diff --git a/.env.example b/.env.example
index 1886d22..517ac38 100644
--- a/.env.example
+++ b/.env.example
@@ -1,5 +1,5 @@
-# App
-NUXT_SESSION_SECRET=change-me
+# App — session sealing key for nuxt-auth-utils (must be ≥32 chars)
+NUXT_SESSION_PASSWORD=change-me-to-a-long-random-string-min-32-chars
 
 # Database (Postgres) — Coolify-managed in prod, docker-compose in dev
 DATABASE_URL=postgres://andon:andon@localhost:5432/andon
@@ -9,10 +9,13 @@ POSTGRES_USER=andon
 POSTGRES_PASSWORD=andon
 POSTGRES_DB=andon
 
-# Google OAuth (Task 9) — restricted to the theodo.com hosted domain
-GOOGLE_CLIENT_ID=
-GOOGLE_CLIENT_SECRET=
-GOOGLE_REDIRECT_URI=
+# Google OAuth (Task 9) — nuxt-auth-utils reads these exact names. Access is
+# restricted server-side to verified @theodo.com emails (the `hd` claim is not
+# trusted on its own). REDIRECT_URL must match an Authorized redirect URI in the
+# Google Cloud console (defaults to <origin>/auth/google/callback if unset).
+NUXT_OAUTH_GOOGLE_CLIENT_ID=
+NUXT_OAUTH_GOOGLE_CLIENT_SECRET=
+NUXT_OAUTH_GOOGLE_REDIRECT_URL=
 
 # Web Push / VAPID (Task 10)
 VAPID_PUBLIC_KEY=
diff --git a/README.md b/README.md
index 2b08d1a..88f8e7f 100644
--- a/README.md
+++ b/README.md
@@ -61,8 +61,10 @@ migrate step is needed.
 1. Point Coolify at this repo; it builds the production `Dockerfile`.
 2. Create a **managed Postgres** in Coolify (automatic backups — [ADR 0003](./docs/adr/0003-use-coolify-managed-postgres-over-sqlite.md))
    and set `DATABASE_URL` to it. _(Alternatively deploy `docker-compose.yml`, which bundles a Postgres service.)_
-3. Set the env vars from [`.env.example`](./.env.example) (`NUXT_SESSION_SECRET`,
-   Google OAuth, VAPID) and route `andon.apoena.dev` to the service.
+3. Set the env vars from [`.env.example`](./.env.example) (`NUXT_SESSION_PASSWORD`,
+   `NUXT_OAUTH_GOOGLE_*`, VAPID) and route `andon.apoena.dev` to the service. Add
+   `https://andon.apoena.dev/auth/google/callback` as an Authorized redirect URI
+   in the Google Cloud OAuth client.
 4. **Enable Coolify's autodeploy** so it builds and deploys on every push to
    `main`. Protect `main` with required PR review + CI so only vetted commits
    reach production.
diff --git a/app/layouts/default.vue b/app/layouts/default.vue
index 334d9db..d6e8677 100644
--- a/app/layouts/default.vue
+++ b/app/layouts/default.vue
@@ -1,6 +1,12 @@
 <script setup lang="ts">
 // Single domain (ADR 0004): report at `/`, view all defects at `/defects`,
 // with a persistent header to move between them.
+const { loggedIn, user, clear } = useUserSession()
+
+async function signOut() {
+  await clear()
+  await navigateTo('/login')
+}
 </script>
 
 <template>
@@ -25,6 +31,12 @@
             </NuxtLink>
           </li>
         </ul>
+        <div v-if="loggedIn" class="flex items-center gap-3 pl-2">
+          <span class="hidden text-sm opacity-70 sm:inline">{{ user?.email }}</span>
+          <button type="button" class="btn btn-ghost btn-sm" @click="signOut">
+            Sign out
+          </button>
+        </div>
       </nav>
     </header>
 
