@@ -0,0 +1,12 @@
+---
+'@object-ui/app-shell': patch
+---
+
+fix(app-shell): a read-only flow node inspector says why its controls are disabled, on hover, on keyboard focus and to assistive tech
+
+Clause-②: yes (widening)
+Metadata-protocol: none
+
+On a read-only package, Studio's flow node inspector disabled every control (ID, Label, Node Type, the config fields, Remove node) and gave no reason anywhere: no tooltip, no accessible description, and Tab skipped the whole panel. The inspector body now carries the treatment Studio's field rail and validation-rule editor carry: it is a tab stop described by the reason, and hovering any disabled control in it shows the reason in a tooltip.
+
+The reason is the host's to give, because the inspector is shared by hosts whose read-only causes differ. `MetadataInspectorProps` gains an optional `readOnlyReason?: string`; an inspector that honours it draws the reason while `readOnly` is true. Studio's Automations pillar passes the read-only package sentence. A host that passes nothing renders exactly as before.
@@ -66,6 +66,15 @@ export interface MetadataInspectorProps {
   onBlockingIssuesChange?: (count: number) => void;
   /** Whether the host is in edit mode. False → disable inputs. */
   readOnly: boolean;
+  /**
+   * Why the inspector is read-only, as the sentence to show, when the host
+   * knows it. The cause is the host's (a read-only package, view mode, a
+   * walled item), so the host says it; an inspector that honours it explains
+   * its disabled controls on hover, on keyboard focus and as an accessible
+   * description. Omitted, the inspector draws no reason. Ignored while
+   * `readOnly` is false.
+   */
+  readOnlyReason?: string;
   /** Active UI locale for i18n. */
   locale: SupportedLocale;
 }
 
