Compare AI models

Specifications
Context window
1M—
API pricing
Input price
$10.00$0.20
Output price
$50.00$1.25
Cached input price
$0.25$0.02
Cheapest input
$10.00Amazon Bedrock$0.10OpenAI
Cheapest output
$50.00Amazon Bedrock$0.625OpenAI
Benchmarks
BullshitBench v2
77%14%
Humanity's Last Exam · with tools
65.6%37.7%
ARC-AGI-2
90%5.7%
Overview
CompanyAnthropicOpenAI
Release dateSep 1 2026Mar 17 2026
AccessClosedClosed
Model detailsView modelView model

Frequently asked questions

Claude Fable 5.1 leads GPT-5.4 nano on 3 of the 3 benchmarks they both report (BullshitBench v2, Humanity's Last Exam, ARC-AGI-2). GPT-5.4 nano is cheaper on both input and output: $0.20 vs $10.00 per million input tokens, and $1.25 vs $50.00 per million output tokens. GPT-5.4 nano shipped 168 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 BullshitBench v2, Claude Fable 5.1 leads at 77% vs GPT-5.4 nano at 14%. On Humanity's Last Exam · with tools, Claude Fable 5.1 leads at 65.6% vs GPT-5.4 nano at 37.7%. On ARC-AGI-2, Claude Fable 5.1 leads at 90% vs GPT-5.4 nano at 5.7%.