feat(web): the title bar is painted, a click survives an editor, and the twin door is gone

improvise-5jna, improvise-0x9u, improvise-seik — three browser-page defects with
one shape: a thing that looks done from every check except running it.

improvise-5jna. `doc_name`/`doc_dirty`/`doc_stored_as` were projected by z754 and
painted by nothing. `render_surface.test.js` could not see it — it is a SUBSTRING
SEARCH over the page's source, so a field named by a function nothing calls reads
as painted, which is also how `model.minibuffer` shipped dead. So the guard is a
harness assertion that loads the page and reads `#doc-name`, proved by writing it
first (`element(s) not found`). The joining is `shell.js::documentTitle`, the
TUI's own `name (stored_as) [+]` minus the chrome; the `[+]` is a node test, not a
harness one, because this deployment persists on every accepted batch and clears
the flag in the same round trip, so the marker is transient. UNPAINTED is now
empty.

improvise-0x9u. From an EDITING state a cell click did nothing at all: the
mousedown moved focus, the input's blur ran `close`, `close` repainted,
`replaceChildren` destroyed the `<td>` the mousedown landed on, and no `click`
was ever dispatched. The old spec pressed Escape between the two clicks, so it
only ever clicked from a non-editing page — this repo's characteristic defect.

Worth recording: moving to `mousedown` is NECESSARY AND NOT SUFFICIENT, and the
first attempt failed the same assertion with the same symptom. Removing a focused
`<input>` fires `blur` SYNCHRONOUSLY, so `close` rebuilt the table from inside
itself and detached the `<td>` again. `close` therefore no longer repaints, the
`blur` arm checks `closed` first, and the handler `preventDefault()`s so no focus
change happens at all — otherwise the default action focuses `#grid` after
`input.focus()` and blurs the new editor. `close` restores the DRAWN text, since
nothing repaints behind it any more.

improvise-seik. `Client::viewport` was a wasm-bindgen door with no caller, kept
for a reason `web/app.js` falsified in the same wave. It is one letter from
`set_viewport` and fails SILENTLY — identical frame, forgotten window, every
cursor key an upstream black hole. Deleted, along with the exported `init()` free
function that duplicated `new Client()`. The guard is not the deletion:
`wasm_surface.test.js` now reads the generated `.d.ts` and requires every
declared method to be one `app.js` calls or to be named in `UNCALLED` with its
reason. Proved by injecting a spare `static viewport(...)` into the built `.d.ts`
and watching it fail by name.

Tests: 1405 Rust (unchanged), 27 node + 4 bundle (was 26 + 3), 24 chromium
harness (was 23).

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01FC2jVn8Au7E9JPkw6bwXXH

context/code/clients.md

@@ -1112,7 +1112,7 @@ reaching it from https means terminating TLS in front of it). From an https page
 an explicit `ws://` is **upgraded** rather than passed through, since passing it
 through can only produce a failure the user cannot act on.
 
-### `set_viewport`, not `Client.viewport`
+### `set_viewport`, and the twin that is gone
 
 Same frame, but it also **records** the window. A client learns its window only
 from what it announced — the row frame's own length is the window clipped to the
@@ -1121,6 +1121,23 @@ arithmetic matters. Without it the client cannot clamp, so every cursor key goes
 upstream into `Host::handle`'s empty vec and the arrow keys silently do nothing
 (improvise-bpq2).
 
+There used to be a frame-only twin, `Client::viewport`, exported beside it and
+called by nobody. Its doc said it was kept because `web/app.js` already spelled
+it — and `web/app.js` called `set_viewport` in the same wave, so the reason was
+false before it was read (improvise-seik). That matters more than an ordinary
+unused function, because **the two are one letter apart and the wrong one fails
+silently**: it sends an identical frame and simply forgets the window, which
+turns every cursor key into the black hole above. It is deleted, along with the
+exported `init()` free function that duplicated `new Client()`.
+
+A deletion is not the guard, though — the next export with no caller arrives the
+same way. `web/tests/bundle/wasm_surface.test.js` now reads the generated
+`.d.ts` and requires every declared method to be one `app.js` calls, or to be
+named in an `UNCALLED` table with its reason. `free` and `initSync` are
+wasm-bindgen's own; `revision` is there because `on_frame` returns it. Proved by
+injecting a spare `static viewport(...)` declaration into the built `.d.ts` and
+watching it fail by name.
+
 ### `frameCost`: what the grid's own frame costs, in whole cells
 
