Siri is on the iPhone, iPad, Apple Watch, and Apple TV, and now it may finally be headed to the Mac. 9to5Mac reports that Apple is adding Siri into the next version of OS X, which should arrive later this year. Apple reportedly plans to add a Siri button in the Mac's menu bar, beside the clock and Spotlight icon, which you'll be able to press to activate it. It may also have an always-listening feature, like the iPhone does, when connected to power. When you activate Siri, its responses will reportedly be displayed on a corner of the desktop in a semi-transparent black window, which should look a lot like Siri's interface on mobile. You can see a mockup at 9to5Mac.
If Siri is to arrive in the next version of OS X, we should get a first look at it in June, during Apple's Worldwide Developers Conference. A public beta may then launch over the summer, with a full launch coming sometime around October, assuming Apple follows its typical release patterns. 9to5Mac reports that some details of Siri on OS X could still change, but it says that Apple has been working on the feature's presentation since as early as 2012 — the year after Siri launched on the iPhone 4S. Though its arrival on the desktop may feel like a long time coming, it wasn't until last year that Apple began bringing Siri to platforms outside of iOS.