How to make the agent say something before leaving the mic open?

Question

Google rejected my app and give the following feedback:

During testing we noticed that when the Action is not able to get data it opens the mic and leaves it open without prompting. Make sure that your agent always says something before leaving the mic open for the user, so that the user knows what they can say. This is particularly important when your agent is first triggered.

I've built my app using API AI tool and webhooks (connects to a web service running on Heroku). Heroku sleeps after 30 minutes of inactivity. I think this error occurs when Heroku takes a long time to respond. Any idea how can I make the agent say something before leaving the mic open?

I am not sure why I got this feedback because in case the web service request times out, Google Home speaks the following response.

Answer 1

It might answer the text response you added on API.ai but at the bottom of the page of your intent (under the text response) click on "Actions on Google" then check "End conversation" Check this screenshot