web/app.js

@@ -38,6 +38,15 @@ import { LoginPage }        from './components/login-page.js';
 import './lib/open-file.js';
 import './lib/open-tool.js';
 import { initI18n } from './lib/i18n.js';
+import { installSessionExpiryWatch } from './lib/session-expiry.js';
+import { installSessionRelogin }     from './components/session-relogin.js';
+
+// Installed before anything can call the API, so no component's first fetch
+// escapes the 401 watch. A session that dies under an open tab is renewed in a
+// modal over the page, leaving the app's state — an unsent message included —
+// exactly where it was.
+installSessionExpiryWatch();
+installSessionRelogin();
 
 customElements.define('app-topbar',           AppTopbar);
 customElements.define('app-sidebar',          AppSidebar);

web/components/login-page.js

@@ -50,6 +50,9 @@ export class LoginPage extends I18nMixin(LightElement) {
         this._error = t('login.error');
         return;
       }
+      // Remembered only to prefill the re-login dialog when this browser's
+      // session dies under an open tab — never a credential, just the name.
+      try { localStorage.setItem('skald.last_user', this._username.trim()); } catch { /* private mode */ }
       // Logged in — reload into the app.
       window.location.reload();
     } catch {

web/components/mobile-app.js

@@ -1,6 +1,8 @@
 import { LitElement, html, nothing } from 'lit';
 import { t }            from '../lib/i18n.js';
 import { LoginPage }    from './login-page.js';
+import { installSessionExpiryWatch } from '../lib/session-expiry.js';
+import { installSessionRelogin }     from './session-relogin.js';
 import './shared/inbox-page.js';
 import './shared/chat-page.js';
 import './shared/projects-page.js';
@@ -10,6 +12,12 @@ import './shared/tool-detail-mobile.js';
 
 customElements.define('login-page', LoginPage);
 
+// A session lost mid-use is renewed in place, over whatever section is open —
+// same seam as the desktop shell. Both are no-ops in the native shell, which
+// authenticates on its own.
+installSessionExpiryWatch();
+installSessionRelogin();
+
 // Sections addressable via the URL hash — same routing style as the desktop
 // sidebar (web/components/sidebar.js). The native iOS shell and mobile browsers
 // share this router so the URL always reflects the active section: native menu

