Agent Red Teaming benchmark

Anthropic's Claude Opus 4.6 system card reports prompt injection attack success separately for tool use (Gray Swan's ART benchmark), coding and computer use (Gray Swan's Shade adaptive attacker), and browser use (an internal Best-of-N attacker), with and without extra safeguards and across different attempt budgets. For Opus 4.6, results range from 0% in coding to 85.7% in computer use with 200 attempts and no safeguards (78.6% with extended thinking). Anthropic notes that, unlike earlier Claude models, extended thinking increased ART attack success for this model.

Zou and colleagues (Gray Swan and collaborators; Anthropic describes the resulting benchmark as developed with the UK AI Security Institute) report a public red-teaming competition with 1.8 million prompt-injection attacks against 22 frontier agents in 44 deployment scenarios, producing over 60,000 successful policy violations. From these they build the Agent Red Teaming (ART) benchmark and find nearly all agents break within 10 to 100 queries for most behaviors, with high transfer and little correlation between robustness and model size or capability.