Claude Code

Setup

1. 1Install Claude Code: npm install -g @anthropic-ai/claude-code.
2. 2Set the base URL to the host without /v1 (https://api.ultragpt.pro) and your key as ANTHROPIC_AUTH_TOKEN (sent as a Bearer token).
3. 3Map Claude Code's model slots to UltraGPT model ids: claude-opus-4.8 for the main model, claude-haiku-5.5 for background tasks (titles, summaries).
4. 4Run claude, then /status: it should show the UltraGPT base URL and the token as the credential.

{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.ultragpt.pro",
    "ANTHROPIC_AUTH_TOKEN": "<your UltraGPT key>",
    "ANTHROPIC_MODEL": "claude-opus-4.8",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "claude-opus-4.8",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-opus-4.8",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "claude-haiku-5.5"
  }
}

Good to know

• Use Claude models: Claude Code is built and tested for them, and Anthropic does not support routing it to other model families.
• The token takes precedence over a saved claude.ai login. Run /logout to clear the login and silence the auth-conflict warning.
• Getting 400 errors about unknown fields? Set CLAUDE_CODE_DISABLE_EXPERIMENTAL_BETAS=1.
• VS Code extension: put the same variables in claudeCode.environmentVariables in your VS Code user settings.