@@ -0,0 +1,22 @@
+---
+'@object-ui/i18n': minor
+'@object-ui/components': minor
+'@object-ui/app-shell': patch
+'@object-ui/plugin-detail': patch
+---
+
+A record action greyed out by its declared `disabled` predicate now says why (objectui#11811). It shows the reason "Not available for this record", and the same text is its accessible description (`aria-describedby`), so a screen reader announces it too. Before, the action carried no tooltip, no `title` and no description, so a user could not learn why it was off.
+
+Where it shows:
+
+- **The record page header** (`page:header`, `@object-ui/components`). On an inline action button, hovering it or focusing it from the keyboard opens a tooltip with the reason. On an action in the ⋯ overflow menu, the reason is a second line under the label. A tooltip there could not be reached from the keyboard, because the menu skips a disabled item and traps Tab.
+- **The `record:quick_actions` bar** (`@object-ui/plugin-detail`), for example a record page's section bar. Hovering or focusing the button opens the tooltip.
+- **The `DeclaredActionsBar`** (`@object-ui/app-shell`), which renders server-declared actions on the approvals surfaces. Hovering or focusing the button opens the tooltip.
+
+A natively disabled button receives no pointer or focus events, so the tooltip's trigger is a focusable wrapper around the button, the pattern Radix documents for a disabled trigger.
+
+What stays unchanged: a button greyed out only while its own action runs shows no reason. So do the header's Edit and Delete that the console injects, whose `disabled` the host computes (for example while the record is locked for approval), and a header action greyed out by a live inline-edit session.
+
+The reason is the same generic sentence for every action. An author-written reason beside the predicate would be a new key on the action spec, which is objectstack's to declare. It is not part of this change.
+
+**Clause-②: yes (widening).** `@object-ui/i18n` gains one language-pack key, `actions.notAvailableForRecord`, translated in all ten packs. No export, prop or type member is added, removed or changed.
@@ -31,7 +31,16 @@
  */
 
 import React, { useCallback, useMemo, useState } from 'react';
-import { Button, Separator, cn, hasDeclaredVisibilityGate } from '@object-ui/components';
+import {
+  Button,
+  Separator,
+  cn,
+  hasDeclaredVisibilityGate,
+  Tooltip,
+  TooltipContent,
+  TooltipProvider,
+  TooltipTrigger,
+} from '@object-ui/components';
 import {
   ActionProvider,
   useAction,
@@ -178,6 +187,8 @@ const DeclaredActionButton: React.FC<{
   // these two lines carried — which existed only because `ActionDef.disabled`
   // could not describe the envelope arm — have nothing left to reach around.
   const isDisabledPred = useCondition(toPredicateInput(action.disabled), predicateRecord);
+  // Called up here with the other hooks: the `visible` gate below returns early.
+  const reasonId = React.useId();
 
   /**
    * Is the button this viewer is looking at an ADMIN OVERRIDE (objectui#5178)?
@@ -371,28 +382,42 @@ const DeclaredActionButton: React.FC<{
   // dialog body can never come from different bundle reads (objectui#4265).
   const label = isOverride ? overrideLabel : declaredLabel;
 
