We present the design and optimization of the forebaffle for the SWIPE telescope, the balloon-borne bolometric instrument of the LSPE mission. LSPE–SWIPE is designed to measure the polarization of the Cosmic Microwave Background on large angular scales. The low amplitude of the target signal makes the experiment particularly sensitive to stray light contamination and other optical systematic effects. Several forebaffle geometries, dimensions, and surface treatments have been studied through electromagnetic simulations of the telescope beam. The resulting angular responses are analyzed with the 𝑙𝑖𝑡𝑒𝑏𝑖𝑟𝑑_𝑠𝑖𝑚 framework, which allows the generation of synthetic sky signals and their convolution with the telescope beam. This preliminary approach enables us to create a pipeline to estimate the impact of forebaffle design and modeling choices on the reconstructed sky maps and angular power spectra.