Next-gen model names surface: Opus 5.5, Fable 5.1, GPT-6 Astra — labs said to be ~2 months ahead internally

haider1 · x · 2026-09-24

A roundup of rumored next-gen model names — Anthropic's Opus 5.5, xAI's Fable 5.1, and OpenAI's GPT-6 Astra — with the claim that both OpenAI and Anthropic have more advanced internal models. OpenAI reportedly showed internal-model performance graphs around its Navier-Stokes work, suggesting internal versions are roughly two months ahead of public releases. Unconfirmed speculation.

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