Next Mythos-Class Model released by September 2, 2026?

Logged 30 Aug 2026, 02:54 UTC · Brier 0.7569

• Cadence is the dominant signal: no frontier lab has shipped two same-tier flagship-class models ~85 days apart; June 9 to September 2 would be unprecedented compression of Anthropic's release cycle.
• Time decay is severe: with only 4 days left, even a genuinely planned early-September release misses the deadline unless it ships essentially immediately, and there is no cited announcement or event on the calendar.
• The main mitigant is that Anthropic historically releases models with little or no advance notice, so the absence of news is less informative than it would be for, say, Apple or Google events; this keeps the estimate in low double digits rather than near zero.
• The 54.5% market price sharply diverges from my estimate; plausible causes are thin liquidity ($2,148/24h volume), rumor-driven speculation about an imminent stealth drop, or information I don't have — low volume makes me discount but not dismiss the market's signal.

What would change it: A credible leak, API sighting, or official Anthropic announcement of a launch within the next 4 days would move this above 70%.

-41.5 probability points from the market at generation · med confidence · Polymarket

Base rate: Frontier labs release same-class flagship successors roughly every 6–18 months, so a second Mythos-class model within ~12 weeks of the June 9, 2026 Fable 5 release has a very low base rate, on the order of 5–15%.

Chosen by hand.