Ulysses supports keywords inside Markdown files to allow for synchronization across platforms and improve compatibility with 3rd-party text editors. In Ulysses, the inline keywords can be added as usual via the keywords section in the attachment section and are organized in the keyword manager. They are stored as hashtags at the last line of the Markdown file, but do not show up in the sheet inside Ulysses’ editor.

If you open the Markdown file in another editor, however, they appear at the end of the text similar to this example file:

Lorem ipsum dolor sit amet, consetetur sadipscing elitr, sed diam nonumy eirmotempor invidunt ut labore et dolore magna aliquyam erat, sed diam voluptua. Atvero eos et accusam et justo duo dolores et ea rebum. Stet clita kasd gubergren, no sea takimata sanctus est Lorem ipsum dolor sit amet. 
#keyword1 #keyword2 #keyword3

The content of these keywords is not restricted: You can use any Unicode character such as letters, numbers—even emojis.