Preamble Spec Attributes

Spec attributes are typed PHP 8.1+ attributes in the OpenApi\Spec namespace — the foundation of the spec-attributes pipeline (--mode spec or --mode hybrid).

They are immutable data containers with no serialization logic. Relationships between attributes are declared via contains() (what children an attribute absorbs) and merge() (what parent an attribute composes into). The Assembler resolves nesting, and Augmenters enrich the collected specification before compilation.

Typed subclasses (e.g. Operation\Get, Parameter\Path, Flow\AuthorizationCode) pre-fill common fields to reduce boilerplate — the base class can always be used directly.