Arbitrary metadata documentation.

docs/guide/defining-documents.rst

@@ -172,11 +172,11 @@ arguments can be set on all fields:
         class Shirt(Document):
             size = StringField(max_length=3, choices=SIZE)
 
-:attr:`help_text` (Default: None)
-    Optional help text to output with the field -- used by form libraries
-
-:attr:`verbose_name` (Default: None)
-    Optional human-readable name for the field -- used by form libraries
+:attr:`**kwargs` (Optional)
+    You can supply additional metadata as arbitrary additional keyword
+    arguments.  You can not override existing attributes, however.  Common
+    choices include `help_text` and `verbose_name`, commonly used by form and
+    widget libraries.
 
 
 List fields

mongoengine/base/fields.py

@@ -64,7 +64,11 @@ class BaseField(object):
             then the default value is set
         :param sparse: (optional) `sparse=True` combined with `unique=True` and `required=False`
             means that uniqueness won't be enforced for `None` values
-        :param **kwargs: (optional) Arbitrary indirection-free metadata for this field.
+        :param **kwargs: (optional) Arbitrary indirection-free metadata for
+            this field can be supplied as additional keyword arguments and
+            accessed as attributes of the field. Must not conflict with any
+            existing attributes. Common metadata includes `verbose_name` and
+            `help_text`.
         """
         self.db_field = (db_field or name) if not primary_key else '_id'