Anthropic launches Opus 5.5

Anthropic released Opus 5.5 on Tuesday, its most capable model tier. It outperforms the larger Fable model on many benchmarks and completes tasks Fable failed.

Prices drop significantly

Output tokens cost $20 per million for Opus 5.5, down from $25 for the previous model. The model also runs faster, requiring less compute to serve.

Better communication style

Opus 5.5 uses less jargon and places important information at the start of responses, making outputs clearer and more accessible to users.

Rapid release schedule continues

Opus 5.5 arrives just two months after Opus 5 in July. Sonnet 5.5 and Haiku 5.5 will launch in the coming weeks with similar improvements.

Safety guardrails remain in place

Opus 5.5 faces the same safeguards as Fable, limiting use for discovering exploits or developing biological weapons. Outside groups like METR will evaluate it pre-release.

CEO commits to pacing progress

CEO Dario Amodei says Anthropic will deliberately slow capability advances to give safety research time to catch up. He calls for more prudence as AI grows more powerful.

“I have become convinced that fully addressing the risks requires even more prudence.”

Building infrastructure for oversight

Anthropic is preparing advanced safety training and monitoring systems for future models. The company says public policy will play a larger role as AI capabilities increase.