reserve id member at top level of attributes object

Tyler Kellen · Tyler Kellen · commit 626b5f9802e4 · 2015-05-01T17:55:18.000-04:00
diff --git a/format/index.md b/format/index.md
@@ -219,7 +219,9 @@ Here's how an article (i.e. a resource of type "articles") might appear in a doc
 
 #### Attributes <a href="#document-structure-resource-object-attributes" id="document-structure-resource-object-attributes"></a>
 
-A resource object **MAY** contain "[attributes]" holding any valid JSON value.
+A resource object **MAY** contain an "[attributes]" object. If included, this
+object **MUST** reserve the `id` member at it's top level, but can otherwise
+contain any valid JSON value.
 
 Although has-one foreign keys (e.g. `author_id`) are often stored internally
 alongside other information to be represented in a resource object, these keys