web/components/session-relogin.js

@@ -0,0 +1,160 @@
+import { html, nothing } from 'lit';
+import { LightElement } from '../lib/base.js';
+import { t, I18nMixin } from '../lib/i18n.js';
+import { notifySessionRestored } from '../lib/session-expiry.js';
+
+/**
+ * Re-login dialog for a session that died under an open tab.
+ *
+ * Sessions live in the server's RAM (blueprint §9), so a restart logs everyone
+ * out while their browser keeps sending a cookie nobody recognises. The obvious
+ * answer — bounce to the login screen — throws away everything the page was
+ * holding, and the composer's half-written message with it. So the session is
+ * renewed **in place**: a modal over the page the user was already on, one
+ * password field, and on success the app carries on with its state intact (the
+ * chat reconnects on `auth-restored`).
+ *
+ * Not dismissible, deliberately: with no session nothing on the page works, and
+ * a dialog you can wave away would leave a UI that silently fails every action.
+ */
+export class SessionRelogin extends I18nMixin(LightElement) {
+
+  static get properties() {
+    return {
+      _open:     { state: true },
+      _username: { state: true },
+      _password: { state: true },
+      _error:    { state: true },
+      _busy:     { state: true },
+    };
+  }
+
+  constructor() {
+    super();
+    this._open     = false;
+    this._username = '';
+    this._password = '';
+    this._error    = null;
+    this._busy     = false;
+  }
+
+  /** Raise the dialog, prefilling the last username known to this browser. */
+  open() {
+    if (this._open) return;
+    let last = '';
+    try { last = localStorage.getItem('skald.last_user') ?? ''; } catch { /* private mode */ }
+    this._username = last;
+    this._password = '';
+    this._error    = null;
+    this._open     = true;
+    // Focus the field the user actually has to fill: the password when we
+    // already know who they are, the username otherwise.
+    this.updateComplete.then(() => {
+      const sel = last ? 'input[type="password"]' : 'input[type="text"]';
+      this.querySelector(sel)?.focus();
+    });
+  }
+
+  _submit(e) {
+    e.preventDefault();
+    if (this._busy) return;
+    this._error = null;
+    if (!this._username.trim() || !this._password) {
+      this._error = t('login.missing');
+      return;
+    }
+    this._doLogin();
+  }
+
+  async _doLogin() {
+    this._busy = true;
+    try {
+      const res = await fetch('/api/auth/login', {
+        method:  'POST',
+        headers: { 'Content-Type': 'application/json' },
+        body:    JSON.stringify({
+          username: this._username.trim(),
+          password: this._password,
+        }),
+      });
+      if (!res.ok) {
+        this._error = t('login.error');
+        return;
+      }
+      try { localStorage.setItem('skald.last_user', this._username.trim()); } catch { /* private mode */ }
+      this._password = '';
+      this._open     = false;
+      // The new cookie is live: tell the app to pick its connections back up.
+      notifySessionRestored();
+    } catch {
+      this._error = t('login.network');
+    } finally {
+      this._busy = false;
+    }
+  }
+
+  render() {
+    if (!this._open) return nothing;
+    const btnLabel = this._busy
+      ? html`<span class="login-spinner"></span>${t('login.signing')}`
+      : t('login.submit');
+
+    return html`
+      <div class="relogin-backdrop">
+        <form class="login-card relogin-card" @submit=${this._submit} autocomplete="on">
+          <h2 class="login-title relogin-title">${t('login.expired.title')}</h2>
+          <p class="login-subtitle">${t('login.expired')}</p>
+
+          ${this._error ? html`<div class="login-error">${this._error}</div>` : null}
+
+          <div class="mb-3">
+            <label class="form-label">${t('login.username')}</label>
+            <input
+              type="text"
+              class="form-control"
+              autocomplete="username"
+              .value=${this._username}
+              @input=${e => this._username = e.target.value}
+              ?disabled=${this._busy} />
+          </div>
+
+          <div class="mb-3">
+            <label class="form-label">${t('login.password')}</label>
+            <input
+              type="password"
+              class="form-control"
+              autocomplete="current-password"
+              .value=${this._password}
+              @input=${e => this._password = e.target.value}
+              ?disabled=${this._busy} />
+          </div>
+
+          <button type="submit" class="btn btn-primary login-submit" ?disabled=${this._busy}>
+            ${btnLabel}
+          </button>
+        </form>
+      </div>
+    `;
+  }
+}
+
+/**
+ * Mount the dialog and wire it to `auth-expired`.
+ *
+ * The element appends itself to `<body>` rather than living in the two shells'
+ * HTML: it belongs to whichever page happens to be open, and desktop and mobile
+ * would otherwise each have to remember to declare it.
+ */
+export function installSessionRelogin() {
+  if (!customElements.get('session-relogin')) {
+    customElements.define('session-relogin', SessionRelogin);
+  }
+  let el = null;
+  window.addEventListener('auth-expired', () => {
+    if (!el) {
+      el = document.createElement('session-relogin');
+      document.body.appendChild(el);
+    }
+    el.open();
+  });
+}

web/css/setup-page.css

@@ -105,3 +105,41 @@
 .login-spinner {
   animation-name: setup-spin;
 }
+
+/* ── Re-login dialog ──────────────────────────────────────────────────────────
+   Raised over the page the user is already on when their session dies (see
+   components/session-relogin.js). Deliberately a scrim rather than an opaque
+   screen: seeing the work still there is the whole point of not navigating
+   away. Reuses `.login-card` so the two login surfaces cannot drift apart. */
+
+.relogin-backdrop {
+  position: fixed;
+  inset: 0;
+  z-index: 10000;                 /* above the login screen's own layer */
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  padding: 24px;
+  background: rgba(0, 0, 0, .5);
+  backdrop-filter: blur(2px);
+  overflow: auto;
+}
+
+.relogin-card {
+  max-width: 400px;
+  padding: 28px 28px 24px;
+}
+
+.relogin-title {
+  font-size: 1.15rem;
+  margin-bottom: 10px;
+}
+
+@media (prefers-reduced-motion: no-preference) {
+  .relogin-card { animation: relogin-in .18s ease-out; }
+}
+
+@keyframes relogin-in {
+  from { opacity: 0; transform: translateY(8px); }
+  to   { opacity: 1; transform: none; }
+}

