Compare AI models

Specifications
Context window
1M—
API pricing
Input price
$10.00—
Output price
$50.00—
Cached input price
$0.25—
Cheapest input
$10.00Amazon Bedrock—
Cheapest output
$50.00Amazon Bedrock—
Benchmarks
SWE-Bench Pro
81.2%55%
Humanity's Last Exam · with tools
65.6%50.4%
ARC-AGI-2
90%42.5%
Overview
CompanyAnthropicMeta
Release dateSep 1 2026Apr 8 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Fable 5.1 leads Muse Spark on 3 of the 3 benchmarks they both report (SWE-Bench Pro, Humanity's Last Exam, ARC-AGI-2). Only Claude Fable 5.1 has a verified first-party API price: $10.00 per million input tokens and $50.00 per million output tokens. No pay-as-you-go API rate is tracked for Muse Spark. Muse Spark shipped 146 days before Claude Fable 5.1, so benchmark comparisons should account for the intervening progress.

Published specifications for these two models are limited — see each model page for the latest details.

On SWE-Bench Pro, Claude Fable 5.1 leads at 81.2% vs Muse Spark at 55%. On Humanity's Last Exam · with tools, Claude Fable 5.1 leads at 65.6% vs Muse Spark at 50.4%. On ARC-AGI-2, Claude Fable 5.1 leads at 90% vs Muse Spark at 42.5%.