 One header row and one header column was right until improvise-anr9: the column
@@ -1216,6 +1233,46 @@ Neither arm leaves one armed.
   1200 reads `"1,200"` and committing that stores the *string* `"1,200"`. Enter
   removes the focused `<input>`, which fires `blur`, which calls `close` again:
   harmless, but only by accident.
+- **The title bar is three fields and one joining.** `doc_name`, `doc_dirty` and
+  `doc_stored_as` come off the cache `src/draw.rs::draw_title` folds; the joining
+  — `name (stored_as) [+]`, in that order — is `shell.js::documentTitle`, which
+  is the TUI's own spelling minus the `improvise ·` chrome and the right-hand
+  key strip. The three were projected by improvise-z754 and painted by nothing
+  for a wave, and `render_surface.test.js` could not see it: that check is a
+  **substring search**, so a field named by a function nothing calls reads as
+  painted. What sees it is `contract.spec.js`, which loads the page and asserts
+  the text (improvise-5jna). The marker itself is a node test rather than a
+  harness one, because the standalone deployment persists on every accepted
+  batch and clears the flag in the same round trip, so `[+]` is transient there.
+
+### The pointer takes cells on `mousedown`
+
+A cell's handler is `mousedown` with `preventDefault()`, not `click`, and the
+reason is an ordering trap worth the paragraph (improvise-0x9u). From an
+**editing** state a `click` never arrived at all: the mousedown moved focus, the
+`<input>`'s `blur` ran `close`, `close` repainted, `replaceChildren` destroyed
+the `<td>` the mousedown had landed on, and no `click` was ever dispatched. The
+pointer was dead until the user pressed Escape or clicked outside the grid.
+
+Three things had to move together, and each is load-bearing:
+
+- **`mousedown`, so the handler runs before any focus change.**
+- **`preventDefault()`, so no focus change happens at all.** Otherwise the
+  default action focuses `#grid` *after* the handler has called `input.focus()`
+  on the new editor, and blurs it immediately. The keyboard listener is on
+  `window`, so nothing needs `#grid` focused.
+- **`close` no longer repaints, and `blur` checks `closed` first.** Removing a
+  focused `<input>` fires `blur` **synchronously**, so a `close` that repainted
+  from inside itself detached the very `<td>` the handler was about to open an
+  editor on. This is the same repair one level down, and it is why the first
+  attempt at the fix still failed: the `blur` arm re-entered and rebuilt the
+  table. `close` restores the **drawn** text rather than the seed, since nothing
+  repaints behind it any more.
+
+The state the old spec could not see is the whole point: it pressed Escape
+before clicking the second cell, so it only ever clicked from a non-editing
+page — this repo's characteristic defect, a test that passes while the thing it
+names is broken in a neighbouring state.
 
 ### The keyboard
 

context/test-evidence/clients.md

@@ -2062,3 +2062,41 @@ done
 The other two losses are deliberate: `pointer.spec.js`'s sidebar test was
 superseded by the open-at-launch ruling, and the widgets file was merged into
 this one.
+
+#### "a click moves the selection from an editing state too"
+
+improvise-0x9u, and the fault was injected by running this assertion against the
+bundle as it stood: `cells.nth(4).locator("input")` came back **0**, with the
+selection still on cell 0, exactly as the bug report measured in Chromium.
+
+Two things about it are worth more than the assertion. First, **what it does not
+do**: it never presses Escape between the two clicks. The sibling test does, and
+that single line is why the property it names ("a click moves the selection") was
+asserted for a whole wave while the neighbouring state was broken — the click
+path from an *editing* page was never exercised.
+
+Second, **the fix's own first attempt failed this same test**, which is the part
+to remember. Moving the handler to `mousedown` is necessary and not sufficient:
+`close` still repainted, and removing a focused `<input>` fires `blur`
+**synchronously**, so `close` rebuilt the table from inside itself and detached
+the `<td>` the handler was about to open an editor on. The assertion could not
+tell that apart from the original bug — same symptom, different cause — so it is
+the debug run rather than the test that separated them. `close` therefore no
+longer repaints, and the `blur` arm checks `closed` before dismissing.
+
+#### "the widgets the demo document fills are drawn, in the state that fills them"
+
+The `#doc-name` row is improvise-5jna, and the reason it belongs in a **browser**
+test rather than in `render_surface.test.js` is that the latter is a substring
+search over the page's source: `doc_name` mentioned by a function nothing calls
+reads as painted. That is how `model.minibuffer` once shipped dead, and how
+z754's three title-bar fields sat projected and unpainted for a wave while the
+static check was green. Proved by adding the assertion first: `element(s) not
+found` for `#doc-name`.
+
+The `[+]` marker is deliberately **not** asserted here. The standalone deployment
+persists on every accepted batch and `effect::Save` clears the flag in the same
+round trip (gotcha 45), so the marker is transient in a browser and any timing
+assertion over it would be flaky rather than discriminating. Its spelling — the
+order `name (stored_as) [+]`, the `null` `stored_as` writing no empty parens — is
+`web/tests/shell.test.js`, over `documentTitle` directly.

