I think as a rule of thumb if you just plan on codegen then no, but if you want to provide compiler features for call sites you would need to since you would have to compile the user module with the plugin so call sites can be resolved by the compiler plugin and insert injections accordingly. Of course you don’t need to use it if you want on the call site a Kotlin vanilla experience that just consumes the generated code. For example the optics plugin would be like this since it would just generate codegen for a companion for the most part