fix(desktop): reseed new chats from profile defaults

apps/desktop/src/app/contrib/hooks/use-background-sync.test.tsx

@@ -0,0 +1,56 @@
+import { renderHook } from '@testing-library/react'
+import { beforeEach, describe, expect, it, vi } from 'vitest'
+
+import { $activeSessionId } from '@/store/session'
+
+import { useBackgroundSync } from './use-background-sync'
+
+vi.mock('@/store/profile', () => ({ refreshActiveProfile: vi.fn() }))
+
+function setup(overrides: Partial<Parameters<typeof useBackgroundSync>[0]> = {}) {
+  const params: Parameters<typeof useBackgroundSync>[0] = {
+    activeIsMessaging: false,
+    activeSessionId: null,
+    freshDraftReady: false,
+    gatewayState: 'open',
+    refreshActiveMessagingTranscript: vi.fn(),
+    refreshCronJobs: vi.fn(),
+    refreshCurrentModel: vi.fn(),
+    refreshHermesConfig: vi.fn(),
+    refreshMessagingSessions: vi.fn(),
+    refreshSessions: vi.fn(),
+    requestGateway: vi.fn(),
+    ...overrides
+  }
+
+  renderHook(() => useBackgroundSync(params))
+
+  return params
+}
+
+describe('useBackgroundSync model reseeding', () => {
+  beforeEach(() => {
+    $activeSessionId.set(null)
+  })
+
+  it('force-reseeds the composer when booting onto a fresh draft', () => {
+    const { refreshCurrentModel } = setup()
+
+    expect(refreshCurrentModel).toHaveBeenCalledWith(true)
+  })
+
+  it('does not force-reseed when booting with a live session', () => {
+    $activeSessionId.set('runtime-1')
+    const { refreshCurrentModel } = setup({ activeSessionId: 'runtime-1' })
+
+    expect(refreshCurrentModel).toHaveBeenCalledTimes(1)
+    expect(refreshCurrentModel).toHaveBeenCalledWith(false)
+  })
+
+  it('force-reseeds when a new-session draft becomes ready', () => {
+    const { refreshCurrentModel, refreshHermesConfig } = setup({ freshDraftReady: true })
+
+    expect(refreshCurrentModel).toHaveBeenCalledWith(true)
+    expect(refreshHermesConfig).toHaveBeenCalledOnce()
+  })
+})

apps/desktop/src/app/contrib/hooks/use-background-sync.ts

@@ -68,7 +68,9 @@ export function useBackgroundSync({
       return
     }
 
-    void refreshCurrentModel()
+    // Opening onto a fresh draft must discard the previous chat's sticky
+    // composer pick. A live session keeps its session-scoped selection.
+    void refreshCurrentModel(!$activeSessionId.get())
     void refreshActiveProfile()
     void refreshSessions()
 
@@ -130,7 +132,7 @@ export function useBackgroundSync({
   // model + config so the composer pill reflects the profile default.
   useEffect(() => {
     if (gatewayState === 'open' && !activeSessionId && freshDraftReady) {
-      void refreshCurrentModel()
+      void refreshCurrentModel(true)
       void refreshHermesConfig()
     }
   }, [activeSessionId, freshDraftReady, gatewayState, refreshCurrentModel, refreshHermesConfig])

apps/desktop/src/app/session/hooks/use-model-controls.test.tsx

@@ -93,7 +93,7 @@ describe('useModelControls', () => {
     expect(getCurrentModelSource()).toBe('default')
   })
 
-  it('does not clobber the active session footer state with global model info', async () => {
+  it('does not clobber the active session footer state even when force-reseeded', async () => {
     setCurrentModel('deepseek/deepseek-v4-pro')
     setCurrentProvider('deepseek')
     $activeSessionId.set('runtime-1')
@@ -109,7 +109,7 @@ describe('useModelControls', () => {
       })
     )
 
-    await result.current.refreshCurrentModel()
+    await result.current.refreshCurrentModel(true)
 
     expect($currentModel.get()).toBe('deepseek/deepseek-v4-pro')
     expect($currentProvider.get()).toBe('deepseek')
@@ -201,10 +201,13 @@ describe('useModelControls', () => {
     setCurrentProvider('anthropic')
     await result.current.refreshCurrentModel()
     expect($currentModel.get()).toBe('anthropic/claude-sonnet-4.6')
+    expect($currentProvider.get()).toBe('anthropic')
 
     // A profile swap forces a reseed to the new profile's default.
     await result.current.refreshCurrentModel(true)
     expect($currentModel.get()).toBe('openai/gpt-5.5')
+    expect($currentProvider.get()).toBe('openai-codex')
+    expect(getCurrentModelSource()).toBe('default')
   })
 
   it('refreshes legacy/default-derived composer state from the profile default', async () => {

apps/desktop/src/app/session/hooks/use-session-actions/index.ts

@@ -258,12 +258,9 @@ export function useSessionActions({
       })
       setSessionStartedAt(null)
       setTurnStartedAt(null)
-      // The composer's model/effort/fast is sticky UI state (persisted in
-      // localStorage) — a new chat FOLLOWS your last pick instead of snapping
-      // back to the profile default, so we deliberately don't reset it here. The
-      // profile default still owns first-run seeding and profile switches (see
-      // refreshCurrentModel). Only $currentServiceTier (a live-session mirror)
-      // is cleared.
+      // Model/provider reseeding happens after this transition, once the fresh
+      // draft is ready (see useBackgroundSync). Effort/fast remain sticky UI
+      // state. Only $currentServiceTier (a live-session mirror) is cleared here.
       setCurrentServiceTier('')
       setYoloActive(false)
       setNewChatWorkspaceTarget(hasWorkspaceTarget ? workspaceTarget : undefined)