frontend/dashboard.css

@@ -768,6 +768,7 @@ textarea { resize: vertical; min-height: 120px; }
 .new-issue { min-height:44px; }
 .find-work-action { min-height:44px; }
 .my-work-actions { display:flex; flex-wrap:wrap; gap:8px; }
+.plan-tomorrow { min-height:44px; }
 .start-work-session { min-height:44px; }
 .resume-today-session, .end-today-session { min-height:44px; }
 .work-session-nav { position:sticky; bottom:0; z-index:5; display:grid; grid-template-columns:repeat(2,minmax(0,1fr)); gap:8px; margin-top:12px; padding:10px 4px; padding-bottom:calc(10px + env(safe-area-inset-bottom)); background:rgba(11,21,38,.98); border-top:1px solid #2a496e; }
@@ -1095,6 +1096,7 @@ textarea { resize: vertical; min-height: 120px; }
   .attention-interruption:not([hidden]) { position:sticky; top:64px; z-index:6; margin-inline:max(0px,env(safe-area-inset-left)) max(0px,env(safe-area-inset-right)); }
   .my-work-header { align-items:flex-start; }
   .my-work-actions { display:none; }
+  .my-work-actions { display:flex; }
   .work-settings > summary { min-height:44px; display:flex; align-items:center; cursor:pointer; padding:0 10px; border:1px solid #2a496e; border-radius:10px; font-weight:700; }
   .work-settings:not([open]) > .work-settings-panel { display:none; }
   .work-settings-panel { display:grid; gap:10px; margin-top:8px; }

frontend/dashboard.js

@@ -376,10 +376,37 @@
   let rolloverReviewPlan = null;
   const outboxCoordinator = createOutboxCoordinator({ storage: localStorage });
   const todayRollover = createTodayRollover();
+  let planningTomorrow = false;
+  const tomorrowPlan = createTomorrowPlan({
+    fetchJson:fetchReviewJson,
+    localDate:todayRollover.localDate,
+    timeZone:todayRollover.timeZone,
+  });
   const todayWork = createTodayWork({
     storage: localStorage,
     getLogin: () => planningOwnerLogin,
   });
+  async function promoteTomorrowIfDue(plan) {
+    try {
+      await tomorrowPlan.load();
+      const promoted = await tomorrowPlan.promote(plan.revision);
+      if (!promoted) return false;
+      todayWork.replace(promoted.ids);
+      todayWork.replacePlanning({
+        capacity_minutes:promoted.capacity_minutes ?? null,
+        estimates:promoted.estimates || {},
+      });
+      refreshMyWorkView();
+      warmTodayOffline();
+      qs('#my-work-action-status').textContent =
+        'Your saved Tomorrow plan is now Today.';
+      return true;
+    } catch (error) {
+      qs('#my-work-action-status').textContent =
+        `${error.message || 'Tomorrow needs review before promotion.'} Open Plan Tomorrow to review.`;
+      return false;
+    }
+  }
   const todaySync = createTodaySync({
     storage: localStorage,
     getLogin: () => planningOwnerLogin,
@@ -392,6 +419,7 @@
     },
     onRemotePlan: plan => {
       if (!planningOwnerLogin) return;
+      promoteTomorrowIfDue(plan);
       todayWork.replacePlanning({
         capacity_minutes: plan.capacity_minutes ?? null,
         estimates: plan.estimates || {},
@@ -2605,6 +2633,7 @@
       return;
     }
     planToday.cancel();
+    planningTomorrow = false;
     qs('#plan-today-sheet').hidden = true;
     document.body.classList.remove('task-overlay-open');
     planTodayTrigger?.focus();
@@ -2638,10 +2667,24 @@
     return true;
   }
 
+  function saveTomorrowPlan(plan) {
+    const normalized = Array.isArray(plan) ?
+      {ids:plan, capacity_minutes:null, estimates:{}} : plan;
+    tomorrowPlan.save(normalized).then(saved => {
+      qs('#my-work-action-status').textContent = saved.ids.length ?
+        `Tomorrow saved for ${saved.plan_date} without changing Today.` :
+        `Tomorrow cleared for ${saved.plan_date}.`;
+    }).catch(error => {
+      qs('#my-work-action-status').textContent =
+        `${error.message || 'Tomorrow could not be saved.'} Reopen Plan Tomorrow to retry.`;
+    });
+    return true;
+  }
+
   const planToday = createPlanToday({
     identity: item => todayWork.identity(item),
     limit: todayWork.limit,
-    save: saveTodayPlan,
+    save: plan => planningTomorrow ? saveTomorrowPlan(plan) : saveTodayPlan(plan),
     start: () => {
       qs('[data-work-filter="today"]').click();
       startTodaySession();
@@ -2919,7 +2962,8 @@
       return;
     }
     if (trigger) planTodayTrigger = trigger;
-    qs('#plan-today-title').textContent = pendingProtectToday ? 'Protect Today' : (rolloverReviewPlan ? 'New day review' : 'Plan Today');
+    qs('#plan-today-title').textContent = planningTomorrow ? 'Plan Tomorrow' :
+      (pendingProtectToday ? 'Protect Today' : (rolloverReviewPlan ? 'New day review' : 'Plan Today'));
     if (actualMinutes) pendingPlanActualMinutes = actualMinutes;
     if (navigate) {
       taskOverlayHistory.open('plan-today');
@@ -2928,8 +2972,18 @@
     const recommendations = actualMinutes || pendingPlanActualMinutes || todayRecapView.pendingReplan()?.actual_minutes;
     pendingPlanActualMinutes = null;
     const protectProposal = pendingProtectToday;
-    const selected = protectProposal?.selected || todayMyWork;
-    planToday.open(selected, activeMyWork, todayWork.planning(), recommendations);
+    const tomorrow = planningTomorrow ? tomorrowPlan.state() : null;
+    const availablePlanningItems = [...todayMyWork, ...activeMyWork].filter((item, index, items) =>
+      items.findIndex(candidate => todayWork.identity(candidate) === todayWork.identity(item)) === index
+    );
+    const selected = planningTomorrow ? availablePlanningItems.filter(item =>
+      tomorrow.ids.includes(todayWork.identity(item))
+    ) : (protectProposal?.selected || todayMyWork);
+    planToday.open(selected, activeMyWork, planningTomorrow ? tomorrow : todayWork.planning(), recommendations);
+    qs('#today-plan-heading').textContent = planningTomorrow ? 'Tomorrow, in order' : 'Today, in order';
+    qs('.plan-today-available').firstChild.textContent = planningTomorrow ? 'Available tomorrow' : 'Available today';
+    qs('#build-today-plan').textContent = planningTomorrow ? 'Build my Tomorrow' : 'Build my Today';
+    qs('#save-and-start-today').hidden = planningTomorrow;
     pendingProtectToday = null;
     qs('#discard-recap-replan').hidden = !todayRecapView.pendingReplan();
     qs('#plan-today-error').textContent = '';
@@ -7633,6 +7687,25 @@
 
