diff --git a/frontend-spec.md b/frontend-spec.md
index c4b800a..b814085 100644
--- a/frontend-spec.md
+++ b/frontend-spec.md
@@ -57,37 +57,40 @@ This plan is adapted to the existing codebase, focusing on refactoring rather th
 
 ## 4. Actionable Implementation Steps
 
-1.  **[ ] Refactor Authentication State & API**:
+1.  **[~] Refactor Authentication State & API**:
     - **Modify `src/api/auth.ts`**:
-      - Replace `login(username: string)` with `login(email, password)`.
-      - Add `createAccount(email, displayName, password)`, `handleGoogleLogin(token)`, and `logout()`.
-      - The API client should handle storing and clearing the auth token (e.g., from `localStorage`).
+      - Added minimal multitenant-ready surface while preserving legacy login:
+        - `loginWithPassword(email, password)` implemented by delegating to legacy `login(username)`; tests added.
+        - `logout()` clears cached user; covered by tests.
+        - Stubs for `createAccount(email, displayName, password)` and `handleGoogleLogin(token)` throw pending-implementation errors; tests assert presence.
+      - Token/JWT storage is still cookie-based (per current backend); no localStorage changes yet.
     - **Modify `src/composables/useAuth.ts`**:
-      - Update the `login` function to accept email/password.
-      - Add a `register` function.
-      - The `user` ref should now hold the global User profile, and you should add a new state for `households` and `activeHousehold`.
-      - The `logout` function should clear the JWT and all user state.
+      - TODO: Update to accept email/password and expose `register`, `logout`, `households`, and `activeHousehold`. Not started.
 
-2.  **[ ] Update Router for Multi-Tenancy**:
+2.  **[~] Update Router for Multi-Tenancy**:
     - **Modify `src/router/index.ts`**:
-      - Add new public routes: `/create-account`, `/welcome`, and `/invitations/accept`.
+      - Added new public routes: `/create-account`, `/welcome`, and `/invitations/accept`.
+      - Feature flag `VUE_APP_MULTITENANT_ENABLED` controls nesting:
+        - When enabled: feature routes are nested under `/:householdSlug/...`.
+        - When disabled: legacy flat routes remain for backward compatibility.
       - **Refactor the `beforeEach` guard**:
         - It should allow access to public routes.
         - After login, it must fetch the user's households.
         - If the user has no households, redirect to `/welcome`.
         - If the user has households but is at the root (`/`), redirect to the first household's dashboard (e.g., `/${householdSlug}/dashboard`).
-      - **Nest existing routes**: All current data-related routes (`/meals`, `/shopping`, etc.) must be moved as children of a new dynamic `/:householdSlug` route.
+      - **Nest existing routes**: Implemented behind feature flag.
 
 3.  **[ ] Implement Onboarding and Invitation Flows**:
     - Build the `Welcome.vue` view for creating the first household.
     - Build the `CreateAccount.vue` view.
     - Build the "Accept Invitation" page (`/invitations/accept?token=...`). It should take the token from the URL, call the API, and redirect on success.
+  - Status: Placeholder views created for all three; logic pending.
 
-4.  **[ ] Integrate Household Context into the App**:
-    - **Create `src/composables/useHousehold.ts`**: This composable should extract the `householdSlug` from the current route's params. It will provide the `activeHouseholdSlug` to any component or service that needs it.
-    - **Implement `HouseholdSwitcher.vue`**: This component will use `useAuth` to get the list of the user's households and render navigation links.
-    - **Update API Services**: All data-fetching calls (e.g., for recipes, meals) must be updated to use the `activeHouseholdSlug` from `useHousehold`. The API client wrapper should be modified to prepend this slug to the request URL.
-      - Example: `api.get('/recipes')` becomes `api.get(\`/${activeHouseholdSlug.value}/recipes\`)`.
+4.  **[~] Integrate Household Context into the App**:
+    - **Create `src/composables/useHousehold.ts`**: Implemented. Extracts `householdSlug` from route and binds provider to API client.
+    - **Implement `HouseholdSwitcher.vue`**: Implemented minimal version and mounted in `App.vue`.
+    - **Update API Services**: Implemented header-injection in `src/api/client.ts` via `X-Household-Slug` using a configurable provider; no path changes.
+      - Verified by `tests/household.header.test.ts`.
 
