diff --git a/frontend-modern/browser-verification.json b/frontend-modern/browser-verification.json
index e489265f1..144c4d492 100644
--- a/frontend-modern/browser-verification.json
+++ b/frontend-modern/browser-verification.json
@@ -1,19 +1,21 @@
 {
   "version": 1,
-  "base_sha": "6c5af82b522b437db91ab077c79cee3d59833a34",
-  "verified_at": "2026-09-02T08:58:36Z",
+  "base_sha": "fc0adf7073d99447e8042d5053d331d323b8a372",
+  "verified_at": "2026-09-02T10:25:49Z",
   "result": "passed",
   "changed_paths": [
-    "frontend-modern/src/components/shared/SearchInputEnhancements.tsx",
-    "frontend-modern/src/components/shared/searchInputEnhancementsModel.ts",
-    "frontend-modern/src/components/shared/useSearchInputEnhancements.ts"
+    "frontend-modern/src/components/AI/Chat/MentionAutocomplete.tsx",
+    "frontend-modern/src/components/AI/Chat/SlashCommandAutocomplete.tsx",
+    "frontend-modern/src/components/AI/Chat/index.tsx"
   ],
   "content_sha256": {
-    "frontend-modern/src/components/shared/SearchInputEnhancements.tsx": "9df1147f092b523655a3503cfe27bbac88fb0572bd3ccb219895d2ffa2f762a7",
-    "frontend-modern/src/components/shared/searchInputEnhancementsModel.ts": "b56c756423156cdce3bf1c7f867aa3b6c2751419f070c2d8e5edad91d3c23dec",
-    "frontend-modern/src/components/shared/useSearchInputEnhancements.ts": "15d750671b420d6566749eac60bc4cb6c87db36037e90a4117cebc60c1635dad"
+    "frontend-modern/src/components/AI/Chat/MentionAutocomplete.tsx": "fde53ef7a82b0ff854a759087a0fc7dfaafd89e7e8933b68335598100adb8955",
+    "frontend-modern/src/components/AI/Chat/SlashCommandAutocomplete.tsx": "2073d3c388590dad8c291dfc7a0d8a3132e4c18a50014918c0a2a90510401c28",
+    "frontend-modern/src/components/AI/Chat/index.tsx": "010def979665a1db9be3dfa3537ebfa8714125fb7ce9212102fb49465d5d22db"
   },
-  "routes": ["/standalone/machines"],
+  "routes": [
+    "/"
+  ],
   "viewports": [
     {
       "width": 1280,
@@ -25,20 +27,20 @@
     }
   ],
   "states": [
-    "Empty recent-search menu with explanatory copy at desktop width",
-    "Populated three-entry menu with keyboard focus on its first, removal, and clear actions at desktop width",
-    "Selected search restored from persisted history after reload at desktop and narrow widths",
-    "Populated menu over the filtered no-match Machines state at narrow width",
-    "Menu closed after outside pointer dismissal and Escape at desktop and narrow widths"
+    "Closed named Assistant composer with no listbox relationship in desktop docked and narrow overlay layouts",
+    "Open slash-command list with the selected active option and the wrapped final option scrolled into view",
+    "Filtered slash-command empty result with listbox ownership and no stale active descendant",
+    "Slash command selected with Tab and popup closed with composer focus restored",
+    "Open resource mention list with the selected active option and the wrapped final option scrolled into view",
+    "Mention selected by pointer and popup closed with composer focus retained",
+    "Autocomplete closed by Escape and outside pointer dismissal without stale relationships"
   ],
   "interactions": [
-    "opened the history menu by pointer, ArrowDown, and ArrowUp and verified menu semantics, aria-controls, and expanded state",
-    "moved focus through entry, item-specific removal, and clear actions with ArrowDown, ArrowUp, Home, and End",
-    "selected a history entry and verified the menu closed while the search field received focus and the selected value",
-    "removed the focused first history entry and verified focus moved to the next item-specific removal action",
-    "cleared all history and verified the menu closed, storage emptied, and search focus returned",
-    "committed a search, reloaded the route, and verified the persisted entry remained available",
-    "dismissed the menu by outside pointer action and Escape and verified Escape returned focus to the toggle",
-    "inspected desktop and narrow pixels for placement, clipping, stacking, responsive width, and visible keyboard focus"
+    "opened Pulse Assistant from the current-view launcher and verified the composer accessible name and focus",
+    "opened slash commands and mentions by typing, then checked aria-controls, aria-activedescendant, aria-selected, and option tab exclusion",
+    "moved active options with ArrowDown and wrapped with ArrowUp, hovered options by pointer, and verified active options remained visible",
+    "selected /new with Tab and selected a mention by pointer while verifying focus remained in the composer",
+    "exercised Escape and outside pointer dismissal, including the no-match slash-command state",
+    "inspected desktop and narrow pixels for popup placement, viewport containment, clipping, stacking, scrolling, and visible composer focus"
   ]
 }
diff --git a/frontend-modern/src/components/AI/Chat/MentionAutocomplete.tsx b/frontend-modern/src/components/AI/Chat/MentionAutocomplete.tsx
index 8421f5039..afff643d5 100644
--- a/frontend-modern/src/components/AI/Chat/MentionAutocomplete.tsx
+++ b/frontend-modern/src/components/AI/Chat/MentionAutocomplete.tsx
@@ -17,8 +17,12 @@ interface MentionAutocompleteProps {
   onSelect: (resource: MentionResource) => void;
   onClose: () => void;
   visible: boolean;
+  onActiveDescendantChange?: (id: string | undefined) => void;
 }
 
