diff --git a/.github/workflows/_promotion-pr.yml b/.github/workflows/_promotion-pr.yml
index 757acb7..69e0fdc 100644
--- a/.github/workflows/_promotion-pr.yml
+++ b/.github/workflows/_promotion-pr.yml
@@ -118,6 +118,18 @@ jobs:
             exit 0
           fi
 
+          # Nothing to promote is a normal state, not a failure. It happens on a
+          # repo whose `dev` was just cut from `main`, and after any push that
+          # adds no commit `main` lacks — a sync merge of `main` back into `dev`,
+          # most often. `gh pr create` answers that with `GraphQL: No commits
+          # between main and dev` and a non-zero exit, so the job has to ask
+          # first: comparing the two refs is one API call and says exactly this.
+          ahead=$(gh api "repos/$GH_REPO/compare/$TARGET...$SOURCE" --jq '.ahead_by')
+          if [ "$ahead" -eq 0 ]; then
+            echo "'$SOURCE' carries no commits '$TARGET' lacks — nothing to promote."
+            exit 0
+          fi
+
           # `gh pr create` has no --json; it prints the PR URL, whose last
           # path segment is the number.
           url=$(gh pr create \