There is some precedent for using host-guest binding thermodynamics to tune force field parameters. For example, experimental binding affinities of octa-acid complexes were used to reoptimize the oxygen Lennard-Jones (LJ) parameters of the TIP3P water model, resulting in a new water model called Bind3P. Bind3P gave a consistent drop in the mean signed error in a host-guest test set and improved HFEs of small organic molecules, while still providing accurate results for the properties of pure water. In another study, selected solute LJ parameters were optimized against experimental cucurbit[n]uril-guest binding enthalpies, leading to improved test-set accuracy. However, although these trial studies yielded favorable results, they did not offer a way of systematizing and automating the process of training force fields against host-guest binding thermodynamics. Here, we implement this concept by extending the OpenFF-Evaluator framework to estimate host-guest binding free energies and their gradients with respect to force field parameters, and integrating this capability with ForceBalance.