Like this, I want to add a Property a

Please do not split topics across several threads. This makes following the conversation in the threads view very hard as the context of the other messages is missing. If you have additional information either edit the original message or post to its thread. Regarding the question, you do not add single properties, you add extensions, that then have properties. You can do this as long as the object you want to add to is

ExtensionAware

. Every instance created through Gradle, for example using

objects.newInstance

or any other way, is automatically

ExtensionAware

, even if it does not formally implement that interface. So given the usual situation, you cast the instance to

ExtensionAware

if it does not declare the interface and then add an extension as on any other

ExtensionAware

object like

project

.