows: Command Prompt, PowerShell, or Windows Terminal
  • macOS: Terminal app (Applications → Utilities → Terminal)
  • Linux: Any terminal emulator (GNOME Terminal, Konsole, etc.)
  • WSL Users: Any WSL 2 terminal with Ubuntu 20.04+ or Debian 10+

2. Claude Account (one of the following):

3. System Requirements

  • macOS: 13 (Ventura) or later
  • Windows: Windows 10 or later
  • Linux: Ubuntu 20.04+ / Debian 10+
  • RAM: 8GB minimum

4. Optional (for npm installation only)

  • Node.js: Version 18 or later (only required if using npm installation method)
  • Deprecated: NPM installation is deprecated. Use the native installation method when possible.

Installation​

Claude Code installation has been simplified with official installers for each platform. Choose your operating system tab below to see platform-specific installation methods.

⚠️ Important: Claude Code requires a bash-compatible shell to run. On Windows, you need either WSL or Git for Windows installed—the installer downloads Claude Code, but it runs inside a bash shell.

Decision Tree:

Which shell environment do you have (or want to install)?
├─ WSL (Windows Subsystem for Linux)
│   └─ Method 1 (WSL) - RECOMMENDED for best experience
│
├─ Git for Windows (Git Bash)
│   └─ Method 2 (Git Bash + PowerShell installer)
│
├─ Neither installed yet
│   └─ Install WSL first (see below), then use Method 1
│
└─ I have Node.js 18+ in WSL or Git Bash
    └─ Method 3 (npm) - See Cross-Platform npm section below

Why recommended: Full Linux environment, best compatibility, recommended by Anthropic.

Step 1: If you don't have WSL, install it first (run in PowerShell as Administrator):

wsl --install

Restart your computer after installation.

Step 2: Open your WSL terminal (Ubuntu) and run:

curl -fsSL https://claude.ai/install.sh | bash

What this does: Downloads and executes the official installer script in your Linux environment.

Requirements: Windows 10 version 2004+ or Windows 11, WSL 1 or WSL 2

Method 2: Native Windows (PowerShell or CMD)​

When to use: You want to run Claude Code natively on Windows without WSL.

Option A - PowerShell:

irm https://claude.ai/install.ps1 | iex

Option B - Command Prompt (CMD):

curl -fsSL https://claude.ai/install.cmd -o install.cmd && install.cmd && del install.cmd

Requirements: Windows 10+, Git for Windows (provides the bash shell Claude Code needs)

Step 1: Install Git for Windows if not already installed.

Step 2: Run one of the install commands above.

Step 3: For portable Git installations, configure the bash path (run in PowerShell):

$env:CLAUDE_CODE_GIT_BASH_PATH="C:\Program Files\Git\bin\bash.exe"

To make this permanent, add to your PowerShell profile:

notepad $PROFILE
# Add the line: $env:CLAUDE_CODE_GIT_BASH_PATH="C:\Program Files\Git\bin\bash.exe"

Step 4: Run Claude Code:

claude

What this does: The installer downloads Claude Code; Git for Windows provides the bash shell it runs in.

Windows Installation Guide

For a detailed step-by-step Windows installation guide with screenshots, see: Claude Code Installation for Windows

Windows Verification​

Open your shell (WSL terminal or Git Bash) and check your installation:

claude --version

Expected output:

X.X.XX (Claude Code)

(Your version number will differ—Claude Code auto-updates frequently.)

💬 AI Colearning Prompt​

"Explain the difference between WSL and Git Bash for Windows developers. When would you choose one over the other for AI-native development workflows?"

Cross-Platform: npm Installation​

When to use this method:

  • You already have Node.js 18+ installed
  • You prefer npm-based workflows
  • You need to manage Claude Code versions via package.json
  • Your platform isn't officially supported by platform-specific installers
  • Deprecated: NPM installation is deprecated. Use the native installation method when possible.

Platforms: Windows, macOS, Linux, WSL

Open your terminal and run:

npm install -g @anthropic-ai/claude-code

What this does: Installs Claude Code globally via npm package manager.

Requirements: Node.js 18 or later (includes npm)

Check Node.js version:

node --version

If you see v18.0.0 or higher, you're good to go.

