Schematic of MOSAIC. Here, “data” refer to spectroscopic and/or photometric observations and the “model” is a pre-computed grid of forward model spectra. θ represents the grid parameters (i.e T_eff, log(g), [M/H]), and θ′ the extra-grids parameters that can be defined separately (or not) for each sub-inversions (i.e., rv, v sin i, …). ln ℒ_final is the final log-likelihood function that goes in the nested-sampling algorithm and is computed with the assumption of independent observations, i.e ln ℒ_final = Σ_i ln ℒ_i.