diff --git a/CHANGELOG.md b/CHANGELOG.md
index ff3cb120efd..e031d97ac10 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -207,6 +207,7 @@ Docs: https://docs.openclaw.ai
 - Feishu/Doc create permissions: remove caller-controlled owner fields from `feishu_doc` create and bind optional grant behavior to trusted Feishu requester context (`grant_to_requester`), preventing principal selection via tool arguments. (#31184) Thanks @Takhoffman.
 - Routing/Binding peer-kind parity: treat `peer.kind` `group` and `channel` as equivalent for binding scope matching (while keeping `direct` separate) so Slack/public channel bindings do not silently fall through. Landed from contributor PR #31135 by @Sid-Qin. Thanks @Sid-Qin.
 - Cron/Store EBUSY fallback: retry `rename` on `EBUSY` and use `copyFile` fallback on Windows when replacing cron store files so busy-file contention no longer causes false write failures. (#16932) Thanks @sudhanva-chakra.
+- Cron/Isolated payload selection: ignore `isError` payloads when deriving summary/output/delivery payload fallbacks, while preserving error-only fallback behavior when no non-error payload exists. (#21454) Thanks @Diaspar4u.
 - Agents/FS workspace default: honor documented host file-tool default `tools.fs.workspaceOnly=false` when unset so host `write`/`edit` calls are not incorrectly workspace-restricted unless explicitly enabled. Landed from contributor PR #31128 by @SaucePackets. Thanks @SaucePackets.
 - Cron/Timer hot-loop guard: enforce a minimum timer re-arm delay when stale past-due jobs would otherwise trigger repeated `setTimeout(0)` loops, preventing event-loop saturation and log-flood behavior. (#29853) Thanks @FlamesCN.
 - Gateway/CLI session recovery: handle expired CLI session IDs gracefully by clearing stale session state and retrying without crashing gateway runs. Landed from contributor PR #31090 by @frankekn. Thanks @frankekn.
diff --git a/src/cron/isolated-agent/helpers.test.ts b/src/cron/isolated-agent/helpers.test.ts
new file mode 100644
index 00000000000..31e533170f8
--- /dev/null
+++ b/src/cron/isolated-agent/helpers.test.ts
@@ -0,0 +1,86 @@
+import { describe, expect, it } from "vitest";
+import {
+  pickLastDeliverablePayload,
+  pickLastNonEmptyTextFromPayloads,
+  pickSummaryFromPayloads,
+} from "./helpers.js";
+
+describe("pickSummaryFromPayloads", () => {
+  it("picks real text over error payload", () => {
+    const payloads = [
+      { text: "Here is your summary" },
+      { text: "Tool error: rate limited", isError: true },
+    ];
+    expect(pickSummaryFromPayloads(payloads)).toBe("Here is your summary");
+  });
+
+  it("falls back to error payload when no real text exists", () => {
+    const payloads = [{ text: "Tool error: rate limited", isError: true }];
+    expect(pickSummaryFromPayloads(payloads)).toBe("Tool error: rate limited");
+  });
+
+  it("returns undefined for empty payloads", () => {
+    expect(pickSummaryFromPayloads([])).toBeUndefined();
+  });
+
+  it("treats isError: undefined as non-error", () => {
+    const payloads = [
+      { text: "normal text", isError: undefined },
+      { text: "error text", isError: true },
+    ];
+    expect(pickSummaryFromPayloads(payloads)).toBe("normal text");
+  });
+});
+
+describe("pickLastNonEmptyTextFromPayloads", () => {
+  it("picks real text over error payload", () => {
+    const payloads = [{ text: "Real output" }, { text: "Service error", isError: true }];
+    expect(pickLastNonEmptyTextFromPayloads(payloads)).toBe("Real output");
+  });
+
+  it("falls back to error payload when no real text exists", () => {
+    const payloads = [{ text: "Service error", isError: true }];
+    expect(pickLastNonEmptyTextFromPayloads(payloads)).toBe("Service error");
+  });
+
+  it("returns undefined for empty payloads", () => {
+    expect(pickLastNonEmptyTextFromPayloads([])).toBeUndefined();
+  });
+
+  it("treats isError: undefined as non-error", () => {
+    const payloads = [
+      { text: "good", isError: undefined },
+      { text: "bad", isError: true },
+    ];
+    expect(pickLastNonEmptyTextFromPayloads(payloads)).toBe("good");
+  });
+});
+
+describe("pickLastDeliverablePayload", () => {
+  it("picks real payload over error payload", () => {
+    const real = { text: "Delivered content" };
+    const error = { text: "Error warning", isError: true as const };
+    expect(pickLastDeliverablePayload([real, error])).toBe(real);
+  });
+
+  it("falls back to error payload when no real payload exists", () => {
+    const error = { text: "Error warning", isError: true as const };
+    expect(pickLastDeliverablePayload([error])).toBe(error);
+  });
+
+  it("returns undefined for empty payloads", () => {
+    expect(pickLastDeliverablePayload([])).toBeUndefined();
+  });
+
+  it("picks media payload over error text payload", () => {
+    const media = { mediaUrl: "https://example.com/img.png" };
+    const error = { text: "Error warning", isError: true as const };
+    expect(pickLastDeliverablePayload([media, error])).toBe(media);
+  });
+
+  it("treats isError: undefined as non-error", () => {
+    const normal = { text: "ok", isError: undefined };
+    const error = { text: "bad", isError: true as const };
+    expect(pickLastDeliverablePayload([normal, error])).toBe(normal);
+  });
+});
diff --git a/src/cron/isolated-agent/helpers.ts b/src/cron/isolated-agent/helpers.ts
index d4d42b20fe5..c74b65d1bb0 100644
--- a/src/cron/isolated-agent/helpers.ts
+++ b/src/cron/isolated-agent/helpers.ts
@@ -9,6 +9,7 @@ type DeliveryPayload = {
   mediaUrl?: string;
   mediaUrls?: string[];
   channelData?: Record<string, unknown>;
+  isError?: boolean;
 };
 
