diff --git a/src/vars.c b/src/vars.c
index 85c6fc4bd..e4e547afd 100644
--- a/src/vars.c
+++ b/src/vars.c
@@ -261,8 +261,8 @@ static char *register_name(const char *name, int len, enum vars_scope *scope,
 		*scope = SCOPE_CHECK;
 	}
 	else {
-		memprintf(err, "invalid variable name '%s'. A variable name must be start by its scope. "
-		               "The scope can be 'proc', 'sess', 'txn', 'req', 'res' or 'check'", name);
+		memprintf(err, "invalid variable name '%.*s'. A variable name must be start by its scope. "
+		               "The scope can be 'proc', 'sess', 'txn', 'req', 'res' or 'check'", len, name);
 		return res;
 	}