crates/improvise-wasm-client/src/lib.rs

@@ -19,9 +19,8 @@ pub struct Client {
     state: ClientState,
 }
 
-/// Allocate a client: an empty view slice and one empty cache per widget. A
+/// An empty view slice and one empty cache per widget. Not exported: the
-/// client that draws before its bootstrap draws an empty grid, correctly.
+/// page's door is `new Client()` (improvise-seik).
-#[wasm_bindgen]
 pub fn init() -> Client {
     Client::default()
 }
@@ -55,14 +54,8 @@ impl Client {
         serde_json::to_string(&message).ok()
     }
 
-    /// The whole client state as JSON: the view slice, every widget cache, and
+    /// Has anything moved? The cheap question, and the one `on_frame` already
-    /// the revision it corresponds to.
+    /// answers by returning it.
-    #[wasm_bindgen]
-    pub fn render_state(&self) -> Result<String, JsError> {
-        self.state_json().map_err(|e| JsError::new(&e.to_string()))
-    }
-
-    /// The cheap half of [`Client::render_state`]: has anything moved?
     #[wasm_bindgen]
     pub fn revision(&self) -> u64 {
         self.state.revision
@@ -71,24 +64,17 @@ impl Client {
     // The transport surface: a handful of string calls and the whole harness a
     // page needs. See `context/code/clients.md`.
 
-    /// The handshake frame, associated rather than a method. **Prefer
+    /// The handshake frame, *and* the record of what this client can show.
-    /// [`Client::set_viewport`]** — this one forgets the window (clients.md).
+    /// The **only** door, and why that matters: `context/code/clients.md`.
     #[wasm_bindgen]
-    pub fn viewport(rows: usize, cols: usize) -> String {
+    pub fn set_viewport(&mut self, rows: usize, cols: usize) -> String {
+        self.state.window = (rows, cols);
         serde_json::to_string(&Self::viewport_frame(rows, cols))
             // Two `usize` in a unit variant; unreachable, and an empty frame
             // is skipped by the server rather than crashing the tab.
             .unwrap_or_default()
     }
 
-    /// The handshake frame, *and* the record of what this client can show —
-    /// which is not derivable from anything the host sends (clients.md).
-    #[wasm_bindgen]
-    pub fn set_viewport(&mut self, rows: usize, cols: usize) -> String {
-        self.state.window = (rows, cols);
-        Self::viewport(rows, cols)
-    }
-
     /// Fold one frame, in arrival order, one at a time; returns the new
     /// revision. Never reorder or coalesce — a split batch loses cells.
     #[wasm_bindgen]
@@ -316,12 +302,15 @@ mod tests {
         );
     }
 
-    /// The handshake frame is the same either way; `set_viewport` also keeps
+    /// The handshake frame, and the window it records — one call, because a
-    /// the window, which is what lets a cursor key resolve at all.
+    /// second door that sent the frame and forgot the window was silent.
     #[test]
-    fn set_viewport_sends_the_same_frame_and_keeps_the_window() {
+    fn set_viewport_sends_the_handshake_frame_and_keeps_the_window() {
         let mut client = init();
-        assert_eq!(client.set_viewport(24, 8), Client::viewport(24, 8));
+        assert_eq!(
+            serde_json::from_str::<ClientFrame>(&client.set_viewport(24, 8)).unwrap(),
+            Client::viewport_frame(24, 8)
+        );
         assert_eq!(client.state().window, (24, 8));
     }
 

crates/improvise-wasm-client/tests/browser_round_trip.rs

@@ -98,10 +98,10 @@ fn a_browser_client_seeds_types_a_number_and_sees_it_come_back() {
 