 5.  **[ ] Implement Invitation UI**:
     - Build the `HouseholdSettings.vue` view for inviting members and listing current members.
@@ -119,11 +122,11 @@ What exists today
 
 Gaps vs requirements
 - Authentication & onboarding
-  - Missing email/password login, Google OAuth, account creation, logout, JWT storage/refresh.
+  - Partial: Added `loginWithPassword` shim and `logout`. Still missing Google OAuth, account creation, JWT storage/refresh beyond cookie.
   - Missing `CreateAccount.vue`, `Welcome.vue`, invitation acceptance flow.
 - Routing & URL-based tenancy
-  - Missing `/:householdSlug/...` route nesting and post-login redirect logic.
-  - No `useHousehold.ts`; no `HouseholdSwitcher.vue`.
+  - Partial: Feature-flagged nesting implemented; still need guard logic for fetching households and redirects.
+  - `useHousehold.ts` and `HouseholdSwitcher.vue` added; further wiring to fetch households pending.
 - API boundary
   - No household scoping passed to backend. Need a typed strategy (prefer header parameter) without breaking OpenAPI typing.
 - Cleanup
@@ -144,6 +147,18 @@ To align with OpenAPI typing and README axioms, do not rewrite request paths to
 
 Action
 - Implement header injection in `api/client.ts` with a pluggable getter for the active slug (decoupled from Vue imports). Update this spec once backend finalizes the parameter shape.
+  - DONE: Implemented with `setHouseholdSlugProvider`. Will align to OpenAPI when backend finalizes.
+
+---
+
+Progress Log (Nov 1, 2025)
+- Established green baseline (typecheck + tests pass).
+- Added auth API tests driving a minimal multitenant-ready surface.
+- Implemented `loginWithPassword`, `logout`, and stubs in `src/api/auth.ts` to satisfy tests.
+- Refactored `useAuth` to add households and activeHousehold state, plus `loginWithPassword` and `logout`. Tests added and passing.
+- Added router tests and implemented feature-flagged nested routes and new public routes. Placeholders for onboarding/invitations added.
+- Implemented `useHousehold.ts`, header injection provider in API client, minimal `HouseholdSwitcher.vue`, and mounted it. Added a header injection test.
+- Next: Update `LoginPage.vue` to email/password UI using `useAuth.loginWithPassword`; implement router guard post-login household redirects; scaffold `HouseholdSettings.vue` and households fetching in `useAuth`.
 
 ---
 
diff --git a/src/App.vue b/src/App.vue
index e96fb13..9368ecd 100644
--- a/src/App.vue
+++ b/src/App.vue
@@ -29,6 +29,7 @@
         </router-link>
       </li>
     </ul>
+    <HouseholdSwitcher />
   </div>
   <div class="viewport">
     <router-view />
@@ -39,6 +40,11 @@
 
 <script setup>
 import AlertToast from './components/AlertToast.vue'
+import HouseholdSwitcher from '@/components/HouseholdSwitcher.vue'
+import { useHousehold } from '@/composables/useHousehold'
+
+// Initialize household slug provider binding to current route
+useHousehold()
 
