Arena launches Alignment Index ranking AI agents on safety across 27 models
Original titleToday, we're announcing our Series B: $200M at a $3.1B valuation, and the release of Arena's Alignment Index.
AISummary
Arena announced a $200M Series B at a $3.1B valuation alongside its new Arena Alignment Index, a benchmark built from 90K+ real-world agent sessions across 27 models.
The index measures Unauthorized Action, False Attribution, and Deceptive Completion, with OpenAI's GPT-6.1-Sol leading at 87.9, ahead of Claude-Opus-5.5 at 83.2 and Grok-4.7 at 82.7.
The source reports that newer models outperform their predecessors across all four labs it covers.
Source: Arena · x.comPublished · added here