This chapter introduces the Human–AI Creative Contribution Scale, or HAICCS, as a conceptual and operational instrument for representing the distribution of human and artificial-intelligence agency in hybrid cultural production. The proposal seeks to move beyond binary labels that classify a work simply as human-made or AI-generated. Instead, it establishes a seven-level ordinal gradient ranging from predominantly autonomous artificial production to exclusively human authorship, with balanced human–AI co-authorship at its midpoint. The chapter presents preliminary psychometric evidence based on more than 400 responses from the general population and examines the scale’s internal consistency, dimensionality and relationships with established measures of critical thinking and AI literacy. The findings provide initial support for interpreting HAICCS as a unidimensional and understandable framework for identifying different levels of AI involvement in cultural creation. The authors propose its potential use in cultural metadata, provenance systems, public communication and future regulatory frameworks aimed at strengthening transparency, authorship recognition, responsibility and trust in hybrid creative ecosystems.