tl;dr: Claude Opus 5.5 agents, running DFT simulations, identified two candidate Luttinger-compensated magnets—semiconductors with zero net spin but spin-sorted electron bands useful for spintronics. One, YBaMnFeO₅, was newly designed but likely hard to synthesize due to atomic disorder; the other, KV[Cr(CN)₆], was actually first made in 1999 as a Prussian blue analog and remains magnetically ordered up to 376 K, but its spin-sorting properties were never recognized. The author suggests remaking and measuring KV[Cr(CN)₆] directly, and has published all computations on GitHub.