This paper presents the research and development of an authoring tool designed to empower teachers to create skill-based analytics for constructionist learning environments. Building upon previous work that identified data requirements and developed a prototype learning analytics dashboard, this study addresses the critical gap in teacher authorability. Specifically, it focuses on uncovering nuanced relationships between learner interactions with open learning tools and 21st-century skills, and designing an interface that allows teachers to articulate these relationships through detailed data patterns. Employing a user-centered design approach, the authoring tool was iteratively redesigned and evaluated by EdTech experts and teachers. Findings demonstrate the tool’s effectiveness in enabling teachers to define and customize skill-based analytics, revealing the nature of complex skill-data relationships. The research contributes to the development of adaptive learning environments that align with modern educational paradigms, emphasizing the importance of teacher-driven analytics for 21st-century skill assessment.