web/i18n/en.js

@@ -79,6 +79,7 @@ export default {
   'chat.rejected':        'Denied.',
   'chat.rejected_by_user': 'Denied by user.',
   'chat.truncated':      'Response truncated by the token limit (↓{tokens} tok).',
+  'chat.not_connected':  'Not connected — reconnecting. Your message is still in the box: press Enter again in a moment.',
 
   // ── Copilot render ─────────────────────────────────────────────────────────
   'copilot.open_in_viewer':     'Open in viewer',
@@ -307,6 +308,8 @@ export default {
   // ── Login ──────────────────────────────────────────────────────────────────
   'login.title':    'Welcome back',
   'login.subtitle': 'Sign in to your account.',
+  'login.expired.title': 'Session expired',
+  'login.expired':  'The server was restarted, so your session ended. Sign in again to carry on — the page keeps everything you had open, including any unsent message.',
   'login.username': 'Username',
   'login.password': 'Password',
   'login.submit':   'Sign in',

web/i18n/fr.js

@@ -79,6 +79,7 @@ export default {
   'chat.rejected':        'Refusé.',
   'chat.rejected_by_user': 'Refusé par l\'utilisateur.',
   'chat.truncated':      'Réponse tronquée par la limite de tokens (↓{tokens} tok).',
+  'chat.not_connected':  'Non connecté — reconnexion en cours. Votre message est resté dans le champ : appuyez de nouveau sur Entrée dans un instant.',
 
   // ── Copilot render ─────────────────────────────────────────────────────────
   'copilot.open_in_viewer':     'Ouvrir dans le visualiseur',
@@ -307,6 +308,8 @@ export default {
   // ── Login ──────────────────────────────────────────────────────────────────
   'login.title':    'Bon retour',
   'login.subtitle': 'Connectez-vous à votre compte.',
+  'login.expired.title': 'Session expirée',
+  'login.expired':  'Le serveur a redémarré, votre session a donc pris fin. Reconnectez-vous pour continuer : la page reste telle quelle, message non envoyé compris.',
   'login.username': 'Nom d\'utilisateur',
   'login.password': 'Mot de passe',
   'login.submit':   'Se connecter',

web/i18n/it.js

@@ -79,6 +79,7 @@ export default {
   'chat.rejected':        'Negata.',
   'chat.rejected_by_user': 'Negata dall\'utente.',
   'chat.truncated':      'Risposta troncata dal limite di token (↓{tokens} tok).',
+  'chat.not_connected':  'Non connesso — riconnessione in corso. Il messaggio è rimasto nella casella: premi di nuovo Invio tra un istante.',
 
   // ── Copilot render ─────────────────────────────────────────────────────────
   'copilot.open_in_viewer':     'Apri nel visualizzatore',
@@ -307,6 +308,8 @@ export default {
   // ── Accesso ────────────────────────────────────────────────────────────────
   'login.title':    'Bentornato',
   'login.subtitle': 'Accedi al tuo account.',
+  'login.expired.title': 'Sessione scaduta',
+  'login.expired':  'Il server è stato riavviato e la sessione è terminata. Accedi di nuovo per proseguire: la pagina resta com\'era, messaggio non inviato compreso.',
   'login.username': 'Nome utente',
   'login.password': 'Password',
   'login.submit':   'Accedi',

web/lib/chat-session.js

@@ -1,6 +1,7 @@
 import { html, nothing } from 'lit';
 import { LightElement } from './base.js';
 import { t } from './i18n.js';
+import { isSessionExpired, notifySessionExpired, probeSession } from './session-expiry.js';
 
