How to add my own musicbrainz tags as mp3 tag

Tags: #<Tag:0x00007f2a5909e540>

I have LastFm and friends which populate my Genre and I don’t want to use this field for my personal classification.

I use now custom mp3 tag my_tags and populate it manually since I know no script or tool will be aware of it and leave it alone. I also add tags via web interface on release.

For example, on album Aphex Twin - Selected Ambient Works genres are populated automatically and are different on each song and I add on picard ‘folder’ my_tags tag and set it to Electronic, Ambient and also click Lookup in browser and add those 2 (user) tags there.

Is it possible to create custom script that will grab my personal (user) tags so that I can enter them only on one place, in browser and picard can pick them up ?