diff --git a/.github/workflows/verify-harness-score.yml b/.github/workflows/verify-harness-score.yml
new file mode 100644
index 0000000..94b6110
--- /dev/null
+++ b/.github/workflows/verify-harness-score.yml
@@ -0,0 +1,35 @@
+name: Verify Harness Score release
+
+on:
+  push:
+    branches:
+      - codex/verify-harness-score-v1-5-3
+  pull_request:
+  workflow_dispatch:
+
+permissions:
+  contents: read
+
+jobs:
+  verify-v1:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v4
+
+      - name: Run Harness Score v1 alias
+        id: score
+        uses: paladini/harness-score@v1
+        with:
+          min-level: '0'
+
+      - name: Verify authoritative outputs
+        shell: bash
+        env:
+          LEVEL: ${{ steps.score.outputs.level }}
+          LEVEL_NAME: ${{ steps.score.outputs.level-name }}
+          PERCENT: ${{ steps.score.outputs.percent }}
+        run: |
+          test -n "$LEVEL"
+          test -n "$LEVEL_NAME"
+          test -n "$PERCENT"
+          printf 'verified v1 alias: L%s %s (%s%%)\n' "$LEVEL" "$LEVEL_NAME" "$PERCENT"