Claude Code is Anthropic's official command-line interface for Claude, designed to help developers with software engineering tasks directly from the terminal. Configuring it properly can dramatically improve your workflow, from setting the right model to defining permission rules that keep your projects safe.
What is Claude Code?
Claude Code is an agentic coding tool that lives in your terminal. It can read and edit files, run commands, search codebases, and help you build software faster. Unlike chat-based interfaces, Claude Code operates directly in your development environment, understanding your project context through file access and command execution.
The settings.json file controls how Claude Code behaves across your projects. You can configure it at three levels: user-wide settings that apply everywhere, project settings shared with your team through version control, and local settings for personal preferences that stay on your machine.
Choosing the Right Model
Claude Code supports multiple AI models, each suited to different tasks. Claude Sonnet is the default and offers a great balance of speed and capability for everyday coding tasks like writing functions, fixing bugs, and generating tests. Claude Opus excels at complex architectural decisions, large refactors, and nuanced code review where deeper reasoning is valuable.
Claude Haiku is the fastest option, ideal for simple completions and quick lookups where response time matters more than depth. You can switch models on the fly, but setting a default in your configuration saves time.
Permission Rules Explained
Permissions are one of the most important settings to configure. They control which tools Claude Code can use automatically and which require your approval. The permission system uses a deny-first approach, meaning you explicitly allow tools rather than blocking them.
Common permission configurations include allowing file reads and writes in your project directory, permitting specific shell commands like npm test or git status, and restricting access to sensitive directories. Well-configured permissions let Claude Code work efficiently while maintaining your control over destructive operations.
Hooks for Custom Workflows
Hooks let you run custom shell commands before or after Claude Code performs certain actions. For example, you can automatically format code after every file edit, run linters before commits, or notify external services when tasks complete. Hooks integrate Claude Code into your existing development pipeline without requiring changes to your workflow.
Each hook specifies a matcher pattern and a command. The matcher determines which tool invocations trigger the hook, while the command defines what runs. This system is flexible enough to support everything from simple formatters to complex CI integrations.
Sandbox and Security
The sandbox setting controls whether Claude Code runs commands in an isolated environment. On macOS, sandbox mode uses Apple's built-in security framework to prevent unintended file system modifications outside your project directory. On Linux, it uses Docker containers for isolation.
For most development work, leaving the sandbox enabled provides an important safety net. You may want to disable it for tasks that require access to system-level tools, databases, or network services outside the sandbox boundary, but do so with caution and re-enable it afterward.
Getting Started
The fastest way to configure Claude Code is to start with a preset that matches your tech stack. This configurator offers curated templates for Python, JavaScript, Git, Docker, and more. Each preset includes sensible defaults for permissions, model selection, and common tool configurations.
After selecting a preset, customize individual settings to match your preferences. Download the generated settings.json file and place it in the appropriate location: ~/.claude/settings.json for user-wide settings, or .claude/settings.json in your project root for project-specific configuration.
Frequently Asked Questions
Where should I put my settings.json file?
Claude Code looks for settings in three locations, in order of precedence. Local settings (.claude/settings.local.json) override everything and are meant for personal preferences you don't want to share. Project settings (.claude/settings.json) are committed to version control and shared with your team. User settings (~/.claude/settings.json) apply to all projects on your machine as a baseline.
Can I use different settings for different projects?
Yes. Place a .claude/settings.json file in each project's root directory. Project settings override your global user settings, so you can have a strict security configuration for a production codebase while using more permissive settings for a personal side project. Local settings (.claude/settings.local.json) let you add personal overrides without affecting your team.
What permissions should I allow?
Start with the minimum permissions needed for your workflow and expand as needed. Most developers allow file read/write access within their project directory, common development commands like npm test, python -m pytest, and git operations, and tool-specific commands for their framework. Avoid allowing unrestricted shell access or write permissions to system directories.
How do I import my existing configuration?
Click the "Import JSON" button in the configurator above and paste your existing settings.json content. The configurator will parse your configuration and populate all the form fields accordingly, allowing you to visually review and modify your settings. You can then download the updated configuration or copy it to your clipboard.
What is the difference between Sonnet, Opus, and Haiku?
These are different Claude models optimized for different use cases. Sonnet is the balanced default, good for most coding tasks. Opus is the most capable model, best for complex reasoning, architecture decisions, and thorough code review. Haiku is the fastest, ideal for simple tasks where speed is the priority. Your choice depends on whether you prioritize depth of reasoning or response speed.
Are my settings sent anywhere when I use this tool?
No. This configurator runs entirely in your browser. Your settings are never sent to any server. The JSON is generated client-side using JavaScript, and the download creates a file locally on your machine. No data is collected, stored, or transmitted. You can verify this by checking the page source or using browser developer tools to monitor network requests.