diff --git a/src/cron/isolated-agent/delivery-dispatch.error-guard.test.ts b/src/cron/isolated-agent/delivery-dispatch.error-guard.test.ts
index 638db06f389..0df33d927e4 100644
--- a/src/cron/isolated-agent/delivery-dispatch.error-guard.test.ts
+++ b/src/cron/isolated-agent/delivery-dispatch.error-guard.test.ts
@@ -319,4 +319,21 @@ describe("dispatchCronDelivery — error output guard", () => {
     expect(state.deliveryAttempted).toBe(false);
     expect(deliverOutboundPayloads).not.toHaveBeenCalled();
   });
+
+  it("preserves shared-delivery flags when skipMessagingToolDelivery is true", async () => {
+    const errorJson = JSON.stringify({
+      type: "error",
+      error: { type: "server_error", message: "fail" },
+    });
+    const params = makeBaseParams({ synthesizedText: errorJson });
+    // Simulate shared-delivery path: agent already sent via message tool
+    (params as Record<string, unknown>).skipMessagingToolDelivery = true;
+    const state = await dispatchCronDelivery(params);
+
+    // Error guard should suppress announce delivery but preserve the
+    // existing message-tool delivery state.
+    expect(state.delivered).toBe(true);
+    expect(state.deliveryAttempted).toBe(true);
+    expect(deliverOutboundPayloads).not.toHaveBeenCalled();
+  });
 });
diff --git a/src/cron/isolated-agent/delivery-dispatch.ts b/src/cron/isolated-agent/delivery-dispatch.ts
index 2ddbf3711a2..41248c992c7 100644
--- a/src/cron/isolated-agent/delivery-dispatch.ts
+++ b/src/cron/isolated-agent/delivery-dispatch.ts
@@ -340,9 +340,13 @@ export async function dispatchCronDelivery(
     logWarn(
       `[cron:${params.job.id}] suppressed announce delivery of raw error output (${source}, ${chars} chars)`,
     );
+    // Preserve shared-delivery state: when skipMessagingToolDelivery is true,
+    // the agent already sent via the message tool — suppressing the error
+    // guard's announce delivery should not overwrite that existing delivery
+    // state in cron logs/metadata.
     return {
-      delivered: false,
-      deliveryAttempted: false,
+      delivered: skipMessagingToolDelivery,
+      deliveryAttempted: skipMessagingToolDelivery,
       summary,
       outputText,
       synthesizedText,