Empirical power-law limb-darkening coefficients as a function of wavelength within the broad H and K bands. Panel (a) shows the offsets between the lower- and higher-wavelength H-band fits and the full-H fit; panel (b) shows the analogous offsets for K. Circles show individual targets, and diamonds show median residuals in broad T_eff bins, with error bars spanning the 16th–84th percentile range. The split-band fits provide an internal check on wavelength sensitivity within each passband.