@@ -0,0 +1,146 @@
+// Copyright (c) 2026 ObjectStack. Licensed under the Apache-2.0 license.
+
+/**
+ * objectstack#28985 — a read-only flow node inspector says why its controls are
+ * disabled, on hover, on keyboard focus and to assistive tech, when its host
+ * hands it the reason (`readOnlyReason`).
+ *
+ * Measured on the card: on a read-only package every control of the node
+ * inspector (ID, Label, Node Type, the config fields, Remove node) was disabled
+ * with no `title`, no `aria-describedby` and no tab stop, so nothing said why.
+ * The inspector body now carries the treatment Studio's field rail and
+ * validation-rule editor carry: a tab stop described by an `sr-only` copy of
+ * the reason, and the trigger of a tooltip that shows it.
+ *
+ * The reason is the host's: the inspector is shared by hosts whose read-only
+ * causes differ, so a host that passes none gets the panel it always had.
+ * Studio's Automations pillar passing the package's reason is pinned in
+ * `StudioDesignSurface.automationsReadOnly-11124.test.tsx`.
+ */
+
+import '@testing-library/jest-dom/vitest';
+import * as React from 'react';
+import { describe, it, expect, vi, afterEach } from 'vitest';
+import { render, screen, cleanup } from '@testing-library/react';
+import userEvent from '@testing-library/user-event';
+
+vi.mock('../previews/useFlowNodePalette', () => ({
+  useActionConfigSchemas: () => ({}),
+  useFlowNodePalette: () => [],
+}));
+vi.mock('../previews/useObjectFields', () => ({
+  useObjectFields: () => ({ fields: [], loading: false, error: null }),
+}));
+
+import { FlowNodeInspector } from './FlowNodeInspector';
+import { t } from '../i18n';
+
+afterEach(cleanup);
+
+vi.stubGlobal(
+  'fetch',
+  vi.fn(async () => new Response('not found', { status: 404 })),
+);
+
+const REASON = 'Read-only package: switch to or create a writable package to edit.';
+
+const DRAFT = {
+  name: 'f',
+  label: 'F',
+  nodes: [
+    { id: 'start', type: 'start', label: 'Start' },
+    {
+      id: 'set_status',
+      type: 'update_record',
+      label: 'Set status',
+      config: { objectName: 'task', fields: { status: 'done' } },
+    },
+    { id: 'end', type: 'end', label: 'End' },
+  ],
+  edges: [
+    { id: 'e1', source: 'start', target: 'set_status' },
+    { id: 'e2', source: 'set_status', target: 'end' },
+  ],
+};
+
+function mount({ readOnly, readOnlyReason }: { readOnly: boolean; readOnlyReason?: string }) {
+  return render(
+    <FlowNodeInspector
+      type="flow"
+      name="f"
+      draft={DRAFT}
+      selection={{ kind: 'node', id: 'set_status', label: 'Set status' }}
+      onPatch={() => {}}
+      onClearSelection={() => {}}
+      readOnly={readOnly}
+      readOnlyReason={readOnlyReason}
+      locale="en-US"
+    />,
+  );
+}
+
+/** The panel's form controls, Remove node included — the ones the reason is about. */
+const controls = (root: HTMLElement) => [
+  ...root.querySelectorAll<HTMLElement>('input, select, textarea, button[role="combobox"]'),
+  screen.getByRole('button', { name: t('engine.inspector.flowNode.remove', 'en-US') }),
+];
+
+describe('Flow node inspector, read-only with a reason from its host (objectstack#28985)', () => {
+  it('the panel is a tab stop described by the reason, named by the node, and holds the disabled controls', () => {
+    const { container } = mount({ readOnly: true, readOnlyReason: REASON });
+    const body = container.querySelector('[data-disabled-reason]') as HTMLElement;
+    expect(body).not.toBeNull();
+    expect(body).toHaveAttribute('tabindex', '0');
+    expect(body).toHaveAccessibleDescription(REASON);
+    expect(body).toHaveAccessibleName('Set status');
+
+    const all = controls(body);
+    // ID, Label, Node Type and Remove node alone are four; a vacuous pass is not one.
+    expect(all.length).toBeGreaterThanOrEqual(4);
+    for (const el of all) {
+      expect(body).toContainElement(el);
+      expect(el).toBeDisabled();
+    }
+  });
+
+  it('hovering the disabled "Remove node" opens a tooltip with the reason', async () => {
+    const user = userEvent.setup();
+    mount({ readOnly: true, readOnlyReason: REASON });
+    const remove = screen.getByRole('button', { name: t('engine.inspector.flowNode.remove', 'en-US') });
+    expect(remove).toBeDisabled();
+    await user.hover(remove);
+    expect(await screen.findByRole('tooltip')).toHaveTextContent(REASON);
+  });
+
+  it('a keyboard user reaches the reason: Tab lands on the described panel, which opens the tooltip', async () => {
+    const user = userEvent.setup();
+    const { container } = mount({ readOnly: true, readOnlyReason: REASON });
+    const body = container.querySelector('[data-disabled-reason]') as HTMLElement;
+    await user.tab();
+    expect(body).toHaveFocus();
+    expect(await screen.findByRole('tooltip')).toHaveTextContent(REASON);
+  });
+});
+
+describe('Flow node inspector — the controls (objectstack#28985)', () => {
+  it('a host that passes no reason gets the panel it always had: no tab stop, no description', () => {
+    const { container } = mount({ readOnly: true });
+    expect(container.querySelector('[data-disabled-reason]')).toBeNull();
+    expect(container.querySelector('[tabindex="0"]')).toBeNull();
+    for (const el of controls(container)) expect(el).toBeDisabled();
+  });
+
+  it('a blank reason counts as none', () => {
+    const { container } = mount({ readOnly: true, readOnlyReason: '  ' });
+    expect(container.querySelector('[data-disabled-reason]')).toBeNull();
+  });
+
+  it('a writable inspector ignores a reason: the controls are live and nothing is described', () => {
+    const { container } = mount({ readOnly: false, readOnlyReason: REASON });
+    expect(container.querySelector('[data-disabled-reason]')).toBeNull();
+    expect(screen.queryByText(REASON)).toBeNull();
+    const all = controls(container);
+    expect(all.length).toBeGreaterThanOrEqual(4);
+    for (const el of all) expect(el).toBeEnabled();
+  });
+});
@@ -22,7 +22,7 @@
 import * as React from 'react';
 import { Plus } from 'lucide-react';
 import { resolveFlowTriggerKind } from '@objectstack/spec/automation';
-import { Input, Label } from '@object-ui/components';
+import { Input, Label, Tooltip, TooltipContent, TooltipProvider, TooltipTrigger } from '@object-ui/components';
 import type { MetadataInspectorProps } from '../inspector-registry.js';
 import { t, tFormat } from '../i18n.js';
 import {
@@ -284,7 +284,17 @@ function FlowNodeIdField({
   );
 }
 
