Indigo is a voice controlled personal assistant for your Windows Phone 8 device. The app was recently updated to version 18.104.22.168 which gives the app the ability to launch the app from the Windows Button.
Now according to the change log you should be able to execute some predefined inputs by pressing the Windows Button but the best we could do is simply launch the app itself. Every time I said "Indigo + [your question/request], a Bing search was launched. Granted my Southern accent could be getting in the way but it feels as a little more fine tuning is needed.
Asides from a few minor fixes, the 22.214.171.124 update also allows the microphone to be opened automatically when Indigo needs more information on the request. Indigo has also learned a few riddles to keep you entertained with.
While we weren't able to launch requests from the Windows Button, being able to launch the app itself does make Indigo a little more accessible.
Indigo is a free app for your Windows Phone 8 device and you can find it here in the Windows Phone Store.
Source: Indigo; Thanks, everyone, for the tips!