     // The handshake. The extent comes first because the snapshot seeds the
     // *visible* cells: one built at extent zero is an empty grid.
-    let handshake: ClientFrame = serde_json::from_str(&Client::viewport(10, 10))
+    let handshake: ClientFrame = serde_json::from_str(&client.set_viewport(10, 10))
         .expect("the viewport frame must be one the server reads");
     let ClientFrame::Viewport { rows, cols } = handshake else {
-        panic!("Client::viewport must produce a Viewport frame");
+        panic!("set_viewport must produce a Viewport frame");
     };
     let (id, snapshot) = host.connect(rows, cols);
     deliver(&mut client, &[snapshot]);
@@ -305,7 +305,7 @@ fn a_resize_reprojects_the_grid_at_the_new_extent() {
         "a one-row viewport is seeded with one row"
     );
 
-    let frames = send(&mut host, id, &Client::viewport(10, 10));
+    let frames = send(&mut host, id, &client.set_viewport(10, 10));
     deliver(&mut client, &frames);
     assert_eq!(
         client.model().rows.len(),

harness/tests/contract.spec.js

@@ -26,6 +26,15 @@ test.describe("every field the render model projects reaches the screen", () =>
     await expect(page.locator("#grid tbody th").first()).toHaveText("Espresso");
     await expect(page.locator("#grid tbody td").first()).not.toHaveText("");
 
+    // `doc_name`, `doc_stored_as`: the title bar. improvise-z754 projected
+    // these and nothing painted them for a wave, which `render_surface`'s
+    // substring search cannot see — only a loaded page can (improvise-5jna).
+    // The dirty marker's own spelling is `web/tests/shell.test.js`: this
+    // deployment persists on every accepted batch, so `[+]` is transient.
+    await expect(page.locator("#doc-name")).toHaveText(
+      "Corner Coffee — 2025 (demo.improv)",
+    );
+
     // `mode`, `hint`, `view_name`, `status`: the header's four facts.
     await expect(page.locator("#mode")).toHaveText("NORMAL");
     await expect(page.locator("#hint")).not.toHaveText("");
@@ -212,4 +221,25 @@ test.describe("a pointer event reaches the client and its answer is painted", ()
     await expect(page.locator("#mode")).toHaveText("FORMULAS");
     await expect(page.locator("#formulas li.selected")).toHaveCount(1);
   });
+
+  // improvise-0x9u. The neighbouring state the assertion above cannot see: it
+  // presses Escape first, so it only ever clicks from a NON-editing page.
+  test("a click moves the selection from an editing state too", async ({ page }) => {
+    await openApp(page);
+    const cells = page.locator("#grid tbody td");
+
+    await cells.nth(0).click();
+    await expect(cells.nth(0).locator("input")).toHaveCount(1);
+
+    // No Escape between the two clicks — that is the whole test. The blur used
+    // to repaint and `replaceChildren` destroyed the <td> the mousedown landed
+    // on, so no click event was ever dispatched and the pointer was dead.
+    await cells.nth(4).click();
+    await expect(cells.nth(4).locator("input")).toHaveCount(1);
+    await expect(cells.nth(0).locator("input")).toHaveCount(0);
+
+    await page.keyboard.press("Escape");
+    await expect(cells.nth(4)).toHaveClass(/selected/);
+    await expect(page.locator("#grid tbody td.selected")).toHaveCount(1);
+  });
 });

web/app.js

@@ -7,6 +7,7 @@ import {
   HANDSHAKE_TIMEOUT_MS,
   ROW_PX,
   createShell,
+  documentTitle,
   extentOf,
   frameCostOf,
   gridPlan,
@@ -35,6 +36,7 @@ const el = {
   help: document.getElementById("help"),
   status: document.getElementById("status"),
   viewName: document.getElementById("view-name"),
+  docName: document.getElementById("doc-name"),
 };
 
 await init();
@@ -60,8 +62,8 @@ function sendViewport() {
   const box = el.grid.getBoundingClientRect();
   const metrics = { rowPx: ROW_PX, colPx: COL_PX };
   const { rows, cols } = extentOf(box, frameCost, metrics);
-  // `client.set_viewport`, NOT the associated `Client.viewport`: the same
+  // `set_viewport` RECORDS the window as well as framing it; the frame-only
-  // frame, but it also RECORDS the window. Why that matters: clients.md.
+  // twin beside it is deleted, so there is nothing to call by mistake (seik).
   transport.send(client.set_viewport(rows, cols));
 }
 
