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An open hand-bound book sculpture whose ivory pages fan out into terracotta clay petals on a dark background, abstract hero artwork for Claude Fable 5

Anthropic

Claude Fable 5

Anthropic's Mythos-class model made safe for general use, strongest on long, complex tasks.

Chat with Claude Fable 5 in Super AgentView pricing

What is Claude Fable 5?

Claude Fable 5 is the Mythos-class model Anthropic released on June 9, 2026, made safe for general use.

Anthropic said its capabilities exceeded any model it had made generally available, with state-of-the-art results on nearly all the benchmarks it tested, especially software engineering, knowledge work, vision and scientific research. The longer and more complex the task, the bigger its lead over other Claude models. Its safeguards hand some sensitive topics to Claude Opus 4.8, which Anthropic says happens in under 5% of sessions on average. Anthropic now lists it as legacy and recommends Claude Fable 5.1.

Provider
Anthropic
Context window
1M tokens
Input
Text, Image
Reasoning
Low to max
Max output
128K tokens
Knowledge cutoff
January 2026
Released
Jun 9, 2026

How Claude Fable 5 performs

Published by Anthropic

Results Anthropic reported for Claude Fable 5. Each lab runs its own setup, so compare these with other models only inside the same table.

Benchmark results Anthropic published for Claude Fable 5
BenchmarkScoreSetting
SWE-Bench Pro80.3%higher of Mythos 5 and Fable 5
FrontierCode (Diamond)29.3%extra high effort, higher of Mythos 5 and Fable 5
GDP.pdf29.8%no tools, higher of Mythos 5 and Fable 5
Blueprint-Bench 238.6%higher of Mythos 5 and Fable 5
AutomationBench17.4%higher of Mythos 5 and Fable 5
OSWorld-Verified85.0%higher of Mythos 5 and Fable 5
Legal Agent Benchmark13.3%higher of Mythos 5 and Fable 5

Source: anthropic.com

What you can do with Claude Fable 5

  • Mythos-class model made safe for general use

  • Lead over other Claude models grows with task length and complexity

  • State of the art at launch on most of Anthropic's capability tests

  • 1M-token context window with image input

How to prompt Claude Fable 5

  • Describe what done looks like, then let it work through the steps on its own.
  • Ask it to check its work against your brief before it reports back.
  • Compare it with Fable 5.1 on the same task; 5.1 is the newer version.

Where Claude Fable 5 fits best

  • Long projects you don't want to babysit

  • Ambiguous briefs that need working out

  • Multi-step research and writing

  • Image-heavy analysis

How Claude Fable 5 compares

Claude Fable 5 compared with other chat models on Flashloop
ModelLMArena textLMArena codingContext windowReasoning
Claude Fable 51503#41551#21M tokensLow to max
Claude Fable 5.11503#51538#131M tokensLow to max
Claude Opus 5.51509#21548#41M tokensLow to max
Claude Opus 51491#131528#231M tokensOff to max
Gemini 3.7 Flash1490#161520#361M tokensLow, medium, high

Good to know before you start

  • Anthropic lists it as legacy and recommends Claude Fable 5.1
  • Safeguards route some topics to Claude Opus 4.8
  • Low effort is as light as it gets; thinking can't be disabled

Start chatting with Claude Fable 5

Chat with Claude Fable 5 in Super Agent

  1. Select Claude Fable 5

    Open Super Agent on Flashloop and choose Claude Fable 5 in the model picker.

  2. Enter your prompt

    Ask for what you need: an answer, a plan, or the images and videos you want the agent to make.

  3. Send and keep going

    Send the message. Claude Fable 5 answers in Super Agent and runs any generations you asked for.

Questions about Claude Fable 5

What is Claude Fable 5 built for?

Long, complex work in coding and knowledge work. Anthropic says its lead over other Claude models grows as tasks get longer and harder.

How does Claude Fable 5 differ from Fable 5.1?

Anthropic says Fable 5.1 is stronger at long-running agentic coding, multistep research and office documents, and cheaper to run for typical workloads.

Which reasoning levels does Claude Fable 5 support in Super Agent?

Low, medium, high, extra high and max. Super Agent starts it at medium.

Why do the Claude Fable 5 benchmarks mention Mythos 5?

Anthropic published one column for Claude Mythos 5 and Fable 5 that shows the higher of the two scores. This page leaves out the rows where Anthropic flagged a larger gap between the two models.

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