Anthropic has announced the release of Claude Sonnet 5, the new medium-sized artificial intelligence model that replaces Sonnet 4.6, launched in February. This upgrade promises performance close to that of the flagship Opus 4.8 model but at a significantly lower cost, making advanced AI more accessible to developers and businesses.
Sonnet 5 is the most agentic Sonnet model ever created
According to Anthropic, Sonnet 5 is designed to be the Sonnet model with the greatest autonomous action capabilities. It can make plans, use tools like browsers and terminals, and run independently at a level that, just a few months ago, required larger and more expensive models. The company emphasizes that the performance gap with Opus 4.8 has narrowed, offering substantial improvements in reasoning, tool use, coding, and knowledge work.
Sponsored Protocol
The new model is available to all Free and Pro Claude users and benefits from an introductory promotional price valid until August 31, 2026. The cost is $2 per million input tokens and $10 per million output tokens. After that, standard pricing will be $3 per million input tokens and $15 per million output tokens. Anthropic has also increased rate limits across Chat, Cowork, Claude Code, and the Claude Platform to accommodate higher token usage.
Mythos 5 and Fable 5: Anthropic's flagship models
In addition to Sonnet 5, Anthropic introduced Mythos 5, a model with fewer guardrails for selected security researchers and platform owners, and Fable 5, the safer version that was briefly available before being blocked by the U.S. government. The company is working to restore access in the future. Claude Opus 4.8 was released at the end of May, while Fable 5 was pulled a few days later. Mythos 5 has been partially restored to some customers.
Sponsored Protocol
The launch of Sonnet 5 comes four months after the previous version. Additionally, today Anthropic released a new desktop app with Claude Science for Mac and Linux. For a comparison with other AI options, see the article on Bernie Sanders and the proposal to tax tech billionaires. To learn more about personalized assistants, check out ChatGPT Custom GPT. Finally, for broader context on AI restrictions in Europe, consult the article on OpenAI and Italian SMEs.
For official details, visit the Anthropic website.
Source: https://9to5mac.com/2026/06/30/anthropic-upgrades-claude-with-new-sonnet-5-model-details-here
