Anthropic says Claude designed protein binders that worked against 14 of 15 targets, with Adaptyv Bio and Twist Bioscience validating 354 binders from 1,320 designs. Hit rates reached 35.1%, well above the field’s usual 10-15%. A separate test saw Claude Opus 5 match a contract lab’s purity reading in 19 minutes. Protein design stays blocked in Fable 5 over bioweapon risks.