diff --git a/src/gateway/server-methods/cron.ts b/src/gateway/server-methods/cron.ts
index 7eccb895534..e854b416e65 100644
--- a/src/gateway/server-methods/cron.ts
+++ b/src/gateway/server-methods/cron.ts
@@ -1,3 +1,4 @@
+import { loadConfig } from "../../config/config.js";
 import { normalizeCronJobCreate, normalizeCronJobPatch } from "../../cron/normalize.js";
 import {
   readCronRunLogEntriesPage,
@@ -6,6 +7,7 @@ import {
 } from "../../cron/run-log.js";
 import type { CronJobCreate, CronJobPatch } from "../../cron/types.js";
 import { validateScheduleTimestamp } from "../../cron/validate-timestamp.js";
+import { listConfiguredMessageChannels } from "../../infra/outbound/channel-selection.js";
 import {
   ErrorCodes,
   errorShape,
@@ -21,6 +23,33 @@ import {
 } from "../protocol/index.js";
 import type { GatewayRequestHandlers } from "./types.js";
 
+/**
+ * Validates that announce-mode delivery has an explicit channel when multiple
+ * channels are configured. Without this, delivery silently fails at runtime
+ * because the "last" channel fallback cannot resolve an unambiguous target.
+ * See: https://github.com/openclaw/openclaw/issues/47524
+ */
+async function validateDeliveryChannelForAnnounce(
+  delivery: Record<string, unknown> | undefined,
+): Promise<string | null> {
+  if (!delivery || typeof delivery !== "object") {
+    return null;
+  }
+  const mode = typeof delivery.mode === "string" ? delivery.mode.trim().toLowerCase() : undefined;
+  if (mode !== "announce") {
+    return null;
+  }
+  if (typeof delivery.channel === "string" && delivery.channel.trim()) {
+    return null;
+  }
+  const cfg = loadConfig();
+  const configured = await listConfiguredMessageChannels(cfg);
+  if (configured.length > 1) {
+    return `delivery.channel is required when mode is "announce" and multiple channels are configured (${configured.join(", ")}). Set --channel explicitly.`;
+  }
+  return null;
+}
+
 export const cronHandlers: GatewayRequestHandlers = {
   wake: ({ params, respond, context }) => {
     if (!validateWakeParams(params)) {
@@ -118,6 +147,13 @@ export const cronHandlers: GatewayRequestHandlers = {
       );
       return;
     }
+    const deliveryChannelError = await validateDeliveryChannelForAnnounce(
+      (jobCreate as { delivery?: Record<string, unknown> }).delivery,
+    );
+    if (deliveryChannelError) {
+      respond(false, undefined, errorShape(ErrorCodes.INVALID_REQUEST, deliveryChannelError));
+      return;
+    }
     const job = await context.cron.add(jobCreate);
     context.logGateway.info("cron: job created", { jobId: job.id, schedule: jobCreate.schedule });
     respond(true, job, undefined);
@@ -165,6 +201,15 @@ export const cronHandlers: GatewayRequestHandlers = {
         return;
       }
     }
+    if (patch.delivery) {
+      const deliveryChannelError = await validateDeliveryChannelForAnnounce(
+        patch.delivery as Record<string, unknown>,
+      );
+      if (deliveryChannelError) {
+        respond(false, undefined, errorShape(ErrorCodes.INVALID_REQUEST, deliveryChannelError));
+        return;
+      }
+    }
     const job = await context.cron.update(jobId, patch);
     context.logGateway.info("cron: job updated", { jobId });
     respond(true, job, undefined);