The Complete Guide to Claude Code: From Installation to Productive Coding

What Is Claude Code

Claude Code is Anthropic's official AI coding assistant that runs directly in your terminal. It understands your entire codebase, helps you write, debug, and refactor code, and integrates deeply with Git. Unlike traditional code completion tools, Claude Code is a true agentic coding tool — it can autonomously read files, run commands, edit multiple files, and manage your version control workflow.

No IDE plugins or complex setup required. One command to install, and it works right in your terminal.

Installation and Setup

Requirements

Node.js 18 or later
macOS, Linux, or Windows (via WSL)
An Anthropic API key or Claude subscription

Getting Started

# Install Claude Code globally
npm install -g @anthropic-ai/claude-code

# Navigate to your project
cd your-project

# Launch Claude Code
claude

On first launch, Claude Code will guide you through authentication. You can use an Anthropic API key or sign in with a Claude Max subscription.

Configuration

Claude Code supports layered configuration:

Global settings: ~/.claude/settings.json — applies to all projects
Project settings: .claude/settings.json in your project root — project-specific
Project instructions: CLAUDE.md file — provides Claude with project context and coding standards

Core Features

Agentic Coding

Claude Code can autonomously complete complex programming tasks. Just describe your goal, and it will:

Analyze project structure and relevant files
Develop an implementation plan
Edit multiple files simultaneously
Run tests to verify results

# Example: ask Claude to implement a feature
> Add email verification to the user model, including sending a verification link and a confirmation endpoint

Multi-File Editing

Claude Code can modify multiple files in a single conversation, understanding dependencies between files to ensure consistency across your entire codebase.

Deep Git Integration

Claude Code works seamlessly with Git:

Auto-generates conventional commit messages
Creates Pull Requests with descriptions
Resolves merge conflicts
Reviews code changes

# Let Claude commit your changes
> Commit my current changes with an appropriate message

# Let Claude create a PR
> Create a PR from this branch to main

Terminal Command Execution

Claude Code runs commands directly in the terminal — running tests, installing dependencies, starting services — no window switching required.

Essential Slash Commands

Command	Description
`/help`	Show help information
`/clear`	Clear current conversation context
`/compact`	Compress conversation history to free up context space
`/init`	Initialize a CLAUDE.md file for your project
`/cost`	Display token usage for the current session
`/permissions`	View and manage tool permissions

Permission Modes

Claude Code offers flexible permission controls for safety:

Suggest mode: Claude asks for confirmation before every action
Auto-accept edits: File edits are applied automatically; command execution still requires confirmation
Full auto mode (YOLO): For high-trust scenarios where Claude can execute all operations autonomously

New users should start with suggest mode and gradually expand permissions as they become comfortable.

Tips for Getting Started

Write a CLAUDE.md first: Create a CLAUDE.md in your project root describing your tech stack, coding conventions, and project structure. Claude reads it automatically
Be specific with instructions: The more precise your prompts, the better Claude's output
Use /compact regularly: After long conversations, compress context to maintain response quality
Break down complex tasks: Split large tasks into smaller steps and verify each one incrementally

FAQ

What programming languages does Claude Code support?

Claude Code supports virtually all mainstream programming languages, including JavaScript/TypeScript, Python, Java, Go, Rust, C/C++, Ruby, PHP, and more. It works by understanding code context rather than relying on syntax highlighting, so it handles diverse languages equally well.

How is Claude Code different from GitHub Copilot?

The key difference is that Claude Code is an agentic tool — it doesn't just suggest code completions, it actively reads files, executes commands, and manages Git operations. Copilot focuses on inline code suggestions, while Claude Code acts more like an independent AI development partner.

Is there a context limit for conversations?

Yes, Claude Code has a context window size limit. When conversations get long, use /compact to compress history or /clear to start fresh. Claude Code intelligently manages context, prioritizing the most relevant information.

Does Claude Code require a paid subscription?

Claude Code requires a valid Anthropic API key (pay-per-token) or a Claude Pro/Max subscription. Costs depend on your usage volume and the model selected.