Anthropic ships Opus 5.5 at $4/$20 — 40% cheaper, 66.4% on Terminal-Bench 4.0
dl_weekly · x · 2026-09-26
Anthropic released Claude Opus 5.5, the first model in the Claude 5.5 family, priced at $4/$20 per million tokens — 40% below Opus 5 — with 30%+ faster output and a 66.4% score on Terminal-Bench 4.0. It performs at Claude Fable 5.1 level, was pre-release tested by Frontier Design and METR, and posts Anthropic's best-ever automated behavioral audit results: less likely to take hard-to-reverse actions and more resistant to prompt injection than Opus 5. One tester completed a 680,000-line code migration in under a day; on a web-app speedup task it succeeded 39 of 40 times where Opus 5 made smaller, behavior-altering improvements.
Related event: Anthropic Launches Claude Opus 5.5 with 40% Lower Cost(2 posts)→
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