Anthropic: Claude Fable 5.1 · fastrouter

Claude Fable 5.1 is Anthropic's generally available, production-safeguarded deployment for demanding reasoning and long-horizon agentic work, sharing underlying weights with Claude Mythos 5.1. It extends Claude Fable 5 with stronger long-running agentic coding, multistep research, and document, spreadsheet, and slide work, plus per-message effort control, turn-scoped system messages, readable in-progress tool-call updates, and content provenance. Adaptive thinking is always on, with the effort parameter controlling reasoning depth (default: high).

Modelo base Todos os modelos desta base Todos os modelos do provedor ao provedor

Entrada, $/1M $10.00

Saída, $/1M $50.00

Leitura de cache $1.00

Gravação de cache —

Contexto 1 000 000

Saída máx. 128 000

Aceita arquivos, imagens, texto

Última verificação 04.11.2026 12:00:14 UTC

Fonte página do provedor

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API

API compatível com OpenAI: os SDKs oficiais da OpenAI funcionam com esta URL base. Substitua YOUR_API_KEY pela sua chave do provedor.

URL base da API	`https://go.fastrouter.ai/api/v1`
Endpoint	`https://go.fastrouter.ai/api/v1/chat/completions`
ID do modelo	`anthropic/claude-fable-5.1`

curl

curl https://go.fastrouter.ai/api/v1/chat/completions \
  -H "Authorization: Bearer YOUR_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{"model": "anthropic/claude-fable-5.1", "messages": [{"role": "user", "content": "Hello!"}], "max_tokens": 256}'

Python

import requests

r = requests.post(
    "https://go.fastrouter.ai/api/v1/chat/completions",
    headers={"Authorization": "Bearer YOUR_API_KEY"},
    json={
      "model": "anthropic/claude-fable-5.1",
      "messages": [
        {
          "role": "user",
          "content": "Hello!"
        }
      ],
      "max_tokens": 256
    },
)
print(r.json())

JavaScript

const r = await fetch("https://go.fastrouter.ai/api/v1/chat/completions", {
  method: "POST",
  headers: {Authorization: "Bearer YOUR_API_KEY", "Content-Type": "application/json"},
  body: JSON.stringify({
    "model": "anthropic/claude-fable-5.1",
    "messages": [
      {
        "role": "user",
        "content": "Hello!"
      }
    ],
    "max_tokens": 256
  }),
});
console.log(await r.json());

Requisição (JSON)

{
  "model": "anthropic/claude-fable-5.1",
  "messages": [
    {
      "role": "user",
      "content": "Hello!"
    }
  ],
  "max_tokens": 256
}

Resposta (JSON)

{
  "id": "chatcmpl-...",
  "object": "chat.completion",
  "model": "anthropic/claude-fable-5.1",
  "choices": [
    {
      "index": 0,
      "message": {
        "role": "assistant",
        "content": "Hi! How can I help?"
      },
      "finish_reason": "stop"
    }
  ],
  "usage": {
    "prompt_tokens": 9,
    "completion_tokens": 12,
    "total_tokens": 21
  }
}

O endereço vem da lista de modelos do provedor; confira na documentação dele.

Documentação da API do provedor

Source: AI Rate Card, https://airatecard.com/pt/c/offer%3Afastrouter%7Canthropic/claude-fable-5.1, prices checked 2026-11-04; seller's page: https://fastrouter.ai/models/anthropic/claude-fable-5.1

Dados técnicos

ID: offer:fastrouter|anthropic/claude-fable-5.1