What is the difference between Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta?

Claude Fable 5.1 is developed by Anthropic while Grok 4.20 Multi-Agent Beta is developed by xAI. Claude Fable 5.1 has a 1.0M token context window vs Grok 4.20 Multi-Agent Beta's 2.0M. You can compare their actual outputs across 10 challenges on Rival to see how they differ in practice.

Which is better, Claude Fable 5.1 or Grok 4.20 Multi-Agent Beta?

It depends on your use case. Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 10 challenges so you can judge which fits your needs best.

How much does Claude Fable 5.1 cost compared to Grok 4.20 Multi-Agent Beta?

Claude Fable 5.1 costs $10/M input tokens and Grok 4.20 Multi-Agent Beta costs $2/M input tokens. Grok 4.20 Multi-Agent Beta is $8.00/M cheaper per input. Check their side-by-side outputs on Rival to see if the price difference is justified by quality.

How can I compare Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta on Rival?

This page shows a side-by-side comparison of Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta across shared challenges. You can vote on which model produced the better output in a blind duel. Browsing and voting are free. No account is needed to look; signing in only saves your votes and likes.

Updated Sep 2026

Claude Fable 5.1vsGrok 4.20 Multi-Agent Beta

Grok 4.20 Multi-Agent Beta is cheaper than Claude Fable 5.1 at $2/M vs $10/M input tokens.

Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta compared across 10 shared prompts
Spec	Claude Fable 5.1	Grok 4.20 Multi-Agent Beta
Input price	$10/M tokens	$2/M tokens
Output price	$50/M tokens	$6/M tokens
Context window	1.0M tokens	2.0M tokens
Weights	Closed	Closed
Free API (OpenRouter)	No	No
Released	Sep 2026	Mar 2026

Our Verdict

Claude Fable 5.1

Grok 4.20 Multi-Agent Beta

Not enough votes to call it. On the specs, nothing separates them.

Grok 4.20 Multi-Agent Beta costs 8.3x less per token.

Too close to call

Reviewing agent-written code?See a Brief PR report

API pricing

Cost per 1M tokens

Claude Fable 5.1

Input

$10.00

Output

$50.00

Grok 4.20 Multi-Agent Beta

Input

$2.00

5.0× cheaper

Output

$6.00

8.3× cheaper

Grok 4.20 Multi-Agent Beta is cheaper on both: 5.0× input, 8.3× output.

Where to run it

5 hosts

Claude Fable 5.14 hosts

HostInOutContextUptime

Amazon Bedrock$10.00 in$50.00 out1M—Anthropic$10.00 in$50.00 out1M99.1% up Azure AI Foundry$10.00 in$50.00 out1M99.1% up Google Vertex AI$10.00 in$50.00 out1M99.8% up

Grok 4.20 Multi-Agent Beta1 host

HostInOutContextUptime

xAI$1.25 in$2.50 out2M78.2% up

Per million tokens. Prices and uptime via OpenRouter, checked 16 Sep 2026.

Research

What we learned reading every model

FAQ

Common questions

Keep exploring

More comparisons

Cost per 1M tokens

5 hosts

What we learned reading every model

Common questions

What is the difference between Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta?

Which is better, Claude Fable 5.1 or Grok 4.20 Multi-Agent Beta?

How much does Claude Fable 5.1 cost compared to Grok 4.20 Multi-Agent Beta?

How can I compare Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages

Cost per 1M tokens

5 hosts

What we learned reading every model

Common questions

What is the difference between Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta?

Which is better, Claude Fable 5.1 or Grok 4.20 Multi-Agent Beta?

How much does Claude Fable 5.1 cost compared to Grok 4.20 Multi-Agent Beta?

How can I compare Claude Fable 5.1 and Grok 4.20 Multi-Agent Beta on Rival?

More comparisons

Against the newest arrivals

Same lab, same size, long tail

Model pages