Has anyone written a gradle plugin in Kotlin that leverages jetbrains code completion?

what is “jetbrains code completion”?

hmmm

No I'm talking about writing my own Gradle plugin

So, you write own Gradle Plugin and you want that users of this plugin have code completion in Gradle Kotlin DSL configs, correct?

That's correct

If you will use recommended approaches for writing Gradle plugin you don't need any additional support, just define tasks, use extensions instead of conventions, avoid any dynamic groovy api

Awesome thank you!!!