diff --git a/java/google/registry/model/domain/DesignatedContact.java b/java/google/registry/model/domain/DesignatedContact.java
index f9b5ef209..62f13e1e0 100644
--- a/java/google/registry/model/domain/DesignatedContact.java
+++ b/java/google/registry/model/domain/DesignatedContact.java
@@ -20,14 +20,22 @@ import com.googlecode.objectify.annotation.Embed;
 import com.googlecode.objectify.annotation.Index;
 import google.registry.model.ImmutableObject;
 import google.registry.model.contact.ContactResource;
-import javax.xml.bind.annotation.XmlAttribute;
 import javax.xml.bind.annotation.XmlEnumValue;
 
 /**
- * XML type for contact identifiers associated with a domain.
+ * Persisted type for storing a domain's contact associations.
+ *
+ * <p>A contact association on a domain consists of the contact key and the contact "type", which is
+ * the designated role of this contact with respect to this domain.  When converting to and from
+ * EPP XML, we use {@link ForeignKeyedDesignatedContact} to replace the contact's Datastore key
+ * with its foreign key, since that is what EPP exposes.
+ *
+ * <p>Note one could in principle store contact foreign keys here in addition to keys, unlike the
+ * situation with hosts where client-side renames would make that data stale.  However, we sometimes
+ * rename contacts internally ourselves, and it's easier to use the same model for both cases.
  *
  * @see <a href="http://tools.ietf.org/html/rfc5731#section-2.2">
- *     RFC 5731 - EPP Domain Name Mapping- Contact and Client Identifiers</a>
+ *     RFC 5731 - EPP Domain Name Mapping - Contact and Client Identifiers</a>
  */
 @Embed
 public class DesignatedContact extends ImmutableObject {
@@ -55,7 +63,6 @@ public class DesignatedContact extends ImmutableObject {
     return instance;
   }
 
-  @XmlAttribute(required = true)
   Type type;
 
   @Index
diff --git a/java/google/registry/model/domain/ForeignKeyedDesignatedContact.java b/java/google/registry/model/domain/ForeignKeyedDesignatedContact.java
index 61ece0625..745936cac 100644
--- a/java/google/registry/model/domain/ForeignKeyedDesignatedContact.java
+++ b/java/google/registry/model/domain/ForeignKeyedDesignatedContact.java
@@ -19,8 +19,11 @@ import javax.xml.bind.annotation.XmlAttribute;
 import javax.xml.bind.annotation.XmlValue;
 
 /**
- * EPP-compatible version of XML type for contact identifiers associated with a domain, which can
- * be converted to a storable {@link DesignatedContact}.
+ * EPP-XML-serializable equivalent of {@link DesignatedContact}.
+ *
+ * <p>This type is used on the wire for EPP XML, where only the contact ID (foreign key) is exposed.
+ * This is converted to and from the persisted type, {@link DesignatedContact}, which stores the
+ * Datastore key instead of the foreign key.
  *
  * @see <a href="http://tools.ietf.org/html/rfc5731#section-2.2">
  *     RFC 5731 - EPP Domain Name Mapping - Contact and Client Identifiers</a>