+export const ASSISTANT_MENTION_LISTBOX_ID = 'assistant-mention-listbox';
+export const getAssistantMentionOptionId = (index: number) => `assistant-mention-option-${index}`;
+
 export function MentionAutocomplete(props: MentionAutocompleteProps) {
   const [selectedIndex, setSelectedIndex] = createSignal(0);
 
@@ -36,6 +40,27 @@ export function MentionAutocomplete(props: MentionAutocompleteProps) {
     setSelectedIndex(0);
   });
 
+  createEffect(() => {
+    const total = filteredResources().length;
+    setSelectedIndex((index) => (total > 0 ? Math.min(index, total - 1) : 0));
+  });
+
+  createEffect(() => {
+    const resources = filteredResources();
+    const activeId =
+      props.visible && resources.length > 0
+        ? getAssistantMentionOptionId(selectedIndex())
+        : undefined;
+    props.onActiveDescendantChange?.(activeId);
+    if (activeId) {
+      queueMicrotask(() => {
+        document.getElementById(activeId)?.scrollIntoView?.({ block: 'nearest' });
+      });
+    }
+  });
+
+  onCleanup(() => props.onActiveDescendantChange?.(undefined));
+
   const consumeMentionKey = (e: KeyboardEvent) => {
     e.preventDefault();
     e.stopPropagation();
@@ -159,7 +184,7 @@ export function MentionAutocomplete(props: MentionAutocompleteProps) {
   return (
     <Show when={props.visible && filteredResources().length > 0}>
       <div
-        class="absolute z-50 bg-surface border border-border rounded-md shadow-sm overflow-hidden min-w-[280px] max-w-[400px]"
+        class="absolute z-50 w-[calc(100vw-36px)] min-w-[280px] max-w-[400px] overflow-hidden rounded-md border border-border bg-surface shadow-sm"
         style={{
           bottom: `${props.position.top}px`,
           left: `${props.position.left}px`,
@@ -168,12 +193,19 @@ export function MentionAutocomplete(props: MentionAutocompleteProps) {
         onClick={(event) => event.stopPropagation()}
       >
         <div class="px-3 py-2 border-b border-border text-xs font-medium text-muted">Resources</div>
-        <div class="max-h-[240px] overflow-y-auto" role="listbox" aria-label="Assistant resources">
+        <div
+          id={ASSISTANT_MENTION_LISTBOX_ID}
+          class="max-h-[240px] overflow-y-auto"
+          role="listbox"
+          aria-label="Assistant resources"
+        >
           <For each={filteredResources()}>
             {(resource, index) => (
               <button
                 type="button"
+                id={getAssistantMentionOptionId(index())}
                 role="option"
+                tabIndex={-1}
                 aria-selected={index() === selectedIndex()}
                 aria-label={`Mention ${resource.label}: ${resource.type}${
                   resource.node ? ` on ${resource.node}` : ''
@@ -181,6 +213,7 @@ export function MentionAutocomplete(props: MentionAutocompleteProps) {
                 class={`w-full px-3 py-2 flex items-center gap-3 text-left hover:bg-surface-hover transition-colors ${
                   index() === selectedIndex() ? 'bg-surface-hover' : ''
                 }`}
+                onPointerDown={(event) => event.preventDefault()}
                 onClick={(event) => {
                   event.stopPropagation();
                   props.onSelect(resource);
diff --git a/frontend-modern/src/components/AI/Chat/SlashCommandAutocomplete.tsx b/frontend-modern/src/components/AI/Chat/SlashCommandAutocomplete.tsx
index 29fddef07..2a929afbd 100644
--- a/frontend-modern/src/components/AI/Chat/SlashCommandAutocomplete.tsx
+++ b/frontend-modern/src/components/AI/Chat/SlashCommandAutocomplete.tsx
@@ -27,8 +27,13 @@ interface SlashCommandAutocompleteProps {
   position: { top: number; left: number };
   onClose: () => void;
   onSelect: (command: AssistantSlashCommand) => void;
+  onActiveDescendantChange?: (id: string | undefined) => void;
 }
 
