How to Configure Base URL and Auth Token?

Claude Code’s ANTHROPIC_BASE_URL and ANTHROPIC_AUTH_TOKEN can be configured in three ways:

Method 1: User-Level Config File (Recommended)

File path: ~/.claude/settings.json

Example:

{
  "env": {
    "ANTHROPIC_AUTH_TOKEN": "your-api-key",
    "ANTHROPIC_BASE_URL": "https://claude-code.club/api"
  }
}

Method 2: Project-Level Config File

File path: <project-root>/.claude/settings.json

Example:

{
  "env": {
    "ANTHROPIC_AUTH_TOKEN": "your-project-specific-api-key",
    "ANTHROPIC_BASE_URL": "https://claude-code.club/api"
  }
}

Method 3: Environment Variables

Configure via your operating system’s environment variables. Refer to the guide for your OS:

• macOS — Set Environment Variables
• Windows — Set Environment Variables
• Linux — Set Environment Variables

Configuration Priority

When multiple configuration methods are present, priority from highest to lowest is:

1. Environment variables — Variables set in the system or shell
2. Project-level config file — <project-root>/.claude/settings.json
3. User-level config file — ~/.claude/settings.json

Priority Explained

• Environment variables: In Claude Code’s official settings hierarchy, environment variables (and command-line arguments) are treated as high-priority inputs that override local config. They are intended for temporary or per-session overrides and generally take precedence over file-based settings of the same name.
• Project-level config ./.claude/settings.json: This is a “project-level” setting, more specific than user-level. It applies to the current project and overrides settings of the same name in ~/.claude/settings.json.
• User-level config ~/.claude/settings.json: This is the most general “user-level” global config, serving as the default for all projects. It only takes effect when a more specific layer (project file or environment variable) does not define the same setting.

Recommended Strategy

• Environment variables: For temporary overrides, such as testing a different API endpoint
• Project-level config: For project-specific configuration, such as using a different key for a particular project
• User-level config: For global defaults that serve as the baseline for all projects

Summary