It's basically the Assistant as it was in the Allo app (RIP) -- when you chat with your friends about things like movies, restaurants and the weather, Assistant will show suggestion bubbles to let you send info cards to your pal. The AI scans your texts for contextual clues as to what you're talking about. Say you've told your friend you want to check out Roma -- Assistant will surface chips to send a little summary of the movie's rating, synopsis and playtimes.
During a demo, Google showed how in a conversation about tapas, reps were able to find nearby restaurants and send a listing to each other. The card for Casa de Tapas Canota that Assistant sent also has shortcuts to make a call to the restaurant, map directions and add a calendar event. You can also send more information by pressing on the Home button and asking Assistant to send specific results to your friend via Messages.
Those of you worried about Google reading your personal messages should rest easy -- the company says the content of your conversations is never sent to Assistant, only the entity listed on the chip you clicked. You decide who sees the info you choose. This feature will be available for English users worldwide and just for movies, restaurants and the weather in the initial rollout, which will happen in the coming months.