💬 AI Colearning Prompt​

"Explain the trade-offs between platform-specific installers (Homebrew, PowerShell) vs npm. When would a developer choose npm over the platform installer?"

Auto-Update Configuration​

Claude Code automatically checks for updates and prompts you to install them. To disable auto-updates (useful for corporate environments or version pinning):

macOS/Linux/WSL:

export DISABLE_AUTOUPDATER=1

Add to your shell profile (~/.bashrc, ~/.zshrc, etc.) to make permanent.

Windows PowerShell:

$env:DISABLE_AUTOUPDATER=1

Add to your PowerShell profile ($PROFILE) to make permanent.

Manual update check:

claude update

Advanced: System Diagnostics​

After installation, verify your system configuration:

claude doctor

What this checks:

  • Installation integrity
  • Authentication status
  • System compatibility
  • Network connectivity to Claude API

Use this command if you encounter issues during installation or authentication.

🎓 Expert Insight​

In AI-native development, terminal comfort is a skill multiplier. The 5 minutes you invest learning basic terminal commands unlocks 10x productivity with AI tools. You're not becoming a "terminal expert"—you're removing the friction between intent and execution.

Uninstallation​

If you need to remove Claude Code (for reinstallation or troubleshooting):

macOS/Linux/WSL (Native Install):

rm -f ~/.local/bin/claude
rm -rf ~/.claude-code
rm ~/.claude.json

Windows PowerShell:

Remove-Item -Path "$env:LOCALAPPDATA\Programs\claude-code" -Recurse -Force
Remove-Item -Path "$env:LOCALAPPDATA\Microsoft\WindowsApps\claude.exe" -Force

Homebrew:

brew uninstall --cask claude-code

npm:

npm uninstall -g @anthropic-ai/claude-code

Optional: Remove Configuration Files

To also remove your settings and credentials:

macOS/Linux/WSL:

rm -rf ~/.claude
rm ~/.claude.json

Windows PowerShell:

Remove-Item -Path "$env:USERPROFILE\.claude" -Recurse -Force
Remove-Item -Path "$env:USERPROFILE\.claude.json" -Force

Authentication: Connecting Claude Code to Your Account​

Once installed, Claude Code needs to authenticate with your Claude account. There are three authentication paths depending on your account type and use case.

Which Authentication Method Should I Use?​

Decision Tree:

What type of Claude access do you have?
├─ Claude.ai subscription (Pro, Max, Team)
│   └─ Method 1: Claude App Authentication (MOST COMMON)
│
├─ Claude Console account with API credits
│   └─ Method 2: Console API Authentication
│
└─ Enterprise account (Bedrock, Vertex AI, Foundry)
    └─ Method 3: Enterprise Authentication

If you have both subscription and Console API: Use Method 1 (Claude App)—it's simpler and provides unified access.

🎓 Expert Insight​

In AI-native development, authentication isn't just about access—it's about resource management. Claude.ai (subscription) vs Console API (pay-per-use) vs Enterprise (dedicated capacity) represents different cost models and usage patterns. Understanding your workflow determines which path saves money.

Method 1: Claude App Authentication (Most Common)​

Who this is for: Users with Claude Pro ($20/month), Claude Max ($200/month), or Team subscriptions.

Benefits: Unified access across Claude web app and Claude Code, simpler authentication flow.

In your terminal, run:

claude

Expected output:

 Claude Code can be used with your Claude subscription or billed based on API usage through your
 Console account.

 Select login method:

 ❯ 1. Claude account with subscription · Pro, Max, Team, or Enterprise

   2. Anthropic Console account · API usage billing

Select Option 1. Your default browser opens to Claude.ai authentication. Log in, review permissions, and authorize.

Return to your terminal. You should see:

Logged in as mr.abc@gmail.com
Login successful. Press Enter to continue

Test your setup:

claude "Hello! Can you confirm Claude Code is working?"

Expected output: Claude responds confirming the connection works.

🤝 Practice Exercise​

Ask your AI: "I just installed Claude Code. Create a simple 'Hello World' workflow that: (a) shows me Claude can read a file, (b) proposes a small change, (c) explains what it did. Use a safe test file."

