The bot checks its notifications and should always respond instantly in any repo. However, since the checker may be down every now and then, you can also configure a Github Webhook for your repository, to be sure it will always respond fast.
The webhook endpoint is:
You should select the content type application/json and select only the issuecomment event (make sure to deselect the push event, which will be selected by default). See the image below for an example: