Does Instagram tell you when a DM is a reply to your story?

Yes. A story reply arrives with a reference to the story it was replying to, including the story's ID. Because stories disappear after 24 hours, save that context when the message comes in if you want it for reporting later.

In the Instagram app you see the story thumbnail above the reply. Tools built on Meta's Messaging API receive the same reference in the message data, which is what lets an inbox link the conversation to the story automatically.

Two practical points for agencies:

• Stories are short-lived. If the link to the story is only stored in the chat, it's easy to lose the context once the story expires. An inbox that records it on arrival keeps it.
• Story replies are some of your best-attributed leads. They're one of the few conversation types where you know exactly what the person saw. If a client's leads mostly come from typed DMs with no source, it can be worth testing more stories with a direct question ("reply with your date and we'll check availability").

The full method is in How to Tell Which Instagram Post a DM Came From (What Meta Tells You, and What It Doesn’t).