 // components in <script setup> are auto-registered by import + usage
 </script>
diff --git a/src/api/auth.ts b/src/api/auth.ts
index d211e77..f1e9db6 100644
--- a/src/api/auth.ts
+++ b/src/api/auth.ts
@@ -28,3 +28,24 @@ export async function login(username: string): Promise<Person> {
   if (!cachedUser) throw new Error('Login failed: empty response')
   return cachedUser
 }
+
+// New multitenant-ready API surface (backward compatible)
+export async function loginWithPassword(email: string, _password: string): Promise<Person> {
+  // Backend currently expects { username }; map email to username until OpenAPI updates
+  return login(email)
+}
+
+export async function createAccount(_email: string, _displayName: string, _password: string): Promise<never> {
+  // Placeholder until backend endpoints and OpenAPI are finalized
+  throw new Error('createAccount not implemented yet')
+}
+
+export async function handleGoogleLogin(_token: string): Promise<never> {
+  // Placeholder until Google OAuth flow is wired
+  throw new Error('handleGoogleLogin not implemented yet')
+}
+
+export async function logout(): Promise<void> {
+  // Clear local cache; server session is cookie-based and will be refreshed on next call
+  cachedUser = null
+}
diff --git a/src/api/client.ts b/src/api/client.ts
index c3d81de..b214122 100644
--- a/src/api/client.ts
+++ b/src/api/client.ts
@@ -9,12 +9,22 @@ const isTest = typeof process !== 'undefined' && (process.env?.VITEST === 'true'
 const defaultBase = ''
 const baseUrl: string = isTest ? 'http://localhost' : (vueCliBase || defaultBase)
 
+let householdSlugProvider: (() => string | null) | null = null
+
+export function setHouseholdSlugProvider(provider: (() => string | null) | null) {
+  householdSlugProvider = provider
+}
+
 export const api = createClient<paths>({
   baseUrl,
   fetch: (input: RequestInfo | URL, init?: RequestInit) => {
+    const headers = new Headers(init?.headers || {})
+    const slug = householdSlugProvider ? householdSlugProvider() : null
+    if (slug) headers.set('X-Household-Slug', slug)
     return globalThis.fetch(input, {
       credentials: 'include',
       ...init,
+      headers,
     })
   },
 })
diff --git a/src/components/HouseholdSwitcher.vue b/src/components/HouseholdSwitcher.vue
new file mode 100644
index 0000000..f2b0213
--- /dev/null
+++ b/src/components/HouseholdSwitcher.vue
@@ -0,0 +1,42 @@
+<template>
+  <div v-if="enabled && households.length > 0" class="household-switcher">
+    <label>Household:</label>
+    <ul>
+      <li v-for="h in households" :key="h.slug">
+        <router-link :to="toHousehold(h.slug)" :class="{ active: h.slug === activeSlug }">
+          {{ h.name }}
+        </router-link>
+      </li>
+    </ul>
+  </div>
+</template>
+
+<script setup lang="ts">
+import { computed } from 'vue'
+import { useRoute } from 'vue-router'
+import { useAuth } from '@/composables/useAuth'
+
+const enabled = (typeof process !== 'undefined' && (process.env?.VUE_APP_MULTITENANT_ENABLED === 'true'))
+const route = useRoute()
+const { households } = useAuth()
+
+const activeSlug = computed(() => (typeof route.params.householdSlug === 'string' ? route.params.householdSlug : null))
+
+function toHousehold(slug: string) {
+  if (enabled) return { name: 'mealplan', params: { householdSlug: slug } }
+  return { name: 'mealplan' }
+}
+</script>
+
+<style scoped>
+.household-switcher {
+  display: inline-block;
+}
+.household-switcher ul {
+  list-style: none;
+  display: inline-flex;
+  gap: 8px;
+  margin: 0 0 0 8px;
+  padding: 0;
+}
+</style>
diff --git a/src/composables/useAuth.ts b/src/composables/useAuth.ts
index c6cdeca..139839c 100644
--- a/src/composables/useAuth.ts
+++ b/src/composables/useAuth.ts
@@ -1,8 +1,12 @@
 import { ref } from 'vue'
-import { currentUser as apiCurrentUser, login as apiLogin } from '@/api/auth'
+import { currentUser as apiCurrentUser, login as apiLogin, loginWithPassword as apiLoginWithPassword, logout as apiLogout } from '@/api/auth'
 import type { Person } from '@/domain/types'
 
+type Household = { id: number; name: string; slug: string }
+
 const user = ref<Person | null>(null)
+const households = ref<Household[]>([])
+const activeHousehold = ref<Household | null>(null)
 let initialized = false
 
 export async function loadUser() {
@@ -18,6 +22,34 @@ export async function login(username: string) {
   return user.value
 }
 
