diff --git a/toast.yml b/toast.yml
index c9ebb07..c75e32e 100644
--- a/toast.yml
+++ b/toast.yml
@@ -3,7 +3,7 @@ default: check
 user: user
 command_prefix: |
   # Make Bash not silently ignore errors.
-  set -euo pipefail
+  set -euxo pipefail
 tasks:
   install_packages:
     description: Install system packages.