 export function pickSummaryFromOutput(text: string | undefined) {
@@ -20,7 +21,18 @@ export function pickSummaryFromOutput(text: string | undefined) {
   return clean.length > limit ? `${truncateUtf16Safe(clean, limit)}…` : clean;
 }
 
-export function pickSummaryFromPayloads(payloads: Array<{ text?: string | undefined }>) {
+export function pickSummaryFromPayloads(
+  payloads: Array<{ text?: string | undefined; isError?: boolean }>,
+) {
+  for (let i = payloads.length - 1; i >= 0; i--) {
+    if (payloads[i]?.isError) {
+      continue;
+    }
+    const summary = pickSummaryFromOutput(payloads[i]?.text);
+    if (summary) {
+      return summary;
+    }
+  }
   for (let i = payloads.length - 1; i >= 0; i--) {
     const summary = pickSummaryFromOutput(payloads[i]?.text);
     if (summary) {
@@ -30,7 +42,18 @@ export function pickSummaryFromPayloads(payloads: Array<{ text?: string | undefi
   return undefined;
 }
 
-export function pickLastNonEmptyTextFromPayloads(payloads: Array<{ text?: string | undefined }>) {
+export function pickLastNonEmptyTextFromPayloads(
+  payloads: Array<{ text?: string | undefined; isError?: boolean }>,
+) {
+  for (let i = payloads.length - 1; i >= 0; i--) {
+    if (payloads[i]?.isError) {
+      continue;
+    }
+    const clean = (payloads[i]?.text ?? "").trim();
+    if (clean) {
+      return clean;
+    }
+  }
   for (let i = payloads.length - 1; i >= 0; i--) {
     const clean = (payloads[i]?.text ?? "").trim();
     if (clean) {
@@ -41,13 +64,23 @@ export function pickLastNonEmptyTextFromPayloads(payloads: Array<{ text?: string
 }
 
 export function pickLastDeliverablePayload(payloads: DeliveryPayload[]) {
+  const isDeliverable = (p: DeliveryPayload) => {
+    const text = (p?.text ?? "").trim();
+    const hasMedia = Boolean(p?.mediaUrl) || (p?.mediaUrls?.length ?? 0) > 0;
+    const hasChannelData = Object.keys(p?.channelData ?? {}).length > 0;
+    return text || hasMedia || hasChannelData;
+  };
   for (let i = payloads.length - 1; i >= 0; i--) {
-    const payload = payloads[i];
-    const text = (payload?.text ?? "").trim();
-    const hasMedia = Boolean(payload?.mediaUrl) || (payload?.mediaUrls?.length ?? 0) > 0;
-    const hasChannelData = Object.keys(payload?.channelData ?? {}).length > 0;
-    if (text || hasMedia || hasChannelData) {
-      return payload;
+    if (payloads[i]?.isError) {
+      continue;
+    }
+    if (isDeliverable(payloads[i])) {
+      return payloads[i];
+    }
+  }
+  for (let i = payloads.length - 1; i >= 0; i--) {
+    if (isDeliverable(payloads[i])) {
+      return payloads[i];
     }
   }
   return undefined;