-export function FlowNodeInspector({ selection, draft, onPatch, onClearSelection, onSelectionChange, locale, readOnly }: MetadataInspectorProps) {
+export function FlowNodeInspector({
+  selection,
+  draft,
+  onPatch,
+  onClearSelection,
+  onSelectionChange,
+  locale,
+  readOnly,
+  readOnlyReason,
+}: MetadataInspectorProps) {
+  const readOnlyReasonId = React.useId();
   // Resolve the selection to a node + how to write it back — a top-level draft
   // node, or a node nested inside a container region (#2670). Every edit goes
   // through loc.write, so the inspector never branches on where the node lives.
@@ -694,7 +704,7 @@ export function FlowNodeInspector({ selection, draft, onPatch, onClearSelection,
   // read-only — those live on the container's Advanced JSON).
   const nested = !!loc?.nested;
 
-  return (
+  const shell = (
     <InspectorShell
       kindLabel={t('engine.inspector.flowNode.kind', locale)}
       title={node.label || node.id}
@@ -884,4 +894,35 @@ export function FlowNodeInspector({ selection, draft, onPatch, onClearSelection,
       )}
     </InspectorShell>
   );
+
+  const reason = readOnly ? readOnlyReason?.trim() : undefined;
+  if (!reason) return shell;
+  // Read-only with a reason from the host: every control above is disabled for
+  // that one reason, and a disabled control takes neither hover nor focus. The
+  // inspector body is the tooltip trigger, so hovering any of them shows it, and
+  // a tab stop described by an `sr-only` copy, so a keyboard or screen-reader
+  // user reaches it too. One trigger for the panel, not one per control: the
+  // reason is the same for all of them. Same treatment as Studio's field rail
+  // and validation-rule editor.
+  return (
+    <TooltipProvider delayDuration={200}>
+      <Tooltip>
+        <TooltipTrigger asChild>
+          <div
+            role="group"
+            aria-label={flowNodeDisplayName(node, locale)}
+            tabIndex={0}
+            aria-describedby={readOnlyReasonId}
+            data-disabled-reason=""
+            data-testid="flow-node-readonly-reason"
+            className="flex h-full min-h-0 flex-col focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-inset focus-visible:ring-ring"
+          >
+            {shell}
+            <span id={readOnlyReasonId} className="sr-only">{reason}</span>
+          </div>
+        </TooltipTrigger>
+        <TooltipContent side="left" align="start">{reason}</TooltipContent>
+      </Tooltip>
+    </TooltipProvider>
+  );
 }
@@ -213,6 +213,12 @@ describe('Automations pillar on a read-only package (objectui#11124)', () => {
     const label = await inspectStartNode();
     expect(label).toBeDisabled();
     expect(within(screen.getByRole('complementary')).getByLabelText('ID')).toBeDisabled();
+    // objectstack#28985 — the pillar hands the inspector the package's reason,
+    // and the inspector body is the tab stop described by it.
+    const body = screen.getByTestId('flow-node-readonly-reason');
+    expect(body).toContainElement(label);
+    expect(body).toHaveAttribute('tabindex', '0');
+    expect(body).toHaveAccessibleDescription(READ_ONLY_REASON);
   });
 
   it('offers no canvas edit: no "add connected node" or "insert node" handle', async () => {
@@ -256,6 +262,7 @@ describe('Automations pillar on a writable package — the control (objectui#111
 
     const label = await inspectStartNode();
     expect(label).toBeEnabled();
+    expect(screen.queryByTestId('flow-node-readonly-reason')).toBeNull();
 
     fireEvent.click(toggle);
     await waitFor(() => expect(server.saves).toHaveLength(1), { timeout: 8000 });
 
@@ -10721,6 +10721,7 @@ export function AutomationsPillar({
           // the Data pillar threads it (objectui#2259). objectstack#28570 —
           // a customized flow's editors are open.
           readOnly: editLocked,
+          readOnlyReason: editLocked ? t('engine.studio.pkg.readonlyHint', locale) : undefined,
           locale,
         })}
       </div>