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Claude Opus 5.5 Launches and Tops Text Arena

Anthropic launched Claude Opus 5.5 with performance matching its predecessor at 40% lower cost; it then topped LMArena's Text Arena leaderboard, with Anthropic models sweeping the top six.

2026-09-25 ~ 2026-09-27 · 2 episodes · 6 posts

Episode 1 · Anthropic Launches Claude Opus 5.5 with 40% Lower Cost (2026-09-25, 2 posts)

Anthropic released Claude Opus 5.5, the first model in the Claude 5.5 family, matching Claude Fable 5.1 on most tasks at 40% lower cost ($4/$20 per million tokens) and scoring 66.4% on Terminal-Bench.

Episode 2 · Claude Opus 5.5 tops Text Arena as Anthropic sweeps top six (2026-09-27, 4 posts)

Claude Opus 5.5 (High) debuts atop LMArena's Text Arena with a score of 1509, leading an Anthropic sweep of the top six spots, while offering strong price-performance at around $16/MToken.