Anthropic has released Claude Sonnet 5, positioning it as the most agentic Sonnet model yet capable of making plans, using tools like browsers and terminals, and running autonomously at levels that previously required larger, more expensive models. Released June 30, 2026, Sonnet 5 represents a significant leap over its predecessor Sonnet 4.6.
Performance Highlights: Sonnet 5 narrows the gap to Anthropic's flagship Opus 4.8 model, delivering comparable performance on many agentic benchmarks at substantially lower prices. On the agentic search evaluation BrowseComp and the computer use evaluation OSWorld-Verified, Sonnet 5 provides a much wider range of cost-performance options than Sonnet 4.6, with higher-effort performance matching Opus 4.8 on certain tasks.
Pricing: Through August 31, 2026, Sonnet 5 launches with introductory pricing of $2 per million input tokens and $10 per million output tokens on the Claude Platform. Regular pricing after that date will be $3/MTok input and $15/MTok output — significantly below Opus 4.8 at $5/$25.
Availability: Sonnet 5 is the default model for Free and Pro plans, and available to Max, Team, and Enterprise users. It can be accessed via Claude Code, Claude Cowork, and the Claude API under the model identifier `claude-sonnet-5`.
Early Partner Feedback: Beta testers reported that Sonnet 5 finishes complex multi-step tasks where previous Sonnet models would stall, checks its own output without explicit prompting, and refuses unsafe requests consistently. Partners including Lovable, Kiro, ClickHouse, and Pace highlighted improvements in sustained coding, brownfield debugging, legal research, and insurance workflow automation.
Safety: Anthropic's safety assessments found Sonnet 5 shows lower rates of undesirable behaviors than Sonnet 4.6 overall and has a reduced ability to perform cybersecurity tasks compared to Opus models — a deliberate safety choice for a more accessible model tier.