Forum:Invoked Mechaba vs Master Peace

My opponent has Invoked Mechaba on his field and i tribute summoned Master Peace the true draco king using a spell and trap, my opponent then activated his Mechaba effect to negate the effect of Master Peace. My question is, is Master peace effect of being able to be summoned by tributing spell and traps an effect thus being able to be negated by Mechaba or is it a summoning condition thus no effect is being activated so Mechaba cannot be chained?