# Anthropic Claude Fable 5.5 API

> Claude Fable 5.5 is the expected successor to Claude Fable 5.1, Anthropic's tier above Opus for repository-scale coding, long-running agents and high-stakes review. Anthropic has not officially released it yet; specifications, pricing and API availability will be confirmed at launch.

Source: https://www.sandbase.ai/models/anthropic/claude-fable-5.5
API reference: https://www.sandbase.ai/models/anthropic/claude-fable-5.5/docs

## Facts

- Provider: Anthropic
- Type: Language model
- Model ID: `anthropic/claude-fable-5.5`
- Price: Coming soon
- Capabilities: chat, vision, reasoning, structured output, function calling
- Billing: pay per use from one SandBase balance; no provider account or subscription needed

## Call it

- Chat Completions API: `POST https://api.sandbase.ai/v1/chat/completions`
- Messages API: `POST https://api.sandbase.ai/v1/messages`

```bash
curl -X POST https://api.sandbase.ai/v1/chat/completions \
  -H "Authorization: Bearer $SANDBASE_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
  "model": "anthropic/claude-fable-5.5",
  "messages": [
    {
      "role": "user",
      "content": "Hello"
    }
  ],
  "max_tokens": 2048
}'
```

## FAQ

### How do I call Anthropic Claude Fable 5.5 through SandBase?

Create a SandBase API key, then send requests with the model ID "anthropic/claude-fable-5.5" to Chat Completions API (/v1/chat/completions) or Messages API (/v1/messages) at https://api.sandbase.ai. The request examples on this page show the exact payload.

### Which features does Anthropic Claude Fable 5.5 support?

Anthropic Claude Fable 5.5 supports vision (image input), reasoning, function calling, structured output. See Specifications above for the full list.

### Do I need a separate Anthropic account?

No. One SandBase API key and balance gives you access to Anthropic Claude Fable 5.5 and the other models in the catalog; you do not need to sign up with Anthropic separately.