This work introduces the Fuzzy Specification Tree Model (FST), a general-purpose framework designed to enhance AI-assisted software engineering. The paper begins by examining the intricate interplay between software engineering and artificial intelligence (AI), emphasizing how AI technologies are reshaping software development methodologies. Building on a foundation of requirements-driven approaches, the study presents a novel adaptation of classical feature modelling to create a versatile, fuzzy logic-based requirements specification model. This model not only facilitates the definition of functionalities for partially completed software but also supports formal methods for project management, version control, and reuse. By employing separate Fuzzy Specification Trees for requirements and the current state of a project, developers gain a dynamic perspective on project completeness and can leverage AI assistance to prioritize tasks, ensuring efficient progression toward project completion with minimal effort.