We are currently using the Agnus Dei from the "Holy Cross Mass" by Isele.
A complete copy of it, with the words, "Lamb of God, You take...." is in the cantor's book, as is a short slip of paper, the "program," which lists what all the music for the Mass is, with the number in the hymnal or page in the missallette.
Between "Amen" and "Communion " it says "Agnus Dei: Isele, Holy Cross, #314.
(I should add that I never, but NEVER program "Mass" parts with words other than those of the Mass, no Bread of Life, no Tree of Life, no Basket of Goodies... nor have done for the four plus years I have been here.)
So at at Mass this evening, I play the intro and the cantor begins to croon, "Ho -o-o-ly Cross, you take away the sins...."
I mean, whuddyagonna do?