diff --git a/app/middleware/auth.global.ts b/app/middleware/auth.global.ts
new file mode 100644
index 0000000..eb52d7a
--- /dev/null
+++ b/app/middleware/auth.global.ts
@@ -0,0 +1,13 @@
+// Redirect unauthenticated visitors to the login page, and bounce already
+// logged-in users away from it (F9). Runs on both SSR and client navigations;
+// the server data API is gated independently in server/middleware/auth.ts.
+export default defineNuxtRouteMiddleware((to) => {
+  const { loggedIn } = useUserSession()
+
+  if (!loggedIn.value && to.path !== '/login') {
+    return navigateTo('/login')
+  }
+  if (loggedIn.value && to.path === '/login') {
+    return navigateTo('/')
+  }
+})
diff --git a/app/pages/login.vue b/app/pages/login.vue
new file mode 100644
index 0000000..2d38e3f
--- /dev/null
+++ b/app/pages/login.vue
@@ -0,0 +1,32 @@
+<script setup lang="ts">
+// Login gate (F9). Standalone (no app header — its nav points at gated routes).
+// The button is a real anchor so it hits the server OAuth route directly.
+definePageMeta({ layout: false })
+
+const route = useRoute()
+const error = computed(() => {
+  if (route.query.error === 'domain') return 'Sign in with your @theodo.com Google account.'
+  if (route.query.error === 'oauth') return 'Sign-in failed — please try again.'
+  return null
+})
+</script>
+
+<template>
+  <main class="flex min-h-screen items-center justify-center p-6">
+    <div class="card bg-base-100 border-base-300 w-full max-w-sm border shadow-sm">
+      <div class="card-body items-center text-center gap-4">
+        <h1 class="flex items-center gap-2 text-2xl font-semibold">
+          <span class="size-2.5 rounded-full bg-[#e11d48]" aria-hidden="true" />
+          Project Board Andon
+        </h1>
+        <p class="opacity-70">Sign in to report and view board defects.</p>
+
+        <p v-if="error" role="alert" class="alert alert-error text-sm">{{ error }}</p>
+
+        <a href="/auth/google/callback" class="btn btn-primary w-full">
+          Sign in with Google
+        </a>
+      </div>
+    </div>
+  </main>
+</template>
diff --git a/docker-compose.yml b/docker-compose.yml
index eaf2ab8..8bb7a13 100644
--- a/docker-compose.yml
+++ b/docker-compose.yml
@@ -13,10 +13,10 @@ services:
       - "3000:3000"
     environment:
       DATABASE_URL: ${DATABASE_URL:-postgres://andon:andon@db:5432/andon}
-      NUXT_SESSION_SECRET: ${NUXT_SESSION_SECRET:-change-me}
-      GOOGLE_CLIENT_ID: ${GOOGLE_CLIENT_ID:-}
-      GOOGLE_CLIENT_SECRET: ${GOOGLE_CLIENT_SECRET:-}
-      GOOGLE_REDIRECT_URI: ${GOOGLE_REDIRECT_URI:-}
+      NUXT_SESSION_PASSWORD: ${NUXT_SESSION_PASSWORD:-}
+      NUXT_OAUTH_GOOGLE_CLIENT_ID: ${NUXT_OAUTH_GOOGLE_CLIENT_ID:-}
+      NUXT_OAUTH_GOOGLE_CLIENT_SECRET: ${NUXT_OAUTH_GOOGLE_CLIENT_SECRET:-}
+      NUXT_OAUTH_GOOGLE_REDIRECT_URL: ${NUXT_OAUTH_GOOGLE_REDIRECT_URL:-}
       VAPID_PUBLIC_KEY: ${VAPID_PUBLIC_KEY:-}
       VAPID_PRIVATE_KEY: ${VAPID_PRIVATE_KEY:-}
       VAPID_SUBJECT: ${VAPID_SUBJECT:-mailto:owner@theodo.com}
diff --git a/nuxt.config.ts b/nuxt.config.ts
index faa1db6..edf20ca 100644
--- a/nuxt.config.ts
+++ b/nuxt.config.ts
@@ -4,7 +4,7 @@ import tailwindcss from '@tailwindcss/vite'
 export default defineNuxtConfig({
   compatibilityDate: '2025-07-15',
   devtools: { enabled: true },
-  modules: ['@nuxt/eslint', '@nuxt/test-utils/module'],
+  modules: ['@nuxt/eslint', '@nuxt/test-utils/module', 'nuxt-auth-utils'],
   css: ['~/assets/css/main.css'],
   // Tailwind v4 integrates as a Vite plugin (no @nuxtjs/tailwindcss module).
   vite: {
diff --git a/package.json b/package.json
index 83a2ea0..6b91ce8 100644
--- a/package.json
+++ b/package.json
@@ -25,6 +25,7 @@
     "arktype": "^2.2.0",
     "drizzle-orm": "^0.45.2",
     "nuxt": "^4.4.6",
+    "nuxt-auth-utils": "^0.5.29",
     "pg": "^8.21.0",
     "vue": "^3.5.34",
     "vue-router": "^5.0.7"
diff --git a/pnpm-lock.yaml b/pnpm-lock.yaml
index 2a7452a..d41973c 100644
--- a/pnpm-lock.yaml
+++ b/pnpm-lock.yaml
@@ -17,6 +17,9 @@ importers:
       nuxt:
         specifier: ^4.4.6
         version: 4.4.6(@babel/plugin-syntax-jsx@7.29.7(@babel/core@7.29.7))(@babel/plugin-syntax-typescript@7.29.7(@babel/core@7.29.7))(@parcel/watcher@2.5.6)(@types/node@25.9.1)(@vue/compiler-sfc@3.5.34)(cac@6.7.14)(db0@0.3.4(drizzle-orm@0.45.2(@types/pg@8.20.0)(pg@8.21.0)))(drizzle-orm@0.45.2(@types/pg@8.20.0)(pg@8.21.0))(eslint@10.4.0(jiti@2.7.0))(ioredis@5.11.0)(lightningcss@1.32.0)(magicast@0.5.3)(optionator@0.9.4)(rollup-plugin-visualizer@7.0.1(rollup@4.60.4))(rollup@4.60.4)(srvx@0.11.16)(terser@5.48.0)(tsx@4.22.3)(typescript@6.0.3)(vite@7.3.3(@types/node@25.9.1)(jiti@2.7.0)(lightningcss@1.32.0)(terser@5.48.0)(tsx@4.22.3)(yaml@2.9.0))(yaml@2.9.0)
+      nuxt-auth-utils:
+        specifier: ^0.5.29
+        version: 0.5.29(magicast@0.5.3)
       pg:
         specifier: ^8.21.0
         version: 8.21.0
@@ -69,6 +72,18 @@ importers:
 
 packages:
 
