diff --git a/ui/desktop/src/hooks/useNavigationSessions.test.tsx b/ui/desktop/src/hooks/useNavigationSessions.test.tsx
new file mode 100644
index 000000000..d3d933fc3
--- /dev/null
+++ b/ui/desktop/src/hooks/useNavigationSessions.test.tsx
@@ -0,0 +1,54 @@
+import { act, renderHook } from '@testing-library/react';
+import { beforeEach, describe, expect, it, vi } from 'vitest';
+
+const navigateMock = vi.hoisted(() => vi.fn());
+const routerState = vi.hoisted(() => ({ searchParams: new URLSearchParams() }));
+
+vi.mock('react-router', () => ({
+  useNavigate: () => navigateMock,
+  useLocation: () => ({ pathname: '/pair', search: routerState.searchParams.toString() }),
+  useSearchParams: () => [routerState.searchParams, vi.fn()],
+}));
+
+vi.mock('../acp/sessions', () => ({
+  acpGetSessionListItem: vi.fn(() => new Promise(() => {})),
+  acpListRecentSessions: vi.fn().mockResolvedValue([]),
+}));
+
+vi.mock('../contexts/ChatContext', () => ({
+  useChatContext: () => ({ chat: { sessionId: undefined } }),
+}));
+
+import { useNavigationSessions } from './useNavigationSessions';
+
+const injectedSessionId = 'session-1&shouldStartAgent=true';
+
+function expectSingleSessionParameter(target: string) {
+  const url = new URL(target, 'http://localhost');
+  expect(url.searchParams.get('resumeSessionId')).toBe(injectedSessionId);
+  expect(url.searchParams.get('shouldStartAgent')).toBeNull();
+}
+
+describe('useNavigationSessions', () => {
+  beforeEach(() => {
+    navigateMock.mockReset();
+    routerState.searchParams = new URLSearchParams();
+  });
+
+  it('keeps a selected session ID in one query parameter', () => {
+    const { result } = renderHook(() => useNavigationSessions());
+
+    act(() => result.current.handleSessionClick(injectedSessionId));
+
+    expectSingleSessionParameter(navigateMock.mock.calls[0][0]);
+  });
+
+  it('keeps a retained session ID in one query parameter', () => {
+    routerState.searchParams = new URLSearchParams({ resumeSessionId: injectedSessionId });
+    const { result } = renderHook(() => useNavigationSessions());
+
+    act(() => result.current.handleNavClick('/pair'));
+
+    expectSingleSessionParameter(navigateMock.mock.calls[0][0]);
+  });
+});
diff --git a/ui/desktop/src/hooks/useNavigationSessions.ts b/ui/desktop/src/hooks/useNavigationSessions.ts
index 9eaad0b1d..3c180f7b3 100644
--- a/ui/desktop/src/hooks/useNavigationSessions.ts
+++ b/ui/desktop/src/hooks/useNavigationSessions.ts
@@ -13,6 +13,11 @@ import { groupSessionsByProject } from '../utils/projectSessions';
 
 const MAX_RECENT_SESSIONS = 25;
 
+function pairSessionPath(sessionId: string): string {
+  const searchParams = new URLSearchParams({ resumeSessionId: sessionId });
+  return `/pair?${searchParams.toString()}`;
+}
+
 export function prependUnique(
   prev: SessionListItem[],
   session: SessionListItem
@@ -188,7 +193,7 @@ export function useNavigationSessions() {
         const sessionId =
           currentSessionId || lastSessionIdRef.current || chatContext?.chat?.sessionId;
         if (sessionId && sessionId.length > 0) {
-          navigate(`/pair?resumeSessionId=${sessionId}`);
+          navigate(pairSessionPath(sessionId));
         } else {
           navigate('/');
         }
@@ -201,7 +206,7 @@ export function useNavigationSessions() {
 
   const handleSessionClick = useCallback(
     (sessionId: string) => {
-      navigate(`/pair?resumeSessionId=${sessionId}`);
+      navigate(pairSessionPath(sessionId));
     },
     [navigate]
   );