MoS₂ is a layered material with outstanding electrical and optical properties. The surface, interfacial, and mechanical properties are important for the design of functional materials and increased control over performance. It has remained challenging to understand and predict such properties for MoS₂ and related 2D materials to support the rational synthesis and performance in applications. Molecular dynamics simulation has become a reliable tool, but interpretability of the forcefield parameters is essential to explain and predict the physical and chemical behavior. Here, parameters for MoS₂ with record accuracy are introduced, including validation and application to explain specific binding of peptides and amino acid residues. The results show in unprecedented detail how simulations can be used to obtain quantitative forecasts of peptide affinity to MoS₂ for any amino acid sequence. The models reproduce lattice parameters, infrared frequencies, surface and interfacial properties, as well as mechanical properties relative to experiments in multiple times higher accuracy compared to prior models.