If buildscript itself needs something to run, use classpath.
If your project needs something to run, use compile.
The buildscript{} block is for the build.gradle itself.
For multi-project building, the top-level build file is for the root project, the specific build file is for sub-project (module).
Top-level build file where you can add configuration options common to all sub-projects/modules.
Do not place your application dependencies in top-level build file, they belong in the individual module build.gradle files