Vals AI

Vals AI tested GPT-6 Sol and Claude Opus 5.5 on Vibe Code Bench as solo agents and as teams. Teams cost 1.8x to 5.1x more, and only one of four comparisons showed a statistically significant improvement. Anthropic's own scaling data and comments from OpenAI's Noam Brown point the same way: more agents mostly buy speed, not quality.

According to testing firm Vals AI, Anthropic's Claude Fable 5.1 independently identified and solved the 'Cyphral Distich,' a 1653 numeric cipher by Sir Thomas Urquhart that had defeated other frontier models. The AI decoded a hidden pro-royalist message by mapping each number to a word in Urquhart's original text.