light.setIntensity

light.setIntensity sets Intensity on a light object. It takes id and v.

light.setIntensity(id, v)

function start() {  light.createPoint('point', 0, 2, 0);  light.setIntensity('point', 0.5);}

light.createPoint is there to give the call something to act on; light.setIntensity is the line that matters. The code sits in start(), which the engine calls once, when the entity spawns.