+  '@adonisjs/hash@9.1.1':
+    resolution: {integrity: sha512-ZkRguwjAp4skKvKDdRAfdJ2oqQ0N7p9l3sioyXO1E8o0WcsyDgEpsTQtuVNoIdMiw4sn4gJlmL3nyF4BcK1ZDQ==}
+    engines: {node: '>=20.6.0'}
+    peerDependencies:
+      argon2: ^0.31.2 || ^0.41.0 || ^0.43.0
+      bcrypt: ^5.1.1 || ^6.0.0
+    peerDependenciesMeta:
+      argon2:
+        optional: true
+      bcrypt:
+        optional: true
+
   '@antfu/install-pkg@1.1.0':
     resolution: {integrity: sha512-MGQsmw10ZyI+EJo45CdSER4zEb+p31LpDAFp2Z3gkSd1yqVZGi0Ebx++YTEMonJy4oChEMLsxZ64j8FH6sSqtQ==}
 
@@ -1667,6 +1682,10 @@ packages:
     resolution: {integrity: sha512-tmmZ3lQxAe/k/+rNnXQRawJ4NjxO2hqiOLTHvWchtGZULp4RyFeh6aU4XdOYBFe2KE1oShQTv4AblOs2iOrNnQ==}
     engines: {node: '>= 10.0.0'}
 
+  '@phc/format@1.0.0':
+    resolution: {integrity: sha512-m7X9U6BG2+J+R1lSOdCiITLLrxm+cWlNI3HUFA92oLO77ObGNzaKdh8pMLqdZcshtkKuV84olNNXDfMc4FezBQ==}
+    engines: {node: '>=10'}
+
   '@pkgjs/parseargs@0.11.0':
     resolution: {integrity: sha512-+1VkjdD0QBLPodGrJUeqarH8VAIvQODIbwh9XpP5Syisf7YoQgsJKPNFoqqLQlu+VQ/tVSshMR6loPMn8U+dPg==}
     engines: {node: '>=14'}
@@ -1683,6 +1702,17 @@ packages:
   '@poppinss/exception@1.2.3':
     resolution: {integrity: sha512-dCED+QRChTVatE9ibtoaxc+WkdzOSjYTKi/+uacHWIsfodVfpsueo3+DKpgU5Px8qXjgmXkSvhXvSCz3fnP9lw==}
 
+  '@poppinss/object-builder@1.1.0':
+    resolution: {integrity: sha512-FOrOq52l7u8goR5yncX14+k+Ewi5djnrt1JwXeS/FvnwAPOiveFhiczCDuvXdssAwamtrV2hp5Rw9v+n2T7hQg==}
+    engines: {node: '>=20.6.0'}
+
+  '@poppinss/string@1.7.2':
+    resolution: {integrity: sha512-A182GLDfi36iDCbhDrHB0xzrPM1fO3GHnhCDIdadf8C6eycgct4m7zusbLwEh6GPaj2Pz5BVos7XK16w7tZ7wQ==}
+
+  '@poppinss/utils@6.10.1':
+    resolution: {integrity: sha512-da+MMyeXhBaKtxQiWPfy7+056wk3lVIhioJnXHXkJ2/OHDaZfFcyKHNl1R06sdYO8lIRXcXdoZ6LO2ARmkAREA==}
+    engines: {node: '>=18.16.0'}
+
   '@rolldown/pluginutils@1.0.1':
     resolution: {integrity: sha512-2j9bGt5Jh8hj+vPtgzPtl72j0yRxHAyumoo6TNfAjsLB04UtpSvPbPcDcBMxz7n+9CYB0c1GxQFxYRg2jimqGw==}
 
@@ -2050,6 +2080,9 @@ packages:
   '@types/pg@8.20.0':
     resolution: {integrity: sha512-bEPFOaMAHTEP1EzpvHTbmwR8UsFyHSKsRisLIHVMXnpNefSbGA1bD6CVy+qKjGSqmZqNqBDV2azOBo8TgkcVow==}
 
+  '@types/pluralize@0.0.33':
+    resolution: {integrity: sha512-JOqsl+ZoCpP4e8TDke9W79FDcSgPAR0l6pixx2JHkhnRjvShyYiAYw2LVsnA7K08Y6DeOnaU6ujmENO4os/cYg==}
+
   '@types/resolve@1.20.2':
     resolution: {integrity: sha512-60BCwRFOZCQhDncwQdxxeOEEkbc5dIMccYLwbxsS4TUNeVECQ/pBJ0j09mrHOl/JJvpRPGwO9SvE4nR2Nb/a4Q==}
 