   qs('#refresh').addEventListener('click', load);
   qs('#plan-today').addEventListener('click', event => openPlanToday(event.currentTarget));
+  qs('#plan-tomorrow').addEventListener('click', async event => {
+    const button = event.currentTarget;
+    if (!planningOwnerLogin) {
+      qs('#my-work-action-status').textContent = 'Planning is unavailable until your operator identity is restored.';
+      return;
+    }
+    button.disabled = true;
+    qs('#my-work-action-status').textContent = 'Loading Tomorrow…';
+    try {
+      await tomorrowPlan.load();
+      planningTomorrow = true;
+      openPlanToday(button);
+      qs('#my-work-action-status').textContent = '';
+    } catch (error) {
+      qs('#my-work-action-status').textContent = `${error.message || 'Tomorrow is unavailable.'} Retry when connected.`;
+    } finally {
+      button.disabled = false;
+    }
+  });
   qs('#cancel-plan-today').addEventListener('click', closePlanToday);
   qs('#plan-today-sheet').addEventListener('click', event => {
     if (event.target === qs('#plan-today-sheet')) closePlanToday();

frontend/index.html

@@ -192,6 +192,7 @@
             <button class="work-filter" data-work-filter="later" aria-pressed="false">Later <span data-work-count="later">0</span></button>
             <button class="work-filter" data-work-filter="draft" aria-pressed="false">Drafts <span data-work-count="draft">0</span></button>
           </div>
+          <button class="plan-tomorrow" id="plan-tomorrow" type="button">Plan Tomorrow</button>
           <label class="milestone-lane" for="work-milestone-filter"><span class="small">Release lane</span>
             <select class="work-milestone-filter" id="work-milestone-filter">
               <option value="all">All milestones</option>
@@ -1918,6 +1919,7 @@
 <script src="static/plan-today.js"></script>
 <script src="static/plan-today-readiness.js"></script>
 <script src="static/plan-today-preview.js"></script>
+<script src="static/tomorrow-plan.js"></script>
 <script src="static/today-sync.js"></script>
 <script src="static/today-rollover.js"></script>
 <script src="static/update-ownership.js"></script>

frontend/service-worker.js

@@ -68,6 +68,7 @@ const SHELL = [
   BASE + 'static/plan-today.js',
   BASE + 'static/plan-today-readiness.js',
   BASE + 'static/plan-today-preview.js',
+  BASE + 'static/tomorrow-plan.js',
   BASE + 'static/today-sync.js',
   BASE + 'static/today-rollover.js',
   BASE + 'static/update-ownership.js',

frontend/tomorrow-plan.js

@@ -0,0 +1,29 @@
+function createTomorrowPlan({fetchJson,localDate,timeZone,createId}={}) {
+  let plan={revision:0,ids:[],capacity_minutes:null,estimates:{}};
+  const state=()=>({...plan,ids:[...plan.ids],estimates:{...plan.estimates}});
+  function adopt(value) {
+    if (!Number.isInteger(value?.revision)||!Array.isArray(value?.ids)) return false;
+    plan={revision:value.revision,ids:[...value.ids],capacity_minutes:value.capacity_minutes??null,
+      estimates:{...(value.estimates||{})},...(value.plan_date?{plan_date:value.plan_date,timezone:value.timezone||null}:{})};
+    return state();
+  }
+  function nextLocalDate() {
+    const [y,m,d]=localDate().split('-').map(Number);
+    return new Date(Date.UTC(y,m-1,d+1)).toISOString().slice(0,10);
+  }
+  async function load(){return adopt(await fetchJson('api/v1/tomorrow'));}
+  async function save(value) {
+    const body={base_revision:plan.revision,ids:[...(value.ids||[])],
+      capacity_minutes:value.capacity_minutes??null,estimates:{...(value.estimates||{})},
+      plan_date:nextLocalDate(),timezone:timeZone()};
+    return adopt(await fetchJson('api/v1/tomorrow',{method:'PUT',headers:{'Content-Type':'application/json'},body:JSON.stringify(body)}));
+  }
+  async function promote(today_revision) {
+    if (!plan.plan_date||plan.plan_date!==localDate()||!plan.ids.length) return false;
+    const promotion_id=createId?.()||globalThis.crypto?.randomUUID?.()||`${plan.plan_date}-${plan.revision}`;
+    return fetchJson('api/v1/tomorrow/promote',{method:'POST',headers:{'Content-Type':'application/json'},
+      body:JSON.stringify({promotion_id,tomorrow_revision:plan.revision,today_revision})});
+  }
+  return {adopt,load,save,promote,state,nextLocalDate};
+}
+if(typeof module!=='undefined'&&module.exports)module.exports=createTomorrowPlan;

