The annotations section of an archetype or template provides a place for ad hoc node-level meta-data to be added. This can be used during the design phase to track dependencies, design decisions, and specific resource references.

Annotations are divided into major named groups. Currently a documentation group is defined, intended for documentary (i.e. human-readable text) annotations. Other groups are likely to be defined in the future for various kinds of processing, where the annotations may be formal expressions or code fragments.

Each annotation is keyed by a path, and may have any number of tagged elements. The path key can either be:

The usual case is the first, since annotations mainly relate to nodes in an archetype. However, it may be the case that within the context of the archetype, there is a need to refer to a part of the Reference Model type on which the archetype is based (OBSERVATION, EVALUATION etc) that is not constrained within the archetype, in order to indicate how it is to be understood within that archetyped structure (remember that an archetype does not need to constrain all possible paths of an information model class, but that such structures may nevertheless be instantiated).

A typical annotations section looks as follows (archetype source). The /subject path is a non-constrained 'RM path'.

Because annotations are defined as a separate section, they can be easily removed in production versions of an archetype or template, and ignored in the generation of digital signatures.