A cat that stands on the toilet seat, paws at the water, or watches its litter box from a distance may be curious rather than ready. Moving ahead too quickly can turn that curiosity into avoidance.
A toilet trainer for cats can provide a staged route from litter box use to toilet use, but the equipment is only one part of the process.
The cat still has to accept a different height, surface, balance point, and bathroom routine. Progress depends on observing those reactions and adjusting the pace before a refusal becomes a habit.