Anthropic launches Claude Opus 5.5, cutting costs by 40%

Anthropic’s latest model arrives with a rare combination in AI releases: it costs less, runs faster, and is harder to manipulate than the version it replaces. Claude Opus 5.5 launched on September 22, 2026, and the headline number is a 40% reduction in overall operating costs compared to Claude Opus 5, which itself only shipped two months ago. What changed and what it costs now The pricing structure tells the clearest story. Input tokens now run at $4 per million, output at $20 per million, each representing a 20% cut from Opus 5’s $5 and $25 rates. Cache reads dropped even further, falling 60% to $0.20 per million tokens. The model also generates output more than 30% faster than its predecessor, which matters less for casual queries and a great deal for agentic tasks that chain dozens of model calls together. Anthropic built Opus 5.5 specifically for long-duration agentic coding and professional workloads, giving it a 1M-token context window and a maximum synchronous output size of 128K tokens. On benchmarks, the model matches or exceeds Claude Fable 5.1, Anthropic’s higher-tier offering, across a range of coding and knowledge-work evaluations. On GDPval-AA v2.1, it scores 1,846 E...