Script- append to a different draft

I’m using Drafts 4. Is it possible to run a script on one draft and then append the result to another draft? Here is a simple example.

1st Draft contents:

12
14

A script could add those numbers and then write 26 to another draft with a known UUID.

I don’t care about the calculation part, just how to send the result to the specific draft.

Any ideas?

That can be done with script in Drafts 5, but not Drafts 4. It could be done with the /append URL scheme in Drafts 4, however. An action can call the app’s own URLs with a URL action step, something like:

drafts4://x-callback-url/append?uuid=MY-KNOWN-UUID&text=[[draft]]

Great! Thanks. I’ll give it a try.