+export const ASSISTANT_SLASH_COMMAND_LISTBOX_ID = 'assistant-slash-command-listbox';
+export const getAssistantSlashCommandOptionId = (index: number) =>
+  `assistant-slash-command-option-${index}`;
+
 export const AssistantSlashCommandIcon = (props: { action: AssistantSlashCommandAction }) => {
   switch (props.action) {
     case 'help':
@@ -82,6 +87,27 @@ export function SlashCommandAutocomplete(props: SlashCommandAutocompleteProps) {
     setSelectedIndex(0);
   });
 
+  createEffect(() => {
+    const total = commands().length;
+    setSelectedIndex((index) => (total > 0 ? Math.min(index, total - 1) : 0));
+  });
+
+  createEffect(() => {
+    const options = commands();
+    const activeId =
+      props.visible && options.length > 0
+        ? getAssistantSlashCommandOptionId(selectedIndex())
+        : undefined;
+    props.onActiveDescendantChange?.(activeId);
+    if (activeId) {
+      queueMicrotask(() => {
+        document.getElementById(activeId)?.scrollIntoView?.({ block: 'nearest' });
+      });
+    }
+  });
+
+  onCleanup(() => props.onActiveDescendantChange?.(undefined));
+
   const selectCommand = (command?: AssistantSlashCommand) => {
     if (!command) return;
     props.onSelect(command);
@@ -140,7 +166,7 @@ export function SlashCommandAutocomplete(props: SlashCommandAutocompleteProps) {
   return (
     <Show when={props.visible}>
       <div
-        class="absolute z-50 min-w-[280px] max-w-[420px] overflow-hidden rounded-md border border-border bg-surface shadow-sm"
+        class="absolute z-50 w-[calc(100vw-36px)] min-w-[280px] max-w-[420px] overflow-hidden rounded-md border border-border bg-surface shadow-sm"
         style={{
           bottom: `${props.position.top}px`,
           left: `${props.position.left}px`,
@@ -149,7 +175,12 @@ export function SlashCommandAutocomplete(props: SlashCommandAutocompleteProps) {
         onClick={(event) => event.stopPropagation()}
       >
         <div class="border-b border-border px-3 py-2 text-xs font-medium text-muted">Commands</div>
-        <div class="max-h-[260px] overflow-y-auto" role="listbox" aria-label="Assistant commands">
+        <div
+          id={ASSISTANT_SLASH_COMMAND_LISTBOX_ID}
+          class="max-h-[260px] overflow-y-auto"
+          role="listbox"
+          aria-label="Assistant commands"
+        >
           <Show
             when={commands().length > 0}
             fallback={
@@ -175,7 +206,9 @@ export function SlashCommandAutocomplete(props: SlashCommandAutocompleteProps) {
                       return (
                         <button
                           type="button"
+                          id={getAssistantSlashCommandOptionId(item.index)}
                           role="option"
+                          tabIndex={-1}
                           aria-selected={item.index === selectedIndex()}
                           aria-disabled={command.disabled ? 'true' : undefined}
                           aria-label={`${
@@ -188,6 +221,7 @@ export function SlashCommandAutocomplete(props: SlashCommandAutocompleteProps) {
                               ? 'cursor-not-allowed opacity-60'
                               : 'hover:bg-surface-hover'
                           } ${item.index === selectedIndex() ? 'bg-surface-hover' : ''}`}
+                          onPointerDown={(event) => event.preventDefault()}
                           onClick={(event) => {
                             event.stopPropagation();
                             selectCommand(command);
diff --git a/frontend-modern/src/components/AI/Chat/__tests__/AIChat.test.tsx b/frontend-modern/src/components/AI/Chat/__tests__/AIChat.test.tsx
index f44c9bda1..14db322d6 100644
--- a/frontend-modern/src/components/AI/Chat/__tests__/AIChat.test.tsx
+++ b/frontend-modern/src/components/AI/Chat/__tests__/AIChat.test.tsx
@@ -2179,7 +2179,12 @@ describe('AIChat', () => {
       fireEvent.input(textarea, { target: { value: '/mo' } });
 
