diff --git a/repos/gems/run/sculpt.run b/repos/gems/run/sculpt.run
index 4efa3c594..b10259a94 100644
--- a/repos/gems/run/sculpt.run
+++ b/repos/gems/run/sculpt.run
@@ -492,6 +492,8 @@ exec gzip -dc [genode_dir]/repos/gems/run/sculpt/machine.vdi.gz > [run_dir]/geno
 #
 # Define 'VERSION' ROM module
 #
+# Note: the string must be exactly 5 bytes long.
+#
 proc sculpt_version { } {
 	return "19.02" }