what to do at carpet edges

I am planning to tile over a concrete floor and would like to know what to do at the edges where my marble tile will but up against already laid carpet.

Should I take the metal edging off of the carpet and put something different there?

Do I grout between the tile and the metal edging of the carpet???

Thank you for your help.

 

Need to know what kind of metal edging you have. Probably, I would remove it and install something like Schluter metal edge guard . It locks under the tile with the thinset and wraps up the side of the tile. The model name you want is called Schiene. Comes in various thicknesses, you could use the one labeled A100, made of aluminum and looks like an inverted "L" the short side covers the edge of the tile so it does not chip. Can be had at Home Depot. Many tile retailers can get it for you in other types of metal like brass and stainless steel. There are several othe companies out there that make similar products so you may find the same thing under a different name.
Good luck