binary_precursor models light curves of supernova (SN) precursors powered by a pre-SN outburst accompanying accretion onto a compact object companion. Though it is only one of the possible models, it is useful for interpretations of (bright) SN precursors highly exceeding the Eddington limit of massive stars, which are observed in a fraction of SNe with dense circumstellar matter (CSM) around the progenitor. It offers a number of editable parameters, including compact object mass, progenitor mass, progenitor radii, and opacity. Initial CSM velocity can be normalized by the progenitor escape velocity (xi parameter), and the CSM mass, ionization temperature, and binary separation can also be specified.