       expect(screen.getByRole('listbox', { name: 'Assistant commands' })).toBeInTheDocument();
-      expect(screen.getByRole('option', { name: /Run \/models/ })).toBeInTheDocument();
+      const selectedOption = screen.getByRole('option', { name: /Run \/models/ });
+      expect(selectedOption).toBeInTheDocument();
+      expect(textarea).toHaveAccessibleName('Message Pulse Assistant');
+      expect(textarea).toHaveAttribute('aria-autocomplete', 'list');
+      expect(textarea).toHaveAttribute('aria-controls', 'assistant-slash-command-listbox');
+      expect(textarea).toHaveAttribute('aria-activedescendant', selectedOption.id);
 
       fireEvent.keyDown(textarea, { key: 'Enter' });
 
@@ -2187,6 +2192,8 @@ describe('AIChat', () => {
         expect(screen.getByTestId('model-selector')).toHaveAttribute('data-open-request', '1');
       });
       expect(screen.queryByRole('listbox', { name: 'Assistant commands' })).not.toBeInTheDocument();
+      expect(textarea).not.toHaveAttribute('aria-controls');
+      expect(textarea).not.toHaveAttribute('aria-activedescendant');
       expect(mockChat.sendMessage).not.toHaveBeenCalled();
     });
 
diff --git a/frontend-modern/src/components/AI/Chat/__tests__/MentionAutocomplete.test.tsx b/frontend-modern/src/components/AI/Chat/__tests__/MentionAutocomplete.test.tsx
index 954095862..e691a0e5f 100644
--- a/frontend-modern/src/components/AI/Chat/__tests__/MentionAutocomplete.test.tsx
+++ b/frontend-modern/src/components/AI/Chat/__tests__/MentionAutocomplete.test.tsx
@@ -179,11 +179,14 @@ describe('MentionAutocomplete', () => {
 
       const listbox = screen.getByRole('listbox', { name: 'Assistant resources' });
       expect(listbox).toBeInTheDocument();
+      expect(listbox.parentElement).toHaveClass('w-[calc(100vw-36px)]');
 
       const firstOption = screen.getByRole('option', {
         name: 'Mention web-server: vm on pve1, running',
       });
       expect(firstOption).toHaveAttribute('aria-selected', 'true');
+      expect(firstOption).toHaveAttribute('id', 'assistant-mention-option-0');
+      expect(firstOption).toHaveAttribute('tabindex', '-1');
 
       fireEvent.keyDown(document, { key: 'ArrowDown' });
 
@@ -194,6 +197,30 @@ describe('MentionAutocomplete', () => {
         }),
       ).toHaveAttribute('aria-selected', 'true');
     });
+
+    it('reports the active descendant and keeps it visible while focus remains in the composer', async () => {
+      const onActiveDescendantChange = vi.fn();
+      renderAutocomplete({ onActiveDescendantChange });
+
+      expect(screen.getByRole('listbox', { name: 'Assistant resources' })).toHaveAttribute(
+        'id',
+        'assistant-mention-listbox',
+      );
+      expect(onActiveDescendantChange).toHaveBeenLastCalledWith('assistant-mention-option-0');
+
+      const secondOption = screen.getByRole('option', {
+        name: 'Mention db-container: system-container on pve2, running',
+      });
+      const scrollIntoView = vi.fn();
+      Object.defineProperty(secondOption, 'scrollIntoView', {
+        configurable: true,
+        value: scrollIntoView,
+      });
+      fireEvent.keyDown(document, { key: 'ArrowDown' });
+
+      expect(onActiveDescendantChange).toHaveBeenLastCalledWith('assistant-mention-option-1');
+      await vi.waitFor(() => expect(scrollIntoView).toHaveBeenCalledWith({ block: 'nearest' }));
+    });
   });
 
   describe('click interaction', () => {
@@ -201,7 +228,12 @@ describe('MentionAutocomplete', () => {
       const onSelect = vi.fn();
       renderAutocomplete({ onSelect });
 
