Cheap Claude Fable 5.1 API

What a top-up buys on Claude Fable 5.1

Output-token count only; input tokens are cheaper. First top-up is at least 2.5×.

When to pick Claude Fable 5.1

Claude Fable 5.1 costs $0.04 per 1,500-in/500-out request at list price, $0.02 effective. It is a premium model: use it for the hardest reasoning and writing, and route simple tasks to a cheaper model.

Claude Fable 5.1 vs similarly priced models

Nearest models to Claude Fable 5.1 by blended price (3 input : 1 output). All run on one Somnus key.

Getting the most out of Claude Fable 5.1 for less

• Input is 5.0× cheaper than output on Claude Fable 5.1, so long context with short answers is the cheapest pattern.
• A $200 top-up gives $500 credit — about 25M blended Claude Fable 5.1 tokens.
• Mix models: send easy steps to DeepSeek V4 Flash and keep Claude Fable 5.1 for the steps that need it.

Other Claude models on Somnus

Every Anthropic model shares the same key and balance.

Use Claude Fable 5.1

import OpenAI from "openai";

const client = new OpenAI({
  apiKey: process.env.SOMNUS_API_KEY,
  baseURL: "https://gateway-production-c837.up.railway.app/v1",
});

const resp = await client.chat.completions.create({
  model: "claude-sonnet-5",
  messages: [
    {"role": "user", "content": "Summarise this in one line"}
  ],
});
console.log(resp.choices[0].message.content);

Copy the exact model id from your dashboard.

Questions

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