Project MMO: Skill Books

Each skill book is set up through a data file. A book can grant experience levels in one skill, or in several, with up to four options a book can offer, and the player chooses one when using it. Skills are listed by their identifier, and the number of levels and the application type are set per entry. Using a book applies the value to the chosen skill straight away.

The experience cost of a book is set in Minecraft levels, and a value of 0 removes the cost. Book appearance can be changed through a texture type and an insignia, with the trim color chosen from plain, iron, gold, emerald or diamond. The item name is translatable, so a language file can supply localized text. Project MMO is required, and the mod is published for Forge and NeoForge on 1.20.1 and 1.21.1.

The 1.21.1 release is the current one; the 1.20.1 build is 2.0.0, and it removes the class system entirely, which the author states is a breaking change. Source code and an issue tracker are public, and the mod is released under the Creative Commons Attribution 4.0 license. It is not open source.