What are user stories used for in Agile development?

User stories are a fundamental aspect of Agile development, serving as a concise way to articulate functional requirements from the perspective of end users. They focus on understanding user needs and expectations, allowing teams to prioritize what features or functionalities should be developed. By emphasizing the user's experience and the value provided, user stories encourage collaboration among team members and stakeholders.

In Agile, user stories typically follow a simple format: "As a [type of user], I want [some goal] so that [some reason]." This format helps to clarify the purpose of a feature and its significance to the user, fostering discussions that lead to a clearer understanding of what needs to be built. Furthermore, user stories help break down complex requirements into manageable pieces, making them easier to implement within iterative development cycles.

Other choices focus on aspects that do not align with the primary function of user stories. For example, defining project timelines is more about planning and scheduling, creating budget estimates deals with financial considerations, and developing team roles pertains to organizational structure rather than to user requirements. Therefore, capturing functional requirements through user stories is essential in guiding development efforts to better match user needs in Agile projects.