Apple has a new patent application published by the USPTO today (via AppleInsider) which details a desktop incarnation of its Siri virtual assistant. The iOS Siri software has long been something observers have expected to make the jump to OS X, but so far, only its voice dictation component has crossed the virtual divide. Now, this patent articulates in great detail how Siri on the Mac might work, which could mean it’s closer than ever to becoming a reality.

The application describes how the Siri app could reside in the dock or in the background, and be activated either by gesture or by voice activation – a good candidate would be the “Hey, Siri” voice prompt that Apple introduced with iOS 8, which will allow phones running that OS to respond to the command when connected to power. Siri would be able to field questions and respond to commands in the same way it can on iOS, but because the desktop is a different beast with more computing power and different interaction standards, it can also do a lot of other things per the patent.

For example, it could use the cursor position to inform how it handles any commands it’s given by a user – so it’ll apply a copy command to a photo the mouse is hovering over, for instance. It could also sort and organize files and folders in Finder, drag and drop files from one app to another, and so on.

One part of the patent also describes how Siri on desktop could be used in lieu of a third input device in addition to mouse and keyboard, or in the specific wording of the patent, how it might act as a “third hand.” This could allow a user to interact with interact with background applications while simultaneously working on a different app in the foreground – finding and copying an image from the web for use in a presentation being worked on in Keynote, for example.

The patent could explain why it has taken so long for Apple to deliver Siri for the Mac; the system described is a significant departure from Siri on mobile, and would require a lot of additional engineering to make it a reality. There’s no Siri present in the OS X Yosemite beta preview, so it’s likely not coming this year, but this patent indicates that it’s something Apple has spent considerable time and resources developing, so hopefully we’ll see it arrive sooner rather than later.