diff --git a/jsonschema-core.xml b/jsonschema-core.xml
index c0c7d99d..11fbe7e5 100644
--- a/jsonschema-core.xml
+++ b/jsonschema-core.xml
@@ -608,6 +608,38 @@
+
+
+ Evaluating an instance against a schema MUST produce one of four general outcomes:
+
+
+
+ success: the evaluation completed without failing any validation assertions
+
+
+ failure: the evaluation completed with assertion failures
+
+
+ runtime error: the schema was understood but the evaluation could not
+ complete
+
+
+ refusal to process: the schema was not understood and evaluation never began
+
+
+
+
+ Runtime errors include but are not limited to: failure of reference resolution,
+ detection of an infinite reference loop, or excessive consumption of memory.
+
+
+ Unlike runtime errors, refusal-to-process is the expected outcome in certain cases.
+ Currently, the only situations where refusal-to-process is either required or allowed
+ are when a vocabulary cannot be supported, or a dialect cannot be determined. These
+ scenarios are noted in the appropriate sections of the specification.
+
+
+
Additional schema keywords and schema vocabularies MAY be defined