CVERInc · cverorg · Sep 24, 2026 · Sep 24, 2026
diff --git a/packages/cardtile/serve/card-worker.mjs b/packages/cardtile/serve/card-worker.mjs
@@ -328,7 +328,7 @@ function sandboxEditorHtml(localeKey, { host = '' } = {}) {
 <html lang="${persona.lang}"><head>
 <meta charset="utf-8">
 <meta name="viewport" content="width=device-width, initial-scale=1">
-<title>${escLite(persona.pageTitle)}</title>
+<title>${escLite(host ? persona.hostPageTitle : persona.pageTitle)}</title>
 <style>${EDIT2_CSS}</style>
 </head>
 <body>

diff --git a/packages/cardtile/serve/card-worker.test.mjs b/packages/cardtile/serve/card-worker.test.mjs
@@ -1057,6 +1057,9 @@ test('host mode: /edit?host=feelreef serves the editor with host opts, noindex,
       assert.deepEqual(optsOf(body), { host, sandbox: false, locale: 'ja', tableBase: '/try/edit/t/ja/' });
       assert.ok(body.includes('id="sandbox-banner" hidden'), 'host mode ships the sandbox banner hidden');
       assert.match(body, /id="host-save"/);
+      // 🔴 host mode never ships the sandbox's "Try Card · feelreef" — before the parent hands over
+      // a real card there is nothing to name yet, so the tab reads the bare product name.
+      assert.match(body, /<title>Card · feelreef<\/title>/, 'host mode ships the placeholder title, not the sandbox\'s');
       assert.deepEqual(touched, []);
     }
   }

diff --git a/packages/cardtile/serve/edit2-assets.mjs b/packages/cardtile/serve/edit2-assets.mjs
diff --git a/packages/cardtile/w/sandbox-i18n.mjs b/packages/cardtile/w/sandbox-i18n.mjs
@@ -20,7 +20,7 @@
 
 /**
  * name → persona → { lang, name, bio, linkLabel, textBody, imageAlt, bannerStatus, bannerText,
- * doorCta, reset, pageTitle }. `lang` is the BCP-47 tag written into the sandbox's `<html lang>`
+ * doorCta, reset, pageTitle, hostPageTitle }. `lang` is the BCP-47 tag written into the sandbox's `<html lang>`
  * and the starter card's own frontmatter `lang:` field.
  */
 export const SANDBOX_LOCALES = {
@@ -37,6 +37,7 @@ export const SANDBOX_LOCALES = {
     doorCta: 'Make this card real',
     reset: 'Start over',
     pageTitle: 'Try Card · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: 'Next you\'ll sign in with your email (first time? your account is made along the way, no password). This card comes with you.',
     doorContinue: 'Continue',
     doorBack: 'Keep editing',
@@ -54,6 +55,7 @@ export const SANDBOX_LOCALES = {
     doorCta: '把這張變成真的',
     reset: '重新開始',
     pageTitle: '試玩 Card · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: '接下來會請你用 email 登入（第一次會順便建好帳號，不用密碼）。這張卡會跟著你過去。',
     doorContinue: '繼續',
     doorBack: '再改一下',
@@ -71,6 +73,7 @@ export const SANDBOX_LOCALES = {
     doorCta: 'これを本物にする',
     reset: 'はじめからやり直す',
     pageTitle: 'Card を試す · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: 'このあとメールアドレスでログインします（はじめての方はアカウントも一緒に作られます。パスワードは不要）。このカードはそのまま持っていけます。',
     doorContinue: '続ける',
     doorBack: 'もう少し直す',
@@ -88,6 +91,7 @@ export const SANDBOX_LOCALES = {
     doorCta: '이 카드를 진짜로 만들기',
     reset: '처음부터 다시',
     pageTitle: 'Card 체험 · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: '다음에는 이메일로 로그인해요（처음이라면 계정도 함께 만들어져요. 비밀번호는 없어요）. 이 카드는 그대로 가져갈 수 있어요.',
     doorContinue: '계속하기',
     doorBack: '조금 더 고치기',
@@ -106,6 +110,7 @@ export const SANDBOX_LOCALES = {
     doorCta: '把这张卡片变成真的',
     reset: '重新开始',
     pageTitle: '试玩 Card · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: '接下来会请你用 email 登录（第一次会顺便建好账号，不用密码）。这张卡片会跟着你过去。',
     doorContinue: '继续',
     doorBack: '再改一下',
@@ -123,6 +128,7 @@ export const SANDBOX_LOCALES = {
     doorCta: 'Diese Karte echt machen',
     reset: 'Von vorn beginnen',
     pageTitle: 'Card ausprobieren · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: 'Als Nächstes melden Sie sich mit Ihrer E-Mail-Adresse an (beim ersten Mal wird Ihr Konto gleich mit angelegt, ohne Passwort). Diese Karte kommt mit.',
     doorContinue: 'Weiter',
     doorBack: 'Weiter bearbeiten',
@@ -140,6 +146,7 @@ export const SANDBOX_LOCALES = {
     doorCta: 'Rendre cette carte réelle',
     reset: 'Recommencer',
     pageTitle: 'Essayer Card · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: 'Ensuite, vous vous connecterez avec votre e-mail (la première fois, votre compte est créé au passage, sans mot de passe). Cette carte vous suit.',
     doorContinue: 'Continuer',
     doorBack: 'Continuer à modifier',
@@ -157,6 +164,7 @@ export const SANDBOX_LOCALES = {
     doorCta: 'Hacer real esta tarjeta',
     reset: 'Empezar de nuevo',
     pageTitle: 'Probar Card · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: 'A continuación iniciarás sesión con tu correo (la primera vez tu cuenta se crea por el camino, sin contraseña). Esta tarjeta se va contigo.',
     doorContinue: 'Continuar',
     doorBack: 'Seguir editando',
@@ -174,6 +182,7 @@ export const SANDBOX_LOCALES = {
     doorCta: 'Tornar este cartão real',
     reset: 'Começar de novo',
     pageTitle: 'Experimentar Card · feelreef',
+    hostPageTitle: 'Card · feelreef',
     doorNote: 'Em seguida você entra com o seu e-mail (na primeira vez a conta é criada junto, sem senha). Este cartão vai com você.',
     doorContinue: 'Continuar',
     doorBack: 'Continuar editando',

