Claude designs smaller quantum circuits than published bests

On Oct. 16, 2026 Anthropic said Claude Mythos 5, given plain-language specs and an automated scorer, designed circuits for eight tasks that used fewer qubits and fewer gates than the best published designs. One elliptic-curve point-addition circuit uses 12 percent more qubits and 17 times fewer gates than the smallest prior design. A Reed-Solomon decoder for decoded quantum interferometry uses about 12 times fewer gates than a prior Google construction. Anthropic said a human set the brief and occasional broader-search prompts, and that the designs came from a closed loop with an evaluator.