The Keyboard Maestro Engine’s do script command only causes the given macro to run and does not collect a return value.
The macro itself would have to output to the Clipboard or to a variable that AppleScript can see.
Using your macro above as an example – you can do something like this:
tell application "Keyboard Maestro Engine" do script "Generic-Test 01" set clipboardContent to getvariable "clip0" end tell
Or you can be more direct:
tell application "Keyboard Maestro Engine" set clipboardContent to process tokens "%PastClipboard%1%" end tell
Thank you very much.