frontend/workspace-bootstrap.js

@@ -11,16 +11,18 @@ async function loadWorkspace({
   window?.addEventListener('online', captureOnline);
   const status = document.querySelector('#my-work-action-status');
   const retryButton = document.querySelector('#retry-workspace');
-  const url = document.querySelector(
-    'meta[name="stackchain-feature-today-timer"]'
-  )?.content || '';
-  const urls = {'today-timer':url};
+  const urls = Object.fromEntries(['today-timer', 'planning'].map(name => [name,
+    document.querySelector(`meta[name="stackchain-feature-${name}"]`)?.content || ''
+  ]));
+  const originalUrls = {...urls};
   const loader = createLoader({document, urls});
 
   let attempts = 0;
   const load = () => {
-    if (attempts++) urls['today-timer'] = url + '?retry=' + attempts;
-    return loader.load('today-timer');
+    if (attempts++) Object.keys(urls).forEach(name => {
+      urls[name] = originalUrls[name] + '?retry=' + attempts;
+    });
+    return Promise.all(Object.keys(urls).map(name => loader.load(name)));
   };
   const waitForRecovery = () => new Promise(resolve => {
     if (status) status.textContent = 'Workspace unavailable. Reconnect or retry.';

src/frontend_bundle.py

@@ -33,10 +33,15 @@ FEATURE_SOURCES = {
         "static/device-storage.js", "static/mobile-device-setup.js",
     ),
     "security-center": ("static/security-center.js",),
+    "planning": (
+        "static/plan-today.js", "static/plan-today-readiness.js",
+        "static/plan-today-preview.js", "static/today-rollover.js",
+        "static/tomorrow-plan.js", "static/mobile-plan-today-nav.js",
+    ),
     "today-timer": (
-        "static/conversation.js", "static/widgets.js", "static/voice-transcript-store.js", "static/voice-conversation-capture.js", "static/mobile-launch.js", "static/mobile-insights.js", "static/mobile-app-shortcuts.js", "static/mobile-plan-today-nav.js", "static/mobile-find-work-nav.js", "static/mobile-pull-refresh.js", "static/live-data-status.js",
+        "static/conversation.js", "static/widgets.js", "static/voice-transcript-store.js", "static/voice-conversation-capture.js", "static/mobile-launch.js", "static/mobile-insights.js", "static/mobile-app-shortcuts.js", "static/mobile-find-work-nav.js", "static/mobile-pull-refresh.js", "static/live-data-status.js",
         "static/today-completion.js", "static/card-planning.js", "static/work-detail-position.js", "static/work-route.js", "static/commands.js", "static/saved-searches.js", "static/task-overlay-history.js", "static/search-preview.js", "static/mobile-search-preview-nav.js", "static/search-reply-draft-store.js", "static/conversation-reply-draft-store.js", "static/conversation-photo-drafts.js", "static/search-defer.js", "static/mobile-search-viewport.js", "static/agenda-replan.js", "static/agenda-calendar.js", "static/my-work.js", "static/protect-today.js", "static/mobile-today-command-bar.js", "static/mobile-task-dock.js", "static/mobile-first-task.js", "static/mobile-work-entry.js", "static/mobile-queue-launcher.js", "static/mobile-delivery-recovery.js", "static/mobile-start-day.js", "static/update-triage-session.js", "static/update-review-handoff.js", "static/update-triage-launcher.js", "static/update-triage-gesture.js", "static/notification-undo.js", "static/today-timer.js", "static/today-break.js", "static/today-progress.js", "static/today-lock-screen.js", "static/today-session-sync.js", "static/today-recap.js", "static/today-wrap-up.js", "static/today-summary.js", "static/today-handoff.js",
-        "static/today-rollover.js", "static/later-work.js", "static/detail-defer.js", "static/later-picker.js", "static/drafts.js", "static/unfiled-captures.js", "static/unfiled-draft-sync.js",
+        "static/later-work.js", "static/detail-defer.js", "static/later-picker.js", "static/drafts.js", "static/unfiled-captures.js", "static/unfiled-draft-sync.js",
         "static/assign-and-start.js", "static/filed-claim.js", "static/queue-today.js", "static/create-and-start.js",
         "static/draft-filing-session.js", "static/draft-capacity-dialog.js", "static/work-selection.js",
         "static/today-work.js", "static/today-sync.js", "static/pick-work.js", "static/batch-find-work.js",

src/main.py

@@ -72,7 +72,10 @@ from src.unfiled_draft_store import (
 from src.security_event_store import SecurityEventStore, SecurityEventStoreError
 from src.suggestion_engine import compute
 from src.later_store import LaterStore
-from src.today_store import TodayPlanFull, TodaySessionConflict, TodayStore
+from src.today_store import (
+    TodayPlanFull, TodayPromotionConflict, TodaySessionConflict, TodayStore,
+    TomorrowPlanConflict,
+)
 from src.state_encryption import PrivateStateEncryptionError
 from src.views import FRONTEND_BUILD, router as frontend_router
 
@@ -658,6 +661,32 @@ class TodayOperationBatch(BaseModel):
     operations: list[TodayOperation] = Field(min_length=1, max_length=50)
 
