Anthropic introduced Claude Sonnet 5.5 on September 28 as the second model in its Claude 5.5 family. The company describes it as a complement to the more capable Opus tier, aimed at well-scoped everyday tasks such as bug fixing, document creation and rapid iteration.
Anthropic says Sonnet 5.5 generates output more than 30% faster than Sonnet 5 and can cost up to 30% less per task in its internal testing. Those are company-reported comparisons, not a guarantee that every workload will see the same result. The broader signal is that model releases are increasingly competing on throughput and total task cost, alongside raw capability.
A different place in the model lineup
The launch separates routine, repeatable work from open-ended tasks that require more sustained judgment. Anthropic says Sonnet is strongest when the problem is well scoped, while positioning Opus for complex work. It also said a Haiku 5.5 model was expected to join the family in the coming weeks.
The practical comparison
For teams choosing a model, headline benchmark scores are only one input. Latency, token use, quality on a team’s own tasks and the cost of review all matter. Sonnet 5.5’s positioning makes those operational measures central to the product story; organizations will need to test them against their own workloads before changing a production workflow.