-export function useAuth() {
-  return { user, loadUser, login }
+export async function loginWithPassword(email: string, password: string) {
+  user.value = await apiLoginWithPassword(email, password)
+  return user.value
+}
+
+export async function logout() {
+  await apiLogout()
+  user.value = null
+  households.value = []
+  activeHousehold.value = null
+}
+
+export function setHouseholds(hs: Household[]) {
+  households.value = Array.isArray(hs) ? hs.slice() : []
+}
+
+export function setActiveHousehold(h: Household | string | null) {
+  if (h == null) {
+    activeHousehold.value = null
+    return
+  }
+  if (typeof h === 'string') {
+    activeHousehold.value = households.value.find((x) => x.slug === h) ?? null
+  } else {
+    activeHousehold.value = h
+  }
+}
+
+export function useAuth() {
+  return { user, households, activeHousehold, loadUser, login, loginWithPassword, logout, setHouseholds, setActiveHousehold }
 }
diff --git a/src/composables/useHousehold.ts b/src/composables/useHousehold.ts
new file mode 100644
index 0000000..088e99a
--- /dev/null
+++ b/src/composables/useHousehold.ts
@@ -0,0 +1,18 @@
+import { computed, watchEffect } from 'vue'
+import { useRoute } from 'vue-router'
+import { setHouseholdSlugProvider } from '@/api/client'
+
+export function useHousehold() {
+  const route = useRoute()
+  const activeHouseholdSlug = computed<string | null>(() => {
+    const p = route.params?.householdSlug
+    return typeof p === 'string' ? p : null
+  })
+
+  // Keep API client in sync with current route's household slug
+  watchEffect(() => {
+    setHouseholdSlugProvider(() => activeHouseholdSlug.value)
+  })
+
+  return { activeHouseholdSlug }
+}
diff --git a/src/router/index.ts b/src/router/index.ts
index ffa0276..5c660d2 100644
--- a/src/router/index.ts
+++ b/src/router/index.ts
@@ -10,55 +10,54 @@ const PurchasedShoppingListPage = () => import('@/components/shopping/PurchasedS
 const CurrentShoppingListPage = () => import('@/components/shopping/CurrentShoppingListPage.vue')
 const EditMealPage = () => import('@/components/meals/EditMealPage.vue')
 const EditRecipePage = () => import('@/components/recipes/EditRecipePage.vue')
+const CreateAccount = () => import('@/views/CreateAccount.vue')
+const Welcome = () => import('@/views/Welcome.vue')
+const InvitationAccept = () => import('@/views/InvitationAccept.vue')
 
 export function createAppRouter(getCurrentUser: () => Promise<unknown> | unknown): Router {
-  const routes: RouteRecordRaw[] = [
-    { path: '/', redirect: { name: 'mealplan' } },
+  const multitenantEnabled = typeof process !== 'undefined' && process.env?.VUE_APP_MULTITENANT_ENABLED === 'true'
+  const publicRoutes: RouteRecordRaw[] = [
     { path: '/login', name: 'login', component: LoginPage },
-    { path: '/mealplan', name: 'mealplan', component: MealPlanPage, meta: { requiresAuth: true } },
-    {
-      path: '/shopping',
-      name: 'shopping',
-      component: MyShoppingPage,
-      meta: { requiresAuth: true },
-    },
-    {
-      path: '/shopping/current',
-      name: 'shopping-current',
-      component: CurrentShoppingListPage,
-      meta: { requiresAuth: true },
-    },
-    {
-      path: '/shopping/:id',
-      name: 'shopping-list',
-      component: PurchasedShoppingListPage,
-      props: true,
-      meta: { requiresAuth: true },
-    },
-    { path: '/recipes', name: 'recipes', component: RecipesPage, meta: { requiresAuth: true } },
-    {
-      path: '/recipes/add',
-      name: 'recipe-add',
-      component: EditRecipePage,
-      meta: { requiresAuth: true },
-    },
-    {
-      path: '/recipes/:id',
-      name: 'recipe-edit',
-      component: EditRecipePage,
-      props: true,
-      meta: { requiresAuth: true },
-    },
-    { path: '/meals/add', name: 'meal-add', component: EditMealPage, meta: { requiresAuth: true } },
-    {
-      path: '/meals/:id',
-      name: 'meal-edit',
-      component: EditMealPage,
-      props: true,
-      meta: { requiresAuth: true },
-    },
+    { path: '/create-account', name: 'create-account', component: CreateAccount },
+    { path: '/welcome', name: 'welcome', component: Welcome },
+    { path: '/invitations/accept', name: 'invitation-accept', component: InvitationAccept },
   ]
 
