TiCoSb half-Heusler in the correct C1b ordering (F-43m, a=5.88 Å): Ti and Sb on the rock-salt 4a/4b sites, Co on 4c, 4d empty. Known-answer control for the Thermoelectrics API: PBE gap ~1.0 eV, |S| > 200 µV/K at 1e20 cm⁻³.