Research & models Oct 22, 2026

Today · research post October 21

Claude designs toxin binders; neutralizing is unconfirmed

Anthropic writes that Claude led the design of proteins that bind scorpion toxins: two labs tested 211 designs and 17 met the binding bar; whether they neutralize venom in a cellular setting is unconfirmed, and Anthropic says plainly this is not an antivenom. Anthropic's post: "We have not confirmed whether these binders neutralize scorpion venom in a cellular environment, so we do not claim to have produced an antivenom." (Anthropic, 2026-10-21). Of the 211 designs, Claude selected 180 and the human team added 31; Anthropic reports these figures. The 17 that met the bar are 8.1% of 211 (our calculation). The 17 span four scorpion toxins. Of 60 single-toxin designs, 11 met the bar; the post's breakdown doesn't say which category the other 6 successful designs belong to. None of the 151 multi-toxin designs bound more than one toxin at once. Testing was done by Adaptyv Bio and Twist Bioscience, two contract labs Anthropic commissioned. The bar: binding in every replicate at both labs, with a dissociation constant (KD) no higher than 1 µM; a lower KD means tighter binding. The two best designs reached single-digit nM, while the three antibodies the post uses for comparison are all below 1 nM. Claude ran autonomously for the first 24 hours; the Anthropic team then added four more rounds of prompts, and most selected designs came after the third added prompt. Our reading: so the 17 designs that met the bar can't be credited to Claude working on its own. The technical report hasn't been reviewed. How we checked →