📅 2026-04-24 · 8 min read

How to Install and Set Up Claude Code CLI in 2026

Everything you need to know to get Claude Code running on your machine — from installation to your first project.

What is Claude Code?

Claude Code is Anthropic's official CLI tool that brings Claude's coding capabilities directly into your terminal and IDE. Unlike browser-based Claude, it can read your codebase, edit files, run commands, and work with git — making it a genuine pair programming partner rather than just a chat interface.

Prerequisites

Before installing Claude Code, make sure you have:

• Node.js 18+ — Required runtime (v22+ recommended)
• An Anthropic API key — Or a Claude Pro/Max subscription that includes CLI access
• Git — For version control integration
• A terminal — macOS Terminal, Windows Terminal, or any Linux shell

Installation Steps

Installation is straightforward via npm:

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

Verify the installation:

claude --version

Authentication

Claude Code supports two authentication methods:

Option 1: API Key — Set your Anthropic API key as an environment variable:

export ANTHROPIC_API_KEY="sk-ant-..."

Option 2: OAuth Login — If you have a Claude Pro/Max subscription:

claude login

This opens a browser window for OAuth authentication. Your credentials are stored locally and encrypted.

Your First Project

Navigate to any codebase and start Claude Code:

cd your-project
            claude

Claude Code automatically reads your project structure, understands the codebase context, and is ready to help. You can ask it to explain code, fix bugs, add features, refactor, or write tests — all with full awareness of your project's files and architecture.

IDE Integration

Claude Code integrates with popular IDEs:

• VS Code — Install the Claude Code extension from the marketplace. Use Ctrl+K to invoke Claude inline.
• JetBrains — Plugin available for IntelliJ, PyCharm, WebStorm, and other JetBrains IDEs.
• Terminal-only — Works perfectly in any terminal with full file editing capabilities.

Best Practices

To get the most out of Claude Code:

1. Use CLAUDE.md files — Create a CLAUDE.md in your project root with coding standards, architecture notes, and conventions. Claude reads this automatically.
2. Be specific in requests — "Fix the null pointer exception in UserService.java line 42" works better than "fix the bug."
3. Leverage the conversation context — Claude remembers everything in the current session. Build on previous answers rather than starting fresh each time.
4. Review before committing — Always review Claude's suggested changes before accepting. Use git diff to inspect modifications.
5. Use permission modes wisely — Start in "plan" mode for complex tasks, then switch to "auto" when you're confident in the approach.

Troubleshooting Common Issues

"Node.js version too old" — Update to Node.js 18+ using nvm or your system package manager.

"Authentication failed" — Verify your API key is correct and hasn't expired. Check that ANTHROPIC_API_KEY is set in your shell profile.

"Permission denied" — On macOS/Linux, you may need to fix npm permissions: sudo chown -R $(whoami) $(npm config get prefix)/{lib/node_modules,bin,share}