 
+class TomorrowPlanUpdate(BaseModel):
+    base_revision: int = Field(ge=0)
+    ids: list[str] = Field(max_length=5)
+    capacity_minutes: int | None = Field(default=None, ge=15, le=1440)
+    estimates: dict[str, int] = Field(default_factory=dict, max_length=5)
+    plan_date: str = Field(min_length=10, max_length=10)
+    timezone: str = Field(min_length=1, max_length=100)
+
+    @model_validator(mode="after")
+    def validate_plan(self):
+        if len(set(self.ids)) != len(self.ids):
+            raise ValueError("Tomorrow IDs must be unique")
+        if any(not item_id or len(item_id) > 500 for item_id in self.ids):
+            raise ValueError("Tomorrow IDs must be bounded")
+        if any(not item_id or len(item_id) > 500 or minutes < 5 or minutes > 1440
+               for item_id, minutes in self.estimates.items()):
+            raise ValueError("estimates must use bounded item IDs and minutes")
+        return self
+
+
+class TomorrowPromotion(BaseModel):
+    promotion_id: str = Field(min_length=1, max_length=100)
+    tomorrow_revision: int = Field(ge=0)
+    today_revision: int = Field(ge=0)
+
+
 class LaterOperationBatch(BaseModel):
     operations: list[LaterOperation] = Field(min_length=1, max_length=50)
 
@@ -1362,7 +1391,7 @@ async def require_operator_session(request: Request, call_next):
 async def prevent_live_api_caching(request, call_next):
     response = await call_next(request)
     path = dashboard_auth.application_path(request)
-    if path in {"/api/v1/context", "/api/v1/background-identity", "/api/v1/events", "/api/v1/live", "/api/v1/available-issues", "/api/v1/search", "/api/v1/work-route", "/api/v1/today", "/api/v1/today/session", "/api/v1/later", "/api/v1/saved-searches", "/api/v1/completed-filed-reviews", "/api/v1/security-events", "/api/v1/push-subscription"} or path.startswith("/api/v1/work/") or (
+    if path in {"/api/v1/context", "/api/v1/background-identity", "/api/v1/events", "/api/v1/live", "/api/v1/available-issues", "/api/v1/search", "/api/v1/work-route", "/api/v1/today", "/api/v1/tomorrow", "/api/v1/tomorrow/promote", "/api/v1/today/session", "/api/v1/later", "/api/v1/saved-searches", "/api/v1/completed-filed-reviews", "/api/v1/security-events", "/api/v1/push-subscription"} or path.startswith("/api/v1/work/") or (
         path.startswith("/api/v1/repos/")
         and path.endswith("/review")
     ) or path.startswith("/api/v1/notifications") or (
@@ -2590,6 +2619,65 @@ async def update_today_plan(payload: TodayOperation | TodayOperationBatch):
         )
 
 
+@app.get("/api/v1/tomorrow")
+async def get_tomorrow_plan():
+    login = await _confirmed_login()
+    try:
+        return await asyncio.to_thread(_today_store().get_tomorrow, login)
+    except (OSError, sqlite3.Error, PrivateStateEncryptionError):
+        raise HTTPException(
+            status_code=503, detail="Tomorrow synchronization is unavailable",
+            headers={"Retry-After": "1"},
+        )
+
+
+@app.put("/api/v1/tomorrow")
+async def replace_tomorrow_plan(payload: TomorrowPlanUpdate):
+    login = await _confirmed_login()
+    try:
+        return await asyncio.to_thread(
+            _today_store().replace_tomorrow, login, **payload.model_dump()
+        )
+    except TomorrowPlanConflict as error:
+        raise HTTPException(
+            status_code=409,
+            detail={"code": "tomorrow_changed", "snapshot": error.snapshot},
+        )
+    except ValueError as error:
+        raise HTTPException(status_code=422, detail=str(error))
+    except (OSError, sqlite3.Error, PrivateStateEncryptionError):
+        raise HTTPException(
+            status_code=503, detail="Tomorrow synchronization is unavailable",
+            headers={"Retry-After": "1"},
+        )
+
+
+@app.post("/api/v1/tomorrow/promote")
+async def promote_tomorrow_plan(payload: TomorrowPromotion):
+    login = await _confirmed_login()
+    try:
+        return await asyncio.to_thread(
+            _today_store().promote_tomorrow, login, **payload.model_dump()
+        )
+    except TomorrowPlanConflict as error:
+        raise HTTPException(
+            status_code=409,
+            detail={"code": "tomorrow_changed", "snapshot": error.snapshot},
+        )
+    except TodayPromotionConflict as error:
+        raise HTTPException(
+            status_code=409,
+            detail={"code": "today_changed", "today": error.today},
+        )
+    except ValueError as error:
+        raise HTTPException(status_code=422, detail=str(error))
+    except (OSError, sqlite3.Error, PrivateStateEncryptionError):
+        raise HTTPException(
+            status_code=503, detail="Tomorrow promotion is unavailable",
+            headers={"Retry-After": "1"},
+        )
+
+
 @app.get("/api/v1/today/session")
 async def get_today_session():
     login = await _confirmed_login()

src/today_store.py

@@ -22,6 +22,22 @@ class TodaySessionConflict(ValueError):
         self.session = session
 
