Choblin(@choblin29):🚨HOLY MOLY. Anthropic just released Claude Opus 5.5. >66.4% Terminal-Bench 4.0 vs GPT-6 Astra’s 57.9% >54.4% FrontierCode >81.8% OSWorld >30%+ faster output >$4/M input + $20/M output Opus 5.5 is so capable at cybersecurity that MOST cyber tasks will be transparently rerouted to the older Opus 4.8. Even Anthropic’s benchmark runs used fallback models when safeguards triggered: cyber → Opus 4.8, biology/frontier-AI work → Opus 5. It beats Opus 5 and Fable 5.1. Sonnet 5.5 + Haiku 5.5 are coming in the next few weeks.

2026.09.22 17:12

🚨HOLY MOLY. Anthropic just released Claude Opus 5.5. >66.4% Terminal-Bench 4.0 vs GPT-6 Astra’s 57.9% >54.4% FrontierCode >81.8% OSWorld >30%+ faster output >$4/M input + $20/M output Opus 5.5 is so capable at cybersecurity that MOST cyber tasks will be transparently rerouted to the older Opus 4.8. Even Anthropic’s benchmark runs used fallback models when safeguards triggered: cyber → Opus 4.8, biology/frontier-AI work → Opus 5. It beats Opus 5 and Fable 5.1. Sonnet 5.5 + Haiku 5.5 are coming in the next few weeks.

Claude@claudeai

2026.09.22 16:31

Introducing Claude Opus 5.5, the first model in our new Claude 5.5 family. It performs at the level of Claude Fable 5.1 for most tasks, and costs 40% less to run than Opus 5.