@@ -2611,6 +2644,10 @@ packages:
   caniuse-lite@1.0.30001793:
     resolution: {integrity: sha512-iwSsYWaCOoh26cV8NwNRViHlrfUvYsHDfRVcbtmw0Kg6PJIZZXwMkj1442FYLBGkeUf1juAsU3DTfxW579mrPA==}
 
+  case-anything@3.1.2:
+    resolution: {integrity: sha512-wljhAjDDIv/hM2FzgJnYQg90AWmZMNtESCjTeLH680qTzdo0nErlCxOmgzgX4ZsZAtIvqHyD87ES8QyriXB+BQ==}
+    engines: {node: '>=18'}
+
   chai@6.2.2:
     resolution: {integrity: sha512-NUPRluOfOiTKBKvWPtSD4PhFvWCqOi0BGStNWs57X9js7XGTprSmFoz5F0tWhR4WPjNeR9jXqdC7/UpSJTnlRg==}
     engines: {node: '>=18'}
@@ -3332,6 +3369,10 @@ packages:
   flatted@3.4.2:
     resolution: {integrity: sha512-PjDse7RzhcPkIJwy5t7KPWQSZ9cAbzQXcafsetQoD7sOJRQlGikNbx7yZp2OotDnJyrDcbyRq3Ttb18iYOqkxA==}
 
+  flattie@1.1.1:
+    resolution: {integrity: sha512-9UbaD6XdAL97+k/n+N7JwX46K/M6Zc6KcFYskrYL8wbBV/Uyk0CTAMY0VT+qiK5PM7AIc9aTWYtq65U7T+aCNQ==}
+    engines: {node: '>=8'}
+
   foreground-child@3.3.1:
     resolution: {integrity: sha512-gIXjKqtFuWEgzFRJA9WCQeSJLZDjgJUOMCMzxtvFq/37KojM1BFGufqsCy0r4qSQmYLsZYMeyRqzIWOMup03sw==}
     engines: {node: '>=14'}
@@ -3596,6 +3637,9 @@ packages:
     resolution: {integrity: sha512-AC/7JofJvZGrrneWNaEnJeOLUx+JlGt7tNa0wZiRPT4MY1wmfKjt2+6O2p2uz2+skll8OZZmJMNqeke7kKbNgQ==}
     hasBin: true
 
+  jose@6.2.3:
+    resolution: {integrity: sha512-YYVDInQKFJfR/xa3ojUTl8c2KoTwiL1R5Wg9YCydwH0x0B9grbzlg5HC7mMjCtUJjbQ/YnGEZIhI5tCgfTb4Hw==}
+
   js-beautify@1.15.4:
     resolution: {integrity: sha512-9/KXeZUKKJwqCXUdBxFJ3vPh467OCckSBmYDwSK/EtV090K+iMJ7zx2S3HLVDIWFQdqMIsZWbnaGiba18aWhaA==}
     engines: {node: '>=14'}
@@ -3947,6 +3991,23 @@ packages:
   nth-check@2.1.1:
     resolution: {integrity: sha512-lqjrjmaOoAnWfMmBPL+XNnynZh2+swxiX3WUE0s4yEHI6m+AwrK2UZOimIRl3X/4QctVqS8AiZjFqyOGrMXb/w==}
 
+  nuxt-auth-utils@0.5.29:
+    resolution: {integrity: sha512-aQ9oD8QR51jUCe2BFEsO/G/E0K+XUy8Skjn3hYcNLiqZ9XE4Y3uT/ozBCmAQ+TR3WW6prj8vUR0wQes8W1N0PA==}
+    peerDependencies:
+      '@atproto/api': ^0.13.15
+      '@atproto/oauth-client-node': ^0.2.0
+      '@simplewebauthn/browser': ^11.0.0
+      '@simplewebauthn/server': ^11.0.0
+    peerDependenciesMeta:
+      '@atproto/api':
+        optional: true
+      '@atproto/oauth-client-node':
+        optional: true
+      '@simplewebauthn/browser':
+        optional: true
+      '@simplewebauthn/server':
+        optional: true
+
   nuxt@4.4.6:
     resolution: {integrity: sha512-QAApJpAx3yGf3pYudALkInuBfv0WkHCiol6ntTvh/lwKwYrcU/MRI1nLNGt0QNyUCgBWdOQukd3z67VJ2xGd0Q==}
     engines: {node: ^22.12.0 || ^24.11.0 || >=26.0.0}
@@ -3965,6 +4026,9 @@ packages:
     engines: {node: '>=18'}
     hasBin: true
 
+  oauth4webapi@3.8.6:
+    resolution: {integrity: sha512-iwemM91xz8nryHti2yTmg5fhyEMVOkOXwHNqbvcATjyajb5oQxCQzrNOA6uElRHuMhQQTKUyFKV9y/CNyg25BQ==}
+
   object-deep-merge@2.0.1:
     resolution: {integrity: sha512-aKttDKcU3pyZqKcCkDhsMn70WmZFG2JGDQLP9EcLyTSIFQRCPWLAmBZRLJnrVUrhPG1jETEEbfdgbNtJf1LyMg==}
 
