Nasdanika A2UI model: a micro-model of the A2UI (Agent-to-User Interface) protocol domain, v0.9 family (v1.0 RC aware). Spec-aligned but pragmatic, not literal, in the manner of the MCP and A2A models. * The protocol in one paragraph: agents emit a declarative JSON payload, a FLAT list of components with ID references (optimized for incremental LLM generation and streaming), plus a separate data model with bindings and user-action events. The client renders only components from a catalog of trusted, pre-approved types, mapping abstract types to native implementations through an open registry (Smart Wrapper) pattern. * Adds the aspect the protocol leaves as an exercise: the trusted catalog’s governance. “Pre-approved” by whom, at what risk, until when: catalog elements extend GovernedElement and Workable; lifecycle (Staged) and roles (Undergoer) join on shared-base convergence, as in sibling models. * Uses: reference documentation and education; governed, federated component catalogs; structural validation of agent-emitted payloads before rendering; capture-replay of sessions for testing and evals; generation of a typed A2UI Java API; transformation to and from the Nasdanika UI model (an a2ui.ui bridge model if the mapping earns types). * NOTE: component composition is modeled as the spec has it: components are CONTAINED flatly by the surface and composed by reference (children, component-valued properties), not by containment. Message class names are aligned with the v0.9 family conceptually; verify exact names and shapes against the specification before publication.