diff --git a/src/renderer/store/slices/teamSlice.ts b/src/renderer/store/slices/teamSlice.ts
index b9f359ac..f3ac7e96 100644
--- a/src/renderer/store/slices/teamSlice.ts
+++ b/src/renderer/store/slices/teamSlice.ts
@@ -89,6 +89,10 @@ import {
   pruneOptimisticMessages,
   upsertOptimisticTeamMessage,
 } from '../team/teamMessagesCache';
+import {
+  loadPersistedMessagesPanelMode,
+  savePersistedMessagesPanelMode,
+} from '../team/teamMessagesPanelModePersistence';
 import {
   clearAllPendingReplyRefreshWaits,
   clearPendingReplyRefreshWaits,
@@ -175,6 +179,10 @@ export type {
   TeamMessagesCacheEntry,
 } from '../team/teamMessagesCache';
 export { selectMemberMessagesForTeamMember, selectTeamMessages } from '../team/teamMessagesCache';
+export {
+  loadPersistedMessagesPanelMode,
+  savePersistedMessagesPanelMode,
+} from '../team/teamMessagesPanelModePersistence';
 export {
   getActiveTeamPendingReplyWaits,
   hasActiveTeamPendingReplyWait,
@@ -2200,33 +2208,6 @@ export interface TeamSlice {
 
 // --- Per-team launch params persistence ---
 const LAUNCH_PARAMS_PREFIX = 'team:launchParams:';
-const MESSAGES_PANEL_MODE_STORAGE_KEY = 'team:messagesPanelMode';
-const DEFAULT_MESSAGES_PANEL_MODE: TeamMessagesPanelMode = 'sidebar';
-const VALID_MESSAGES_PANEL_MODES: ReadonlySet<TeamMessagesPanelMode> = new Set([
-  'sidebar',
-  'inline',
-  'bottom-sheet',
-  'floating-composer',
-]);
-
-export function loadPersistedMessagesPanelMode(): TeamMessagesPanelMode {
-  try {
-    const persisted = localStorage.getItem(MESSAGES_PANEL_MODE_STORAGE_KEY);
-    return VALID_MESSAGES_PANEL_MODES.has(persisted as TeamMessagesPanelMode)
-      ? (persisted as TeamMessagesPanelMode)
-      : DEFAULT_MESSAGES_PANEL_MODE;
-  } catch {
-    return DEFAULT_MESSAGES_PANEL_MODE;
-  }
-}
-
-export function savePersistedMessagesPanelMode(mode: TeamMessagesPanelMode): void {
-  try {
-    localStorage.setItem(MESSAGES_PANEL_MODE_STORAGE_KEY, mode);
-  } catch {
-    // ignore - best-effort UI preference persistence
-  }
-}
 
 export function getCurrentProvisioningProgressForTeam(
   state: Pick<TeamSlice, 'currentProvisioningRunIdByTeam' | 'provisioningRuns'>,
diff --git a/src/renderer/store/team/teamMessagesPanelModePersistence.ts b/src/renderer/store/team/teamMessagesPanelModePersistence.ts
new file mode 100644
index 00000000..4a53086b
--- /dev/null
+++ b/src/renderer/store/team/teamMessagesPanelModePersistence.ts
@@ -0,0 +1,29 @@
+import type { TeamMessagesPanelMode } from '@renderer/types/teamMessagesPanelMode';
+
+const MESSAGES_PANEL_MODE_STORAGE_KEY = 'team:messagesPanelMode';
+const DEFAULT_MESSAGES_PANEL_MODE: TeamMessagesPanelMode = 'sidebar';
+const VALID_MESSAGES_PANEL_MODES: ReadonlySet<TeamMessagesPanelMode> = new Set([
+  'sidebar',
+  'inline',
+  'bottom-sheet',
+  'floating-composer',
+]);
+
+export function loadPersistedMessagesPanelMode(): TeamMessagesPanelMode {
+  try {
+    const persisted = localStorage.getItem(MESSAGES_PANEL_MODE_STORAGE_KEY);
+    return VALID_MESSAGES_PANEL_MODES.has(persisted as TeamMessagesPanelMode)
+      ? (persisted as TeamMessagesPanelMode)
+      : DEFAULT_MESSAGES_PANEL_MODE;
+  } catch {
+    return DEFAULT_MESSAGES_PANEL_MODE;
+  }
+}
+
+export function savePersistedMessagesPanelMode(mode: TeamMessagesPanelMode): void {
+  try {
+    localStorage.setItem(MESSAGES_PANEL_MODE_STORAGE_KEY, mode);
+  } catch {
+    // ignore - best-effort UI preference persistence
+  }
+}
diff --git a/test/renderer/store/teamMessagesPanelModePersistence.test.ts b/test/renderer/store/teamMessagesPanelModePersistence.test.ts
new file mode 100644
index 00000000..baea02fb
--- /dev/null
+++ b/test/renderer/store/teamMessagesPanelModePersistence.test.ts
@@ -0,0 +1,67 @@
+import { afterEach, beforeEach, describe, expect, it, vi } from 'vitest';
+
+import {
+  loadPersistedMessagesPanelMode,
+  savePersistedMessagesPanelMode,
+} from '../../../src/renderer/store/team/teamMessagesPanelModePersistence';
+
+import type { TeamMessagesPanelMode } from '../../../src/renderer/types/teamMessagesPanelMode';
+
+const STORAGE_KEY = 'team:messagesPanelMode';
+
+describe('teamMessagesPanelModePersistence', () => {
+  beforeEach(() => {
+    window.localStorage.clear();
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('defaults to sidebar when no value was persisted', () => {
+    expect(loadPersistedMessagesPanelMode()).toBe('sidebar');
+  });
+
+  it('loads each supported persisted mode', () => {
+    const modes: TeamMessagesPanelMode[] = [
+      'sidebar',
+      'inline',
+      'bottom-sheet',
+      'floating-composer',
+    ];
+
+    for (const mode of modes) {
+      window.localStorage.setItem(STORAGE_KEY, mode);
+
+      expect(loadPersistedMessagesPanelMode()).toBe(mode);
+    }
+  });
+
+  it('falls back to sidebar for invalid persisted values', () => {
+    window.localStorage.setItem(STORAGE_KEY, 'bad-mode');
+
+    expect(loadPersistedMessagesPanelMode()).toBe('sidebar');
+  });
+
+  it('persists the selected mode', () => {
+    savePersistedMessagesPanelMode('inline');
+
+    expect(window.localStorage.getItem(STORAGE_KEY)).toBe('inline');
+  });
+
+  it('falls back to sidebar when localStorage read fails', () => {
+    vi.spyOn(Storage.prototype, 'getItem').mockImplementation(() => {
+      throw new Error('blocked');
+    });
+
+    expect(loadPersistedMessagesPanelMode()).toBe('sidebar');
+  });
+
+  it('ignores localStorage write failures', () => {
+    vi.spyOn(Storage.prototype, 'setItem').mockImplementation(() => {
+      throw new Error('blocked');
+    });
+
+    expect(() => savePersistedMessagesPanelMode('bottom-sheet')).not.toThrow();
+  });
+});