I just updated my ‘Publish to Micro.blog’ shortcut to version 1.1:

• Added a setup step to specify your microblog’s ID number so that posts always get sent to the right blog. (Handy if you accidentally leave Micro.blog set to one of your other blogs.) If left blank, it will default to the last blog you used on your account.
• Added a fallback if no input is passed to the shortcut. It will show your clipboard contents and allow you to edit them and continue or cancel.

Get it from the HeyDingus Shortcuts Library.