If you don't already use IFTTT, you can download that here.
I created a great recipe that sends my wife a text, every time I am running late. All I have to do is say "OK Google, I'm running late" and the message gets sent. It should be noted that it will utilize the Messenger to send the message if you are using Hangouts as your default SMS. Since I am a Project Fi user I prefer Hangouts due to the desktop implementation. I cannot confirm how it will work with any other default SMS applications.
The setup is very simple and the IFTTT recipe creation walks you through the steps for whatever channels you are using. Currently there are 59 suggested existing recipes on the IFTTT site for the Google Assistant.
Hopefully this integration will prove to be advantageous for you to make your lives more productive as a result of the Google Assistant.
Please note: this does not currently work with Google Assistant in the Allo application.