Manual setup

The script is recommended

The one-command install performs every step below correctly and backs up your old settings automatically. Only go manual if you really need to.

Install Claude Code

Terminal

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

Edit settings.json

Open (or create) the settings file for your OS:

Path: ~/.claude/settings.json

Replace the entire file content with the block below, substituting YOUR_API_KEY with your real key:

settings.json

{
  "env": {
    "ANTHROPIC_AUTH_TOKEN": "YOUR_API_KEY",
    "ANTHROPIC_BASE_URL": "https://codex.hungnguyen.codes",

    "ANTHROPIC_DEFAULT_FABLE_MODEL": "claude-fable-5",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "claude-opus-5",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-sonnet-5",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "claude-haiku-4-5-20251001",

    "CLAUDE_CODE_SUBAGENT_MODEL": "claude-sonnet-5",

    "CLAUDE_CODE_DISABLE_NONESSENTIAL_TRAFFIC": "1",
    "API_TIMEOUT_MS": "3000000",
    "CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS": "0",
    "CLAUDE_CODE_DISABLE_1M_CONTEXT": "1",
    "CLAUDE_CODE_NO_FLICKER": "1"
  },

  "permissions": {
    "allow": [],
    "deny": []
  },

  "model": "default",
  "autoUpdatesChannel": "latest",
  "skipDangerousModePermissionPrompt": false
}

On macOS/Linux, restrict read access to the file holding your key:

Terminal

chmod 600 ~/.claude/settings.json

Windows: mind the encoding

If you edit with PowerShell 5.1, avoid Set-Content -Encoding UTF8 (it prepends a BOM that breaks JSON). Saving from VS Code with UTF-8 encoding is the safest option.

Verify

Open a new terminal:

Terminal

claude --version
claude

Install Claude Code

Edit settings.json

Verify

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