I came across a slightly more detailed explanation of how to write feature titles in FDD, basically:
So an example would be, Add an Item to the Shopping Cart or Calculate Total Registrations for Class. Having just gone through an exercise of planning out some features and estimating ‘story points’ on a project, this makes a lot of sense. It seems to reinforce that they are small task level items instead of things like full Use Cases such as Manage Customer Orders or Build Giant Report. I’ll have to try this out with the next Scrum product backlog list I develop.