Question 1

What is Fable 5?

Accepted Answer

Fable 5 (Claude Fable 5) is Anthropic's most powerful generally available AI model, released on June 9, 2026. It is a Mythos-class conversational model made safe for general use, with state-of-the-art results across software engineering, knowledge work, vision, and scientific research — positioned as a new tier above Claude Opus 4.8.

Question 2

Is fable5.io an official Anthropic or Fable 5 site?

Accepted Answer

No. fable5.io is an independent community guide and prompt workspace. It is not affiliated with, endorsed by, or operated by Anthropic. Claude and Fable are Anthropic's marks, used here only to describe the model this guide covers.

Question 3

How can I access the Fable 5 model?

Accepted Answer

Fable 5 is available in the Claude apps on paid plans (included on Pro, Max, Team, and seat-based Enterprise until June 22, 2026, with usage credits afterwards), via the Claude API under the model ID claude-fable-5, on AWS, Google Cloud, and Microsoft Foundry, in GitHub Copilot, and through routers such as OpenRouter (anthropic/claude-fable-5).

Question 4

How much does Fable 5 cost?

Accepted Answer

API pricing is $10 per million input tokens and $50 per million output tokens — double Claude Opus 4.8 — with a 1M-token context window and up to 128K output tokens. Prompt caching offers a 90% input-token discount on cached content. App availability depends on your Claude plan.

Question 5

Does the Playground use the real Fable 5 model?

Accepted Answer

No. Fable 5 is a paid API model, so the free Playground routes prompts to free open-weight models through OpenRouter instead. Use it to refine prompt structure at no cost, then run the finished prompt in your own Claude app or API account.

Question 6

What's the difference between the Chat and the Playground?

Accepted Answer

The Chat is a free, claude-style streaming conversation: multi-turn, Markdown answers, model picker, and history saved in your browser. The Playground is a one-shot tool for refining a single prompt with four structured modes (Refine, Creative, Analytical, Safety Review). Both run free open-weight models via OpenRouter — neither is Fable 5 itself.

Question 7

Which AI models power the Playground?

Accepted Answer

Free open-weight models routed through OpenRouter — currently OpenAI GPT-OSS 120B, Moonshot Kimi K2.6, Meta Llama 3.3 70B, Qwen3 Next 80B, and GLM 4.5 Air, with automatic fallback when a free provider is busy. The Models page lists context windows and pricing for the wider catalogue, refreshed daily.

Fable 5 Chat — free AI chat on open models