Microsoft officially unveiled Cortana at the Build Developer Conference on Wednesday, its own take on a personal assistant for mobile devices. We’ve known about Cortana for quite some time, as repeated leaks have slowly revealed the specifics of the new feature, but Microsoft is finally ready to share everything we need to know. Cortana, which will be launching as a beta alongside Windows Phone 8.1, takes the form of two concentric circles which animate when she speaks. Unlike Siri or S Voice, Cortana will be a focal point of the mobile operating system, replacing search entirely on Windows Phone devices. When you access Cortana, you’ll see continually updating suggestions for what you should search, many of which will be contextual depending on the