We present high-accuracy relativistic coupled-cluster calculations of the P-odd interaction coefficient WA describing the nuclear anapole moment effect on the molecular electronic structure. The molecule under study, BaF, is considered a promising candidate for the measurement of the nuclear anapole moment, and the preparation for the experiment is now underway [E. Altuntaş, Phys. Rev. Lett. 120, 142501 (2018)PRLTAO0031-900710.1103/PhysRevLett.120.142501]. The influence of various computational parameters (size of the basis set, treatment of relativistic effects, and treatment of electron correlation) on the calculated WA coefficient is investigated and a recommended value of 147.7Hz with an estimated uncertainty of 1.5% is proposed.