Stop probing a sentinel document in grid mode

index.jsx

@@ -3742,7 +3742,7 @@ function App({ appId }) {
   const collection = useMemo3(() => makeNoteCollection({ onConflict }), [onConflict]);
   const openId = view.mode === "editor" ? view.id : null;
   const openNote = openId ? notes.find((n) => n.meta.id === openId && !n.placeholder) : null;
-  const openPath = openId ? openNote?.storagePath || notePath(openId) : "__notes_no_open__.json";
+  const openPath = openId ? openNote?.storagePath || notePath(openId) : null;
   useEffect6(() => {
     openIdRef.current = openId;
   }, [openId]);

mobius.json

@@ -1,7 +1,7 @@
 {
   "id": "notes",
   "name": "Notes",
-  "version": "1.2.29",
+  "version": "1.2.30",
   "description": "Markdown notes that render as you type, with checklists, pins, colors, search, and images.",
   "author": "mobius-os",
   "license": "MIT",

package.json

@@ -1,6 +1,6 @@
 {
   "name": "app-notes",
-  "version": "1.2.29",
+  "version": "1.2.30",
   "private": true,
   "type": "module",
   "description": "Markdown notes for Möbius — live-inline editor, offline, git-tracked.",

src/app.jsx

@@ -32,8 +32,8 @@ import EditorPanel from './ui/EditorPanel.jsx'
 import ConfirmModal from './ui/ConfirmModal.jsx'
 import { Icon } from './ui/icons.jsx'
 
-// A no-op document handle: the value the open-note hook returns when no note is
-// open (the sentinel path) or under the unit-test harness, where window.mobius
+// A no-op document handle: the value the open-note hook returns under the
+// unit-test harness, where window.mobius
 // is absent. Keeps a stable shape so callers can read .value/.status/.lastError
 // unconditionally.
 const NO_DOC = { value: null, status: 'idle', lastError: null, update: async () => {}, set: async () => {}, refresh: async () => {} }
@@ -291,25 +291,23 @@ export default function App({ appId }) {
   // mode 'lww' (per-note files avoid same-path clobber; backend CAS isn't live).
   const openId = view.mode === 'editor' ? view.id : null
   const openNote = openId ? notes.find((n) => n.meta.id === openId && !n.placeholder) : null
-  const openPath = openId ? (openNote?.storagePath || notePath(openId)) : '__notes_no_open__.json'
+  const openPath = openId ? (openNote?.storagePath || notePath(openId)) : null
   // Keep the debounced-gc mirrors current (read in scheduleGc's setTimeout body).
   useEffect(() => { openIdRef.current = openId }, [openId])
   useEffect(() => { notesRef.current = notes }, [notes])
   useEffect(() => { draftRef.current = draft }, [draft])
   useEffect(() => { failedSaveIdsRef.current = failedSaveIds }, [failedSaveIds])
   const mergeNote = useMemo(() => makeMergeNote(onConflict), [onConflict])
-  // The deployed runtime keys its refresh/subscription effects on these option
-  // references. Keeping both the callback and options object stable prevents an
-  // unrelated render from tearing down the subscription and re-reading the same
-  // document in a tight loop.
+  // A null path is the runtime's explicit idle document state: no read,
+  // subscription, or write. Keeping the live options stable also prevents an
+  // unrelated render from re-arming an open note's subscription.
   const openDocOptions = useMemo(() => ({
     initial: null,
     identity: NOTE_DOC_IDENTITY,
     merge: mergeNote,
     mode: 'lww',
   }), [mergeNote])
-  // Always called (stable hook position); inert when no note is open (the
-  // sentinel path is never written) or under the test harness (returns NO_DOC).
+  // Always called at a stable hook position; the test harness returns NO_DOC.
   const liveDoc = useDocument(openPath, openDocOptions)
   // useDocument returns a FRESH handle object every render, so depending on the whole
   // `liveDoc` in writeNote would rebuild writeNote → persist → the editor's flushSave

test/autosave-deps-stable.test.js

@@ -37,6 +37,7 @@ function installMobius() {
   const pathSubs = new Map()
   const docSubs = new Map()
   let docEffectRuns = 0
+  const documentPaths = []
   function notify(path) {
     const v = store.has(path) ? store.get(path) : null
     for (const cb of pathSubs.get(path) || []) { try { cb(v) } catch {} }
@@ -73,10 +74,11 @@ function installMobius() {
   }
   function createUseDocument(React) {
     return function useDocument(path, opts) {
+      documentPaths.push(path)
       const [value, setValue] = React.useState(opts?.initial ?? null)
       const baseRef = React.useRef(null)
       React.useEffect(() => {
-        if (!path || path.startsWith('__notes_no_open__')) return undefined
+        if (!path) return undefined
         docEffectRuns++
         let s = docSubs.get(path); if (!s) { s = new Set(); docSubs.set(path, s) }
         const cb = (v) => { baseRef.current = v; setValue(v) }
@@ -111,6 +113,7 @@ function installMobius() {
   }
   return {
     store,
+    documentPaths,
     seed(path, val) { store.set(path, val) },
     get docEffectRuns() { return docEffectRuns },
   }
@@ -168,6 +171,14 @@ const editorProps = () => { const n = safeFind((x) => x.props && Object.prototyp
 // its onQuery prop on the element to drive a search-query state change.
 const topBar = () => safeFind((n) => n.props && typeof n.props.onQuery === 'function')
 
+test('grid mode uses the runtime idle-document contract instead of a sentinel file', async () => {
+  shim.mount(() => App({ appId: '1', token: 't' }))
+  await flush()
+  assert.equal(env.documentPaths.at(-1), null)
+  assert.equal(env.documentPaths.includes('__notes_no_open__.json'), false)
+  shim.unmount()
+})
+
 test('onSave (persist) keeps a stable identity across an unrelated re-render (autosave deps do not churn)', async () => {
   env.seed(notePath('n1'), { meta: { id: 'n1', title: 'T', type: 'note', color: null, pinned: false, attachments: [], updated: '2026-01-01T00:00:00.000Z' }, body: 'hello' })
   shim.mount(() => App({ appId: '1', token: 't' }))

test/runtime-integration.test.js

@@ -104,6 +104,22 @@ async function renderDoc(storage, path, opts) {
   }
 }
 
+test('runtime useDocument: a null path is idle and performs no storage work', { skip: !HAVE_RUNTIME ? 'platform runtime not present' : false }, async () => {
+  const calls = []
+  const storage = {
+    async get() { calls.push('get'); return null },
+    async getWithVersion() { calls.push('getWithVersion'); return { value: null, version: null } },
+    async durableWrite() { calls.push('durableWrite'); return { durability: 'synced' } },
+    subscribe() { calls.push('subscribe'); return () => {} },
+  }
+  const doc = await renderDoc(storage, null, { initial: null })
+  assert.equal(doc.get().status, 'idle')
+  assert.deepEqual(calls, [])
+  await assert.rejects(doc.get().update(() => ({ body: 'must not write' })), /document path/)
+  assert.deepEqual(calls, [])
+  doc.cleanup()
+})
+
 test('runtime useDocument + app mergeNote: an edit on an existing note lands durably (loads base, writes through the real writer)', { skip: !HAVE_RUNTIME ? 'platform runtime not present' : false }, async () => {
   const { freshEnv, waitFor } = await import(HARNESS)
   const { server } = freshEnv()