 
+class TomorrowPlanConflict(ValueError):
+    """Raised when Tomorrow was edited from an obsolete revision."""
+
+    def __init__(self, snapshot: dict):
+        super().__init__("Tomorrow plan changed on another device")
+        self.snapshot = snapshot
+
+
+class TodayPromotionConflict(ValueError):
+    """Raised when rollover would overwrite a changed Today plan."""
+
+    def __init__(self, today: dict):
+        super().__init__("Today changed before Tomorrow could be promoted")
+        self.today = today
+
+
 class TodayStore:
     def __init__(
         self,
@@ -50,7 +66,7 @@ class TodayStore:
 
     def _initialize(self) -> None:
         connection = connect_private_sqlite(self.path, timeout=self.timeout)
-        if connection.execute("PRAGMA user_version").fetchone()[0] >= 3:
+        if connection.execute("PRAGMA user_version").fetchone()[0] >= 4:
             connection.close()
             return
         connection.execute("PRAGMA journal_mode=WAL")
@@ -137,7 +153,16 @@ class TodayStore:
         session_columns = {row[1] for row in connection.execute("PRAGMA table_info(today_sessions)")}
         if "break_deadline_at" not in session_columns:
             connection.execute("ALTER TABLE today_sessions ADD COLUMN break_deadline_at INTEGER")
-        connection.execute("PRAGMA user_version = 3")
+        connection.execute(
+            "CREATE TABLE IF NOT EXISTS tomorrow_plans ("
+            "login TEXT PRIMARY KEY, revision INTEGER NOT NULL, payload TEXT NOT NULL)"
+        )
+        connection.execute(
+            "CREATE TABLE IF NOT EXISTS tomorrow_promotions ("
+            "login TEXT NOT NULL, promotion_id TEXT NOT NULL, result TEXT NOT NULL, "
+            "created_at REAL NOT NULL, PRIMARY KEY (login, promotion_id))"
+        )
+        connection.execute("PRAGMA user_version = 4")
         connection.commit()
         connection.close()
 
@@ -231,6 +256,151 @@ class TodayStore:
                 )
         return snapshot
 
+    @staticmethod
+    def _empty_tomorrow(revision: int = 0) -> dict:
+        return {"revision": revision, "ids": [], "capacity_minutes": None, "estimates": {}}
+
+    def _tomorrow_snapshot(self, row, login: str) -> dict:
+        if row is None:
+            return self._empty_tomorrow()
+        payload, _legacy = self._cipher.open(row[1], binding=f"tomorrow:{login}")
+        if not isinstance(payload, dict):
+            raise PrivateStateEncryptionError("private state could not be decrypted")
+        snapshot = {"revision": int(row[0]), **payload}
+        if not isinstance(snapshot.get("ids"), list) or not isinstance(snapshot.get("estimates"), dict):
+            raise PrivateStateEncryptionError("private state could not be decrypted")
+        return snapshot
+
+    def get_tomorrow(self, login: str) -> dict:
+        login = self._normalize_login(login)
+        with self._connect() as connection:
+            row = connection.execute(
+                "SELECT revision, payload FROM tomorrow_plans WHERE login = ?", (login,)
+            ).fetchone()
+            return self._tomorrow_snapshot(row, login)
+
+    def _normalize_tomorrow(
+        self, *, ids: list[str], capacity_minutes: int | None,
+        estimates: dict[str, int], plan_date: str, timezone: str,
+    ) -> dict:
+        try:
+            if date.fromisoformat(plan_date or "").isoformat() != plan_date:
+                raise ValueError
+        except (TypeError, ValueError):
+            raise ValueError("plan_date must be an ISO calendar date") from None
+        if not isinstance(timezone, str) or not timezone.strip() or len(timezone) > 100:
+            raise ValueError("timezone is required and bounded")
+        if not isinstance(ids, list) or len(ids) > self.limit or any(
+            not isinstance(item_id, str) or not item_id or len(item_id) > 500 for item_id in ids
+        ):
+            raise ValueError("Tomorrow IDs are invalid or exceed the plan limit")
+        if len(set(ids)) != len(ids):
+            raise ValueError("Tomorrow IDs must be unique")
+        if capacity_minutes is not None and (
+            not isinstance(capacity_minutes, int) or isinstance(capacity_minutes, bool)
+            or capacity_minutes < 15 or capacity_minutes > 1440
+        ):
+            raise ValueError("capacity_minutes must be between 15 and 1440")
+        if not isinstance(estimates, dict):
+            raise ValueError("estimates must be an object")
+        normalized_estimates = {}
+        for item_id, minutes in estimates.items():
+            if item_id not in ids:
+                continue
+            if not isinstance(minutes, int) or isinstance(minutes, bool) or minutes < 5 or minutes > 1440:
+                raise ValueError("estimate minutes must be between 5 and 1440")
+            normalized_estimates[item_id] = minutes
+        return {
+            "ids": list(ids), "capacity_minutes": capacity_minutes,
+            "estimates": normalized_estimates, "plan_date": plan_date,
+            "timezone": timezone.strip(),
+        }
+
+    def replace_tomorrow(self, login: str, *, base_revision: int, **plan) -> dict:
+        login = self._normalize_login(login)
+        if not isinstance(base_revision, int) or isinstance(base_revision, bool) or base_revision < 0:
+            raise ValueError("base_revision must be a non-negative integer")
+        normalized = self._normalize_tomorrow(**plan)
+        with self._connect() as connection:
+            connection.execute("BEGIN IMMEDIATE")
+            row = connection.execute(
+                "SELECT revision, payload FROM tomorrow_plans WHERE login = ?", (login,)
+            ).fetchone()
+            current = self._tomorrow_snapshot(row, login)
+            if current["revision"] != base_revision:
+                raise TomorrowPlanConflict(current)
+            snapshot = {"revision": base_revision + 1, **normalized}
+            sealed = self._cipher.seal(normalized, binding=f"tomorrow:{login}")
+            connection.execute(
+                "INSERT INTO tomorrow_plans(login, revision, payload) VALUES (?, ?, ?) "
+                "ON CONFLICT(login) DO UPDATE SET revision=excluded.revision, payload=excluded.payload",
+                (login, snapshot["revision"], sealed),
+            )
+            return snapshot
+
+    def promote_tomorrow(
+        self, login: str, *, promotion_id: str, tomorrow_revision: int, today_revision: int,
+    ) -> dict:
+        login = self._normalize_login(login)
+        if not isinstance(promotion_id, str) or not promotion_id.strip() or len(promotion_id) > 100:
+            raise ValueError("promotion_id is required and bounded")
+        promotion_id = promotion_id.strip()
+        with self._connect() as connection:
+            connection.execute("BEGIN IMMEDIATE")
+            receipt = connection.execute(
+                "SELECT result FROM tomorrow_promotions WHERE login = ? AND promotion_id = ?",
+                (login, promotion_id),
+            ).fetchone()
+            if receipt:
+                result, _legacy = self._cipher.open(
+                    receipt[0], binding=f"tomorrow-promotion:{login}:{promotion_id}"
+                )
+                if not isinstance(result, dict):
+                    raise PrivateStateEncryptionError("private state could not be decrypted")
+                return result
+            tomorrow_row = connection.execute(
+                "SELECT revision, payload FROM tomorrow_plans WHERE login = ?", (login,)
+            ).fetchone()
+            tomorrow = self._tomorrow_snapshot(tomorrow_row, login)
+            if tomorrow["revision"] != tomorrow_revision or not tomorrow.get("plan_date"):
+                raise TomorrowPlanConflict(tomorrow)
+            today_row = connection.execute(
+                "SELECT revision, ids, capacity_minutes, estimates, plan_date, timezone "
+                "FROM today_plans WHERE login = ?", (login,)
+            ).fetchone()
+            today, _legacy = self._snapshot(today_row, login)
+            if today["revision"] != today_revision:
+                raise TodayPromotionConflict(today)
+            result = {"revision": today_revision + 1, **{
+                key: tomorrow[key] for key in
+                ("ids", "capacity_minutes", "estimates", "plan_date", "timezone")
+            }}
+            sealed_today = self._sealed_plan(login, result)
+            connection.execute(
+                "INSERT INTO today_plans(login, revision, ids, capacity_minutes, estimates, plan_date, timezone) "
+                "VALUES (?, ?, ?, NULL, '{}', NULL, NULL) ON CONFLICT(login) DO UPDATE SET "
+                "revision=excluded.revision, ids=excluded.ids, capacity_minutes=NULL, estimates='{}', "
+                "plan_date=NULL, timezone=NULL",
+                (login, result["revision"], sealed_today),
+            )
+            empty = self._empty_tomorrow(tomorrow_revision + 1)
+            sealed_empty = self._cipher.seal(
+                {key: empty[key] for key in ("ids", "capacity_minutes", "estimates")},
+                binding=f"tomorrow:{login}",
+            )
+            connection.execute(
+                "UPDATE tomorrow_plans SET revision = ?, payload = ? WHERE login = ?",
+                (empty["revision"], sealed_empty, login),
+            )
+            sealed_result = self._cipher.seal(
+                result, binding=f"tomorrow-promotion:{login}:{promotion_id}"
+            )
+            connection.execute(
+                "INSERT INTO tomorrow_promotions(login, promotion_id, result, created_at) VALUES (?, ?, ?, ?)",
+                (login, promotion_id, sealed_result, self.clock()),
+            )
+            return result
+
     @staticmethod
     def _empty_session() -> dict:
         return {

