We anchored our generation on three clinically validated or approved VHH framework regions (FRs): 7xl0 (vobarilizumab), 7eow (caplacizumab), and 8xvj (ozoralizumab). For each framework, we systematically explored the combinatorial space of CDR lengths: CDR1 (3 lengths), CDR2 (3 lengths), and CDR3 (9 lengths), resulting in 81 unique length combinations per framework. Using IgGM-1.5, we generated 1,000 sequences for each combination, yielding an initial pool of 243,000 VHH sequences.