対象物とメタデータを関連付けるオブジェクト http://jsonschemalint.com/ でバリデート済み。 *.jsはJSONP版。

item.schema.json

{
    "$schema": "http://json-schema.org/draft-03/schema",
    "id": "https://gist.github.com/TakashiSasaki/5420814/raw/schema.json",
    "title": "root",
    "title-authority": [
        "http://json-schema.org/latest/json-schema-validation.html#anchor97",
        "http://json-schema.org/latest/json-schema-core.html#anchor7"
    ],
    "title-description": "Title is a metadata keyword and will preferrably be short.",
    "description": null,
    "description-autority": [
        "http://json-schema.org/latest/json-schema-validation.html#anchor97"
    ],
    "description-description": "A description will provide explanation about the purpose of the instance described by this schema.",
    "type": "object",
    "type-authority": [
        "http://json-schema.org/latest/json-schema-core.html#anchor8"
    ],
    "type-description": null,
    "arbitrary-property": "JSON schema allows arbitrary properties not described in the specifications.",
    "subjectMetadata": {
        "title": "subjectMetadata",
        "type": "object",
        "description": "対象物とメタデータを関連付けるオブジェクト",
        "properties": {
            "subjects": {
                "type": "array",
                "items": {
                    "type": "string"
                }
            },
            "subjects-authority": null,
            "subjects-description": null,
            "metadata": {
                "type": "string"
            },
            "metadata-authority": null,
            "metadata-description": null
        },
        "required": [
            "subjects",
            "metadata"
        ],
        "required-authority": [
            "http://json-schema.org/latest/json-schema-hypermedia.html#rfc.section.5.1.1.3"
        ]
    },
    "locationMetadata": {
        "title": "locationMetadata",
        "type": "object",
        "description": "対象物を発見するためのメタデータ",
        "properties": {},
        "required": []
    },
    "links": [
        {
            "rel": "full",
            "rel-authority": [
                "http://json-schema.org/latest/json-schema-hypermedia.html#anchor27"
            ],
            "full-description": "This indicates that the target of the link is the full representation for the instance object. The instance that contains this link may not be the full representation.",
            "href": "{id}",
            "href-authority": [
                "http://json-schema.org/latest/json-schema-hypermedia.html#href"
            ],
            "href-description": "The value of the href link description property is a template used to determine the target URI of the related resource."
        },
        {
            "rel": "describedBy",
            "describedBy-description": "This indicates the target of the link is a schema describing the instance object. This MAY be used to specifically denote the schemas of objects within a JSON object hierarchy, facilitating polymorphic type data structures.",
            "href": "{+($schema)}"
        }
    ]
}

sample.schema.js

XbcG({
   "$schema":"http://json-schema.org/draft-03/schema",
   "title":"root",
   "description":"aaa",
   "type":"object",
   "a":"a",
   "properties":{
      "subjects":{
         "description":"none",
         "type":"array",
         "items":{
            "type":"string"
         },
         "required":true
      },
      "metadata":{
         "type":"string",
         "required":true
      }
   },
   "links":[
      {
         "rel":"describedBy",
         "href":"{+($schema)}"
      }
   ]
});

sample.schema.json

{
   "$schema":"https://gist.github.com/TakashiSasaki/5420814/raw/schema.json",
   "subjects":[
      "a",
      "b"
   ],
   "metadata":"xyz"
}