tests/e2e/test_mobile_home_bootstrap_release.py

@@ -219,6 +219,18 @@ def test_release_artifact_bootstraps_mobile_home_and_returns_from_insights(
                 bounds = control.bounding_box()
                 assert bounds and bounds["height"] >= 44
 
+            page.locator("#work-settings-toggle").click()
+            tomorrow = page.locator("#plan-tomorrow")
+            expect(tomorrow).to_be_visible()
+            tomorrow_bounds = tomorrow.bounding_box()
+            assert tomorrow_bounds and tomorrow_bounds["height"] >= 44
+            tomorrow.click()
+            expect(page.locator("#plan-today-sheet")).to_be_visible()
+            expect(page.locator("#plan-today-title")).to_have_text("Plan Tomorrow")
+            expect(page.locator("#save-and-start-today")).to_be_hidden()
+            assert page.evaluate("document.documentElement.scrollWidth <= window.innerWidth")
+            page.locator("#cancel-plan-today").click()
+
             page.locator('[data-mobile-task="queues"]').click()
             delivery_queue = page.locator('[data-mobile-queue="delivery"]')
             expect(delivery_queue).to_be_visible()

tests/test_frontend_bundle.py

@@ -50,7 +50,7 @@ def test_product_workflows_are_stable_lazy_feature_chunks(tmp_path):
 
     assert set(first.feature_bundles) == {
         "comment-actions", "issue-capture", "pull-workflow", "push-notifications", "sign-out", "device-setup",
-        "today-timer", "security-center",
+        "today-timer", "security-center", "planning",
     }
     assert first.dashboard_html.count("<script src=") == 1
     assert f'<script src="{first.runtime_name}"></script>' in first.dashboard_html
@@ -71,6 +71,9 @@ def test_product_workflows_are_stable_lazy_feature_chunks(tmp_path):
     assert b"function createAssignAndStart" in first.feature_bundles["today-timer"].runtime_bytes
     assert b"function createQueueToday" not in first.runtime_bytes
     assert b"function createQueueToday" in first.feature_bundles["today-timer"].runtime_bytes
+    assert b"function createPlanToday" in first.feature_bundles["planning"].runtime_bytes
+    assert b"function createTomorrowPlan" in first.feature_bundles["planning"].runtime_bytes
+    assert b"function createPlanToday" not in first.runtime_bytes
     assert b"function createConversationPager" in first.feature_bundles["today-timer"].runtime_bytes
     assert b"function createConversationPager" not in first.feature_bundles["comment-actions"].runtime_bytes
     assert b"function createMobileDeliveryRecovery" not in first.runtime_bytes

