Anthropic Ships Claude Sonnet 5.5 at Unchanged Prices and Claims 30 Percent Lower Cost Per Task

Anthropic released Claude Sonnet 5.5 on Sunday, six days after Opus 5.5. The company describes it as a model that runs 30 percent faster and costs up to 30 percent less for most work. Token prices are unchanged at $2 per million input tokens and $10 per million output tokens, so the savings come from using fewer tokens per task rather than from a price cut.

The positioning is explicit about scope. Russian-language coverage of the launch summarised it as the fast, inexpensive complement to Opus 5.5 for well-specified everyday work such as bug fixes, documents, slides and spreadsheets. Anthropic's own framing matches that description.

The benchmark numbers in circulation are worth separating by source. One roundup reports Sonnet 5.5 scoring 70.6 percent on Terminal-Bench 4.0 against 66.4 percent for Opus 5.5, 81.3 percent on SWE-Bench Pro against 89.9 percent for Opus 5.5 and 63.2 percent for Sonnet 5, and 90.3 percent on SWE-Bench Multilingual. A cheaper model outscoring its larger sibling on an agentic terminal benchmark, while trailing it by more than eight points on repository-level coding, looks like a harness advantage rather than a broad capability gain. Neither figure has an independent reproduction yet.