Google is rolling out a new Shortcuts feature for Assistant on Android that is similar to Samsung's Bixby Routines and iPhone's Siri Shortcuts. The feature will allow users to set up in-app behavior and link it to a custom voice command. For example, if one wishes to, they can enable the "New tweet" option for the Twitter app and then say "Hey Google, new tweet" or any other keyword that they prefer to use Assistant for directly composing a tweet.
Just like Siri Shortcuts on iPhone, Google is also offering shortcut recommendations from your frequently used apps. There's also a 'Your shortcuts' tab where one can go through all their custom shortcuts.
The biggest limitation with Shortcuts right now is that it does not allow one to chain a series of commands and they are also limited to actions inside apps. Additionally, in its current form, Shortcuts cannot do anything inside an app, they can only get you to a specific screen inside them. For example, you cannot set a shortcut in Google Assistant to search for a specific keyword on Instagram, though you can use it to open the Explore tab. Developers will also need to update their applications to take advantage of shortcuts.
Shortcuts in Google Assistant is slowly being rolled out by Google as a server-side switch. You can check if you have got the feature on your device or not by going to Google Assistant settings. Shortcuts can also be accessed from the Routines section of the app.
Source: Android Police