Claude Sonnet 5 Now Available

Anthropichas released Claude Sonnet 5 as of June 30, 2026, positioning it as a cost-effective option for developers building AI agents. The model will become the default for Free and Pro plans starting July 1, 2026.

Introductory Pricing Through August

During the introductory period through August 31, 2026, Claude Sonnet 5 is priced at $2 per million input tokens and $10 per million output tokens. Following that date, pricing moves to $3 per million input tokens and $15 per million output tokens.

Performance on Agentic Tasks

On an agentic coding benchmark, Sonnet 5 scores 63.2%, trailing Claude Opus 4.8 at 69.2% but ahead of Claude Sonnet 4.6 at 58.1%. On knowledge work benchmarks, Sonnet 5 slightly outperforms Opus 4.8.

Cost Comparison

Sonnet 5 is cheaper than Opus 4.8, OpenAI’s GPT-5.5, and Google’s Gemini 3.1 Pro, though it is more expensive than Gemini 3.5 Flash.

Safety Improvements

Sonnet 5 demonstrates a lower rate of undesirable behaviors like cooperation with misuse and deception compared to Sonnet 4.6. The model also hallucinates and engages in sycophantic behavior at a lower rate than its predecessor. Additionally, Sonnet 5 has a lower ability to perform dangerous cybersecurity tasks than Opus models.

Market Context

Sonnet 5’s launch comes as the AI agent space intensifies. OpenAI’s GPT-5.6 Sol launched in preview in late June 2026 as the firm’s most agentic model yet, while Google’s Gemini 3.5 Flash launched in May 2026, representing a shift from conversational chatbot to agentic tool. Claude Sonnet 4.6 was released in February 2026.

Source: TechCrunch