+  const featureChildren: RouteRecordRaw[] = [
+    { path: 'recipes', name: 'recipes', component: RecipesPage, meta: { requiresAuth: true } },
+    { path: 'recipes/add', name: 'recipe-add', component: EditRecipePage, meta: { requiresAuth: true } },
+    { path: 'recipes/:id', name: 'recipe-edit', component: EditRecipePage, props: true, meta: { requiresAuth: true } },
+    { path: 'mealplan', name: 'mealplan', component: MealPlanPage, meta: { requiresAuth: true } },
+    { path: 'meals/add', name: 'meal-add', component: EditMealPage, meta: { requiresAuth: true } },
+    { path: 'meals/:id', name: 'meal-edit', component: EditMealPage, props: true, meta: { requiresAuth: true } },
+    { path: 'shopping', name: 'shopping', component: MyShoppingPage, meta: { requiresAuth: true } },
+    { path: 'shopping/current', name: 'shopping-current', component: CurrentShoppingListPage, meta: { requiresAuth: true } },
+    { path: 'shopping/:id', name: 'shopping-list', component: PurchasedShoppingListPage, props: true, meta: { requiresAuth: true } },
+  ]
+
+  const routes: RouteRecordRaw[] = []
+
+  if (multitenantEnabled) {
+    routes.push({ path: '/', redirect: { name: 'login' } })
+    routes.push(...publicRoutes)
+    routes.push({ path: '/:householdSlug', component: { template: '<router-view />' }, children: featureChildren })
+  } else {
+    routes.push({ path: '/', redirect: { name: 'mealplan' } })
+    routes.push(...publicRoutes)
+    // legacy flat routes
+    routes.push(
+      { path: '/recipes', name: 'recipes', component: RecipesPage, meta: { requiresAuth: true } },
+      { path: '/recipes/add', name: 'recipe-add', component: EditRecipePage, meta: { requiresAuth: true } },
+      { path: '/recipes/:id', name: 'recipe-edit', component: EditRecipePage, props: true, meta: { requiresAuth: true } },
+      { path: '/mealplan', name: 'mealplan', component: MealPlanPage, meta: { requiresAuth: true } },
+      { path: '/meals/add', name: 'meal-add', component: EditMealPage, meta: { requiresAuth: true } },
+      { path: '/meals/:id', name: 'meal-edit', component: EditMealPage, props: true, meta: { requiresAuth: true } },
+      { path: '/shopping', name: 'shopping', component: MyShoppingPage, meta: { requiresAuth: true } },
+      { path: '/shopping/current', name: 'shopping-current', component: CurrentShoppingListPage, meta: { requiresAuth: true } },
+      { path: '/shopping/:id', name: 'shopping-list', component: PurchasedShoppingListPage, props: true, meta: { requiresAuth: true } },
+    )
+  }
+
   const router = createRouter({
     history: createWebHashHistory(),
     routes,
diff --git a/src/views/CreateAccount.vue b/src/views/CreateAccount.vue
new file mode 100644
index 0000000..aeb7001
--- /dev/null
+++ b/src/views/CreateAccount.vue
@@ -0,0 +1,10 @@
+<template>
+  <div>
+    <h1>Create Account</h1>
+    <p>Placeholder for email, display name, password, and Google signup.</p>
+  </div>
+</template>
+
+<script setup lang="ts">
+// TODO: Implement form per spec
+</script>
diff --git a/src/views/InvitationAccept.vue b/src/views/InvitationAccept.vue
new file mode 100644
index 0000000..67f0d6e
--- /dev/null
+++ b/src/views/InvitationAccept.vue
@@ -0,0 +1,10 @@
+<template>
+  <div>
+    <h1>Accept Invitation</h1>
+    <p>Processing your invitation token...</p>
+  </div>
+</template>
+
+<script setup lang="ts">
+// TODO: Read token from route, call API, and redirect
+</script>
diff --git a/src/views/Welcome.vue b/src/views/Welcome.vue
new file mode 100644
index 0000000..9facc91
--- /dev/null
+++ b/src/views/Welcome.vue
@@ -0,0 +1,10 @@
+<template>
+  <div>
+    <h1>Welcome</h1>
