GPT-6 Astra Lands, 99.9% on ARC With the Right Harness & the Model That Hides Its Thoughts

OpenAI shipped GPT-6 Astra , priced exactly like Fable at $10 in and $50 out, and the day split three ways. The capability story is real: 99.9% on ARC-AGI-3, two Lean-verified Erdős problems no model had touched, a prime-gap bound improved for the first time since the 1930s, and Latent Space's writeup after 20 billion tokens calling it an AI engineer you can hire for under six dollars an hour. The benchmark story is messier: the ARC score needs OpenAI's own harness that preserves hidden reasoning state (the standard harness gets 62.7%), Artificial Analysis has Astra level with GPT-5.6 Sol and five points behind Fable 5.1 on general intelligen