What happened
On June 30, 2026, Anthropic launched Claude Sonnet 5. Anthropic calls it its most agentic Sonnet yet. Agentic means good at multi-step tasks done with little help. It says Sonnet 5 nears its top Opus 4.8 model at Sonnet's lower price. Sonnet 5 scores 72.7% on SWE-bench Verified, a test of fixing real software bugs. It is now the default model on Free and Pro plans.
The context
Sonnet is Anthropic's middle tier, between the small Haiku and large Opus. Making it the default puts it in front of most users.
What this means for you
👤EverydayFree and Pro users get a stronger model without changing anything. Answers and task help should improve.
💼At workCoders and analysts get near-top quality for routine jobs at a lower cost.
🏢BusinessFirms can handle more work on the cheaper tier and save the priciest model for hard cases.
🌍The worldStrong mid-tier models spread capable AI to more people at lower cost.
Ledger entry: Release execution · Materiality 4 · T1 Primary → ▲ for Anthropic
Sources
- Anthropic, https://www.anthropic.com/news/claude-sonnet-5 T1 Primary