Claude Code Beginner's Guide & Best Practices (2026)

Claude Code Beginner's Guide & Best Practices (2026)

Claude Code is Anthropic's official command-line AI coding agent. Unlike browser-based AI assistants, Claude Code runs directly in your terminal, reads and writes files in your codebase, executes commands, and interacts with tools like Git and GitHub. It is one of the most capable agentic coding tools available in 2026.

This guide covers everything a beginner needs to know: installation, basic usage, configuration, and the best practices that will make you productive immediately.

What Makes Claude Code Different

Claude Code is not just a chatbot in your terminal. It is a full coding agent that can:

• Read and edit files across your entire project
• Run shell commands and interpret the output
• Search your codebase with grep and glob patterns
• Create commits, open pull requests, and resolve merge conflicts
• Use tools via the Model Context Protocol (MCP)
• Work in non-interactive (headless) mode for CI/CD pipelines

Feature	Claude Code	Traditional Chat
File access	Direct read/write	Copy-paste
Terminal	Runs commands	Manual execution
Context	Full codebase	What you paste
Git integration	Native	None
Automation	Headless mode	Not possible

Step 1: Install Claude Code

Claude Code requires Node.js 18 or later. Install it globally via npm:

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

Verify the installation:

claude --version

If you prefer not to install globally, you can use npx:

npx @anthropic-ai/claude-code

Step 2: Authenticate

On first run, Claude Code will prompt you to authenticate. You have two options:

Option A: Anthropic API Key

Set your API key as an environment variable:

export ANTHROPIC_API_KEY=sk-ant-your-key-here

Add this to your shell profile (~/.bashrc, ~/.zshrc, or similar) to persist across sessions.

Option B: Anthropic Console Login

Simply run claude and follow the browser-based OAuth flow. This is the easiest option if you have an Anthropic account.

claude
# Opens browser for authentication

Step 3: Basic Usage

Interactive Mode

Navigate to your project directory and start Claude Code:

cd /path/to/your/project
claude

You are now in an interactive session where you can type natural language requests:

You: Explain the structure of this project
You: Find all TODO comments in the codebase
You: Add input validation to the user registration endpoint

One-Shot Mode

For quick tasks, pass your prompt directly:

claude "what does the main function in src/index.ts do?"

Pipe Mode

Send input through stdin:

git diff | claude "review this diff for bugs"
cat error.log | claude "explain this error and suggest a fix"

Print Mode

Get output without an interactive session (useful for scripting):

claude -p "list all exported functions in src/utils.ts"

Step 4: Configure Claude Code

CLAUDE.md Files

The most important configuration mechanism is the CLAUDE.md file. Place one in your project root to give Claude Code persistent instructions:

# CLAUDE.md

## Project Overview
This is a Next.js 15 application with TypeScript, Tailwind CSS, and Prisma ORM.

## Conventions
- Use functional components with TypeScript
- Prefer named exports over default exports
- Use Zod for input validation
- Write tests with Vitest
- Use kebab-case for file names

## Commands
- `pnpm dev` - Start dev server
- `pnpm test` - Run tests
- `pnpm lint` - Lint code
- `pnpm build` - Production build

## Important Notes
- Always run `pnpm lint` before committing
- Database migrations are in `prisma/migrations/`
- Environment variables are documented in `.env.example`

Claude Code reads this file automatically at the start of every session. You can also place CLAUDE.md files in subdirectories for context-specific instructions.

Settings File

Claude Code also supports a settings file at ~/.claude/settings.json:

{
  "model": "claude-sonnet-4-20250514",
  "theme": "dark",
  "verbose": false,
  "allowedTools": ["bash", "read", "write", "glob", "grep"],
  "maxTurns": 20
}

Best Practices

1. Write a Good CLAUDE.md

This is the single most impactful thing you can do. A well-written CLAUDE.md file eliminates repetitive instructions and ensures consistent code quality.