 // Slash commands handled entirely server-side: they reply with a `Done` and never
 // echo back as a `user_message`, so they are the only commands rendered
@@ -109,10 +110,12 @@ export class ChatSession extends LightElement {
     // Each entry: { name, path, mimetype, filesize, uploading? }. While an upload
     // is in flight the entry has `uploading: true` and no `path` yet.
     this._attachments       = [];
+    this._onAuthRestored    = this._onAuthRestored.bind(this);
   }
 
   async connectedCallback() {
     super.connectedCallback();
+    window.addEventListener('auth-restored', this._onAuthRestored);
     // Fire-and-forget: availability of a transcription provider determines
     // whether the mic button is rendered at all.
     this._checkTranscribe();
@@ -120,6 +123,11 @@ export class ChatSession extends LightElement {
     this._connectWS();
   }
 
+  disconnectedCallback() {
+    super.disconnectedCallback?.();
+    window.removeEventListener('auth-restored', this._onAuthRestored);
+  }
+
   // ── Source identity — override in subclass ────────────────────────────────────
 
   // Static default source for this component. Subclasses override (e.g. 'mobile').
@@ -223,7 +231,38 @@ export class ChatSession extends LightElement {
       }
     };
     ws.onmessage = (ev) => this._handleServerMsg(JSON.parse(ev.data));
-    ws.onclose   = ()   => { this._reconnecting = true; setTimeout(() => this._connectWS(), 2000); };
+    ws.onclose   = ()   => { this._reconnecting = true; this._scheduleReconnect(); };
+  }
+
+  /**
+   * Reconnect after an unexpected close — unless we were dropped because the
+   * server no longer knows this browser. Sessions live in the server's RAM
+   * (blueprint §9), so a restart refuses the WS upgrade, and a refused upgrade
+   * reaches `onclose` looking exactly like a flaky network: the loop used to
+   * retry every 2 s forever behind "Not connected", against a server that would
+   * never accept it again. So ask first, and let the re-login dialog take it
+   * from there — the socket comes back on `auth-restored`.
+   */
+  async _scheduleReconnect() {
+    if (isSessionExpired()) return;               // the dialog is already up
+    if ((await probeSession()) === 'expired') {
+      notifySessionExpired();
+      // A shell that handles auth itself (native mobile) ignores the report;
+      // there is no dialog coming, so keep retrying as before.
+      if (isSessionExpired()) return;
+    }
+    setTimeout(() => this._connectWS(), 2000);
+  }
+
+  /**
+   * A new session was obtained without leaving the page: reconnect and reconcile
+   * like any other unexpected disconnection (the `_reconnecting` flag is what
+   * makes `onopen` re-sync tool state that advanced while we were away).
+   */
+  _onAuthRestored() {
+    if (this._ws && this._ws.readyState !== WebSocket.CLOSED) return;
+    this._reconnecting = true;
+    this._connectWS();
   }
 
   /**
@@ -665,14 +704,26 @@ export class ChatSession extends LightElement {
     // Don't send while an attachment is still streaming to disk, or its path
     // would be missing from the message.
     if (this._attachments.some(a => a.uploading)) return;
-    this._clearInput();
-
+    // Handled entirely over HTTP (and it reconnects the socket itself), so it must
+    // stay available precisely when the socket is down.
     if (content === '/new' || content === '/clear') {
+      this._clearInput();
       this._attachments = [];
       await this._startNewSession();
       return;
     }
 
+    // Nothing below this point may run while the socket is down: everything from
+    // here on is destructive to what the user typed (the input is cleared, the
+    // attachment chips are dropped). Bailing first is what keeps a long message
+    // recoverable — the composer still holds it, so retrying after the automatic
+    // reconnect is one Enter, not a retype.
+    if (this._ws?.readyState !== WebSocket.OPEN) {
+      this._pushError(t('chat.not_connected'));
+      return;
+    }
+    this._clearInput();
+
     // Strip client-only fields; the server persists these as message metadata.
     const attachments = this._attachments.map(({ name, path, mimetype, filesize }) =>
       ({ name, path, mimetype, filesize }));
@@ -692,13 +743,7 @@ export class ChatSession extends LightElement {
       this._push({ kind: 'user', content, attachments });
     }
     this._waiting = true;
-
-    if (this._ws?.readyState === WebSocket.OPEN) {
     this._ws.send(JSON.stringify({ content, attachments }));
-    } else {
-      this._pushError('Not connected — reconnecting, please retry.');
-      this._waiting = false;
-    }
   }
 
