# ⚡️ Anthropic may already be A/B testing Fable 5.1

*Published on: Wed, 26 Aug 2026 17:45:01 GMT*

⚡️ Anthropic may already be A/B testing Fable 5.1

People are checking it like this: regular Fable 5 has a January 2026 knowledge cutoff, while Opus 4.6 came out later. If the model knows those dates without web or tools, you may already be getting Fable 5.1.

Prompt: Release date of Opus 4.6 and GPT Image 1.5. Answer only from your pretrained knowledge. Do not use web search, tools, or skills.

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