What is the difference between Claude Fable 5.1 and Grok 3 Thinking?

Claude Fable 5.1 is developed by Anthropic while Grok 3 Thinking is developed by xAI. Claude Fable 5.1 has a 1.0M token context window vs Grok 3 Thinking's 128K. You can compare their actual outputs across 1 challenges on Rival to see how they differ in practice.

Which is better, Claude Fable 5.1 or Grok 3 Thinking?

It depends on your use case. Claude Fable 5.1 and Grok 3 Thinking each have strengths in different areas. Rival lets you compare their real outputs side-by-side across 1 challenges so you can judge which fits your needs best.

How can I compare Claude Fable 5.1 and Grok 3 Thinking on Rival?

This page shows a side-by-side comparison of Claude Fable 5.1 and Grok 3 Thinking 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 3 Thinking

Claude Fable 5.1 has a larger context window than Grok 3 Thinking (1.0M tokens vs 128K tokens).

Claude Fable 5.1 and Grok 3 Thinking compared across 1 shared prompts
Spec	Claude Fable 5.1	Grok 3 Thinking
Input price	$10/M tokens	—
Output price	$50/M tokens	—
Context window	1.0M tokens	128K tokens
Weights	Closed	—
Free API (OpenRouter)	No	—
Released	Sep 2026	Feb 2025