Expected Outcome: Confidence that Claude Code can read, propose changes, and explain actions—plus understanding of the approval workflow.

Method 2: Console API Authentication (Developers)​

Who this is for: Developers with Claude Console API credits but no Claude.ai subscription. Pay-per-use model based on token consumption.

Use case: API-first workflows, programmatic access, usage-based billing.

In your terminal, run:

claude

Expected output:

 Claude Code can be used with your Claude subscription or billed based on API usage through your
 Console account.

 Select login method:

   1. Claude account with subscription · Pro, Max, Team, or Enterprise

 ❯ 2. Anthropic Console account · API usage billing

Select Option 2. Go to https://console.anthropic.com/settings/keys, create an API key, copy it, and paste when prompted.

You should see:

API key validated successfully
Login successful. Press Enter to continue

Test your setup:

claude "Hello! Can you confirm Claude Code is working?"

Expected output: Claude responds confirming the connection works.

⚠️ Important for Console API Users:

  • Set usage limits in Console: https://console.anthropic.com/settings/limits
  • Monitor token usage (displayed after each interaction)
  • Console authentication uses API billing, not subscription credits
  • Consider cost management strategies for high-volume usage

Method 3: Enterprise Authentication (Advanced)​

Who this is for: Enterprise customers using Amazon Bedrock, Google Vertex AI, or Anthropic Foundry (dedicated capacity).

Use case: Organizations with existing cloud infrastructure, compliance requirements, or dedicated capacity needs.

Platform Options:

Amazon Bedrock Integration​

Claude Code can authenticate with Claude via AWS Bedrock:

Requirements:

  • AWS account with Bedrock access
  • Claude models enabled in Bedrock
  • AWS CLI configured with appropriate credentials

Configuration: Contact your Enterprise administrator for Bedrock configuration details specific to your organization.

Google Vertex AI Integration​

Claude Code can authenticate with Claude via Google Cloud Vertex AI:

Requirements:

  • Google Cloud account with Vertex AI access
  • Claude models enabled in Vertex AI
  • Google Cloud SDK configured

Configuration: Contact your Enterprise administrator for Vertex AI configuration details specific to your organization.

Anthropic Foundry​

Claude Code can connect to dedicated Claude capacity via Anthropic Foundry:

Requirements:

  • Anthropic Foundry account with dedicated capacity
  • Enterprise API keys

Configuration: Contact your Anthropic Enterprise support for Foundry setup.

📚 Enterprise Documentation: For detailed enterprise configuration, see https://docs.anthropic.com/en/api/claude-on-amazon-bedrock or contact your Enterprise administrator.

Security and Best Practices​

Before moving forward, let's address important security considerations:

1. File System Access

  • Claude Code can read and write files in directories where you run it
  • Best Practice: Start Claude Code sessions in project directories, not system directories
  • Review file changes Claude proposes before approving them

2. Command Execution

  • Claude Code can execute terminal commands with your permissions
  • Best Practice: Review commands Claude suggests, especially sudo or administrative commands
  • Claude Code will ask for approval before executing destructive actions

3. Cost Management (Console API Users)

Try With AI​

Now that Claude Code is installed, let's build confidence through safe exploration and establish good security practices.

🛡️ Establish Safety Boundaries:

"I just installed Claude Code and I'm nervous about file access and command execution. Help me set up safe boundaries: What directories should I AVOID running Claude Code in? What commands should I NEVER approve without careful review? Create a practical safety checklist I can follow until I'm more comfortable."

🎯 Practice First Commands:

"I completed installation successfully! Give me 3-5 safe 'Hello World' style prompts I can try RIGHT NOW that will: (a) verify Claude Code works, (b) won't modify important files, (c) demonstrate basic capabilities. Include what I should expect to see for each prompt."

🧪 Test Your Installation:

"Walk me through testing my Claude Code installation step-by-step. Start with checking the version, then test file reading (on a safe test file), then test a simple command execution (like checking current directory). Explain what each output means and how to know if something's wrong."

🚀 Configure for Your Workflow:

"I work primarily with [describe your tech stack: Python/JavaScript/Go/etc.]. Help me verify Claude Code can handle my environment: check for required tools, test reading my project structure, and suggest first productive task I could try that's relevant to my actual work."