diff --git a/.github/workflows/e2e-nightly.yml b/.github/workflows/e2e-nightly.yml
index c54044af5..c18697d15 100644
--- a/.github/workflows/e2e-nightly.yml
+++ b/.github/workflows/e2e-nightly.yml
@@ -12,8 +12,11 @@ on:
 permissions:
   contents: read
 
+# Scheduled runs target dev (active development trunk). GitHub loads scheduled
+# workflow files from the repo's default branch, so this file must be kept in
+# sync on main for the schedule to use it.
 env:
-  GIT_BRANCH: ${{ github.ref_name }}
+  GIT_BRANCH: dev
   UBUNTU_GOLD_IMAGE: /mnt/disk1/gold-images/spinifex-image-builder-ubuntu-24.04.qcow2
 
 jobs: