Workflow Integration
AppleScript
Marked has a basic AppleScript dictionary, and allows you to get the currently open file from multiple windows, as well as open files from scripts. This allows some workflow integration if you know a little bit of AppleScript. You can have any application which can trigger an AppleScript open a document in Marked, or have it pull the currently-previewed document in Marked in for editing.
The AppleScript integration also allows applications such as Tags.app to function directly within Marked.
Marked Bonus Pack
The Marked Bonus Pack is a collection of scripts, commands and services. Some work with multiple editors, some are specific to certain editors. The Services will generally work with any editor that has the necessary capabilities. The rest are organized in folders based on the application they work with.
You can download the Bonus Pack and find instructions for installing and using it in this knowledge base article.