diff --git a/frontend/src/__tests__/purchases-deeplink.test.ts b/frontend/src/__tests__/purchases-deeplink.test.ts
index 477929a01..ee04a444c 100644
--- a/frontend/src/__tests__/purchases-deeplink.test.ts
+++ b/frontend/src/__tests__/purchases-deeplink.test.ts
@@ -47,6 +47,35 @@ describe('handlePurchaseDeeplink approve (issue #247)', () => {
     expect(window.location.pathname).toBe('/purchases');
   });
 
+  it.each([
+    [403, 'forbidden', 'view:purchases'],
+    [404, 'execution not found', 'not found or is outside your account access'],
+  ])('details fetch failing with %s is permanent: no retry advice, keeps server message', async (status, message, wording) => {
+    (api.getPurchaseDetails as jest.Mock).mockRejectedValue(Object.assign(new Error(message), { status }));
+
+    await expect(handlePurchaseDeeplink()).resolves.toBe(true);
+
+    const text = document.querySelector('[role="alert"]')?.textContent ?? '';
+    expect(text).toContain(wording);
+    expect(text).toContain(`(${message})`);
+    expect(text).not.toContain('retry');
+  });
+
+  it.each([
+    [500, 'internal error'],
+    [401, 'unauthorized'],
+    [undefined, 'Failed to fetch'],
+  ])('details fetch failing with %s keeps the retry path', async (status, message) => {
+    (api.getPurchaseDetails as jest.Mock).mockRejectedValue(Object.assign(new Error(message), { status }));
+
+    await expect(handlePurchaseDeeplink()).resolves.toBe(true);
+
+    const text = document.querySelector('[role="alert"]')?.textContent ?? '';
+    expect(text).toContain('Open the approval link again to retry.');
+    expect(text).toContain(`(${message})`);
+    expect(text).not.toContain('view:purchases');
+  });
+
   it('shows the upfront amount and approves when details load', async () => {
     (api.getPurchaseDetails as jest.Mock).mockResolvedValue({
       execution_id: EXEC_ID, status: 'pending', total_upfront_cost: 1200, estimated_savings: 10,
diff --git a/frontend/src/approval-details.ts b/frontend/src/approval-details.ts
index 61d756e11..587266990 100644
--- a/frontend/src/approval-details.ts
+++ b/frontend/src/approval-details.ts
@@ -351,7 +351,21 @@ export async function buildApprovalDetailsBody(executionId: string): Promise<HTM
   return renderApprovalDetailsBody(details, accountsById, hostAWSAccountID);
 }
 
+/** True for a 403/404 on the details fetch: retrying cannot succeed. */
+export function isPermanentDetailsError(err: unknown): boolean {
+  const status = (err as { status?: number } | null)?.status;
+  return status === 403 || status === 404;
+}
+
 export function approvalDetailsUnavailableMessage(err: unknown): string {
   const cause = err instanceof Error ? err.message : String(err);
-  return `This purchase cannot be approved without showing the amount, and its details could not be loaded (${cause}).`;
+  const base = `This purchase cannot be approved without showing the amount, and its details could not be loaded (${cause}).`;
+  const status = (err as { status?: number } | null)?.status;
+  if (status === 403) {
+    return `${base} Loading details requires the view:purchases permission and access to the purchase's account.`;
+  }
+  if (status === 404) {
+    return `${base} The purchase was not found or is outside your account access.`;
+  }
+  return base;
 }
diff --git a/frontend/src/purchases-deeplink.ts b/frontend/src/purchases-deeplink.ts
index d0cf920d6..6230a5789 100644
--- a/frontend/src/purchases-deeplink.ts
+++ b/frontend/src/purchases-deeplink.ts
@@ -21,7 +21,7 @@
 import { apiRequest } from './api/client';
 import { showToast } from './toast';
 import { confirmDialog } from './confirmDialog';
-import { approvalDetailsUnavailableMessage, buildApprovalDetailsBody } from './approval-details';
+import { approvalDetailsUnavailableMessage, buildApprovalDetailsBody, isPermanentDetailsError } from './approval-details';
 
 type DeeplinkAction = 'approve' | 'cancel';
 
@@ -88,7 +88,9 @@ export async function handlePurchaseDeeplink(): Promise<boolean> {
     } catch (err) {
       console.error('Failed to load purchase details for approval:', err);
       showToast({
-        message: `${approvalDetailsUnavailableMessage(err)} Open the approval link again to retry.`,
+        message: isPermanentDetailsError(err)
+          ? approvalDetailsUnavailableMessage(err)
+          : `${approvalDetailsUnavailableMessage(err)} Open the approval link again to retry.`,
         kind: 'error',
         timeout: null,
       });
diff --git a/frontend/tests-e2e/history-action-confirmation.spec.ts b/frontend/tests-e2e/history-action-confirmation.spec.ts
index 857db70df..4d27b96d6 100644
--- a/frontend/tests-e2e/history-action-confirmation.spec.ts
+++ b/frontend/tests-e2e/history-action-confirmation.spec.ts
@@ -122,7 +122,7 @@ test('approve is not offered when the purchase details cannot be loaded (issue #
   await page.route(`**/api/purchases/${ID}`, route => {
     detailGets++;
     return detailGets === 1
-      ? route.fulfill({ status: 403, json: { error: 'forbidden' } })
+      ? route.fulfill({ status: 500, json: { error: 'internal error' } })
       : route.fulfill({ json: DETAILS });
   });
   await page.goto('/purchases/history');
@@ -137,6 +137,21 @@ test('approve is not offered when the purchase details cannot be loaded (issue #
   await expect.poll(() => fixture.posts.length).toBe(1);
 });
 
+for (const [status, wording] of [[403, 'view:purchases'], [404, 'outside your account access']] as const) {
+  test(`approval link with details ${status} shows permanent wording without retry advice (issue #529)`, async ({ page }) => {
+    const fixture = await historyFixture(page, 'approve');
+    await page.route(`**/api/purchases/${ID}`, route => route.fulfill({ status, json: { error: 'denied by server' } }));
+    await page.goto(`/purchases/approve/${ID}?token=tok`);
+    const alert = page.getByRole('alert');
+    await expect(alert).toContainText('cannot be approved without showing the amount');
+    await expect(alert).toContainText(wording);
+    await expect(alert).toContainText('denied by server');
+    await expect(alert).not.toContainText(/try again|retry/i);
+    await expect(page.locator('.modal-confirm-backdrop')).toHaveCount(0);
+    expect(fixture.posts).toHaveLength(0);
+  });
+}
+
 test('canceling an independent row does not steal focus from another confirmation', async ({ page }) => {
   const fixture = await historyFixture(page, 'approve');
   const details = gate();