Anthropic launches Claude Sonnet 5.5: 30% faster and up to 30% cheaper

bcherny · x · 2026-09-29

Anthropic officially introduced Claude Sonnet 5.5, the second model in the Claude 5.5 family: a clear upgrade over Sonnet 5 that runs more than 30% faster and costs up to 30% less for most work.

Claude Code creator Boris Cherny showed the model fixing a bug inside Claude Code at 30% faster with 30% less token usage.

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