Claude Opus 5.5

Changes from previous version

Major step up from Claude Opus 5: Terminal-Bench 4.0 rises from 52.3% to 66.4%, CursorBench 4.0 from 46.6% to 57.8%, and GDPval-AA v2.1 from 1708 to 1846. List rates fall from $5/$25 to $4/$20, cache reads from $0.50 to $0.20, and Anthropic reports about 40% lower cost on typical workloads. Communication is clearer, and the model is the strongest Claude yet on Anthropic's automated behavioral audit. Per-message effort (beta) can change thinking depth mid-conversation without invalidating the prompt cache; changing the top-level effort value still does.

Release Summary

First model in Anthropic's Claude 5.5 family. Performs at the level of Claude Fable 5.1 on most work and costs about 40% less to run than Claude Opus 5 on typical workloads. Leads the announcement table on Terminal-Bench 4.0 (66.4% at xhigh vs 55.8% for Fable 5.1), FrontierCode v1.1 Main (54.4%), CursorBench 4.0 (57.8%), and GDPval-AA v2.1 (1846 Elo). Input and output tokens are $4 and $20 per million, 20% below Opus 5; cache reads are $0.20 per million, 60% below Opus 5. Output is more than 30% faster. Fast mode is available at 2.5x speed for $8/$40. Ships with Fable-class cyber, biology, and distillation safeguards, including preserved thinking. Available as claude-opus-5-5 on the Claude Platform, Amazon Web Services, Google Cloud, and Microsoft Azure. 1M-token context, 128k max output, knowledge cutoff June 2026. Claude Sonnet 5.5 and Claude Haiku 5.5 are scheduled to follow in the coming weeks.

Timeline

Other Claude Opus versions