Comparison of gas-phase metallicity predictions (Z_pred) from the MTLforGalSpecZ model with true values (Z_true) for star-forming galaxies. The main panel shows a scatter density plot of gas-phase metallicity: the solid black line indicates the 1:1 relation, the red line shows the median predicted metallicity against the true value, and the dashed purple lines represent the 1σ scatter around the median. The top panel shows the residual distribution (∆Z = Z_pred - Z_true ).