How to specify a generic type in OpenAPI?

I faced with problem in generating code due to:

• no generic types in open api

i cant specify:
Pageable:
  type: object
  properties:
    objects:
      type: <GenericType> 

• no custom validation messages

payment:
  type: object
  properties:
    value:
      amount: number
      min:
        value: 3
        message: "i need " <------- i can do that
        messageMeta: "i18n.code.for.clients" <--- i would like to i18n error messages

• can not add description near $ref
• can not add meta info for code generators

Question:

1. how to fix that
2. maybe some another another specification (not openApi) provide that