Claude Sonnet 5.5

Claude Sonnet 5.5 (28 September 2026) is the faster, cheaper partner to Opus 5.5 — aimed at well-scoped everyday work, bug fixing and polished documents, slides and spreadsheets. Anthropic says it runs 30%+ faster than Sonnet 5 and costs up to 30% less per task.

Best for

• The everyday default for coding assistants and production agents
• Bug fixing and well-defined engineering tasks
• Documents, slide decks and spreadsheets from a brief
• High request volume where Opus would be overkill

How it compares — and the India angle

• On Anthropic's own numbers it scores higher than Opus 5.5 on Terminal-Bench 4.0 (70.6% vs 66.4%) and within a point on OSWorld 2.1 and GDPval-AA — at half the price. For most teams this, not Opus, should be the default.
• Opus 5.5 is still the better pick for complex, open-ended work — Anthropic says so itself.
• Cache reads were halved to $0.10 per million at launch, which matters more than the headline rate for agents that re-read the same context all day.