Google has always been able to read text messages sent through the native Messages app or Hangouts. But it wasn’t able to read messages from other messaging services wasn’t an option. Until now, that is. According to Android Police, Assistant will now read messages from apps like Slack, WhatsApp, Telegram, GroupMe, Discord, and the like, as well as reply to these messages. To try this out, say “Read my messages” to Assistant. You will need to allow the Google app to access your notifications for this to work.
Once that’s done, a card will pop up with the last text message or messages you’ve received and then it’ll read these out loud. Assistant will say which app it’s from and the name of the sender. You will then be asked if you want to type or dictate a reply. When Assistant has sent your reply, the original message will be marked as read and the notification will go away. However, it won’t read messages containing things like audio notes, pictures, or videos. Assistant will just say things like: “the message just contains an audio attachment.” And then it won’t play this back. You can try this out the next time you get notifications to see if the feature made its way to you.
Source: Android Police