Exoplanet_atmosphere_model_vMCMC_coreT_3000K_dist.py is a version of the simulated annealing/MCMC code used to model planetary embryo chemical equilibrium in Young et al. (2023, Nature). Input file initial_atm_vMCMC.txt includes initial conditions and the potential temperature assuming a core-mantle temperature of 3000K. Initial moles of H2 are varied as needed in the input file to derive solutions for different mass fractions of primary atmosphere.