Megadose AI progress, ranked and analyzed.

Claude Sonnet 5.5

Simon Willison ·
Anthropic’s new Sonnet is faster and cheaper than Sonnet 5, and it is now powering Claude’s free tier.

Willison says Anthropic claims Sonnet 5.5 runs more than 30% faster and costs up to 30% less for most work, while beating Sonnet 5 across benchmarks. His test still hit the same “max” thinking-effort failure he saw with Opus 5.5, burning 128,000 tokens without producing an SVG. At lower effort, it produced a WebGL pelican-on-a-bicycle page he called a solid effort. Simon Willison's note

score 8

Categories: Model Releases