The metamodel targets the entire rose-ash domain model, not just the blog — the finish
line of the host-on-sx strangler off Quart: define the domain schema as data instead of
porting each service's bespoke models. Records the three honest additions store/events
surface beyond a/b/c+d: (1) typed scalar ATTRIBUTES (datatype properties: price:Money,
stock:Int) alongside entity relations — a real addition, likely Slice 8; (2) behaviour/
lifecycle composes from the substrate loops (flow/commerce/events), not reinvented;
(3) integrations (payments/federation/media) stay referenced services. Structure+validation
from the metamodel, behaviour from substrates, integrations as services.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>