@@ -162,6 +164,13 @@ function repaint() {
   paintMinibuffer(model);
   shell.setModel(model.status);
   el.viewName.textContent = model.view_name;
+  // The title bar, off the cache `src/draw.rs::draw_title` folds — one
+  // derivation, both front ends (improvise-z754, improvise-5jna).
+  el.docName.textContent = documentTitle(
+    model.doc_name,
+    model.doc_dirty,
+    model.doc_stored_as,
+  );
   el.grid.replaceChildren(gridTable(model));
   // The flag is the client's answer, not the page's: `C` toggles it and the
   // TUI draws the panel on exactly the same condition (improvise-wsaw).
@@ -299,7 +308,12 @@ function gridTable(model) {
       // Every cell moves the selection; an editable one also opens its editor,
       // which is the pointer's `i`. Not repainted in that branch: `edit` has
       // set `editing`, and a repaint would take the <input> away.
-      td.addEventListener("click", () => {
+      // On MOUSEDOWN, and defaulted away: from an editing state the input's
+      // blur repainted first and this <td> was gone before `click` could fire
+      // (improvise-0x9u). See context/code/clients.md.
+      td.addEventListener("mousedown", (event) => {
+        event.preventDefault();
+        if (editing) editing.close(false);
         const frame = client.click_cell(cell.row, cell.col);
         if (frame) transport.send(frame);
         if (cell.editable) edit(td, cell.row, cell.col, cell.editText);
@@ -314,10 +328,12 @@ function gridTable(model) {
  *  back is the server's, never the string typed here. */
 function edit(td, row, col, seed) {
   if (editing) return;
-  editing = { row, col };
   // `seed` is `RenderCell::edit_text` -- the STORED value, not the drawn one:
   // `td.textContent` has been through the number format.
   const original = seed;
+  // What was on the screen, kept so closing can put it back: `close` no longer
+  // always repaints, so restoring `seed` would leave `1200` where `1,200` was.
+  const drawn = td.textContent;
   const input = document.createElement("input");
   input.value = original;
   td.replaceChildren(input);
@@ -327,6 +343,8 @@ function edit(td, row, col, seed) {
   // Enter removes the focused <input>, which fires `blur`, which calls
   // `close` again. Harmless before, but only by accident.
   let closed = false;
+  // `close` does NOT repaint: a caller about to open another editor on a live
+  // <td> must not have the table rebuilt under it (improvise-0x9u).
   const close = (commit) => {
     if (closed) return;
     closed = true;
@@ -337,19 +355,28 @@ function edit(td, row, col, seed) {
       // follows restores whatever the server now says is there.
       if (frame) transport.send(frame);
     }
-    td.replaceChildren(original);
+    td.replaceChildren(drawn);
     painted = -1;
+  };
+  const dismiss = (commit) => {
+    close(commit);
     repaint();
   };
+  editing = { row, col, close };
 
   input.addEventListener("keydown", (e) => {
-    if (e.key === "Enter") close(true);
+    if (e.key === "Enter") dismiss(true);
-    else if (e.key === "Escape") close(false);
+    else if (e.key === "Escape") dismiss(false);
     // The editor owns the keyboard while it is open; the page-level handler
     // below must not also see these.
     e.stopPropagation();
   });
-  input.addEventListener("blur", () => close(false));
+  // Removing the focused <input> fires `blur` SYNCHRONOUSLY, so a caller that
+  // already closed this editor must not have the table rebuilt from inside its
+  // own `close` — that is what detached the <td> in improvise-0x9u's repair.
+  input.addEventListener("blur", () => {
+    if (!closed) dismiss(false);
+  });
 }
 
 /** A side panel. An empty row list is what says it is closed — the page asks

web/index.html

@@ -34,6 +34,7 @@
     -->
     <header>
       <h1>improvise</h1>
+      <span id="doc-name"></span>
       <span id="view-name"></span>
       <span id="mode"></span>
       <span id="hint"></span>

web/shell.js

@@ -16,6 +16,12 @@ export function composeStatus(shell, model) {
   return [shell, model].filter(Boolean).join(" · ");
 }
 
