Good question! I am curious about that too. The workaround I would use now is this:

Create a custom command and give it the

Code (Text):

1. executable by: console

property.
Then create an event that listens to this custom command and execute your code. Because this custom command can only be executed by console (and thus command blocks), the event should only trigger when that happens.

 

with skript-reflect?

Code (Text):

1. set {_cmdblock} to block at location ....
2. set {_state} to {_cmdblock}.getState()
3. set {_cmd} to {_state}.getCommand()

 

Using SkBee

Code (Text):

1.  
2. set {_command to }tag "Command" of nbt compound of target block
3.