Create an extension in chrome for instagram

I need an extension that, when clicked while on an Instagram profile, will detect if the user has uploaded a story. For example, if there are initially 3 stories and the user adds a new one, the script should detect the 4th story and comment "Test, 1234". If I click on the extension, it should check every 1 second to detect if a new story has been added.

It should be a chrome extension.