@@ -4000,6 +4064,9 @@ packages:
     resolution: {integrity: sha512-smsWv2LzFjP03xmvFoJ331ss6h+jixfA4UUV/Bsiyuu4YJPfN+FIQGOIiv4w9/+MoHkfkJ22UIaQWRVFRfH6Vw==}
     engines: {node: '>=20'}
 
+  openid-client@6.8.4:
+    resolution: {integrity: sha512-QSw0BA08piujetEwfZsHoTrDpMEha7GDZDicQqVwX4u0ChCjefvjDB++TZ8BTg76UpwhzIQgdvvfgfl3HpCSAw==}
+
   optionator@0.9.4:
     resolution: {integrity: sha512-6IpQ7mKUxRcZNLIObR0hz7lxsapSSIYNZJwXPGeF0mTVqGKFIXj1DQcMoT22S3ROcLyY/rz0PWaWZ9ayWmad9g==}
     engines: {node: '>= 0.8.0'}
@@ -4480,6 +4547,10 @@ packages:
   safe-buffer@5.2.1:
     resolution: {integrity: sha512-rp3So07KcdmmKbGvgaNxQSJr7bGVSVk5S9Eq1F+ppbRo70+YeaDxkw5Dd8NPN+GD6bjnYm2VuPuCXmpuYvmCXQ==}
 
+  safe-stable-stringify@2.5.0:
+    resolution: {integrity: sha512-b3rppTKm9T+PsVCBEOUR46GWI7fdOs00VKZ1+9c1EWDaDMvjQc6tUwuFyIprgGgTcWoVHSKrU8H31ZHA2e0RHA==}
+    engines: {node: '>=10'}
+
   sax@1.6.0:
     resolution: {integrity: sha512-6R3J5M4AcbtLUdZmRv2SygeVaM7IhrLXu9BmnOGmmACak8fiUtOsYNWUS4uK7upbmHIBbLBeFeI//477BKLBzA==}
     engines: {node: '>=11.0.0'}
@@ -4491,6 +4562,9 @@ packages:
   scule@1.3.0:
     resolution: {integrity: sha512-6FtHJEvt+pVMIB9IBY+IcCJ6Z5f1iQnytgyfKMhDKgmzYG+TeH/wx1y3l27rshSbLiSanrR9ffZDrEsmjlQF2g==}
 
+  secure-json-parse@4.1.0:
+    resolution: {integrity: sha512-l4KnYfEyqYJxDwlNVyRfO2E4NTHfMKAWdUuA8J0yve2Dz/E/PdBepY03RvyJpssIpRFwJoCD55wA+mEDs6ByWA==}
+
   semver@6.3.1:
     resolution: {integrity: sha512-BR7VvDCVHO+q2xBEWskxS6DJE1qRnb7DxzUrogb71CWoSficBxYsiAGd+Kl0mmq/MprG9yArRkyrQxTO6XjMzA==}
     hasBin: true
@@ -4558,6 +4632,10 @@ packages:
     resolution: {integrity: sha512-ZA6oR3T/pEyuqwMgAKT0/hAv8oAXckzbkmR0UkUosQ+Mc4RxGoJkRmwHgHufaenlyAgE1Mxgpdcrf75y6XcnDg==}
     engines: {node: '>=14.16'}
 
+  slugify@1.6.9:
+    resolution: {integrity: sha512-vZ7rfeehZui7wQs438JXBckYLkIIdfHOXsaVEUMyS5fHo1483l1bMdo0EDSWYclY0yZKFOipDy4KHuKs6ssvdg==}
+    engines: {node: '>=8.0.0'}
+
   smob@1.6.2:
     resolution: {integrity: sha512-RQsvleCbF8cVHEv+xuDGaA4pOizFqJ0GgjtMSRo6oP8pnN7WsigHgVGey6aILRBKv4W2YOMHLqbKdnB6hpB9fw==}
     engines: {node: '>=20.0.0'}
@@ -5234,6 +5312,11 @@ packages:
 
 snapshots:
 
+  '@adonisjs/hash@9.1.1':
+    dependencies:
+      '@phc/format': 1.0.0
+      '@poppinss/utils': 6.10.1
+
   '@antfu/install-pkg@1.1.0':
     dependencies:
       package-manager-detector: 1.6.0
@@ -6654,6 +6737,8 @@ snapshots:
       '@parcel/watcher-win32-ia32': 2.5.6
       '@parcel/watcher-win32-x64': 2.5.6
 
+  '@phc/format@1.0.0': {}
+
   '@pkgjs/parseargs@0.11.0':
     optional: true
 
@@ -6671,6 +6756,24 @@ snapshots:
 
   '@poppinss/exception@1.2.3': {}
 
+  '@poppinss/object-builder@1.1.0': {}
+
+  '@poppinss/string@1.7.2':
+    dependencies:
+      '@types/pluralize': 0.0.33
+      case-anything: 3.1.2
+      pluralize: 8.0.0
+      slugify: 1.6.9
+
+  '@poppinss/utils@6.10.1':
+    dependencies:
+      '@poppinss/exception': 1.2.3
+      '@poppinss/object-builder': 1.1.0
+      '@poppinss/string': 1.7.2
+      flattie: 1.1.1
+      safe-stable-stringify: 2.5.0
+      secure-json-parse: 4.1.0
+
   '@rolldown/pluginutils@1.0.1': {}
 
