Claude Mythos 5 vs Claude Opus 4.8: Glasswing Frontier vs Shipping Flagship

Claude Mythos 5Claude Opus 4.8
arenaElo14931435
humanEval9894.5
sweBench7867
mmlu95.193
gpqa9267.5
aime94.590
Price in/out ($/M)$10 / $50$5 / $25

Our verdict

Mythos 5 is the most capable Claude, but it stays gated behind Project Glasswing at $10 / $50 per M tokens with always-on thinking and 30-day retention. Opus 4.8 is the practical flagship you can ship on today: generally available at $5 / $25, leading agentic coding and computer use. Pick Mythos 5 only if you have a Glasswing seat and your use case needs the absolute frontier; otherwise Opus 4.8 (or the GA Fable 5) is the default.

Claude Mythos 5 · Claude Opus 4.8 · All AI model comparisons