How to Add Custom Tooltip Borders with a Resource Pack

Preparing the Pack

Custom borders are supplied through a resource pack, not through the config alone. Create a resource pack folder with a pack.mcmeta file, then add the folder structure the mod expects for its border assets. The mod supports a limited number of custom borders, so plan which ones you need before building the pack.

Adding Border Textures

Place each border's texture in the correct assets folder. Borders are typically nine-slice style images, meaning the corners, edges, and center stretch independently. Draw your border so the corners are not stretched and the edges tile cleanly. Keep the center transparent if the tooltip background should show through.

Registering the Border

Alongside the texture, provide a definition file that names the border and points to its texture. This is what makes the border appear in the mod's selection list. Give each border a unique identifier so it does not clash with built-in ones.

Applying and Testing

Enable the pack, then open the mod config and assign your new border to an item or category. Hover the item in-game to verify the border renders correctly. If it looks stretched or misaligned, adjust the nine-slice margins in the definition until the corners and edges line up.