   '@rollup/plugin-alias@6.0.0(rollup@4.60.4)':
@@ -6937,6 +7040,8 @@ snapshots:
       pg-protocol: 1.14.0
       pg-types: 2.2.0
 
+  '@types/pluralize@0.0.33': {}
+
   '@types/resolve@1.20.2': {}
 
   '@types/whatwg-mimetype@3.0.2': {}
@@ -7540,6 +7645,8 @@ snapshots:
 
   caniuse-lite@1.0.30001793: {}
 
+  case-anything@3.1.2: {}
+
   chai@6.2.2: {}
 
   change-case@5.4.4: {}
@@ -8260,6 +8367,8 @@ snapshots:
 
   flatted@3.4.2: {}
 
+  flattie@1.1.1: {}
+
   foreground-child@3.3.1:
     dependencies:
       cross-spawn: 7.0.6
@@ -8503,6 +8612,8 @@ snapshots:
 
   jiti@2.7.0: {}
 
+  jose@6.2.3: {}
+
   js-beautify@1.15.4:
     dependencies:
       config-chain: 1.1.13
@@ -8895,6 +9006,24 @@ snapshots:
     dependencies:
       boolbase: 1.0.0
 
+  nuxt-auth-utils@0.5.29(magicast@0.5.3):
+    dependencies:
+      '@adonisjs/hash': 9.1.1
+      '@nuxt/kit': 4.4.6(magicast@0.5.3)
+      defu: 6.1.7
+      h3: 1.15.11
+      hookable: 6.1.1
+      jose: 6.2.3
+      ofetch: 1.5.1
+      openid-client: 6.8.4
+      pathe: 2.0.3
+      scule: 1.3.0
+      uncrypto: 0.1.3
+    transitivePeerDependencies:
+      - argon2
+      - bcrypt
+      - magicast
+
   nuxt@4.4.6(@babel/plugin-syntax-jsx@7.29.7(@babel/core@7.29.7))(@babel/plugin-syntax-typescript@7.29.7(@babel/core@7.29.7))(@parcel/watcher@2.5.6)(@types/node@25.9.1)(@vue/compiler-sfc@3.5.34)(cac@6.7.14)(db0@0.3.4(drizzle-orm@0.45.2(@types/pg@8.20.0)(pg@8.21.0)))(drizzle-orm@0.45.2(@types/pg@8.20.0)(pg@8.21.0))(eslint@10.4.0(jiti@2.7.0))(ioredis@5.11.0)(lightningcss@1.32.0)(magicast@0.5.3)(optionator@0.9.4)(rollup-plugin-visualizer@7.0.1(rollup@4.60.4))(rollup@4.60.4)(srvx@0.11.16)(terser@5.48.0)(tsx@4.22.3)(typescript@6.0.3)(vite@7.3.3(@types/node@25.9.1)(jiti@2.7.0)(lightningcss@1.32.0)(terser@5.48.0)(tsx@4.22.3)(yaml@2.9.0))(yaml@2.9.0):
     dependencies:
       '@dxup/nuxt': 0.4.1(magicast@0.5.3)(typescript@6.0.3)
@@ -9031,6 +9160,8 @@ snapshots:
       pathe: 2.0.3
       tinyexec: 1.2.2
 
+  oauth4webapi@3.8.6: {}
+
   object-deep-merge@2.0.1: {}
 
   obug@2.1.1: {}
@@ -9071,6 +9202,11 @@ snapshots:
       powershell-utils: 0.1.0
       wsl-utils: 0.3.1
 
+  openid-client@6.8.4:
+    dependencies:
+      jose: 6.2.3
+      oauth4webapi: 3.8.6
+
   optionator@0.9.4:
     dependencies:
       deep-is: 0.1.4
@@ -9587,6 +9723,8 @@ snapshots:
 
   safe-buffer@5.2.1: {}
 
+  safe-stable-stringify@2.5.0: {}
+
   sax@1.6.0: {}
 
   scslre@0.3.0:
@@ -9597,6 +9735,8 @@ snapshots:
 
   scule@1.3.0: {}
 
+  secure-json-parse@4.1.0: {}
+
   semver@6.3.1: {}
 
   semver@7.8.1: {}
@@ -9670,6 +9810,8 @@ snapshots:
 
