Anthropic Releases Claude 5.5 Flagship Models With 40% Cost Reductions and Enhanced Performance

Anthropic has launched Claude Opus 5.5 on September 22 and Claude Sonnet 5.5 on September 28, 2026, introducing the first models in its new 5.5 family with significantly lower costs and stronger performance across coding and agentic tasks. The release represents Anthropic's first major update since the company committed to deliberately pacing frontier AI capabilities.