Claude Code Configuration: Settings, Environment Variables, and Defaults

The Settings File

Claude Code stores project-level and global configuration in claude_settings.json. In your home directory for global defaults, or in a project root for per-project settings. The project-level file overrides global settings.

{
  "defaultModel": "sonnet-4-6",
  "maxTokens": 8192,
  "autoMode": false
}

Run claude --help to see the full list of configuration options and what they do.

Environment Variables

Claude Code respects standard environment variables for API configuration:

• ANTHROPIC_API_KEY — your API key (if not using default credentials)
• CLAUDE_CODE_CONFIG_DIR — override where Claude Code looks for settings
• HTTP_PROXY / HTTPS_PROXY — if you need a proxy for API calls

For team deployments, you can set these in a .env.local that Claude Code reads on startup.

Model Selection Per Project

Set the default model per project by adding claude_settings.json to your project root:

{
  "defaultModel": "opus-4.7",
  "autoMode": false
}

This is useful when some projects need the extra reasoning of Opus while others are fine with Sonnet. The setting persists for that project without affecting other work.

Hook Configuration

Hooks are configured in the same settings file:

{
  "hooks": {
    "preCommand": "./scripts/pre-command.sh",
    "postCommit": "echo 'Commit complete'"
  }
}

Hooks run shell scripts at specific points in Claude Code's workflow. Useful for notification systems, quality gates, and project-specific automation.