With Opus 5.5 and Sonnet 5.5 both apparently outperforming Sol and Astra, Anthropic has technically made OpenAI’s Dev Day a lot more interesting. OpenAI is reportedly planning 20+ launches tomorrow, so I’m really curious to see what they have in store now. The timing couldn’t be more interesting. 😅

This story is from 2026-09-29. It is preserved in the archive; the latest stories are on the live feed.

They launched Sonnet 5.5 just day before Dev Day and is almost matching benchmarks of Opus 5.5

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1. 2026-09-29 04:29 · r/OpenAI
   With Opus 5.5 and Sonnet 5.5 both apparently outperforming Sol and Astra, Anthropic has technically made OpenAI’s Dev Day a lot more interesting. OpenAI is reportedly planning 20+ launches tomorrow, so I’m really curious to see what they have in store now. The timing couldn’t be more interesting. 😅