Anthropic released Claude Sonnet 5.5 on September 28. The price matches Sonnet 5 at $2 per million input tokens and $10 per million output tokens, with cache reads at $0.20 per million. Anthropic says the model typically needs far fewer tokens for the same work, cutting cost per task by up to 30% in its tests, and generates output 30% or more faster. It is available on the Claude Platform as `claude-sonnet-5-5` and on Amazon Web Services, Google Cloud, and Microsoft Azure, with zero data retention available. Anthropic calls it the first Sonnet with cyber safeguards and fallbacks. The price per token did not move, so any saving depends on how the model is used. Anthropic's figure comes from its own testing and is worth confirming on your own workloads. Switching to a new model version can change how an existing tool behaves, and Anthropic notes that anyone running Sonnet with thinking off has to change a setting first. Zero data retention is available, which matters if prompts contain customer or company information. Run your own cost and quality check on a real task before switching from Sonnet 5.