Claude Opus 5.5 Debuts Second on Agent Arena at 40-56% Lower Cost

Claude Opus 5.5 (High) debuted second on Agent Arena, behind only Fable 5.1 Max, with a +12.15% net improvement over Opus 5 while cutting costs by 40-56%, reshaping the price-performance Pareto frontier.

2026-09-29 ~ 2026-09-29 · 2 related posts

• Opus 5.5 (High) hits #2 in Agent Arena at 40-56% lower cost, new Pareto frontier — arena · 2026-09-29
• Opus 5.5 (High) hits #2 on Agent Arena, matching Opus 5 quality at 40-56% lower cost — arena · 2026-09-29