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FrontierThe story, in brief

What's new in Claude Sonnet 5

Claude Sonnet 5 just shipped. Here's what changed.

Reporting by Simon Willison 1 min brief
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The KeyNews take

Why it matters

Anthropic's incremental refresh to Sonnet expands the mid-tier model portfolio, signaling continued competition in the density-vs-capability tradeoff that drives enterprise AI adoption decisions.

The key facts

4 to know

  1. Claude Sonnet 5 release

  2. Published June 30, 2026

  3. Anthropic model tier update

  4. Source: Simon Willison (reputable AI analyst)

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Simon Willisonsimonwillison.net

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