+    <p>Choose to create a new household or join via invitation link.</p>
+  </div>
+</template>
+
+<script setup lang="ts">
+// TODO: Implement onboarding flow per spec
+</script>
diff --git a/tests/auth.api.test.ts b/tests/auth.api.test.ts
new file mode 100644
index 0000000..451ec1d
--- /dev/null
+++ b/tests/auth.api.test.ts
@@ -0,0 +1,42 @@
+import { describe, it, expect } from 'vitest'
+import { server, http, HttpResponse } from './test-setup'
+import { currentUser, logout, loginWithPassword, createAccount, handleGoogleLogin } from '@/api/auth'
+
+describe('auth api (multitenant prep)', () => {
+  it('loginWithPassword proxies to /auth/login with username=email', async () => {
+    server.use(
+      http.post('*/api/v1/auth/login', async ({ request }) => {
+        const body = await request.json()
+        expect(body).toEqual({ username: 'test@example.com' })
+        return HttpResponse.json({ id: 123, name: 'Test User' })
+      })
+    )
+    const person = await loginWithPassword('test@example.com', 'secret')
+    expect(person.id).toBe(123)
+    expect(person.name).toBe('Test User')
+  })
+
+  it('logout clears cached user; subsequent currentUser returns null', async () => {
+    // First refresh returns a user
+    server.use(
+      http.post('*/api/v1/auth/refresh', () => {
+        return HttpResponse.json({ id: 1, name: 'Ada' })
+      })
+    )
+    const first = await currentUser()
+    expect(first?.name).toBe('Ada')
+
+    // After logout, next refresh returns 401 and currentUser should resolve to null
+    await logout()
+    server.use(
+      http.post('*/api/v1/auth/refresh', () => new HttpResponse(null, { status: 401 }))
+    )
+    const second = await currentUser()
+    expect(second).toBeNull()
+  })
+
+  it('createAccount and handleGoogleLogin exist but are not implemented yet', async () => {
+    await expect(createAccount('new@example.com', 'New User', 'pw')).rejects.toBeInstanceOf(Error)
+    await expect(handleGoogleLogin('token-123')).rejects.toBeInstanceOf(Error)
+  })
+})
diff --git a/tests/household.header.test.ts b/tests/household.header.test.ts
new file mode 100644
index 0000000..8b7a3d9
--- /dev/null
+++ b/tests/household.header.test.ts
@@ -0,0 +1,23 @@
+import { describe, it, expect } from 'vitest'
+import { server, http, HttpResponse } from './test-setup'
+import { api } from '@/api/client'
+
+describe('API household header injection', () => {
+  it('sends X-Household-Slug when provider returns slug', async () => {
+    server.use(
+      http.get('*/api/v1/recipes', ({ request }) => {
+        // Should include our header set by client provider
+        const slug = request.headers.get('x-household-slug') || request.headers.get('X-Household-Slug')
+        if (!slug) return new HttpResponse(null, { status: 400 })
+        return HttpResponse.json([])
+      })
+    )
+
+    // Directly set provider without Vue router by calling internal setter via dynamic import
+    const { setHouseholdSlugProvider } = await import('@/api/client')
+    setHouseholdSlugProvider(() => 'the-smiths')
+
+    const res = await api.GET('/api/v1/recipes', { params: {} })
+    expect(res.response.ok).toBe(true)
+  })
+})
diff --git a/tests/router.multitenant.test.ts b/tests/router.multitenant.test.ts
new file mode 100644
index 0000000..14750fc
--- /dev/null
+++ b/tests/router.multitenant.test.ts
@@ -0,0 +1,36 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+describe('router multitenant routing', () => {
+  beforeEach(() => {
+    vi.resetModules()
+    delete (process.env as any).VUE_APP_MULTITENANT_ENABLED
+  })
+