+/** The title bar's one line, in the order and spelling `src/draw.rs::draw_title`
+ *  uses. The three facts are the host's; only the joining is here (clients.md). */
+export function documentTitle(name, dirty, storedAs) {
+  return `${name}${storedAs ? ` (${storedAs})` : ""}${dirty ? " [+]" : ""}`;
+}
+
 /** The collapse glyph. `collapsed` is the fact, decided by the view and
  *  carried on the frame; only this spelling is the page's (gotcha 26). */
 export function indicator(collapsed) {

web/style.css

@@ -49,6 +49,10 @@ header h1 {
   color: var(--accent);
 }
 
+#doc-name {
+  opacity: 0.85;
+}
+
 #mode {
   color: var(--accent);
 }

web/tests/bundle/wasm_surface.test.js

@@ -86,6 +86,29 @@ test("the page still reaches the client through a handful of calls", () => {
   );
 });
 
+/// Methods on `Client` the page does not call, each with the reason it is
+/// still exported. A door with no caller and no entry here is improvise-seik:
+/// the dangerous kind, because calling the wrong one of a pair is silent.
+const UNCALLED = {
+  free: "wasm-bindgen's own destructor, not ours to remove",
+  initSync: "wasm-bindgen's own module loader, beside the default export",
+  revision: "on_frame returns it; a page that stores it can skip a repaint",
+};
+
+test("the bundle exports no client door the page has no reason to hold", () => {
+  const declared = declarations("pkg/improvise_wasm_client.d.ts");
+  const called = new Set(callsOn("app.js", "client").map((c) => c.name));
+  // `constructor` is `new Client()`, which `callsOn` cannot see as a call.
+  const spare = [...declared.keys()].filter(
+    (name) => name !== "constructor" && !called.has(name),
+  );
+  assert.deepEqual(
+    spare.sort(),
+    Object.keys(UNCALLED).sort(),
+    "an exported method nothing calls — delete it, or add it to UNCALLED with the reason",
+  );
+});
+
 test("every worker call web/worker.js makes is declared, with that arity", () => {
   const declared = declarations("worker-pkg/improvise_worker_server.d.ts");
   const calls = callsOn("worker.js", "server");

web/tests/render_surface.test.js

@@ -17,14 +17,10 @@ const code = (rel) =>
 
 /// Fields the page deliberately does not read, each with the reason. A field
 /// belongs here only with an argument; the list is the debt, written down.
-// improvise-z754 put the title bar's facts in one shared cache and taught
+// Empty since improvise-5jna painted the title bar. Note what this check CANNOT
-// `src/draw.rs::draw_title` to fold it; this page never learned to. That is
+// see, and why the harness asserts the painted text too: it is a substring
-// improvise-5jna, open, and this list is what stops it being forgotten.
+// search, so a field named by a function nothing calls reads as painted.
-const UNPAINTED = {
+const UNPAINTED = {};
-  doc_name: "improvise-5jna: the title bar is drawn by the TUI and not here",
-  doc_dirty: "improvise-5jna",
-  doc_stored_as: "improvise-5jna",
-};
 
 /// The `pub` fields of `RenderModel`, read off the Rust that defines it.
 function renderModelFields() {

web/tests/shell.test.js

@@ -7,6 +7,7 @@ import assert from "node:assert/strict";
 import {
   composeStatus,
   createShell,
+  documentTitle,
   extentOf,
   frameCostOf,
   indicator,
@@ -160,3 +161,17 @@ test("the collapse glyph points right when collapsed", () => {
   assert.equal(indicator(true), "▶");
   assert.equal(indicator(false), "▼");
 });
+
+test("the title bar spells the document the way the TUI's own title does", () => {
+  // `src/draw.rs::draw_title`: name, then what it is stored as in parens, then
+  // the dirty marker. The harness cannot pin `[+]` — the standalone deployment
+  // persists on every accepted batch, so the marker is transient there.
+  assert.equal(
+    documentTitle("Corner Coffee", true, "demo.improv"),
+    "Corner Coffee (demo.improv) [+]",
+  );
+  assert.equal(documentTitle("Corner Coffee", false, "demo.improv"), "Corner Coffee (demo.improv)");
+  // A host with nowhere to write it: `stored_as` is `None` over the wire, which
+  // arrives as `null`, and an empty pair of parens would be a lie about storage.
+  assert.equal(documentTitle("Untitled", true, null), "Untitled [+]");
+});