I made a custom creature and it works fine in the dev kit I’ve got the Dino entry and egg in but when i upload the mod it has no files I can’t spawn my creature and the mod is only 440 kilobytes when similar mods are usually around 60 megabytes or more.
Did you load the map for your mod and set primarygamedata to the mods in the world data?
Then cook and upload.
I added the basic egg and spawn entries and it appears that fixed the issue.