+  it('includes public routes and legacy flat routes when flag disabled', async () => {
+    const { createAppRouter } = await import('@/router/index')
+    const router = createAppRouter(() => null)
+    const paths = router.getRoutes().map((r) => r.path)
+    expect(paths).toContain('/login')
+    expect(paths).toContain('/create-account')
+    expect(paths).toContain('/welcome')
+    expect(paths).toContain('/invitations/accept')
+    // legacy flat routes
+    expect(paths).toContain('/recipes')
+    expect(paths).toContain('/shopping')
+  })
+
+  it('nests routes under /:householdSlug when flag enabled', async () => {
+    ;(process.env as any).VUE_APP_MULTITENANT_ENABLED = 'true'
+    const { createAppRouter } = await import('@/router/index')
+    const router = createAppRouter(() => null)
+    const paths = router.getRoutes().map((r) => r.path)
+    // Public routes still exist
+    expect(paths).toContain('/login')
+    expect(paths).toContain('/create-account')
+    // Nested route example
+    const hasNestedRecipes = paths.some((p) => p === '/:householdSlug/recipes')
+    expect(hasNestedRecipes).toBe(true)
+    // Legacy route should not be present when nested is enabled
+    expect(paths).not.toContain('/recipes')
+  })
+})
diff --git a/tests/useAuth.multitenant.test.ts b/tests/useAuth.multitenant.test.ts
new file mode 100644
index 0000000..7f0c806
--- /dev/null
+++ b/tests/useAuth.multitenant.test.ts
@@ -0,0 +1,62 @@
+import { describe, it, expect, vi, beforeEach } from 'vitest'
+
+vi.mock('@/api/auth', () => {
+  return {
+    currentUser: vi.fn(async () => ({ id: 42, name: 'Grace Hopper' })),
+    login: vi.fn(async (username: string) => ({ id: 7, name: username })),
+    loginWithPassword: vi.fn(async (email: string) => ({ id: 8, name: email })),
+    logout: vi.fn(async () => {}),
+    createAccount: vi.fn(async () => {
+      throw new Error('createAccount not implemented yet')
+    }),
+    handleGoogleLogin: vi.fn(async () => {
+      throw new Error('handleGoogleLogin not implemented yet')
+    }),
+  }
+})
+
+import { useAuth, loadUser } from '@/composables/useAuth'
+
+describe('useAuth (multitenant state)', () => {
+  beforeEach(() => {
+    // Reset modules and state between tests
+    vi.resetModules()
+  })
+
+  it('exposes households and activeHousehold state with setters', async () => {
+    const { user, households, activeHousehold, setHouseholds, setActiveHousehold } = useAuth()
+    expect(user.value).toBeNull()
+    expect(households.value).toEqual([])
+    expect(activeHousehold.value).toBeNull()
+
+    const hs = [
+      { id: 1, name: 'Smiths', slug: 'the-smiths' },
+      { id: 2, name: 'Johnsons', slug: 'the-johnsons' },
+    ]
+    setHouseholds(hs)
+    expect(households.value.length).toBe(2)
+    setActiveHousehold(hs[1])
+    expect(activeHousehold.value?.slug).toBe('the-johnsons')
+    setActiveHousehold('the-smiths')
+    expect(activeHousehold.value?.slug).toBe('the-smiths')
+  })
+
+  it('supports loading current user, loginWithPassword, and logout clearing user', async () => {
+    const { user, loginWithPassword, logout } = useAuth()
+    // load current user
+    await loadUser()
+    expect(user.value?.name).toBe('Grace Hopper')
+    // login with email/password
+    await loginWithPassword('user@example.com', 'pw')
+    expect(user.value?.name).toBe('user@example.com')
+    // logout clears user
+    await logout()
+    expect(user.value).toBeNull()
+  })
+
+  it('keeps legacy login(username) available for now', async () => {
+    const { user, login } = useAuth()
+    await login('legacy-user')
+    expect(user.value?.name).toBe('legacy-user')
+  })
+})