---
title: Claude Code
---


[Claude Code](https://claude.com/claude-code) is Anthropic's official command-line coding assistant. It lets you override the API endpoint, so once you point it at CrossModel you can drive every model in the catalog from inside Claude Code.

## Quickstart

### 1. Install Claude Code

macOS / Linux:

```bash
curl -fsSL https://claude.ai/install.sh | bash
```

Or install with npm (requires Node.js 18+):

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

### 2. Create an API key

Sign in to the [Console](/console/api-keys) and create a key that starts with `cm-` on the **API Keys** page. The key is shown only once, so copy it somewhere safe.

### 3. Point Claude Code at CrossModel

The cleanest place is your project's `.claude/settings.json`, under `env`:

```json
{
  "env": {
    "ANTHROPIC_BASE_URL": "https://api.crossmodel.ai",
    "ANTHROPIC_AUTH_TOKEN": "cm-YOUR_KEY",
    "ANTHROPIC_API_KEY": ""
  }
}
```

You can also export them from your shell profile (`~/.zshrc` or `~/.bashrc`):

```bash
export ANTHROPIC_BASE_URL=https://api.crossmodel.ai
export ANTHROPIC_AUTH_TOKEN=cm-YOUR_KEY
export ANTHROPIC_API_KEY=
```

<Callout type="warning">
  Set `ANTHROPIC_API_KEY` to an empty value explicitly. If a stale key lingers there, it conflicts with `ANTHROPIC_AUTH_TOKEN` and your requests will keep going to Anthropic directly.
</Callout>

### 4. Sign out of any existing account

If you've logged in with an Anthropic account before, sign out first so a cached session doesn't override the config above:

```
/logout
```

### 5. Launch and verify

Start Claude Code from your project directory:

```bash
cd /path/to/your/project
claude
```

Run `/status` and confirm that **Anthropic base URL** points to `https://api.crossmodel.ai` and that auth is using `ANTHROPIC_AUTH_TOKEN`.

## How it works

By default Claude Code talks to Anthropic's API. Setting `ANTHROPIC_BASE_URL` redirects every request to CrossModel's `/v1/messages` endpoint, authenticated with your `cm-` key carried in `ANTHROPIC_AUTH_TOKEN`.

Claude Code appends `/v1/messages` to the base URL for you, so `ANTHROPIC_BASE_URL` should be `https://api.crossmodel.ai` — without a trailing `/v1`.

## Choosing models

Claude Code maps its work onto three tiers — opus, sonnet, and haiku. Use these environment variables to point each tier at a CrossModel model ID:

```bash
export ANTHROPIC_DEFAULT_OPUS_MODEL=anthropic/claude-opus-4.7
export ANTHROPIC_DEFAULT_SONNET_MODEL=anthropic/claude-sonnet-4.6
export ANTHROPIC_DEFAULT_HAIKU_MODEL=anthropic/claude-haiku-4.5
```

If you're using `.claude/settings.json`, drop these into the same `env` object. Browse the full list of model IDs in the [model catalog](/models), or fetch them from `/v1/models`.

<Callout type="info">
  Prefer not to edit these env vars every time you switch models? Set up [model aliases](/docs/model-aliases) on your API key — point each tier at a stable alias like `cross-model-opus` once, then change the real model it maps to from the dashboard. A prefix alias can also catch the exact `claude-*` ids Claude Code sends.
</Callout>

## Troubleshooting

| Symptom | What to check |
|---------|---------------|
| "Model not found" | Make sure the model ID appears in the `/v1/models` response, and note the `vendor/short_name` format. |
| Auth failure (401) | Confirm `ANTHROPIC_API_KEY` is empty and `ANTHROPIC_AUTH_TOKEN` holds a valid `cm-` key. |
| Requests still hit Anthropic | Check that you ran `/logout`, and that the env vars are active in the current shell (reopen the terminal or `source` your profile). |
| Insufficient balance (402) | Top up in the [Console](/console/billing). |