Claude Fable 5.1

by Anthropic

anthropic/claude-fable-5.1
Input
$14.00/1M tokens
Output
$70.00/1M tokens
Context
1Mtokens
Max output
128Ktokens
Knows to
-
Released
1 Sep 2026

About

Claude Fable 5.1 improves on Claude Fable 5 across the board, with the biggest gains in agentic coding, long-running agentic workflows, and knowledge work: long code refactors, front-end and visual...

Pricing

Input$14.00per 1M prompt tokens
Output$70.00per 1M generated tokens, reasoning included
Cached input$0.35per 1M tokens read back from the prompt cache
Cache write$17.50per 1M tokens written to the prompt cache
Web search$0.014per request that uses the provider’s built-in search

What a request costs

Typical requestEachPer 1,000
Short chat reply1,500 in · 400 out$0.049$49.00
Question over a long document40,000 in · 800 out$0.616$616.00
Agent tool step20,000 in · 1,200 out$0.364$364.00

At the developer-API rate, before any provider promotion or prompt-cache saving. In the app, the model picker shows what a message costs on your plan before you send it.

Benchmarks

Intelligence53.4#5 of 285
Coding81.6#1 of 163
Agentic57.9#1 of 127

Head-to-head rankings

  1. #1Full stackAgent arenaElo 132657% wins
  2. #1Godot gamesAgent arenaElo 132761% wins
  3. #1SlidesAgent arenaElo 132863% wins
  4. #1Web appsAgent arenaElo 131156% wins
  5. #3Mobile appsAgent arenaElo 126556% wins
  6. #3ASCII artModel arenaElo 132565% wins
  7. #3Game devModel arenaElo 138466% wins
  8. #5Data vizModel arenaElo 134662% wins
  9. #5SVGModel arenaElo 130156% wins
  10. #73DModel arenaElo 139368% wins

Scores from Artificial Analysis; bars are scaled to the best model on our list. Rankings from Design Arena head-to-head votes. Published by OpenRouter alongside its catalogue.

Call it from code

OpenAI-compatible: point any OpenAI SDK at https://api.privateer.pro/v1 and set model. Keys are created in the app under Settings.

cURL
curl https://api.privateer.pro/v1/chat/completions \
  -H "Authorization: Bearer $PRIVATEER_API_KEY" \
  -H "Content-Type: application/json" \
  -d '{
    "model": "anthropic/claude-fable-5.1",
    "messages": [{ "role": "user", "content": "Hello" }]
  }'
Python
import os
from openai import OpenAI

client = OpenAI(
    base_url="https://api.privateer.pro/v1",
    api_key=os.environ["PRIVATEER_API_KEY"],
)
reply = client.chat.completions.create(
    model="anthropic/claude-fable-5.1",
    messages=[{"role": "user", "content": "Hello"}],
)
print(reply.choices[0].message.content)
JavaScript
import OpenAI from "openai";

const client = new OpenAI({
  baseURL: "https://api.privateer.pro/v1",
  apiKey: process.env.PRIVATEER_API_KEY,
});
const reply = await client.chat.completions.create({
  model: "anthropic/claude-fable-5.1",
  messages: [{ role: "user", content: "Hello" }],
});
console.log(reply.choices[0].message.content);

Parameters this model accepts

include_reasoningmax_completion_tokensmax_tokensreasoningreasoning_effortresponse_formatstopstructured_outputstool_choicetoolsverbosity

API reference → · How API billing works →

Prices are USD at the developer-API rate, as of 16 Oct 2026, rebuilt daily from the providers’ live catalogues. ← All models