PM Bot helps product managers and others, create well-structured stories fast.
PM Bot does this by asking specific questions about the use case, and creates then constructs a product story with the following elements:
SCENARIO: Buyer adds item to shopping cart because she wants to buy the item
GIVEN: Buyer is on the item page
WHEN: Buyer clicks on 'Add Item' button
THEN: The quantity of items in the buyer's cart should go up
AND: Buyer gets a confirmation that an item has been added to the cart
The purpuse of this structure is take out ambiguities. It also has the benefit of a common pattern for the entire team.
Convention over configuration for your stories.
See this article for more:
https://blog.pivotal.io/labs/labs/well-formed-stories