> ## Documentation Index
> Fetch the complete documentation index at: https://backstage.spotify.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Anthropic

> Configure direct Anthropic API access in AI Gateway for Claude models, with optional gateway routing and custom headers.

## Overview

Anthropic is the creator of the Claude family of large language models. AI Gateway can be configured to use Anthropic models directly via the Anthropic API.

## Configuration

To use Anthropic, configure it in the Plugin settings page under the `AI Gateway` section:

| Field        | Description                                    | Example                                           |
| ------------ | ---------------------------------------------- | ------------------------------------------------- |
| **API Key**  | Your Anthropic API key                         | `your-anthropic-api-key`                          |
| **Base URL** | Optional, to point at a gateway                | `https://ai-gateway.example.com/anthropic`        |
| **Headers**  | Optional, e.g. for authentication with gateway | Key: `X-Custom-Header`<br />Value: `custom-value` |

Then set the default language model (or configure it per-plugin):

```
Language Model: anthropic|claude-sonnet-5
```

### Supported Models

All models available on your Anthropic account are supported — the model list is fetched dynamically from the Anthropic API using your configured API key. See the [Anthropic documentation](https://docs.anthropic.com/en/docs/about-claude/models) for the full list of available models.

<Note>
  Anthropic models do not support re-ranking. If you need re-ranking
  capabilities, configure a separate provider such as [Cohere](./cohere) or [AWS
  Bedrock](./aws-bedrock).
</Note>