Final answer:
A brief description of deliverable value is known as a user story in Agile software development, describing software features from the end-user's perspective in simple language to facilitate discussion and clarify details.
Step-by-step explanation:
A brief description of deliverable value for a specific user, as referenced in the question, is known as a user story. A user story is a tool used in Agile software development and project management to capture a description of a software feature from an end-user perspective. The user story describes the type of user, what they want, and why; a form of requirement that is expressed in a simple, concise language which is easy to understand. User stories are often written on index cards or sticky notes and arranged on walls or tables to facilitate planning and discussion as development progresses.
User stories serve as a promise for a conversation to clarify details and ensure that the development team correctly understands the requirements. They help the team to deliver the most important features first, by continually discussing and prioritizing them. User stories are not only scopes of work but they also focus on providing value to the user.