Extending the Google Assistant

The Google Assistant gives users their own personal Google that helps them find, organize, and get things done in their world. The main way users interact with the Google Assistant is by carrying on a conversation with it.

Apps extend the Google Assistant by letting you build actions that let users get things done with your products and services.

Unlike with traditional mobile or desktop apps, users interact with apps for the Assistant through a conversation, natural-sounding back and forth exchanges, and not traditional, computer-centric paradigms.

When you build an app for the Assistant, you design your conversations for a variety of surfaces, such as a voice-centric conversation for voice-activated speakers or a visual conversation on an Android phone. This lets users get things done quickly the way they want, either with voice or display affordances.

Read more about Conversational UI

How Actions on Google works with the Assistant

When users request an action to be fulfilled:

  1. The Assistant asks Actions on Google to invoke the best app to fulfill the intent.
  2. Actions on Google sends a request to the app's fulfillment and receives a response that it hands off to the Assistant.
  3. The Assistant renders the response in its UI and displays it to the user. The conversation between the user and the app begins.
  4. The Assistant sends subsequent user input directly to the app and the app responds directly to the Assistant. This conversation continues until the app gathers the user input it needs to fulfill the intent.

Here's an example of how this works with an imaginary retail shop app named Geeknum.

  1. A user talks to the Assistant and requests an action, "I want to learn about numbers". The Assistant asks Actions on Google to find the best app to handle the action and Actions on Google returns an app named "Geeknum".
  2. The Assistant asks the user if she wants to invoke the Geeknum app and she says "Yes". The Assistant introduces Geeknum, then hands off the user to the Geeknum app.
  3. The app displays a welcome message and the conversation begins with the user.
  4. During the conversation, the Assistant brokers the conversation between the user and Geeknum, and the two exchange information so Geeknum can gather the information it needs to fulfill the intent.
  5. Finally, the conversation ends when the user is done learning about numbers.