tests/test_service_worker.py

@@ -1212,6 +1212,7 @@ def test_install_precaches_complete_subpath_scoped_app_shell():
         "/dashboard/static/plan-today.js",
         "/dashboard/static/plan-today-readiness.js",
         "/dashboard/static/plan-today-preview.js",
+        "/dashboard/static/tomorrow-plan.js",
         "/dashboard/static/today-sync.js",
         "/dashboard/static/today-rollover.js",
         "/dashboard/static/update-ownership.js",

tests/test_tomorrow_plan.py

@@ -0,0 +1,112 @@
+import sqlite3
+
+import pytest
+
+from src import main
+from src.today_store import TodayStore, TomorrowPlanConflict, TodayPromotionConflict
+
+
+def test_tomorrow_plan_is_encrypted_scoped_and_promotes_atomically_exactly_once(tmp_path):
+    path = tmp_path / "today.sqlite3"
+    key = b"n" * 32
+    store = TodayStore(path, encryption_key=key)
+    store.apply("timmy", "today-1", "add", "issue:r:1:")
+
+    tomorrow = store.replace_tomorrow(
+        "Timmy", base_revision=0,
+        ids=["issue:secret/repo:3:", "issue:secret/repo:2:"],
+        capacity_minutes=150,
+        estimates={"issue:secret/repo:3:": 60, "issue:secret/repo:2:": 45},
+        plan_date="2026-08-20", timezone="America/Los_Angeles",
+    )
+
+    assert tomorrow == {
+        "revision": 1,
+        "ids": ["issue:secret/repo:3:", "issue:secret/repo:2:"],
+        "capacity_minutes": 150,
+        "estimates": {"issue:secret/repo:3:": 60, "issue:secret/repo:2:": 45},
+        "plan_date": "2026-08-20",
+        "timezone": "America/Los_Angeles",
+    }
+    assert store.get("timmy")["ids"] == ["issue:r:1:"]
+    assert store.get_tomorrow("alexander")["ids"] == []
+    retained = path.read_bytes()
+    assert b"issue:secret/repo" not in retained
+    assert b"America/Los_Angeles" not in retained
+
+    promoted = store.promote_tomorrow(
+        "timmy", promotion_id="rollover-2026-08-20",
+        tomorrow_revision=1, today_revision=1,
+    )
+    replay = store.promote_tomorrow(
+        "timmy", promotion_id="rollover-2026-08-20",
+        tomorrow_revision=1, today_revision=1,
+    )
+
+    assert replay == promoted
+    assert promoted["ids"] == tomorrow["ids"]
+    assert promoted["capacity_minutes"] == 150
+    assert promoted["plan_date"] == "2026-08-20"
+    assert store.get_tomorrow("timmy") == {
+        "revision": 2, "ids": [], "capacity_minutes": None, "estimates": {}
+    }
+
+
+def test_tomorrow_edit_and_promotion_reject_stale_revisions_without_touching_today(tmp_path):
+    store = TodayStore(tmp_path / "today.sqlite3", encryption_key=b"s" * 32)
+    original_today = store.apply("timmy", "today", "add", "issue:r:1:")
+    first = store.replace_tomorrow(
+        "timmy", base_revision=0, ids=["issue:r:2:"], capacity_minutes=60,
+        estimates={"issue:r:2:": 30}, plan_date="2026-08-20", timezone="UTC",
+    )
+
+    with pytest.raises(TomorrowPlanConflict) as stale_edit:
+        store.replace_tomorrow(
+            "timmy", base_revision=0, ids=["issue:r:9:"], capacity_minutes=None,
+            estimates={}, plan_date="2026-08-20", timezone="UTC",
+        )
+    assert stale_edit.value.snapshot == first
+
+    store.apply("timmy", "today-changed", "add", "issue:r:3:")
+    with pytest.raises(TodayPromotionConflict) as stale_today:
+        store.promote_tomorrow(
+            "timmy", promotion_id="rollover", tomorrow_revision=1,
+            today_revision=original_today["revision"],
+        )
+    assert stale_today.value.today["ids"] == ["issue:r:1:", "issue:r:3:"]
+    assert store.get_tomorrow("timmy") == first
+
+
+def test_tomorrow_validation_is_bounded_and_date_specific(tmp_path):
+    store = TodayStore(tmp_path / "today.sqlite3")
+    with pytest.raises(ValueError, match="ISO calendar date"):
+        store.replace_tomorrow(
+            "timmy", base_revision=0, ids=[], capacity_minutes=None, estimates={},
+            plan_date="tomorrow", timezone="UTC",
+        )
+    with pytest.raises(ValueError, match="unique"):
+        store.replace_tomorrow(
+            "timmy", base_revision=0, ids=["same", "same"], capacity_minutes=None,
+            estimates={}, plan_date="2026-08-20", timezone="UTC",
+        )
+
+
+@pytest.mark.anyio
+async def test_tomorrow_api_round_trip_and_conflict_contract(monkeypatch, tmp_path):
+    async def user():
+        return {"login": "timmy"}
+
+    store = TodayStore(tmp_path / "today.sqlite3", encryption_key=b"a" * 32)
+    monkeypatch.setattr(main, "current_user", user)
+    monkeypatch.setattr(main, "_today_store", lambda: store)
+    payload = main.TomorrowPlanUpdate(
+        base_revision=0, ids=["issue:r:2:"], capacity_minutes=90,
+        estimates={"issue:r:2:": 45}, plan_date="2026-08-20", timezone="UTC",
+    )
+    saved = await main.replace_tomorrow_plan(payload)
+    assert await main.get_tomorrow_plan() == saved
+
+    with pytest.raises(main.HTTPException) as raised:
+        await main.replace_tomorrow_plan(payload)
+    assert raised.value.status_code == 409
+    assert raised.value.detail == {"code": "tomorrow_changed", "snapshot": saved}

