diff --git a/ui/src/pages/Alerts/RuleEditor/RuleEditorWizard.tsx b/ui/src/pages/Alerts/RuleEditor/RuleEditorWizard.tsx
index 250f5bdc..d33f916b 100644
--- a/ui/src/pages/Alerts/RuleEditor/RuleEditorWizard.tsx
+++ b/ui/src/pages/Alerts/RuleEditor/RuleEditorWizard.tsx
@@ -20,7 +20,10 @@ import { ConditionStep } from './ConditionStep';
 import { TriggerStep } from './TriggerStep';
 import { NotifyStep } from './NotifyStep';
 import { ReviewStep } from './ReviewStep';
-import { prefillFromPromotion } from './promotion-prefill';
+import { prefillFromPromotion, type PrefillWarning } from './promotion-prefill';
+import { useCatalog } from '../../../api/queries/catalog';
+import { useOutboundConnections } from '../../../api/queries/admin/outboundConnections';
+import { useSelectedEnv } from '../../../api/queries/alertMeta';
 import css from './wizard.module.css';
 
 const STEP_LABELS: Record<WizardStep, string> = {
@@ -47,8 +50,20 @@ export default function RuleEditorWizard() {
   const promoteRuleId = search.get('ruleId') ?? undefined;
   const sourceRuleQuery = useAlertRule(promoteFrom ? promoteRuleId : undefined);
 
+  // Target-env data for promotion warnings.
+  const env = useSelectedEnv();
+  const targetEnv = search.get('targetEnv') ?? env;
+  const { data: targetCatalog } = useCatalog(targetEnv ?? undefined);
+  const { data: connections } = useOutboundConnections();
+
+  const targetAppSlugs = (targetCatalog ?? []).map((a) => a.slug);
+  const targetAllowedConnIds = (connections ?? [])
+    .filter((c) => c.allowedEnvironmentIds.length === 0 || (!!targetEnv && c.allowedEnvironmentIds.includes(targetEnv)))
+    .map((c) => c.id);
+
   const [step, setStep] = useState<WizardStep>('scope');
   const [form, setForm] = useState<FormState | null>(null);
+  const [warnings, setWarnings] = useState<PrefillWarning[]>([]);
 
   // Initialize form once the existing or source rule loads.
   useEffect(() => {
@@ -58,14 +73,29 @@ export default function RuleEditorWizard() {
       return;
     }
     if (promoteFrom && sourceRuleQuery.data) {
-      const { form: prefilled } = prefillFromPromotion(sourceRuleQuery.data);
+      const { form: prefilled, warnings: w } = prefillFromPromotion(sourceRuleQuery.data, {
+        targetEnvAppSlugs: targetAppSlugs,
+        targetEnvAllowedConnectionIds: targetAllowedConnIds,
+      });
       setForm(prefilled);
+      setWarnings(w);
       return;
     }
     if (!isEdit && !promoteFrom) {
       setForm(initialForm());
     }
-  }, [form, isEdit, existingQuery.data, promoteFrom, sourceRuleQuery.data]);
+    // Intentionally depend on join()'d slug/id strings so the effect
+    // doesn't retrigger on new array identities when contents are equal.
+    // eslint-disable-next-line react-hooks/exhaustive-deps
+  }, [
+    form,
+    isEdit,
+    existingQuery.data,
+    promoteFrom,
+    sourceRuleQuery.data,
+    targetAppSlugs.join(','),
+    targetAllowedConnIds.join(','),
+  ]);
 
   const create = useCreateAlertRule();
   const update = useUpdateAlertRule(id ?? '');
@@ -124,6 +154,18 @@ export default function RuleEditorWizard() {
           </div>
         )}
       </div>
+      {warnings.length > 0 && (
+        <div className={css.promoteBanner}>
+          <strong>Review before saving:</strong>
+          <ul style={{ margin: '4px 0 0 16px', padding: 0 }}>
+            {warnings.map((w) => (
+              <li key={w.field}>
+                <code>{w.field}</code>: {w.message}
+              </li>
+            ))}
+          </ul>
+        </div>
+      )}
       <nav className={css.steps}>
         {WIZARD_STEPS.map((s, i) => (
           <button