diff --git a/packages/cardtile/w/sandbox-i18n.test.mjs b/packages/cardtile/w/sandbox-i18n.test.mjs
@@ -25,7 +25,7 @@ test('SANDBOX_LOCALES: every one of the nine has a complete persona (no missing
     // the door: its button, the sentence before it, and the two ways out of that sentence. A locale
     // missing any of these is a locale where the door opens onto silence — see bootSandbox().
     'doorCta', 'doorNote', 'doorContinue', 'doorBack',
-    'reset', 'pageTitle', 'coachMark'];
+    'reset', 'pageTitle', 'hostPageTitle', 'coachMark'];
   for (const key of NINE) {
     const p = SANDBOX_LOCALES[key];
     assert.ok(p, `${key}: missing from SANDBOX_LOCALES entirely`);

diff --git a/packages/cardtile/w2/edit2.mjs b/packages/cardtile/w2/edit2.mjs
@@ -1280,8 +1280,28 @@ function hostSaveKey(doc) {
   }, true);
 }
 
+/** the card's own name — the frontmatter `title:` line `setTitle` writes — or '' if there is none.
+ * Read-only sibling of `setTitle`'s fence-scoped parse: never reads a `title:`-looking sentence
+ * from an author's lead prose, only the frontmatter fence itself. */
+function cardTitleFromMd(md) {
+  const pre = (() => { try { return parseCard(md).pre || ''; } catch { return ''; } })();
+  const fence = /^---\r?\n([\s\S]*?)\r?\n---[ \t]*$/m.exec(pre);
+  const m = fence && /^title:\s*(.*)$/m.exec(fence[1]);
+  return m ? m[1].trim() : '';
+}
+
+/** host mode's `<title>` — "Card · feelreef" until a real card lands, then that card's own name
+ * ahead of it. The sandbox keeps its own localised "Try Card · feelreef" (set server-side, in
+ * card-worker.mjs's `sandboxEditorHtml`, and never touched here). */
+function paintHostTitle(cardTitle) {
+  if (typeof document === 'undefined') return;
+  const brand = SANDBOX_LOCALES[primaryLocale(S.locale)].hostPageTitle;
+  document.title = cardTitle ? `${cardTitle} · ${brand}` : brand;
+}
+
 function bootHost() {
   document.body.dataset.hostWaiting = '1';          // nothing to edit until the parent hands a card over
+  paintHostTitle('');                                // same placeholder the server already rendered
   const saveBtn = el('host-save');
   saveBtn.textContent = T.pubSave;
   saveBtn.hidden = false;
@@ -1295,6 +1315,7 @@ function bootHost() {
       S.undo = [];
       delete document.body.dataset.hostWaiting;
       commit(md, { undoable: false });
+      paintHostTitle(cardTitleFromMd(md) || S.handle || '');
     },
   });
   saveBtn.onclick = () => S.bridge.save();

diff --git a/packages/cardtile/w2/host-boot.test.mjs b/packages/cardtile/w2/host-boot.test.mjs
@@ -59,7 +59,7 @@ function bootHost() {
   ctx.window.__cardtileW2Boot({ host: HOST, sandbox: false, locale: 'en', tableBase: '/try/edit/t/en/' });
   const runTimers = () => { const due = timers.splice(0); for (const t of due) if (t.fn) t.fn(); };
   const message = (data, origin = HOST) => { for (const fn of listeners.message || []) fn({ origin, data }); };
-  return { get, body, posted, runTimers, message, timers };
+  return { get, body, document, posted, runTimers, message, timers };
 }
 
 test('🔴 host mode with no card:load: the canvas never receives the seed, and the page says it is waiting', () => {
@@ -90,6 +90,23 @@ test('host mode: card:load renders THE card, and the ready announcements stop',
   assert.ok(h.posted.length >= before);
 });
 
+// 🔴 the bug this pair guards: before card:load lands, `/edit?host=…` used to carry the SANDBOX's
+// title ("Try Card · feelreef") even while framed in the owner's dashboard editing a real card —
+// see card-worker.mjs's sandboxEditorHtml() and the `hostPageTitle` it now renders instead.
+test('host mode: document.title is the bare placeholder before card:load, the card\'s own name after', () => {
+  const h = bootHost();
+  assert.equal(h.document.title, 'Card · feelreef');
+  h.message({ type: 'card:load', v: 1, md: REAL, handle: 'mei', cardUrl: 'https://card.feelreef.com/mei' });
+  assert.equal(h.document.title, '小美 · Card · feelreef');
+});
+
+test('host mode: document.title falls back to the handle when the loaded card carries no frontmatter title', () => {
+  const h = bootHost();
+  const noTitle = ['## cards', '', '- [ ] %% card: profile w=6 %% a real bio'].join('\n') + '\n';
+  h.message({ type: 'card:load', v: 1, md: noTitle, handle: 'mei', cardUrl: 'https://card.feelreef.com/mei' });
+  assert.equal(h.document.title, 'mei · Card · feelreef');
+});
+
 test('CONTROL: the stub does record a painted seed (loaded through card:load)', () => {
   // without this, "no srcdoc" above could mean the stub never records a paint at all
   const h = bootHost();