The MDMI specification identifies the semantic unit in a message to be a Message MessageElement and MessageElementSet. The term Message Element and associated class names may be confused with the term Message Element in The ISO 20022 specification for those using the specification for financial service mapping. Since the central hub dictionary used in these mappings will most likely be the ISO 20022 data dictionary.

For better documentation, there is no reason why there should not be a description attribute for each class but this must be integrated into any table or spreadsheet UI.

A key concept of MDMI is that it requires a domain dictionary as a hub in its "hub and spoke design". The current specification does not associate a Message Model with a domain dictionary. If the specification is to work, such a reference will be important. Otherwise, the specification will not be clear and maps may be ambiguous.

Current text
In particular, an implementation needs to support a design-time activity with all of the steps involved in generating the conversion maps, and the runtime application of the generated maps to a source physical message in order to create a target physical message.
New text
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Rationale
Must all implementations have a design-time activity? Don't we expect to have more implementations that use the conversion maps than implementations that can create the maps?