Anthropic Launches Claude Sonnet 5.5: 30% Faster, Up to 30% Cheaper

_catwu · x · 2026-09-29

Anthropic officially released Claude Sonnet 5.5, the second model in the Claude 5.5 family, calling it a clear upgrade over Sonnet 5 that runs over 30% faster and costs up to 30% less for most work. Anthropic's catwu adds that Claude Code users get 30% more tasks done versus Sonnet 5, since the smarter model needs fewer tokens: a tool-call demo finished 24s faster with 6K fewer tokens.

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