An addon for Geckolib3 and Custom NPC that allows the use of geckolib models for your NPC
CNPC-Gecko-Addon is an addon for CustomNPCs and Geckolib3. So in order to use it you need to have these two mod installed.
Addon also uses Mixins. It means that on 1.16.5 you need to install a special mod called MixinBootstrap.
You can also use any other mixin loading mod you know.
On 1.18.2 the mixin system is integrated into the minecraft itself, so you don't need to install mixin loader.
The addon is version-dependent, so to choose the correct version of CNPC-Gecko-Addon, you need to look at the last four digits of your CNPC version.
For example, if you have CustomNPCs-1.16.5.20220728snapshot.jar, you should use CNPC-Gecko-Addon-1.16.5-0728-x.x.x.jar.
Mod Wiki

An addon for Custom NPC and Geckolib3 that allows the use of geckolib models for your NPC