As noted above, we provided input files in a variety of formats. Participants were advised that (a) further equilibration of the host with the guest might or might not be needed (for TrimerTrip, we pre-equilibrated the host structure as discussed in Methods) and (b) to exercise their best judgment on the state modeled (i.e protonation, conformer, binding mode, etc.). In essence, part of the host-guest challenge for some systems included binding mode prediction.