---
title: "Claude Code: ANTHROPIC_BASE_URL and key — AI Creator API"
description: "How to connect Claude Code to AI Creator API: base URL, key, models, aliases and the background model."
url: https://llm.aicreator.app/en/docs/claude-code/
lang: en
updated: 2026-11-10
---

# Claude Code

Claude Code speaks Anthropic Messages, and we answer in kind: streaming, tools, thinking and prompt caching work as with the official API. The stream is passed through, not translated or repacked.

## Setup

Set the environment variables and run `claude`:

```bash
unset ANTHROPIC_API_KEY
export ANTHROPIC_BASE_URL=https://api.aicreator.app
export ANTHROPIC_AUTH_TOKEN=sk-aic-…
export ANTHROPIC_DEFAULT_OPUS_MODEL=claude-opus-5-5
export ANTHROPIC_DEFAULT_SONNET_MODEL=claude-sonnet-5-5
export ANTHROPIC_DEFAULT_HAIKU_MODEL=claude-haiku-5-5
claude
```

- `unset ANTHROPIC_API_KEY` — required when the variable is set. Claude Code sends its value in the `x-api-key` header, which we read before `Authorization`: with an old Anthropic key in it the answer is 401.
- `ANTHROPIC_BASE_URL` — `https://api.aicreator.app`, without `/v1`: Claude Code adds the path itself.
- `ANTHROPIC_AUTH_TOKEN` — your `sk-aic-…` key.
- `ANTHROPIC_DEFAULT_OPUS_MODEL`, `ANTHROPIC_DEFAULT_SONNET_MODEL`, `ANTHROPIC_DEFAULT_HAIKU_MODEL` — the models behind the names Opus, Sonnet and Haiku. We accept only the ids of our own list, so pin them.

### Settings file

A shell export lasts until the terminal closes. To make the setup hold wherever Claude Code runs, background agents included, put the same variables in the `env` block of `~/.claude/settings.json`. When a variable is set both there and in the shell, the file wins.

```json title="~/.claude/settings.json"
{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.aicreator.app",
    "ANTHROPIC_AUTH_TOKEN": "sk-aic-…",
    "ANTHROPIC_DEFAULT_OPUS_MODEL": "claude-opus-5-5",
    "ANTHROPIC_DEFAULT_SONNET_MODEL": "claude-sonnet-5-5",
    "ANTHROPIC_DEFAULT_HAIKU_MODEL": "claude-haiku-5-5"
  }
}
```

Keep the key out of a project’s `.claude/settings.json`: that file is committed to the repository.

### Check

Run `claude` and type `/status`: the `Anthropic base URL` line should show `https://api.aicreator.app`, and the `Auth token` line should name `ANTHROPIC_AUTH_TOKEN`.

## Models

Short names in the `model` field are resolved on our side:

| Name in Claude Code | Model               |
| ------------------- | ------------------- |
| `opus`              | `claude-opus-5-5`   |
| `sonnet`            | `claude-sonnet-5-5` |
| `haiku`             | `claude-haiku-5-5`  |
| `fable`             | `claude-fable-5-1`  |

Other models on the Claude Code protocol take their full id: in `ANTHROPIC_MODEL` or with the `/model` command. Which models work on this protocol is in the Protocols column of the [pricing page](https://llm.aicreator.app/en/pricing/). An id that is not on our list gets 400 `model_not_available`.

To have the models of our list show up in the `/model` picker, add the variable `CLAUDE_CODE_ENABLE_GATEWAY_MODEL_DISCOVERY=1`: Claude Code will ask us for `/v1/models` at startup.

## Background model

Claude Code runs session titles and other housekeeping on its Haiku model, not on the one picked for the work. Which model that is comes from `ANTHROPIC_DEFAULT_HAIKU_MODEL`. In the setup above it is `claude-haiku-5-5`, which we carry for this role.

To run background tasks on another model, put its id in this variable: any model on the Claude Code protocol will do. What the background model spends is its own line in the stats.

## Subagents and parallel requests

One key runs up to 4 requests at a time. Claude Code with subagents easily opens more: the extra request gets 429 `concurrent_requests` with a `retry-after` header, and Claude Code retries it by itself. The work goes on, only slower.

A second ceiling counts by IP address, not by key: 60 requests per minute and 1,200 per hour from one machine. A long session with subagents can reach it; the answer is the same, a 429 with `retry-after`, and Claude Code waits by itself.

## If something is off

- 401 means the key was copied in part or revoked, or `ANTHROPIC_API_KEY` is still set in the environment.
- 400 `model_not_available` means Claude Code asked for a model id that is not on our list: pin the models with the variables of the setup.
- 402 means the balance ran out: top it up in the dashboard.
- 429 means a key, IP address or provider limit hit; Claude Code retries by itself following the `retry-after` header.

A step-by-step walk-through is in [Troubleshooting](https://llm.aicreator.app/en/docs/troubleshooting/), and every code in [Errors and limits](https://llm.aicreator.app/en/docs/errors/).