Google Assistant has received a comprehensive update of its messaging features in the background, allowing the AI helper to read messages from third-party apps.
The lack of an official announcement for the new feature is strange, especially considering that Android users have wanted this functionality for some time. Previously, Google Assistant could only read messages from Android Messages and Google Hangouts – and not very well. Now heaven is the limit: Google Assistant can read your messages from third-party apps like Slack, WhatsApp, Discord, Telegram, and even Google's own tricky apps like Google Voice.
First, go to Google Assistant with "Hey, Google," "Okay, Google," or by pressing the / Google Assistant icon on your device, if any. Then say it "read my messages".
The wizard then dictates all unread messages that you have in the given order, and even switches between different apps if you have a backlog across multiple messaging services. The only exceptions are media messages where Google Assistant simply states that the message contains media but does not open the attached file.
In addition to reading the messages themselves, you can also request to know who the sender is and from which app they were sent. Once Google Assistant reads the message out loud, it will be removed from your notifications.
To respond to one of your messages, you can use Google Assistant to respond by voice or by typing in your answer. Once you have sent your answer, you can continue listening to your remaining unread messages. (via Android Police)