diff --git a/script/cibuild b/script/cibuild
index c973b54d..acc4b70e 100755
--- a/script/cibuild
+++ b/script/cibuild
@@ -1,5 +1,7 @@
 #! /bin/bash
 
+set -e
+
 script/branding
 script/proof
 script/test
diff --git a/script/proof b/script/proof
index d491fdc5..31db4375 100755
--- a/script/proof
+++ b/script/proof
@@ -3,6 +3,8 @@
 # Usage:
 #   script/proof
 
+set -e
+
 git diff --name-only origin $(git log --pretty=format:"%h" -2 | tail -1) | grep '^site/' || {
     echo "No site files changed. We'll skip proofing."
     exit 0