Claude Sonnet 5.5 extends the new model family
Claude Sonnet 5.5 is the second model in Anthropic’s new family. It is positioned for well-scoped coding and knowledge work, including documents, spreadsheets and presentations.
A model for repeated iteration
In the Sonnet 5.5 release, Anthropic describes the model as a faster, lower-cost complement to Opus 5.5. The announcement emphasizes bug fixing, artifact creation, image understanding and collaboration on everyday tasks.
Iteration is part of the task
- Report boundary
- Iteration needs preserved constraints and a reviewer who can assess the finished task.
View data
| Evidence | Meaning |
|---|---|
| Report boundary | Iteration needs preserved constraints and a reviewer who can assess the finished task. |
Anthropic · published 2026-09-28. Source-bound illustration, not a performance benchmark.
Download imageIts cost comparisons reflect the company’s testing and the amount of work needed per task, not just the listed token rates. Anthropic also describes new cyber safeguards for Sonnet. Published benchmarks can help choose an evaluation candidate, but do not settle whether a particular workbook or code change meets a team’s standards.
Original sources
- Anthropic: original announcementwww.anthropic.com
Checked 9 Oct 2026 · A manually curated edition. Availability may change; company performance claims are not Trion test results. Editorial method.