1 files changed, 1 insertions, 1 deletions
diff --git a/vs-c.md b/vs-c.md
index bceaab1..b6cbcd5 100644
--- a/vs-c.md
+++ b/vs-c.md
@@ -45,7 +45,7 @@ Some type modifiers in C only apply in very specific circumstances and so aren't
 Some C features are footguns by default, so Crowbar ensures that they are only used correctly.
 
 -   Unions are not robust by default.
-    Crowbar only supports unions when they are [tagged unions](tagged-unions.md).
+    Crowbar only supports unions when they are [tagged unions](tagged-unions.md) (or declared and used with the `fragile` keyword).
 
 C's syntax isn't perfect, but it's usually pretty good.
 However, sometimes it just sucks, and in those cases Crowbar makes changes.