Context
Common Data Environment is the official ISO 19650 term for the agreed single source of information about a project or asset. The standard defines it as 'an agreed source of information for any given project or asset, for collecting, managing and disseminating each information container through a managed process.' Beyond the formal definition, there is broad confusion about what counts as a CDE in practice, and what merely calls itself one.
A CDE is a discipline first and a tool second.
Explanation
Three things make a system a CDE in ISO 19650 terms, and most products that ship with the label only meet one or two of them.
A defined metamodel
Every information container has a known type and structure. A document management system stores files; a CDE knows what those files describe and how they relate to each other. Without a metamodel, you have a filing cabinet: useful, but not a CDE.
Lifecycle-managed information containers
Every container moves through Work in Progress → Shared → Published → Archived under a defined approval workflow. Status is queryable; nothing slips through informal channels. Approval cannot happen by email.
Federation across sources
A CDE is the agreed source of information, not the only place it lives. Existing tools (BIM authoring, requirements management, scheduling) integrate as federated sources rather than being replaced.
Weaver implements all three. The metamodel is ISO 15926-11. The lifecycle is ISO 19650-2. Federation runs through open APIs (REST, GraphQL, OData, SPARQL) and the buildingSMART suite (IFC, BCF, openCDE). A CDE that meets all three criteria is in a different category of tool from a document management system, and most of the practical value comes from the third property.