   slash@5.1.0: {}
 
+  slugify@1.6.9: {}
+
   smob@1.6.2: {}
 
   source-map-js@1.2.1: {}
diff --git a/server/api/defects.post.ts b/server/api/defects.post.ts
index dc20d19..7bbf48e 100644
--- a/server/api/defects.post.ts
+++ b/server/api/defects.post.ts
@@ -11,5 +11,5 @@ export default defineEventHandler(async (event) => {
   if (input instanceof type.errors) {
     throw createError({ statusCode: 400, statusMessage: input.summary })
   }
-  return createDefect(getDb(), { ...input, reporterEmail: getReporter(event) })
+  return createDefect(getDb(), { ...input, reporterEmail: await getReporter(event) })
 })
diff --git a/server/middleware/auth.ts b/server/middleware/auth.ts
new file mode 100644
index 0000000..f7abd5a
--- /dev/null
+++ b/server/middleware/auth.ts
@@ -0,0 +1,15 @@
+import { isPublicApiPath } from '../utils/authPaths'
+
+// Default-deny gate for the data API (F9). Every `/api` route requires an
+// authenticated session except the explicitly public ones (health probe, the
+// session endpoint). Pages are guarded separately by app/middleware/auth.global
+// so static assets and the OAuth route stay reachable while unauthenticated.
+export default defineEventHandler(async (event) => {
+  if (!event.path.startsWith('/api/')) return
+  if (isPublicApiPath(event.path)) return
+
+  const { user } = await getUserSession(event)
+  if (!user) {
+    throw createError({ statusCode: 401, statusMessage: 'Authentication required' })
+  }
+})
diff --git a/server/routes/auth/google/callback.get.ts b/server/routes/auth/google/callback.get.ts
new file mode 100644
index 0000000..7d86e33
--- /dev/null
+++ b/server/routes/auth/google/callback.get.ts
@@ -0,0 +1,25 @@
+import { isAllowedGoogleUser, type GoogleUserInfo } from '../../../utils/allowedGoogleUser'
+
+// Google OAuth entry + callback (F9). nuxt-auth-utils uses one handler for
+// both legs: with no `?code` it redirects to Google; on return it exchanges the
+// code and hands us the verified userinfo. We then re-check the email domain
+// server-side (the `hd` claim is not trusted) before minting a session.
+export default defineOAuthGoogleEventHandler({
+  config: {},
+  async onSuccess(event, { user }) {
+    const info = user as GoogleUserInfo
+    if (!isAllowedGoogleUser(info)) {
+      await clearUserSession(event)
+      return sendRedirect(event, '/login?error=domain')
+    }
+    await setUserSession(event, {
+      // isAllowedGoogleUser guarantees a present email; narrow for the compiler.
+      user: { email: info.email!, name: user.name, picture: user.picture },
+    })
+    return sendRedirect(event, '/')
+  },
+  onError(event, error) {
+    console.error('Google OAuth error:', error)
+    return sendRedirect(event, '/login?error=oauth')
+  },
+})
diff --git a/server/utils/allowedGoogleUser.ts b/server/utils/allowedGoogleUser.ts
new file mode 100644
index 0000000..3fe0cbb
--- /dev/null
+++ b/server/utils/allowedGoogleUser.ts
@@ -0,0 +1,21 @@
+// Authorisation gate for Google identities (F9, DESIGN T9).
+//
+// Access is restricted to the company's verified email domain. We deliberately
+// ignore Google's `hd` (hosted-domain) claim as the source of truth: a personal
+// account can be made to present an `hd`, so we re-derive the domain from the
+// email Google itself reports as verified.
+const ALLOWED_EMAIL_DOMAIN = 'theodo.com'
+
+export interface GoogleUserInfo {
+  email?: string
+  email_verified?: boolean | string
+  // `hd` is intentionally not consulted — see the module comment.
+  hd?: string
+}
+
+export function isAllowedGoogleUser(user: GoogleUserInfo): boolean {
+  const verified = user.email_verified === true || user.email_verified === 'true'
+  if (!verified || !user.email) return false
+  const domain = user.email.split('@')[1]?.toLowerCase()
+  return domain === ALLOWED_EMAIL_DOMAIN
+}
diff --git a/server/utils/authPaths.ts b/server/utils/authPaths.ts
new file mode 100644
index 0000000..c567d1e
--- /dev/null
+++ b/server/utils/authPaths.ts
@@ -0,0 +1,12 @@
+// Which `/api` routes bypass the default-deny auth middleware (F9).
+//
+// `/api/health` must answer for the orchestrator's liveness probe before any
+// session exists; `/api/_auth/*` is nuxt-auth-utils' own session endpoint that
+// the client uses to read/clear the session. Everything else under `/api`
+// requires an authenticated session.
+const PUBLIC_API_PREFIXES = ['/api/health', '/api/_auth/']
+
+export function isPublicApiPath(path: string): boolean {
+  const pathname = path.split('?')[0]!
+  return PUBLIC_API_PREFIXES.some((prefix) => pathname.startsWith(prefix))
+}
diff --git a/server/utils/getReporter.ts b/server/utils/getReporter.ts
index 0bcdda3..fb9946d 100644
--- a/server/utils/getReporter.ts
+++ b/server/utils/getReporter.ts
@@ -2,9 +2,14 @@ import type { H3Event } from 'h3'
 
