Anthropic releases Claude Opus 5.5

Anthropic has released Claude Opus 5.5, the first model in its Claude 5.5 family and its first release since it called for "pacing the frontier." External evaluators, including Frontier Design and METR, tested the model before launch.

Pricing. Input and output tokens cost $4 and $20 per million, 20% below Opus 5. Cache reads, which Anthropic says make up most of the cost of agentic and coding work, drop 60% to $0.20 per million. The company says output is more than 30% faster than Opus 5. It is also raising five-hour usage limits on Pro, Max, Team and seat-based Enterprise plans.

Benchmarks. Anthropic reports Opus 5.5 at 66.4% on Terminal-Bench 4.0 (±2.6 pts), compared with 55.8% for Fable 5.1 and 57.9% for OpenAI's GPT-6 Astra. It also reports 1846 on GDPval-AA and 81.8% on OSWorld 2.0. GPT-6 Astra scores higher on AutomationBench (41.4% vs 40.0%) and Terminal-Bench-Science (64.6% vs 58.7%). Anthropic says benchmark margins have become "a less reliable guide" and that the real-world gap to Fable 5.1 is narrower than the scores suggest.

Safety. Anthropic says Opus 5.5 has the best score of any model it has tested on its automated behavioral audit. Because the model's biology and cybersecurity capabilities are comparable to Claude Mythos 5.1, it ships with Fable-level safeguards. Access for biology research goes through a Life Sciences Verification Program, and a Cyber Verification Program will expand in the coming weeks.

Claude Sonnet 5.5 and Haiku 5.5 will follow in the coming weeks. None of these results have been independently verified yet.