Do include:

• Project architecture and tech stack
• Coding conventions and style preferences
• Common commands (build, test, lint, deploy)
• File naming conventions
• Important caveats or gotchas

Do not include:

• Sensitive information (API keys, secrets)
• Frequently changing information
• Excessively long documentation (keep it focused)

2. Start with Small, Focused Tasks

When you are new to Claude Code, start with specific, well-defined tasks:

Good: "Add input validation to the POST /api/users endpoint using Zod"
Bad:  "Make the app better"

As you build confidence, you can move to larger tasks:

"Refactor the authentication module to use JWT refresh tokens.
Update the middleware, token service, and add tests."

3. Use the Review-Approve Workflow

Claude Code asks for permission before making changes. Always review the proposed changes before approving:

Claude wants to edit src/api/users.ts
[View diff] [Approve] [Reject] [Edit]

Take the time to read the diffs. This is where you catch mistakes and learn how Claude approaches problems.

4. Leverage Git Integration

Claude Code integrates natively with Git. Use it for common Git workflows:

You: Create a commit with a good message for the changes I just made
You: Open a pull request for this branch with a summary
You: Help me resolve merge conflicts on this branch

5. Use Headless Mode for Automation

Claude Code can run without interaction, making it perfect for CI/CD pipelines:

# In your CI pipeline
claude -p --max-turns 5 "Run the test suite and fix any failing tests" --output-format json

6. Chain with Unix Pipes

Combine Claude Code with standard Unix tools:

# Review only changed files
git diff --name-only | xargs -I {} claude -p "review {} for potential issues"

# Generate docs for new functions
git diff --name-only | xargs -I {} claude -p "add JSDoc comments to any undocumented functions in {}"

7. Use Slash Commands

Claude Code supports slash commands for common operations:

Command	Description
/help	Show available commands
/clear	Clear conversation history
/compact	Summarize conversation to save context
/model	Switch models mid-conversation
/cost	Show token usage and cost for the session
/vim	Toggle vim mode for input

8. Manage Context Wisely

Claude Code has a context window limit. For long sessions:

• Use /compact to summarize the conversation periodically
• Break large tasks into smaller, focused sessions
• Reference specific files instead of asking Claude to search broadly
• Use CLAUDE.md to front-load important context

9. Use Multiple Models Strategically

Switch models based on the task:

# Use Opus for complex architectural decisions
claude --model claude-opus-4-20250514 "Design the database schema for our multi-tenant system"

# Use Sonnet for everyday coding tasks
claude --model claude-sonnet-4-20250514 "Add pagination to the user list endpoint"

# Use Haiku for quick lookups
claude --model claude-haiku-3-5-20241022 "What port does the dev server run on?"

10. Customize Tool Permissions

For security, restrict which tools Claude Code can use:

# Read-only mode (no file writes, no shell commands)
claude --allowedTools read,glob,grep "explain how authentication works in this project"

# No shell access
claude --allowedTools read,write,glob,grep "refactor this function"

Common Workflows

Code Review

gh pr diff 42 | claude -p "Review this PR. Focus on:
1. Logic errors
2. Security issues
3. Performance concerns
4. Missing edge cases"

Test Generation

You: Write comprehensive tests for src/services/auth.ts
     Use Vitest. Cover happy paths, error cases, and edge cases.

Debugging

You: The /api/checkout endpoint returns a 500 error when the cart
     has more than 10 items. Help me find and fix the bug.

Refactoring

You: Refactor the user service to use the repository pattern.
     Keep the existing API contract the same. Update tests.

Troubleshooting

Issue	Solution
"Authentication failed"	Re-run claude and complete OAuth, or check ANTHROPIC_API_KEY
"Context window exceeded"	Use /compact or start a new session
Slow responses	Check your network connection; consider using Sonnet instead of Opus
"Permission denied" on file	Check file permissions; Claude Code runs as your user
High API costs	Use /cost to monitor; switch to cheaper models for simple tasks

Conclusion

Claude Code is a powerful tool that becomes more effective as you learn its patterns and configure it for your workflow. Start with a solid CLAUDE.md, begin with focused tasks, and gradually expand into more complex agentic workflows.

If you are building applications that involve AI-generated media like images, video, or audio, Hypereal AI provides simple, affordable APIs that you can call directly from your codebase or even orchestrate through Claude Code itself.