[[draft] will reference the loaded draft when you trigger your action.
Can you share how you are creating the new draft?
To be able to reference that new draft we need to understand what reference you have to it once you have created it.
Chances are you’ll either need a template tag to be set to the content of the new draft (so the original draft temporarily gets to hold the content of the new draft as a custom template tag you can then m substitute into your URL), or you carry out the callback call in script rather than an action step.
I did exactly that to get it done. And I have way more options using scripts.
Re templates. Need to read about how to use them
Thank you very much for your detailed answers.
Edit
Ahh, now I see! Instead of the step „Create new Draft“ I used „Define Template Tag“ instead, created my template in there, gave it a name and used that name in my callback URL. Worked like a charm. Thank you!