ChromaRail and Chromagent A Named Visual-Semantic Grammar for Placed Chroma Entities, Task-Bound Agents, and Soft Continuity Above Runtime Primitives

Abstract This paper defines a named visual-semantic grammar for portable semantic entities in human-agent systems. It introduces Chroma as a bounded state-bearing unit, Chromagent as a task-bound chroma placed in a meaningful location, and ChromaRail as the habitat or distributed meaning surface in which such entities can be placed, grouped, moved, and softened into continuity. The contribution claimed here is not that color, task visualization, ambient surfaces, traces, or post-app semantic layers are novel in isolation. Those elements already exist across human-computer interaction, ambient computing, spatial interfaces, and recent multi-agent orchestration environments. The claim is narrower: that Rail / Trail / Veil can function as a single named grammar for coordinating human attention and task-bound agents through placed chroma entities on meaning-bearing surfaces, while treating conventional implementation forms such as JSON, tool calls, event streams, and runtimes as lower layers rather than as the primary interface language. Within this grammar, a Rail is a placeable habitat or carrying surface. A Trail is the low-symbolic residue of movement, passage, or handoff. A Veil is softened continuity after active carry, preserving bounded persistence without requiring full symbolic retention. A Chroma carries state through color, payload, placement, and carry. A Chromagent extends this into role and task, making agentic behavior visible, bounded, environmental, and situational rather than hidden inside dashboards or orchestration layers. The result is a conservative but explicit contribution: a named coordination grammar for portable state-bearing and task-bearing entities on placed meaning surfaces, intended as a higher-abstraction semantic layer above conventional runtime primitives in human-agent systems.