-  return (
+  // Is a `disabled` gate DECLARED? The same question the `visible` gate
+  // above asks, so it reads the same definition rather than re-spelling it.
+  // The name is historic — objectui#3492 arrived through `visible` — and the
+  // predicate is key-neutral: "declared" is `!= null && !== ''`, because an
+  // empty predicate is nothing to evaluate. Kept under that name
+  // deliberately (objectui#3842 ruling): one implementation behind two names
+  // is a dialect, not a clarification.
+  //
+  // `!= null` alone was a real defect here, and NOT for the reason it was on
+  // `visible`: the evaluation entry reads an empty predicate as "no
+  // condition → true", which on `visible` means SHOW (so an over-broad
+  // "declared" test cancels out and `''` renders either way), but here means
+  // DISABLE. A `disabled: ''` on a server-declared approval action rendered
+  // a permanently greyed-out Approve / Reject — the mirror image of
+  // objectui#3835 on the same surface, and equally impossible to tell from
+  // deliberate metadata by looking at it.
+  //
+  // Held apart from `loading` (objectui#11811): only the declared predicate is
+  // a fact about the record, so only it earns the "not available" reason. A
+  // button greyed out while its own action runs already says why — the spinner.
+  const disabledByPredicate = hasDeclaredVisibilityGate(action.disabled) ? isDisabledPred : false;
+  // The generic reason (objectui#11811). An author-written reason beside the
+  // predicate would be a spec key, which is objectstack's to declare — not one
+  // this bar may invent — so every predicate-disabled action says the same
+  // thing for now.
+  const disabledReason = disabledByPredicate
+    ? String(t('actions.notAvailableForRecord', { defaultValue: 'Not available for this record' }))
+    : undefined;
+
+  const button = (
     <Button
       type="button"
       size="sm"
       variant={variant as any}
-      // Is a `disabled` gate DECLARED? The same question the `visible` gate
-      // above asks, so it reads the same definition rather than re-spelling it.
-      // The name is historic — objectui#3492 arrived through `visible` — and the
-      // predicate is key-neutral: "declared" is `!= null && !== ''`, because an
-      // empty predicate is nothing to evaluate. Kept under that name
-      // deliberately (objectui#3842 ruling): one implementation behind two names
-      // is a dialect, not a clarification.
-      //
-      // `!= null` alone was a real defect here, and NOT for the reason it was on
-      // `visible`: the evaluation entry reads an empty predicate as "no
-      // condition → true", which on `visible` means SHOW (so an over-broad
-      // "declared" test cancels out and `''` renders either way), but here means
-      // DISABLE. A `disabled: ''` on a server-declared approval action rendered
-      // a permanently greyed-out Approve / Reject — the mirror image of
-      // objectui#3835 on the same surface, and equally impossible to tell from
-      // deliberate metadata by looking at it.
-      disabled={(hasDeclaredVisibilityGate(action.disabled) ? isDisabledPred : false) || loading}
+      disabled={disabledByPredicate || loading}
+      aria-describedby={disabledReason ? reasonId : undefined}
       onClick={handleClick}
       // Amber warning treatment for an override (objectui#5178) — the same
       // palette the approvals surfaces already use for "waiting / attention",
@@ -420,6 +445,35 @@ const DeclaredActionButton: React.FC<{
       {label}
     </Button>
   );
+  if (!disabledReason) return button;
+  // A natively `disabled` button fires no pointer or focus events, and the
+  // Button primitive adds `disabled:pointer-events-none` on top — so a tooltip
+  // (or a native `title`) on the button itself never opens: hovering or
+  // focusing it showed nothing (objectui#11811). The wrapping span is the
+  // trigger instead, the idiom Radix documents for a disabled button: it takes
+  // the hover, and `tabIndex={0}` lets a keyboard user focus it, which opens
+  // the tooltip too. The reason is ALSO a persistent accessible description
+  // (`aria-describedby` on both the button and the span, onto an `sr-only`
+  // copy), so a screen reader reaching either one hears it with the tooltip
+  // closed. Same shape as `record:quick_actions`' button.
+  return (
+    <TooltipProvider delayDuration={200}>
+      <Tooltip>
+        <TooltipTrigger asChild>
+          <span
+            tabIndex={0}
+            aria-describedby={reasonId}
+            data-disabled-reason=""
+            className="inline-flex rounded-md focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-ring focus-visible:ring-offset-2"
+          >
+            {button}
+            <span id={reasonId} className="sr-only">{disabledReason}</span>
+          </span>
+        </TooltipTrigger>
+        <TooltipContent>{disabledReason}</TooltipContent>
+      </Tooltip>
+    </TooltipProvider>
+  );
 };
 
