Anthropic · Claude · Fable · Mythos

Claude Opus 4.8

Released 28 May 2026 · 42 days after Claude Opus 4.7

notable release

~4x less likely to let flaws in its own code pass.

Intelligence

—

no index score yet

Price

$10.00

per 1M tokens, 3:1 in/out · $5 in / $25 out

Speed

—

not measured

Weights

Closed

US lab

Anthropic’s best score over time