Rune Protocol: A Four-Sigil Reactive Binding Protocol

Rune Protocol is a minimal, embeddable protocol that gives any document format, framework, or domain four reactive binding operations: @ (read), ~ (sync), ! (act), and ? (intent). The four runes are bounded complete — no fifth operation is possible without redundancy. The ? primitive is novel: structured intent that travels with the binding, is co-located with the code it describes, versioned in source control, and queryable at runtime. No existing binding protocol has this. Rune operates as a governance layer — each rune is a governance primitive that makes mutation surfaces explicit, action boundaries structural, and rationale permanent. Reference implementations are provided in C#, TypeScript/React, and SQL (PostgreSQL). Rune was extracted from the Mere workbook format, where the four sigils were working before the protocol had a name.