evaluation context requirement to allow fetching all custom fields

Signed-off-by: Robert Grassian <[email protected]>

Author: rgrassian-split

specification/sections/03-evaluation-context.md

@@ -32,6 +32,10 @@ The targeting key uniquely identifies the subject (end-user, or client service)
 
 see: [structure](../types.md#structure), [datetime](../types.md#datetime)
 
+#### Requirement 3.1.3
+
+> The evaluation context **MUST** support fetching the custom fields by key and also fetching all of the keys and values.
+
 ### Merging Context
 
 #### Requirement 3.2.1