What is Claude Sonnet 5?

Claude Sonnet 5 is Anthropic's mid-tier AI model, released on June 30, 2026 — the workhorse of the Claude family, sitting between the budget Haiku models and the flagship Opus and Fable lines. It's the model most teams actually run in production: capable enough for serious coding and analysis work, priced for everyday volume.

The launch came with two headline numbers. First, capability: Sonnet 5 scores 85.2% on the SWE-bench Verified coding benchmark (as tracked by llm-stats, July 2026), within a few points of Claude Opus 4.8's 88.6% — flagship-adjacent performance at a fraction of the cost. Second, price: an introductory $2 per million input tokens and $10 per million output tokens through August 31, 2026, after which standard pricing of $3/$15 applies.

Technically, it ships with a 1-million-token context window, up to 128K tokens of output, and prompt caching that makes repeated large contexts cheap. The API model ID is claude-sonnet-5, and it's available on the Claude API, AWS Bedrock, and Google Vertex. For most Claude workloads as of July 2026, Sonnet 5 is the sensible default — you escalate to Opus or Fable only when a task genuinely needs the extra reasoning depth.