diff --git a/.gitea/workflows/sonarqube.yml b/.gitea/workflows/sonarqube.yml
index 3aaa215..4e7754c 100644
--- a/.gitea/workflows/sonarqube.yml
+++ b/.gitea/workflows/sonarqube.yml
@@ -46,6 +46,10 @@ jobs:
           SONAR_HOST_URL: ${{ vars.SONAR_HOST_URL }}
           SONAR_TOKEN: ${{ secrets.SONAR_TOKEN }}
         run: |
+          if [ -z "$SONAR_HOST_URL" ] || ! echo "$SONAR_HOST_URL" | grep -qE '^https?://'; then
+            echo "::error::SONAR_HOST_URL is missing or invalid (got: '$SONAR_HOST_URL'). Set it as a repo variable with full URL (e.g. https://sonar.example.com)."
+            exit 1
+          fi
           sonar-scanner \
             -Dsonar.host.url="$SONAR_HOST_URL" \
             -Dsonar.login="$SONAR_TOKEN" \