103.5 - Common Data Model (GraphQL)

Produce the conceptual data model for a project as GraphQL SDL: a documentation-only schema that is never deployed as an API. It captures the same domain knowledge as 103-common-data-model (entities, relationships, business rules) plus two things markdown tables express poorly — role-based access rules and field-level validation constraints — in a format with mature parsing, diffing, and visualization tooling already built for it.

It is implementation-independent, same as 103: not a database schema, ORM design, API contract, or frontend state model. The physical implementation (relational, NoSQL, event-based) is a downstream decision informed by, not dictated by, this schema.

This is an alternative engine for the same D03 slot as 103-common-data-model, not an addition to it. A project uses one or the other. Downstream skills that reference "D03" generically keep working either way.