diff --git a/tiramisu_json_api/api.py b/tiramisu_json_api/api.py
index df44d37..549fdac 100644
--- a/tiramisu_json_api/api.py
+++ b/tiramisu_json_api/api.py
@@ -83,7 +83,7 @@ class TiramisuOptionOption:
 
     def properties(self) -> List[str]:
         props = []
-        model = self.model[self._path]
+        model = self.model.get(self._path, {})
         if model.get('required'):
             #FIXME 'empty', 'needs_len'
             props.append('mandatory')
@@ -435,8 +435,7 @@ class ContextValue(_Value):
         self.form = form
         first = next(iter(schema.keys()))
         self.path = first.rsplit('.', 1)[0]
-        schema = {'properties': schema}
-        self.schema = schema
+        self.schema = {'properties': schema}
         self.temp = temp
 
     def __call__(self) -> TiramisuOptionValue:
@@ -448,6 +447,14 @@ class ContextValue(_Value):
                                    path,
                                    index)
 
+    def mandatory(self):
+        # config.value.mandatory()
+        for key, value in self.dict().items():
+            if self.model.get(key, {}).get('required') and \
+                    value is None or \
+                    (self.schema.get('isMulti') and (None in value or '' in value)):
+                yield key
+
 
 class Config:
     # config