Claude Opus 5.5
Points and comments are a snapshot, not live.
Anthropic launches Claude Opus 5.5, claiming frontier performance at 40% lower cost than Opus 5.
Claude Opus 5.5 is the first model in the new Claude 5.5 family, performing at the level of Claude Fable 5.1 on most work while costing 40% less to run. Input tokens are $4 per million and output tokens $20 per million, both 20% less than Opus 5, with cache reads dropping 60% to $0.20 per million tokens. On benchmarks, Opus 5.5 leads in agentic coding (Terminal-Bench 4.0: 66.4% vs Fable 5.1's 55.8%) and knowledge work (GDPval-AA v2.1: 1846 Elo). Early testers reported a 680,000-line code migration completed in under a day. The model achieved the best scores on Anthropic's automated behavioral audit and is more resistant to prompt injection. Anthropic is deploying it with safeguards similar to those on Claude Fable 5.1, including verified access programs for biology and cybersecurity research. Claude Sonnet 5.5 and Haiku 5.5 will follow in coming weeks.
What commenters are saying
Top comments split into two camps: those skeptical of the timing after a recent outage and those relieved about improved writing style. Multiple commenters noted Opus 5's verbose output was "unusable," forcing teams back to Opus 4.6. One tester confirmed that with concise output settings the new model is much better. Several users criticized the announcement page's scroll-hijacking animation, calling it "scrollslop" and noting it breaks back/forward navigation; enabling "reduce motion" in accessibility settings serves a plain version. One commenter questioned the naming: "If 5.5 performs similar to Fable and costs 40% less, then 5.5 really should've just been Opus 5."