diff --git a/grammar.txt b/grammar.txt
index 8f2f37b17..aad7d610c 100644
--- a/grammar.txt
+++ b/grammar.txt
@@ -22,6 +22,7 @@ command:
   | EXPORT <file>
   | COLOR
   | DELETE <id>
+  | UNDELETE <id>
   | INFO <id>
   | START <id>
   | DONE <id>