MEI-encoded scores are versatile music information resources representing musical meaning within a finely addressable XML structure. The Verovio MEI engraver reflects the hierarchy and identifiers of these encodings into its generated SVG output, supporting presentation of digital scores as richly interactive Web applications. Typical MEI workflows initially involve scholarly or editorial activities to generate an encoding, followed by its subsequent publication and use. Further iterations may derive new encodings from precedents; but the suitability of MEI to interactive applications also offers more dynamic alternatives, in which the encoding provides a framework connecting data that is generated and consumed simultaneously in real-time. Exemplars include compositions which self-modify according to external contextual parameters, such as the current weather at time of performance, or which are assembled by user-imposed external semantics, such as a performer’s explicit choices and implicit performative success at playing musical triggers within a composition. When captured, these external semantic signals (interlinked with the MEI structure) themselves encode the evolution of a dynamic score during a particular performance. They have value beyond the immediate performance context; when archived, they allow audiences to revisit and compare different performances.