   // ── Attachments ────────────────────────────────────────────────────────────

web/lib/session-expiry.js

@@ -0,0 +1,96 @@
+/**
+ * Session-expiry detection for an already-open tab.
+ *
+ * A session lives in the server's RAM (blueprint §9), so a restart invalidates
+ * every token while the browser keeps happily sending its cookie. From that
+ * moment every gated `/api` call answers 401 and the chat socket is refused at
+ * the upgrade — and a refused upgrade is indistinguishable, in `onclose`, from a
+ * dropped wifi. That is why the chat used to sit forever behind "Not connected —
+ * reconnecting": it was reconnecting, correctly, to a server that will never
+ * accept it again.
+ *
+ * This module is the single place that turns "the server says I am nobody" into
+ * a fact the app can act on: the `auth-expired` event, answered by the re-login
+ * dialog (`components/session-relogin.js`), and `auth-restored` once a new
+ * session is in hand. Nothing here touches the DOM — reporting and reacting stay
+ * apart, so a second reactor (a banner, a mobile-specific screen) costs nothing.
+ */
+
+let expired = false;
+
+// The native mobile shell authenticates in the background and must never be
+// gated by a web login form (the rule `mobile.html`'s bootstrap already states).
+// Guarding the report rather than each producer means no future caller can
+// reintroduce the dialog there.
+const NATIVE_SHELL = new URLSearchParams(location.search).get('native') === 'true';
+
+/** True once the server has told us this browser has no session anymore. */
+export function isSessionExpired() {
+  return expired;
+}
+
+/**
+ * Report a lost session. Idempotent and one-way: the first call fires the
+ * `auth-expired` window event, every later one is a no-op — several components
+ * discover the same 401 at once, and the dialog must be raised once.
+ */
+export function notifySessionExpired() {
+  if (expired || NATIVE_SHELL) return;
+  expired = true;
+  window.dispatchEvent(new CustomEvent('auth-expired'));
+}
+
+/**
+ * Report that a fresh session has been obtained (the re-login dialog succeeded).
+ * Re-arms the detector and fires `auth-restored`, on which the live connections
+ * that gave up — the chat socket above all — pick themselves back up.
+ */
+export function notifySessionRestored() {
+  if (!expired) return;
+  expired = false;
+  window.dispatchEvent(new CustomEvent('auth-restored'));
+}
+
+/**
+ * Ask the server whether this browser still has a session.
+ *
+ * Returns `'ok'`, `'expired'`, or `'unknown'` when the server could not be
+ * reached — the caller must treat that third case as "keep retrying", never as a
+ * logout: a box that is merely down comes back, and throwing the user at a login
+ * form they cannot submit would be strictly worse than waiting.
+ */
+export async function probeSession() {
+  try {
+    const res = await fetch('/api/auth/me');
+    if (res.status === 401) return 'expired';
+    return res.ok ? 'ok' : 'unknown';
+  } catch {
+    return 'unknown';
+  }
+}
+
+/**
+ * Wrap `window.fetch` so that a 401 from any gated `/api` endpoint reports an
+ * expired session, wherever in the app it happens.
+ *
+ * A wrapper rather than a helper every call site opts into: the components call
+ * `fetch` directly in dozens of places, and a seam that has to be remembered is
+ * one that will be forgotten by the next page. The auth endpoints are excluded
+ * because 401 is a *normal* answer there — `auth/me` is the "am I logged in?"
+ * probe and `auth/login` answers it to a wrong password; treating either as an
+ * expiry would raise the login screen from the login screen.
+ */
+export function installSessionExpiryWatch() {
+  const native = window.fetch.bind(window);
+  window.fetch = async (input, init) => {
+    const res = await native(input, init);
+    if (res.status === 401) {
+      const url = typeof input === 'string' ? input : (input?.url ?? '');
+      const path = url.startsWith('http') ? new URL(url).pathname : url;
+      if (path.startsWith('/api/') && !path.startsWith('/api/auth/') && !path.startsWith('/api/setup/')) {
+        notifySessionExpired();
+      }
+    }
+    return res;
+  };
+}