diff --git a/tests/browser/workspace-images-delete.spec.mjs b/tests/browser/workspace-images-delete.spec.mjs
index 6984c2cd..bf727731 100644
--- a/tests/browser/workspace-images-delete.spec.mjs
+++ b/tests/browser/workspace-images-delete.spec.mjs
@@ -122,3 +122,50 @@ test('Delete… in the viewer closes it after the delete', async ({ page }) => {
     await expect(viewer).toBeHidden();
     await expect(page.locator(CARDS)).toHaveCount(before - 1);
 });
+
+// The review never starts a delete without an explicit choice (live test 2026-10-29): every activation of the
+// aria-disabled primary is ignored, the dialog has no form to submit, and a chosen primary starts once.
+test('without a chosen mode nothing can start a delete', async ({ page }) => {
+    const before = await openImages(page);
+    await check(page, 0);
+    const applies = [];
+    page.on('request', request => { if (request.url().includes('/maintenance/apply')) applies.push(request.postDataJSON()); });
+    await bar(page).getByRole('button', { name: 'Delete…', exact: true }).click();
+    const dialog = review(page);
+    await expect(dialog).toBeVisible();
+    const primary = dialog.locator('.dialog-actions button.danger');
+    await expect(primary).toHaveAttribute('aria-disabled', 'true');
+    await expect(primary).toHaveText('Choose what happens to the files');
+    // Visibly dimmed while no mode is chosen.
+    await expect(primary).toHaveCSS('opacity', '0.55');
+    await expect(primary).toHaveCSS('cursor', 'not-allowed');
+    await primary.click({ force: true });
+    await primary.dblclick({ force: true });
+    await primary.focus();
+    await page.keyboard.press('Enter');
+    await page.keyboard.press('Space');
+    await dialog.locator('#modal-title').click();
+    await page.keyboard.press('Enter');
+    expect(await dialog.locator('form').count()).toBe(0);
+    await page.evaluate(() => document.querySelector('dialog#modal[open]')?.dispatchEvent(new Event('submit', { bubbles: true })));
+    await expect(dialog).toBeVisible();
+    expect(applies).toEqual([]);
+    for (const radio of await dialog.getByRole('radio').all()) await expect(radio).not.toBeChecked();
+    await dialog.getByRole('button', { name: 'Cancel', exact: true }).click();
+    await expect(page.locator(CARDS)).toHaveCount(before);
+    expect(applies).toEqual([]);
+});
+
+test('a chosen mode starts exactly one delete, with that mode, however often it is pressed', async ({ page }) => {
+    const before = await openImages(page);
+    await check(page, 0);
+    const applies = [];
+    page.on('request', request => { if (request.url().includes('/maintenance/apply')) applies.push(request.postDataJSON()); });
+    const { primary } = await deleteChecked(page, 'library');
+    await primary.dblclick();
+    await expect(toast(page)).toContainText('Removed 1 image from the library.');
+    await expect(page.locator(CARDS)).toHaveCount(before - 1);
+    expect(applies.length).toBe(1);
+    expect(applies[0].mode).toBe('library');
+    expect(Object.keys(applies[0]).sort()).toEqual(['mode', 'token']);
+});
diff --git a/tests/js/workspace-images-delete.test.js b/tests/js/workspace-images-delete.test.js
index 9e98f50a..90782294 100644
--- a/tests/js/workspace-images-delete.test.js
+++ b/tests/js/workspace-images-delete.test.js
@@ -139,3 +139,11 @@ test('apply sends the token and the mode, and toasts that the job started', asyn
         store, plan: plan(), mode: 'library', notify: text => toasts.push(text) });
     assert.equal(refused, null);
 });
+
+test('apply refuses to send a delete without an explicit mode', async () => {
+    const { applyDelete } = module();
+    const api = { post: () => assert.fail('no request without a mode') };
+    for (const mode of [undefined, null, '', 'TRASH', 'delete']) {
+        await assert.rejects(applyDelete({ api, store: null, plan: plan(), mode, notify: () => {} }), TypeError);
+    }
+});
diff --git a/tests/test_image_delete_routes.py b/tests/test_image_delete_routes.py
index d199a511..1fb364df 100644
--- a/tests/test_image_delete_routes.py
+++ b/tests/test_image_delete_routes.py
@@ -106,10 +106,38 @@ class TestReview(ImageDeleteTestCase):
 
