Add breakfast as an amenity entails much more than just breakfast.
If you prepare breakfast, in my area you need a local license and you change your tax bracket when filing your income tax returns. Health Department regulations for food preparation may also be requested.
I find it easier to have all supplies on hand and indicate guests do the preparations, clean up and wash & dry the dishes.
If you choose to do so try to find out if your area has requirements beforehand.
I leave out cereals and show guests a shelf in the fridge where milk, bread, jams and peanut butter are for toast that they prepare for themselves, I ask on my listings that they leave the kitchen as they found it but also leave a note on the side for them in the morning to remind them to wash and dry their plates and bowls and to leave the kitchen as they found it and I wish them a good day. Some of them still wash the bowls and leave them draining on the draining board.