What is Fable 5.1?

Sui 2 scored 50% on Frontier Code 1.1 at a 64% cost reduction versus comparable frontier models.

“For example, the model scored 50% on Frontier Code 1.1, putting it slightly ahead of GPT56 Soul and just behind Fable 5.1, but at a 64% reduction in cost.”

GPT-6 Astra scored 61 on the Artificial Analysis intelligence index, matching GPT-56 Soul and trailing Fable 5.1 by five points at launch.

“Initially, Astra scored a 61 on the intelligence index. That gave it the same score as GPT56 Soul and left it a full five points behind Fable 5.1.”

Advanced practitioners are reverting from GPT-6 Astra to older models, citing unpredictable behavior and doubled effective spend as reasons it is hard to justify.

“GBT6 Astra might be the smartest and dumbest model I've ever worked with. I can't deal with its mood swings, especially the absurd shortcuts it takes to arrive at something technically working.”

Claude Code paired with Fable 5.1, and Codex paired with GPT-6 Astra, are cited as one-shot architecture tools for rapidly assembling raw customer assets into initial working outputs.

“Dump them into either cloud code with Fable 5.1 or codeex with Astra and at least for the sake of the first time, ask it to architect and put everything together to see what it does in one shot.”