 /**
 
@@ -0,0 +1,168 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * DeclaredActionsBar — a declared action greyed out by its `disabled`
+ * predicate says why (objectui#11811).
+ *
+ * The bar evaluates the spec `disabled` predicate itself (`useCondition`), so
+ * it knows a button is off BY DECLARATION. Before the fix it rendered that
+ * button with no tooltip, no `title` and no `aria-describedby`, and a natively
+ * disabled button (with the Button primitive's `disabled:pointer-events-none`)
+ * never fires the hover or focus a tooltip would need. The generic reason now
+ * rides a focusable wrapper span — the tooltip trigger — and a persistent
+ * `sr-only` description both the button and the span point at. A button that
+ * is disabled only while its own action runs is NOT "not available", and says
+ * nothing.
+ *
+ * Only the action DISPATCH and the console runtime shell are doubled, as in
+ * the sibling suites. The predicate entry, the Button, the Radix tooltip and
+ * the language packs are the shipped ones — the zh case reads the real zh pack
+ * through a real `I18nProvider`.
+ */
+
+import { describe, it, expect, vi, beforeEach } from 'vitest';
+import { render, screen, fireEvent, act } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+import '@testing-library/jest-dom';
+import React from 'react';
+
+const executeSpy = vi.fn().mockResolvedValue({ success: true });
+
+vi.mock('@object-ui/react', async (importOriginal) => {
+  const actual = await importOriginal<typeof import('@object-ui/react')>();
+  return {
+    ...actual,
+    ActionProvider: ({ children }: { children: React.ReactNode }) => <>{children}</>,
+    useAction: () => ({ execute: executeSpy }),
+  };
+});
+vi.mock('../../hooks/useConsoleActionRuntime', () => ({
+  useConsoleActionRuntime: () => ({ actionProviderProps: {}, dialogs: null }),
+}));
+vi.mock('../../providers/AdapterProvider', () => ({ useAdapter: () => ({}) }));
+vi.mock('../../utils/getIcon', () => ({ getIcon: () => () => null }));
+
+import { I18nProvider } from '@object-ui/i18n';
+import { DeclaredActionsBar } from '../DeclaredActionsBar';
+
+const REASON_EN = 'Not available for this record';
+const REASON_ZH = '对此记录不可用';
+
+/**
+ * The `disabled`-predicate specimen the card measured (showcase Archive), in
+ * the shape the server SERVES it: the authored CEL string compiled into a
+ * `{ dialect: 'cel', source }` envelope. The bare string would take the legacy
+ * `${…}` evaluator, where `has()` faults — and a faulting `disabled` greys the
+ * action out on both rows (fail-soft), so the "disabled" case would pass for
+ * the wrong reason and the control below would go red. The envelope reaches a
+ * real verdict both ways.
+ */
+const ARCHIVE = {
+  name: 'showcase_archive_task',
+  type: 'script',
+  label: 'Archive',
+  locations: ['record_section'],
+  disabled: { dialect: 'cel', source: 'has(record.done) && record.done != true' },
+};
+
+function mount(
+  record: Record<string, unknown>,
+  actions: Record<string, unknown>[] = [ARCHIVE],
+  wrap: (node: React.ReactElement) => React.ReactElement = (node) => node,
+) {
+  return render(
+    wrap(
+      <DeclaredActionsBar
+        objectName="showcase_task"
+        record={{ id: 't-1', ...record }}
+        location="record_section"
+        actions={actions as any}
+      />,
+    ),
+  );
+}
+
+const archive = () => screen.getByTestId('declared-action-showcase_archive_task');
+/** The element an `aria-describedby` names, or `null`. */
+const describedBy = (el: HTMLElement) => {
+  const id = el.getAttribute('aria-describedby');
+  return id ? document.getElementById(id) : null;
+};
+
+beforeEach(() => executeSpy.mockReset().mockResolvedValue({ success: true }));
+
+describe('DeclaredActionsBar — a predicate-disabled action says why (objectui#11811)', () => {
+  it('disabled by its predicate: the button carries the reason as its accessible description', () => {
+    mount({ done: false });
+    const button = archive();
+    expect(button).toBeDisabled();
+    expect(describedBy(button)).toHaveTextContent(REASON_EN);
+    // A DESCRIPTION, never folded into the accessible name.
+    expect(button).toHaveAccessibleName('Archive');
+  });
+
+  it('hovering the disabled action opens a tooltip with the reason', async () => {
+    const user = userEvent.setup();
+    mount({ done: false });
+    const trigger = archive().parentElement as HTMLElement;
+    expect(trigger).toHaveAttribute('data-disabled-reason');
+    await user.hover(trigger);
+    const tooltip = await screen.findByRole('tooltip');
+    expect(tooltip).toHaveTextContent(REASON_EN);
+  });
+
+  it('a keyboard user reaches the reason: Tab lands on the trigger, which opens the tooltip and is described by it', async () => {
+    const user = userEvent.setup();
+    mount({ done: false });
+    const trigger = archive().parentElement as HTMLElement;
+    await user.tab();
+    expect(trigger).toHaveFocus();
+    expect(describedBy(trigger)).toHaveTextContent(REASON_EN);
+    const tooltip = await screen.findByRole('tooltip');
+    expect(tooltip).toHaveTextContent(REASON_EN);
+  });
+
+  it('control — the predicate does not hold: the action is live and says nothing', () => {
+    mount({ done: true });
+    const button = archive();
+    expect(button).not.toBeDisabled();
+    expect(button).not.toHaveAttribute('aria-describedby');
+    expect(button.parentElement).not.toHaveAttribute('data-disabled-reason');
+    expect(screen.queryByText(REASON_EN)).toBeNull();
+  });
+
+  it('control — a button greyed out only while its own action runs gives no "not available" reason', async () => {
+    let finish: (v: unknown) => void = () => {};
+    executeSpy.mockReturnValueOnce(new Promise((resolve) => { finish = resolve; }));
+    const SLOW = { name: 'slow', type: 'script', label: 'Slow', locations: ['record_section'] };
+    mount({}, [SLOW]);
+    fireEvent.click(screen.getByTestId('declared-action-slow'));
+    const slow = screen.getByTestId('declared-action-slow');
+    expect(slow).toBeDisabled();
+    expect(slow).not.toHaveAttribute('aria-describedby');
+    expect(screen.queryByText(REASON_EN)).toBeNull();
+    await act(async () => { finish({ success: true }); });
+    expect(screen.getByTestId('declared-action-slow')).not.toBeDisabled();
+  });
+
+  it('the reason comes from the language pack — zh', async () => {
+    mount({ done: false }, [ARCHIVE], (node) => (
+      <I18nProvider config={{ defaultLanguage: 'zh', detectBrowserLanguage: false }} persistLanguage={false}>
+        {node}
+      </I18nProvider>
+    ));
+    const reason = await screen.findByText(REASON_ZH);
+    expect(describedBy(archive())).toBe(reason);
+    expect(screen.queryByText(REASON_EN)).toBeNull();
+  });
+
+  it('the reason comes from the language pack — en', async () => {
+    mount({ done: false }, [ARCHIVE], (node) => (
+      <I18nProvider config={{ defaultLanguage: 'en', detectBrowserLanguage: false }} persistLanguage={false}>
+        {node}
+      </I18nProvider>
+    ));
+    const reason = await screen.findByText(REASON_EN);
+    expect(describedBy(archive())).toBe(reason);
+  });
+});