     async def test_mode_is_required_and_only_for_this_plan(self):
         self.write("a.png", b"aaa")
+        self.link("a.png")
         plan = await self.review(["a.png"])
-        await self.post(APPLY, {"token": plan["token"]}, 400)
-        await self.post(APPLY, {"token": plan["token"], "mode": "delete"}, 400)
+        # No explicit, exact mode: refused, never a default (least of all trash).
+        for body in (
+            {"token": plan["token"]},
+            {"token": plan["token"], "mode": None},
+            {"token": plan["token"], "mode": ""},
+            {"token": plan["token"], "mode": "TRASH"},
+            {"token": plan["token"], "mode": "delete"},
+            {"token": plan["token"], "mode": ["trash"]},
+            {"token": plan["token"], "mode": True},
+        ):
+            with self.subTest(body=body):
+                await self.post(APPLY, body, 400)
         self.assertTrue((self.output_dir / "a.png").exists())
+        self.assertEqual(self.fake.moved, [])
+        self.assertEqual(self.count("SELECT COUNT(*) FROM generated_images"), 1)
+        # The refusals left the token usable: an explicit mode still applies.
+        body = await self.post(APPLY, {"token": plan["token"], "mode": "library"}, 202)
+        job = self.api._jobs.get(body["job"]["id"])
+        await asyncio.wait_for(asyncio.shield(job.task), DISK_BOUND_SECONDS)
+        self.assertEqual(job.scope["mode"], "library")
+        self.assertTrue((self.output_dir / "a.png").exists())
+        self.assertEqual(self.fake.moved, [])
+
+    async def test_mode_on_another_plan_is_refused(self):
+        plan = await self.post(
+            "/prompt_manager/maintenance/preview",
+            {"operation": "missing_links", "options": {}},
+            200,
+        )
+        await self.post(APPLY, {"token": plan["token"], "mode": "trash"}, 400)
 
 
 class TestLibraryMode(ImageDeleteTestCase):
diff --git a/web/js/workspace/images-delete.mjs b/web/js/workspace/images-delete.mjs
index baa0b286..7f53015e 100644
--- a/web/js/workspace/images-delete.mjs
+++ b/web/js/workspace/images-delete.mjs
@@ -195,12 +195,12 @@ export function showDeleteReview(plan, {scope, count, trigger = null, onApply})
         openCloseOnlyReview({scope, title, grid: deleteRows(plan, 'library'), sentence: reason, trigger});
         return null;
     }
-    let mode = null;
+    let mode = null, started = false;
     const list = el('dl', undefined, 'meta-grid');
     list.hidden = true;
     const notes = el('div', undefined, 'image-delete-notes');
     const cancel = createButton('Cancel');
-    const start = createButton(primaryLabel('library', modeCount(plan, 'library')), 'danger');
+    const start = createButton('Choose what happens to the files', 'danger image-delete-start');
     start.setAttribute('aria-disabled', 'true');
     function render() {
         list.replaceChildren();
@@ -219,8 +219,12 @@ export function showDeleteReview(plan, {scope, count, trigger = null, onApply})
     }
     const group = modeGroup(value => { mode = value; render(); });
     cancel.addEventListener('click', () => closeWorkspaceDialog());
+    // Nothing starts without an explicit mode: an aria-disabled primary ignores every activation (click, Enter, Space),
+    // and a chosen one starts once however often it is pressed. The dialog has no form, so Enter elsewhere submits nothing.
     start.addEventListener('click', () => {
-        if (!mode || start.getAttribute('aria-disabled') === 'true') return;
+        if (started || !MODES.some(choice => choice.value === mode) || start.getAttribute('aria-disabled') === 'true') return;
+        started = true;
+        start.setAttribute('aria-disabled', 'true');
         const chosen = mode;
         closeWorkspaceDialog();
         onApply(chosen);
@@ -233,6 +237,7 @@ export function showDeleteReview(plan, {scope, count, trigger = null, onApply})
 
 /** Apply `plan` in `mode`; the started job, or null (a toast said why). */
 export async function applyDelete({api, store, plan, mode, notify = showWorkspaceToast}) {
+    if (!MODES.some(choice => choice.value === mode)) throw new TypeError('A delete needs an explicit mode');
     let result;
     try {
         result = await api.post(APPLY_URL, {token: plan.token, mode});
diff --git a/web/js/workspace/workspace.css b/web/js/workspace/workspace.css
index de08fa2f..b421d847 100644
--- a/web/js/workspace/workspace.css
+++ b/web/js/workspace/workspace.css
@@ -478,6 +478,7 @@ pre.prompt-text { font: inherit; font-size: 12px; line-height: 1.75; margin-bloc
 /* D147 (#430): a state that blocks Save shows its reason on its own row above the sticky actions, with Refresh for a
    changed source; the disabled actions look disabled; a refused capture's empty preview says so. */
 .tagging-modal .dialog-actions [aria-disabled="true"], .tagging-modal .tag-model-panel [aria-disabled="true"] { opacity: .55; cursor: not-allowed; /* D147 */ }
+#modal .dialog-actions .image-delete-start[aria-disabled="true"] { opacity: .55; cursor: not-allowed; /* #480 D159: no mode chosen yet */ }
 .tagging-modal .tag-action-notice { flex: 1 0 100%; display: flex; flex-wrap: wrap; align-items: center; justify-content: space-between; gap: 8px; margin: 0; color: var(--ca-text); font-size: 12px; /* D147 */ }
 .tagging-modal .tag-action-notice > span { flex: 1 1 16em; }
 .tag-image-preview.tag-preview-empty { display: grid; place-items: center; padding: 8px; text-align: center; font-size: 12px; color: var(--ca-muted); background: var(--ca-field); box-sizing: border-box; /* D147 */ }