diff --git a/README.md b/README.md
index fbbe612..95bfa83 100644
--- a/README.md
+++ b/README.md
@@ -754,7 +754,7 @@ func NewErrorDetails(err error, details ...interface{}) ErrorDetails {
 }
 
 func (err *errDetails) Error() string {
-    return fmt.Sprintf("%v: %v", err.details)
+    return fmt.Sprintf("%v: %v", err.errtype, err.details)
 }
 
 func (err *errDetails) Type() error {