Fireplaces, Heating Stoves, Flues and Chimneys - Tiling over a Fireplace

I was reading a lot about tiling over a brick fireplace. I was curious to know what people generally do for inside the lip. It seems that it is not really shown what to do for the 4 inches inside the firplace and only the outside is tiled. Do you leave this brick bare or do you frame a border inside?

Welcome to the forums! Is this a wood burning fireplace or gas logs? Vented or unvented?

This is a normal wood burning fireplace with a damper. It is made of brick about 5 feet high x 5 feet wide and comes out about 6 inches from the wall. The mantel and hearth are made of 1.5 inch field stone slab. The only thing different is it has a knob on the wall of the brick to turn and open the flu rather than reaching inside which is really nice. I thought I might put thinset over the brick and put marble tiles over it. reading various websites, it is mentioned to make a 1x3 shelf to rest the tile on near the edge of the top of the fireplace opening. (So the tile would be flush with the opening). All of this is fine but this would mean you would still see the brick frame inside left/right and underneathe top. So I was wondering if it is recommended to leave this (since a fireplace screen insert would hide it) or if I should cut 4 inch strips to "edge" the inside frame? I believe if I were to edge this area, I would have to make a slight overhang with the outside tiles so you do not see the seem from the inside tile edge.

I guess the hole thing is, tile the outside only and use a glass screen insert so you do not see the outside structure was originally brick or run the tile just inside the lip (width of brick) so it looks more finshed and an insert would not be necessary?

Welcome to the forums! Is this a wood burning fireplace or gas logs? Vented or unvented?