  The two-particle correlation technique applied to $K^-\Lambda$ pairs in pp
collisions at LHC recently provided the most precise data on the strangeness
$S=-2$ meson-baryon interaction. In this letter, we use for the first time
femtoscopic data to constrain the parameters of a low-energy effective QCD
Lagrangian. The tuned model delivers new insights on the molecular nature of
the $\Xi(1620)$ and $\Xi(1690)$ states. This procedure opens the possibility to
determine higher order corrections, directly constraining QCD effective models
particularly in the multi-strange and charm sectors.