 /**
  * Resolves the reporter's email — the one seam between filing and auth (ADR
- * 0002). For now it returns a fixed dev identity so the filing slice works
- * before OAuth exists; Task 9 swaps this to read the verified session email.
+ * 0002). Backed by the authenticated Google session (Task 9) so defects record
+ * the true reporter. The auth middleware already gates the filing endpoint, so
+ * a missing session here is an unexpected 401, not a normal path.
  */
-export function getReporter(_event: H3Event): string {
-  return process.env.DEV_REPORTER_EMAIL ?? 'dev@theodo.com'
+export async function getReporter(event: H3Event): Promise<string> {
+  const { user } = await getUserSession(event)
+  if (!user?.email) {
+    throw createError({ statusCode: 401, statusMessage: 'Authentication required' })
+  }
+  return user.email
 }
diff --git a/shared/auth.d.ts b/shared/auth.d.ts
new file mode 100644
index 0000000..4c4fa7e
--- /dev/null
+++ b/shared/auth.d.ts
@@ -0,0 +1,12 @@
+// Shape of the authenticated session for nuxt-auth-utils (Task 9, F9).
+// Lives in shared/ so both the app and server TS projects pick up the
+// #auth-utils augmentation.
+declare module '#auth-utils' {
+  interface User {
+    email: string
+    name?: string
+    picture?: string
+  }
+}
+
+export {}
diff --git a/tasks/todo.md b/tasks/todo.md
index 6d4ff3b..c36f6af 100644
--- a/tasks/todo.md
+++ b/tasks/todo.md
@@ -19,10 +19,10 @@ review.
 - [x] **T6** Defects read API: feed + per-section counts (C7) — F6 (M) — _deps: T3_
 - [x] **T7** Dashboard DotMap (C5) — F4 (M) — _deps: T2, T6_
 - [x] **T8** VerbatimModal + Feed (C6) — F5 (M) — _deps: T6, T7_
-- [ ] ⛳ **Checkpoint:** dashboard dot map + feed + modal work, ≤350ms @2k, human review
+- [x] ⛳ **Checkpoint:** dashboard dot map + feed + modal work, ≤350ms @2k, human review
 
 ## Phase 4 — Authentication (G4)
-- [ ] **T9** Google OAuth + session + domain-check middleware (C9) — F9 (M) — _deps: T1, retrofits T5_
+- [x] **T9** Google OAuth + session + domain-check middleware (C9) — F9 (M) — _deps: T1, retrofits T5_
 - [ ] ⛳ **Checkpoint:** both views gated to @theodo.com, reporters real, human review
 
 ## Phase 5 — Notifications (G3)
@@ -35,7 +35,7 @@ review.
 - [ ] ⛳ **Checkpoint:** data survives redeploy, both subdomains live, ready for review
 
 ## Blocked on open questions (see plan.md)
-- [ ] Google OAuth client provisioning (blocks T9)
+- [x] Google OAuth client provisioning (blocks T9) — client provided; redirect URI `…/auth/google/callback`
 - [ ] Confirm pnpm + Vitest + Playwright vs Theodo template (affects T1)
 - [ ] Coolify two-domain routing model (affects T12)
 - [ ] "Owner only" vs any subscribed user for push (affects T10/T11)
diff --git a/tests/auth.spec.ts b/tests/auth.spec.ts
new file mode 100644
index 0000000..50f4a87
--- /dev/null
+++ b/tests/auth.spec.ts
@@ -0,0 +1,52 @@
+import { describe, it, expect } from 'vitest'
+import { isAllowedGoogleUser } from '../server/utils/allowedGoogleUser'
+import { isPublicApiPath } from '../server/utils/authPaths'
+
+// F9: access is restricted to verified @theodo.com identities. The Google
+// `hd` (hosted-domain) claim is NOT trusted on its own — we re-derive the
+// domain from the verified email server-side (DESIGN T9).
+describe('isAllowedGoogleUser', () => {
+  it('allows a verified @theodo.com email', () => {
+    expect(isAllowedGoogleUser({ email: 'jane@theodo.com', email_verified: true })).toBe(true)
+  })
+
+  it('denies a non-theodo verified email even when hd claims theodo.com', () => {
+    expect(
+      isAllowedGoogleUser({ email: 'attacker@gmail.com', email_verified: true, hd: 'theodo.com' }),
+    ).toBe(false)
+  })
+
+  it('denies a theodo email that Google has not verified', () => {
+    expect(isAllowedGoogleUser({ email: 'jane@theodo.com', email_verified: false })).toBe(false)
+  })
+
+  it('matches the domain case-insensitively', () => {
+    expect(isAllowedGoogleUser({ email: 'jane@Theodo.COM', email_verified: true })).toBe(true)
+  })
+
+  it('denies when the email is missing', () => {
+    expect(isAllowedGoogleUser({ email_verified: true, hd: 'theodo.com' })).toBe(false)
+  })
+
+  it('denies a look-alike domain that merely ends in theodo.com', () => {
+    expect(isAllowedGoogleUser({ email: 'eve@nottheodo.com', email_verified: true })).toBe(false)
+  })
+})
+
+describe('isPublicApiPath', () => {
+  it('treats the health check as public', () => {
+    expect(isPublicApiPath('/api/health')).toBe(true)
+  })
+
+  it('treats the session endpoint as public', () => {
+    expect(isPublicApiPath('/api/_auth/session')).toBe(true)
+  })
+
+  it('gates the defects API', () => {
+    expect(isPublicApiPath('/api/defects')).toBe(false)
+  })
+
+  it('ignores the query string when matching', () => {
+    expect(isPublicApiPath('/api/health?probe=1')).toBe(true)
+  })
+})