Claude Sonnet 5.5 (Azure Anthropic)

Anthropic released Claude Sonnet 5.5 on September 28, 2026, keeping Sonnet 5's pricing at $2 per million input tokens and $10 per million output tokens, while generating output more than 30% faster and costing up to 30% less per task. The model is available on AWS, Google Cloud, and Microsoft Azure under the model ID claude-sonnet-5-5, with zero data retention. Anthropic describes Sonnet 5.5 as a faster, lower-cost complement to Opus 5.5, targeted at well-scoped tasks like debugging and polished document creation. Benchmark highlights include 70.6% on Terminal-Bench 4.0 (vs Sonnet 5's 10.3%), 55.5% on CursorBench 4.0, GDPval-AA v2.1 score of 1844 (two points below Opus 5.5's 1846 and about 400 above Sonnet 5's 1449), and 80.1% partial credit on OSWorld 2.1. Sonnet 5.5 is the first Sonnet model to beat Pokémon Red working only from screenshots, and Artificial Analysis independently ran GDPval-AA and AA-Briefcase evaluations on a pre-release deployment.

Anthropic released Claude Sonnet 5.5 on September 28, 2026, as the second model in its Claude 5.5 family, generating output more than 30% faster and cutting per-task costs by up to 30% through more efficient token usage. Sonnet 5.5 nearly matches the top-tier Opus 5.5 on several benchmarks at a fraction of the cost, with Anthropic positioning it for well-defined everyday work like bug fixing, documentation, presentations, and spreadsheets. The model is available on AWS, Google Cloud, and Microsoft Azure. Coding performance jumps sharply: Sonnet 5.5 scores 70.6% on Terminal-Bench 4.0 versus Sonnet 5's 10.3%, and 55.5% on CursorBench 4.0, reflecting major gains in agentic coding evaluations. Anthropic also added new safeguards against cybersecurity risks and distillation attacks for the more capable model. A Claude Haiku 5.5 variant is announced for the coming weeks, focused on high-throughput, low-cost use cases.

Anthropic announced Claude Sonnet 5.5 as a faster, more efficient update to its mid-tier workhorse model, generating output more than 30% faster than Sonnet 5 and reducing total cost per task by up to 30% through fewer tokens and tool calls rather than a lower sticker price. API pricing remains $2/$10 per million input/output tokens, with $0.20 per million cache-read tokens and $2.50 per million cache-write tokens, compared to Opus 5.5 at $4/$20. On GDPval-AA, Sonnet 5.5 scores 1844, nearly identical to Opus 5.5's 1846 and well ahead of Sonnet 5's 1449, while AA-Briefcase gives Sonnet 5.5 a score of 1811 against Opus 5.5's 1822. The model reaches 80.1% on OSWorld 2.1, narrowing the gap between Sonnet and Opus tiers substantially across several workloads.