Quickstart: Claude Code

Claude Code speaks the Anthropic messages format, which this API serves. Three environment variables and it runs on a model from this line.

shell

export ANTHROPIC_BASE_URL="https://uncensoredopencode.com"
export ANTHROPIC_AUTH_TOKEN="sk-nc-..."
export ANTHROPIC_MODEL="glm-5.3-flash-uncensored"
claude

What to know

The base URL has no /v1 on the end. Claude Code adds the path itself.
The variables only apply to the shell they are set in. Open a new terminal to go back to your usual setup.
Tools you define are passed through. Anthropic's own server tools are not available and are dropped from the request.
The thinking field is dropped. A model that reasons still does, and its reasoning comes back as a thinking block.

On Windows

PowerShell

$env:ANTHROPIC_BASE_URL = "https://uncensoredopencode.com"
$env:ANTHROPIC_AUTH_TOKEN = "sk-nc-..."
$env:ANTHROPIC_MODEL = "glm-5.3-flash-uncensored"
claude

If it does not work

"Missing API key" means the token variable is not set in this shell.
A 404 naming the model means ANTHROPIC_MODEL is not an id on this API. In the messages format an unknown model is a 404, not a 400.
Claude Code also calls a small model for background jobs. If you see errors about a model you did not choose, set ANTHROPIC_DEFAULT_HAIKU_MODEL to an id from Models as well.

How the messages format is mapped, field by field, is on Formats.