1. A neural stimulator, comprising: a neural stimulation delivery system configured to stimulate a vagus nerve; and a controller operationally connected to the neural stimulation delivery system, the controller configured to deliver a programmed neural stimulation therapy through the neural stimulation delivery system according to a programmed neural stimulation schedule, the programmed neural stimulation therapy including a stimulation signal with modifiable stimulation parameters, the modifiable stimulation parameters including at least one modifiable schedule parameter, the controller including a neural stimulation scheduler with a programmed limit for allowed modifications to the at least one modifiable schedule parameter.