-      fireEvent.click(screen.getByText('web-server'));
+      const option = screen.getByText('web-server').closest('button')!;
+      const pointerDown = new Event('pointerdown', { bubbles: true, cancelable: true });
+      option.dispatchEvent(pointerDown);
+      expect(pointerDown.defaultPrevented).toBe(true);
+
+      fireEvent.click(option);
       expect(onSelect).toHaveBeenCalledOnce();
       expect(onSelect).toHaveBeenCalledWith(defaultResources[0]);
     });
diff --git a/frontend-modern/src/components/AI/Chat/__tests__/SlashCommandAutocomplete.test.tsx b/frontend-modern/src/components/AI/Chat/__tests__/SlashCommandAutocomplete.test.tsx
index 862501cff..4d9ed28dc 100644
--- a/frontend-modern/src/components/AI/Chat/__tests__/SlashCommandAutocomplete.test.tsx
+++ b/frontend-modern/src/components/AI/Chat/__tests__/SlashCommandAutocomplete.test.tsx
@@ -1,11 +1,64 @@
 import { afterEach, describe, expect, it, vi } from 'vitest';
-import { cleanup, render, screen } from '@solidjs/testing-library';
+import { cleanup, fireEvent, render, screen } from '@solidjs/testing-library';
 import { filterAssistantSlashCommands } from '../assistantSlashCommands';
 import { SlashCommandAutocomplete } from '../SlashCommandAutocomplete';
 
 afterEach(cleanup);
 
