diff --git a/src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts b/src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts
index 4ed41f7de3a..1602b9d1b4d 100644
--- a/src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts
+++ b/src/cron/isolated-agent/delivery-dispatch.double-announce.test.ts
@@ -467,4 +467,59 @@ describe("dispatchCronDelivery — double-announce guard", () => {
       vi.unstubAllEnvs();
     }
   });
+
+  it("suppresses NO_REPLY payload in direct delivery so sentinel never leaks to external channels", async () => {
+    vi.mocked(countActiveDescendantRuns).mockReturnValue(0);
+    vi.mocked(isLikelyInterimCronMessage).mockReturnValue(false);
+
+    const params = makeBaseParams({ synthesizedText: "NO_REPLY" });
+    // Force the useDirectDelivery path (structured content) to exercise
+    // deliverViaDirect without going through finalizeTextDelivery.
+    (params as Record<string, unknown>).deliveryPayloadHasStructuredContent = true;
+    const state = await dispatchCronDelivery(params);
+
+    // NO_REPLY must be filtered out before reaching the outbound adapter.
+    expect(deliverOutboundPayloads).not.toHaveBeenCalled();
+    // Mark as silently delivered so the job is persisted as successful.
+    expect(state.delivered).toBe(true);
+    // deliveryAttempted must be true so the heartbeat timer does not fire
+    // a fallback enqueueSystemEvent with the NO_REPLY sentinel text.
+    expect(state.deliveryAttempted).toBe(true);
+
+    // Verify timer guard agrees: shouldEnqueueCronMainSummary returns false
+    expect(
+      shouldEnqueueCronMainSummary({
+        summaryText: "NO_REPLY",
+        deliveryRequested: true,
+        delivered: state.delivered,
+        deliveryAttempted: state.deliveryAttempted,
+        suppressMainSummary: false,
+        isCronSystemEvent: () => true,
+      }),
+    ).toBe(false);
+  });
+
+  it("suppresses NO_REPLY payload with surrounding whitespace", async () => {
+    vi.mocked(countActiveDescendantRuns).mockReturnValue(0);
+    vi.mocked(isLikelyInterimCronMessage).mockReturnValue(false);
+
+    const params = makeBaseParams({ synthesizedText: "  NO_REPLY  " });
+    (params as Record<string, unknown>).deliveryPayloadHasStructuredContent = true;
+    const state = await dispatchCronDelivery(params);
+
+    expect(deliverOutboundPayloads).not.toHaveBeenCalled();
+    expect(state.delivered).toBe(true);
+    expect(state.deliveryAttempted).toBe(true);
+
+    expect(
+      shouldEnqueueCronMainSummary({
+        summaryText: "  NO_REPLY  ",
+        deliveryRequested: true,
+        delivered: state.delivered,
+        deliveryAttempted: state.deliveryAttempted,
+        suppressMainSummary: false,
+        isCronSystemEvent: () => true,
+      }),
+    ).toBe(false);
+  });
 });
diff --git a/src/cron/isolated-agent/delivery-dispatch.ts b/src/cron/isolated-agent/delivery-dispatch.ts
index eda32740e4a..9584c711bc2 100644
--- a/src/cron/isolated-agent/delivery-dispatch.ts
+++ b/src/cron/isolated-agent/delivery-dispatch.ts
@@ -1,5 +1,5 @@
 import { countActiveDescendantRuns } from "../../agents/subagent-registry.js";
-import { SILENT_REPLY_TOKEN } from "../../auto-reply/tokens.js";
+import { isSilentReplyText, SILENT_REPLY_TOKEN } from "../../auto-reply/tokens.js";
 import type { ReplyPayload } from "../../auto-reply/types.js";
 import { createOutboundSendDeps, type CliDeps } from "../../cli/outbound-send-deps.js";
 import type { OpenClawConfig } from "../../config/config.js";
@@ -331,14 +331,28 @@ export async function dispatchCronDelivery(
       delivery,
     });
     try {
-      const payloadsForDelivery =
+      const rawPayloads =
         deliveryPayloads.length > 0
           ? deliveryPayloads
           : synthesizedText
             ? [{ text: synthesizedText }]
             : [];
+      // Suppress NO_REPLY sentinel so it never leaks to external channels.
+      const payloadsForDelivery = rawPayloads.filter(
+        (p) => !isSilentReplyText(p.text, SILENT_REPLY_TOKEN),
+      );
       if (payloadsForDelivery.length === 0) {
-        return null;
+        // Mark as silently delivered so the heartbeat timer does not fire a fallback
+        // and the job is persisted as successfully delivered.
+        deliveryAttempted = true;
+        delivered = true;
+        return params.withRunSession({
+          status: "ok",
+          summary,
+          outputText,
+          delivered: true,
+          ...params.telemetry,
+        });
       }
       if (params.isAborted()) {
         return params.withRunSession({