Automatically add file name to metadata caption

I am trying to find a way to get the title of the image to be added to the metadata description automatically, so that I can batch export a bunch of images. The idea being that then when I upload them to an album on Facebook, the image metadata description is automatically added as the photo description in Facebok, and I would like each photo to have its title in that description, so that if someone wishes to purchase an image, they can tell me the exact image title, as opposed to me having to search for the image manually by eye.

I would like either the title of the image (e.g. PANA2035) to be added

OR

More ideally, the user specified custom output title to be added. What I mean by this is, in the export window, you can have custom file naming, and I have a few different presets but they all are based on the following: Date (YYMMDD)_File name (PANA2035)_Custom text etc...

Ideally, I am trying to figure out how I can get that custom file name to be added to the metadata caption automatically on export.

Any help?