 describe('SlashCommandAutocomplete', () => {
+  it('prevents pointer selection from taking focus from the composer', () => {
+    const onSelect = vi.fn();
+    render(() => (
+      <SlashCommandAutocomplete
+        query="new"
+        visible
+        position={{ top: 58, left: 0 }}
+        onClose={vi.fn()}
+        onSelect={onSelect}
+      />
+    ));
+
+    const option = screen.getByRole('option', { name: /Run \/new/ });
+    const pointerDown = new Event('pointerdown', { bubbles: true, cancelable: true });
+    option.dispatchEvent(pointerDown);
+    expect(pointerDown.defaultPrevented).toBe(true);
+
+    fireEvent.click(option);
+    expect(onSelect).toHaveBeenCalledWith(expect.objectContaining({ action: 'new' }));
+  });
+
+  it('reports the active option, keeps it visible, and excludes options from the tab order', async () => {
+    const onActiveDescendantChange = vi.fn();
+    render(() => (
+      <SlashCommandAutocomplete
+        query=""
+        visible
+        position={{ top: 58, left: 0 }}
+        onClose={vi.fn()}
+        onSelect={vi.fn()}
+        onActiveDescendantChange={onActiveDescendantChange}
+      />
+    ));
+
+    const listbox = screen.getByRole('listbox', { name: 'Assistant commands' });
+    expect(listbox).toHaveAttribute('id', 'assistant-slash-command-listbox');
+    expect(listbox.parentElement).toHaveClass('w-[calc(100vw-36px)]');
+    const options = screen.getAllByRole('option');
+    expect(options[0]).toHaveAttribute('id', 'assistant-slash-command-option-0');
+    expect(options[0]).toHaveAttribute('tabindex', '-1');
+    expect(onActiveDescendantChange).toHaveBeenLastCalledWith('assistant-slash-command-option-0');
+
+    const scrollIntoView = vi.fn();
+    Object.defineProperty(options[1], 'scrollIntoView', {
+      configurable: true,
+      value: scrollIntoView,
+    });
+    fireEvent.keyDown(document, { key: 'ArrowDown' });
+
+    expect(onActiveDescendantChange).toHaveBeenLastCalledWith('assistant-slash-command-option-1');
+    await vi.waitFor(() => expect(scrollIntoView).toHaveBeenCalledWith({ block: 'nearest' }));
+  });
+
   it('consumes local command navigation keys before later document handlers see them', () => {
     const onClose = vi.fn();
     const onSelect = vi.fn();
diff --git a/frontend-modern/src/components/AI/Chat/index.tsx b/frontend-modern/src/components/AI/Chat/index.tsx
index 5da9af3ee..291cc810f 100644
--- a/frontend-modern/src/components/AI/Chat/index.tsx
+++ b/frontend-modern/src/components/AI/Chat/index.tsx
@@ -168,8 +168,15 @@ import {
 import { ChatMessages } from './ChatMessages';
 import { AssistantCommandHelpDialog } from './AssistantCommandHelpDialog';
 import { ModelSelector } from './ModelSelector';
-import { MentionAutocomplete, type MentionResource } from './MentionAutocomplete';
-import { SlashCommandAutocomplete } from './SlashCommandAutocomplete';
+import {
+  ASSISTANT_MENTION_LISTBOX_ID,
+  MentionAutocomplete,
+  type MentionResource,
+} from './MentionAutocomplete';
+import {
+  ASSISTANT_SLASH_COMMAND_LISTBOX_ID,
+  SlashCommandAutocomplete,
+} from './SlashCommandAutocomplete';
 import { getAssistantActiveTurnStatus } from './activeTurnStatus';
 import { selectQuickResumeSessions } from './recentSessionsModel';
 import {
@@ -761,6 +768,8 @@ export const AIChat: Component<AIChatProps> = (props) => {
   const [pastedBlocks, setPastedBlocks] = createSignal<PastedTextBlock[]>([]);
   const [slashCommandActive, setSlashCommandActive] = createSignal(false);
   const [slashCommandQuery, setSlashCommandQuery] = createSignal('');
+  const [mentionActiveDescendant, setMentionActiveDescendant] = createSignal<string>();
+  const [slashCommandActiveDescendant, setSlashCommandActiveDescendant] = createSignal<string>();
   let textareaRef: HTMLTextAreaElement | undefined;
   let transcriptFallbackTextareaRef: HTMLTextAreaElement | undefined;
   let interruptArmTimeout: ReturnType<typeof setTimeout> | undefined;
@@ -5353,6 +5362,22 @@ export const AIChat: Component<AIChatProps> = (props) => {
                   onKeyDown={handleKeyDown}
                   onPaste={handleComposerPaste}
                   placeholder={AI_CHAT_INPUT_PLACEHOLDER}
+                  aria-label="Message Pulse Assistant"
+                  aria-autocomplete="list"
+                  aria-controls={
+                    mentionActive() && mentionActiveDescendant()
+                      ? ASSISTANT_MENTION_LISTBOX_ID
+                      : slashCommandActive()
+                        ? ASSISTANT_SLASH_COMMAND_LISTBOX_ID
+                        : undefined
+                  }
+                  aria-activedescendant={
+                    mentionActive()
+                      ? mentionActiveDescendant()
+                      : slashCommandActive()
+                        ? slashCommandActiveDescendant()
+                        : undefined
+                  }
                   rows={1}
                   class="max-h-40 min-h-[54px] flex-1 resize-none bg-transparent px-3.5 py-3.5 pr-14 text-sm leading-5 text-base-content placeholder-slate-400 focus:outline-none"
                 />
@@ -5364,6 +5389,7 @@ export const AIChat: Component<AIChatProps> = (props) => {
                     onSelect={handleMentionSelect}
                     onClose={() => setMentionActive(false)}
                     visible={mentionActive()}
+                    onActiveDescendantChange={setMentionActiveDescendant}
                   />
                 </div>
                 <SlashCommandAutocomplete
@@ -5373,6 +5399,7 @@ export const AIChat: Component<AIChatProps> = (props) => {
                   onSelect={handleSlashCommandSelect}
                   onClose={() => closeSlashCommandAutocomplete({ clearTransientDraft: true })}
                   visible={slashCommandActive()}
+                  onActiveDescendantChange={setSlashCommandActiveDescendant}
                 />
                 <div class="absolute bottom-2 right-2 flex items-center gap-1.5">
                   <ActionIconButton