What do 'user stories' represent in Agile development?

User stories in Agile development are simple descriptions of features from an end-user perspective. They are designed to convey what the user needs from the system in a straightforward manner, often using language that is easily understood by both the development team and stakeholders. Each user story typically follows a format that describes who the user is, what they want to achieve, and why it is important, which helps to ensure that development is user-centered.

This focus on the user perspective aids in prioritizing development efforts based on actual user needs, ensuring that features are relevant and beneficial. By capturing requirements in this format, Agile teams can maintain flexibility and adapt to changes more easily throughout the development process, since user stories are more negotiable than detailed specifications.

The other mentioned options do not accurately encapsulate what user stories represent. Detailed technical specifications are more rigid and less user-focused, while descriptive narratives of project requirements may not be as succinct or actionable as user stories. Comprehensive reports on application performance fall outside the scope of defining user needs and are more about evaluating the effectiveness of a developed application rather than guiding its development.