diff --git a/infrastructure/main.tf b/infrastructure/main.tf
index c7a39ff3..c6abc320 100644
--- a/infrastructure/main.tf
+++ b/infrastructure/main.tf
@@ -95,8 +95,8 @@ resource "local_file" "mwaa_variables" {
       ecs_cluster_name        = module.mwaa.cluster_name
       log_group_name          = module.mwaa.log_group_name
       mwaa_execution_role_arn = module.mwaa.mwaa_role_arn
-      assume_role_read_arn    = var.assume_role_arns[0]
-      assume_role_write_arn   = var.assume_role_arns[0]
+      assume_role_read_arn    = length(var.assume_role_arns) > 0 ? var.assume_role_arns[0] : ""
+      assume_role_write_arn   = length(var.assume_role_arns) > 0 ? var.assume_role_arns[1] : ""
       account_id              = local.account_id
       aws_region              = local.aws_region
       cognito_app_secret      = var.workflows_client_secret