powerEvents is a Vault extension, which allows you to take advantage of the Vault Client events, such as check-in/-out, lifecycle change and the like.

You can write custom code that will be executed on the according event via PowerShell.
Let’s say you would like to fill or clear some properties on a lifecycle state change, automatically rename files when imported via drag&drop or prevent a lifecycle state transition when a combination of properties does not match your rules, etc.
powerEvents makes it easy to create such logic in a simple PowerShell script.