Introduction
Claude Code is Anthropic's AI coding assistant for the terminal. It can write, debug, and refactor code directly while also handling Git operations. Anthropic has said that internal use of Claude Code increased code output per engineer by 200% over the past year, which is why it matters beyond simple experimentation.
Since its first release in 2025, Claude Code has evolved quickly. Features such as Skills, Memory, Hooks, Auto Mode, Agent Teams, and 1M context have all been added in succession. This guide covers the practical path from installation to advanced usage.
1. Installation and Basic Setup
Mac and Linux Installation
npm install -g @anthropic-ai/claude-code
cd your-project
claude
Windows Installation Without WSL
On Windows, Claude Code can be installed directly without WSL. After installing Node.js 18 or newer, the same npm install -g @anthropic-ai/claude-code command works.
Basic Workflow
- Start with the
claudecommand from a project directory - Request a task in natural language, such as "Add error handling to this function"
- Claude analyzes the code and proposes a change
- Once approved, the change is applied directly to files
2. Core CLI Commands
Basic Commands
claude-> start interactive modeclaude "question"-> ask a one-shot questionclaude -p "prompt"-> pipeline mode using stdin and stdoutclaude commit-> let AI generate a commit message automaticallyclaude review-> review a PR
Advanced Commands
claude --model opus-> choose a model such as sonnet, opus, or haikuclaude --dangerously-skip-permissions-> skip all permission checks, which is powerful but riskyclaude mcp add <name> -- <command>-> add an MCP server/memory-> open memory management/compact-> compress context
3. Auto Mode: Running Without Endless Approval Popups
One of the most frustrating parts of using Claude Code used to be the approval flow. Even a simple ls could trigger "Do you want to allow this?" That pushed many users toward --dangerously-skip-permissions, which removes friction but also removes meaningful safety.
Auto Mode, added in March 2026, solves that problem. Instead of approving everything, it auto-approves safe commands and asks for confirmation only on risky ones.
In practice, the recommended setup is to auto-approve read operations such as file reads, grep, and git status, while keeping write operations such as file edits or git push on manual approval.
4. The Skills System
The Skills system, introduced in January 2026 with v2.1.0, lets users customize Claude Code's behavioral patterns. It replaced Custom Commands and makes it possible to define how AI should work at the project or personal level.
Bundled Skills
/simplify-> review changed code for reuse, quality, and efficiency, then improve it/batch-> process multiple tasks in one pass/debug-> support error analysis and debugging
Custom Skills
Custom skills are written as Markdown files inside .claude/skills/. For example, a project can define a skill that says "Always use TypeScript, prefer arrow functions, and use Vitest for testing."
Skills vs. Plugins
Skills are text-based instructions that expand the AI's prompt behavior. Plugins are executable code. Skills change how the AI thinks; plugins extend what the AI can do. In most cases, skills are enough, and plugins through MCP are only needed when external system integration is required.
The Spread of Agent Skills
The Skills system started by Anthropic has also been adopted by OpenAI Codex and Google Gemini CLI, which means file-based skill definitions such as CLAUDE.md are becoming a de facto industry standard.
5. The Memory System
Claude Code Memory preserves context across sessions. It remembers project conventions, user preferences, and work history so the same explanations do not need to be repeated every time.
Memory Components
CLAUDE.md: the main memory file at the project root, typically used for architecture notes, build commands, and conventions- User memory: personal preferences stored in
~/.claude/ - Project memory: project-specific memory stored in
.claude/
Auto Memory vs. Auto Dream
The phrase "Claude Code Memory 2.0" circulates in the community. Another rumored feature, "Auto Dream," describes the AI organizing memory while idle. The practical summary is this: "Memory 2.0" is not an official product term, and Auto Dream is not in the official docs, but the functionality appears to exist in the codebase. It can be seen in the /memory menu and is described as automatically recording important information when a session ends.
6. The 1M Context Window
Official support for a 1M-token context window began on March 13, 2026. Starting with Opus 4.6, it is enabled by default on Max, Team, and Enterprise plans, with no extra fee and no rate-limit penalty.
Why It Matters
- Analyze an entire large codebase in a single pass
- Refactor while referencing dozens of files at once
- Drop in long documents or logs and inspect them whole
Practical Caution
More context is not automatically better. If too much information is included, the "lost in the middle" effect can degrade quality, and token usage also rises. In practice, selectively providing only the necessary files often works better.
7. Claude Code Review
Claude Code Review makes Anthropic's internal AI-assisted code review system available to users. It is available on Team and Enterprise plans and can leave automated reviews on GitHub PRs.
Why It Matters
Claude Code may increase code output by 200%, but reviewer bandwidth does not scale the same way. PR queues build up, review quality drops into superficial scanning, and subtle bugs can slip through. AI code review exists to support humans in handling that increased volume.
Code Review Principles in the AI Era
Simon Willison's framing is useful here: when AI writes code, the developer's responsibility shifts from "writing the code" to "verifying the code." Human review remains mandatory, and AI can help strengthen that review process.
8. cmux: A Terminal for AI Agents
When multiple AI agents such as Claude Code, OpenAI Codex, and Gemini CLI run in parallel, plain tmux starts to feel limited. cmux is a terminal multiplexer designed specifically for AI agents.
cmux vs. tmux
- tmux: terminal management built for humans, with sessions, windows, and panes
- cmux: terminal management built for AI agents, with shared agent state, browser-based UI, and isolated environments per agent
It lets users monitor multiple agents on one screen and share context between them more naturally.
9. SuperClaude
SuperClaude is a community project that extends Claude Code. By adding structured instructions to CLAUDE.md, it gives finer control over coding quality, architecture decisions, and code style.
In practical cases such as fixing UI bugs in React projects, users report that it can produce more structured and consistent results than default Claude Code. The tradeoff is higher token consumption due to longer prompts.
10. Practical Tips
- Maintain
CLAUDE.mdcarefully: document build commands, test commands, coding conventions, and architectural guidance there - Manage context deliberately: use
/compactwhen conversations grow too long - Combine with MCP: GitHub MCP, Playwright MCP, and Supabase MCP all expand what Claude Code can do
- Use Auto Mode: auto-approve reads and keep writes on manual approval to reduce friction without giving up safety
- Let AI handle commits:
claude committurns the diff into a consistent and detailed commit message
Closing
Claude Code is evolving from a code-completion tool into a full AI coding partner that spans the entire development workflow. Skills customize behavior, Memory preserves context, MCP connects external tools, and Agent Teams enable parallel work across multiple agents. That is what modern development looks like in 2026.
The most important point is not that AI writes code instead of the developer. It is that the developer can reach the goal faster and more accurately with AI. Using Claude Code well means knowing what to delegate to AI and what still requires direct human judgment.