Claude Sonnet 5
The first Sonnet-class Claude model to top Anthropic's flagship writing benchmarks
Claude Sonnet 5 launched on June 30, 2026 as Anthropic’s most agentic Sonnet model yet, built to plan multi-step tasks and use tools like browsers and terminals with less hand-holding than earlier Sonnet versions. It performs close to Claude Opus 4.8 on most benchmarks, including roughly 85.2 percent on SWE-bench Verified and 63.2 percent on SWE-bench Pro, while costing noticeably less, which is why Anthropic and reviewers have framed it as a cheaper way to run coding agents at scale. It carries a 1 million token context window with context compaction to manage long agent sessions, and reads both text and images. Anthropic priced it at an introductory $2 per million input tokens and $10 per million output tokens through August 31, 2026, after which it moves to standard pricing of $3/$15, and it is now the default model for free and Pro Claude.ai plans.