• Anthropic said the model generates outputs more than 30% faster than its predecessor.
• The model carries the same per-token pricing as Sonnet 5 but uses fewer tokens, lowering the cost per task.
• Anthropic is launching the model with cybersecurity safeguards similar to those used for its more capable models.

Anthropic has introduced Claude Sonnet 5.5, the second model in its Claude 5.5 family, saying the new model improves performance across coding and knowledge work while generating outputs more than 30% faster than its predecessor. The company also said in a blog post that Sonnet 5.5 can cost up to 30% less per task because it requires fewer tokens to complete the same work.

Stronger Performance Across Benchmarks

Anthropic said Sonnet 5.5 improves on Sonnet 5 across multiple domains, with the model performing comparably to Opus 5.5 on some evaluations when running at maximum effort.

On Terminal-Bench 4.0, an agentic coding evaluation, Sonnet 5.5 scored 70.6%, compared with 10.3% for Sonnet 5.

Anthropic said Sonnet 5.5 also performs strongly on image understanding.

Sonnet 5.5 Steps Up Its Coding Game

The company said the model’s performance gains are particularly noticeable in coding.

At High effort on FrontierCode, Sonnet 5.5 scored 10 points higher than Sonnet 5 at the same setting while costing about one fifteenth as much per task. On CursorBench, which evaluates models using tasks from real Cursor coding sessions, its best score came within about two points of Opus 5.5.

Early testers highlighted the model’s ability to understand codebases quickly. They also added that Sonnet 5.5 batches tool calls more frequently than Sonnet 5, resulting in fewer steps and lower costs.

Faster And Less Expensive

Anthropic said Sonnet 5.5 generates outputs more than 30% faster than Sonnet 5, making it the fastest Sonnet model to date.

The model has the same pricing as Sonnet 5 at $2 per million input tokens, $10 per million output tokens, and $0.20 per million tokens for cache reads. However, Anthropic said Sonnet 5.5 usually requires fewer tokens to complete the same work, resulting in costs up to 30% less per task.

Anthropic said Sonnet 5.5 improves on or matches Sonnet 5 on most measures in its automated behavioral audit. Because its cybersecurity capabilities are comparable to Opus 5, Sonnet 5.5 is the first Sonnet model to launch with cybersecurity safeguards and fallbacks developed for Anthropic’s most capable models.

Anthropic Retail View

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