Reservoir computing is an emergent field in which dynamical systems are exploited for temporal information processing. Our previous work found a feature that makes a reservoir valuable: contractive dynamics of the reservoir toward input-dependent fixed points. These results are enhanced in our latest paper by finding conditions that guarantee a crucial aspect of the reservoir’s design: distinguishing between different input sequences to ensure a faithful representation of temporal input data. This work contributes to analyzing valuable reservoirs in terms of their input dependence.