tests/test_tomorrow_plan_frontend.py

@@ -0,0 +1,100 @@
+import json
+import subprocess
+from pathlib import Path
+
+
+FRONTEND = Path(__file__).parents[1] / "frontend"
+CONTROLLER = FRONTEND / "tomorrow-plan.js"
+INDEX = FRONTEND / "index.html"
+CSS = FRONTEND / "dashboard.css"
+
+
+def run_controller(scenario: str) -> dict:
+    harness = f"""
+const createTomorrowPlan = require({json.dumps(str(CONTROLLER))});
+(async()=>{{ {scenario} }})().catch(error=>{{console.error(error);process.exit(1);}});
+"""
+    completed = subprocess.run(
+        ["node", "-e", harness], check=True, capture_output=True, text=True
+    )
+    return json.loads(completed.stdout)
+
+
+def test_tomorrow_planner_loads_and_saves_independently_from_today():
+    result = run_controller("""
+const requests=[];
+const fetchJson=async (url, options={})=>{
+  requests.push({url,method:options.method||'GET',body:options.body ? JSON.parse(options.body) : null});
+  if ((options.method||'GET') === 'GET') return {
+    revision:2, ids:['issue:r:2:'], capacity_minutes:90,
+    estimates:{'issue:r:2:':45}, plan_date:'2026-08-20', timezone:'UTC'
+  };
+  return {revision:3,...JSON.parse(options.body)};
+};
+const planner=createTomorrowPlan({fetchJson, localDate:()=> '2026-08-19', timeZone:()=> 'UTC'});
+const loaded=await planner.load();
+const saved=await planner.save({ids:['issue:r:3:'],capacity_minutes:120,estimates:{'issue:r:3:':60}});
+console.log(JSON.stringify({loaded,saved,requests}));
+""")
+
+    assert result["loaded"]["ids"] == ["issue:r:2:"]
+    assert result["saved"]["plan_date"] == "2026-08-20"
+    assert result["requests"] == [
+        {"url": "api/v1/tomorrow", "method": "GET", "body": None},
+        {
+            "url": "api/v1/tomorrow",
+            "method": "PUT",
+            "body": {
+                "base_revision": 2,
+                "ids": ["issue:r:3:"],
+                "capacity_minutes": 120,
+                "estimates": {"issue:r:3:": 60},
+                "plan_date": "2026-08-20",
+                "timezone": "UTC",
+            },
+        },
+    ]
+    assert all(request["url"] != "api/v1/today" for request in result["requests"])
+
+
+def test_tomorrow_planner_promotes_only_on_matching_local_date():
+    result = run_controller("""
+const requests=[];
+const fetchJson=async (url, options={})=>{
+  requests.push({url,body:options.body ? JSON.parse(options.body) : null});
+  return {ids:['issue:r:2:'],revision:8};
+};
+const before=createTomorrowPlan({fetchJson,localDate:()=> '2026-08-19',timeZone:()=> 'UTC',createId:()=> 'rollover-id'});
+before.adopt({revision:3,ids:['issue:r:2:'],capacity_minutes:60,estimates:{},plan_date:'2026-08-20',timezone:'UTC'});
+const early=await before.promote(7);
+const due=createTomorrowPlan({fetchJson,localDate:()=> '2026-08-20',timeZone:()=> 'UTC',createId:()=> 'rollover-id'});
+due.adopt({revision:3,ids:['issue:r:2:'],capacity_minutes:60,estimates:{},plan_date:'2026-08-20',timezone:'UTC'});
+const promoted=await due.promote(7);
+console.log(JSON.stringify({early,promoted,requests}));
+""")
+
+    assert result["early"] is False
+    assert result["promoted"]["revision"] == 8
+    assert result["requests"] == [{
+        "url": "api/v1/tomorrow/promote",
+        "body": {
+            "promotion_id": "rollover-id",
+            "tomorrow_revision": 3,
+            "today_revision": 7,
+        },
+    }]
+
+
+def test_tomorrow_plan_has_a_touch_safe_mobile_entry_and_reuses_the_ordered_planner():
+    index = INDEX.read_text()
+    css = CSS.read_text()
+    dashboard = (FRONTEND / "dashboard.js").read_text()
+
+    assert '<button class="plan-tomorrow" id="plan-tomorrow" type="button">Plan Tomorrow</button>' in index
+    assert ".plan-tomorrow { min-height:44px;" in css
+    assert '<script src="static/tomorrow-plan.js"></script>' in index
+    assert "const tomorrowPlan = createTomorrowPlan" in dashboard
+    assert "qs('#plan-tomorrow').addEventListener('click'" in dashboard
+    assert "planningTomorrow ? saveTomorrowPlan(plan) : saveTodayPlan(plan)" in dashboard
+    assert "tomorrowPlan.load()" in dashboard
+    assert "tomorrowPlan.promote(plan.revision)" in dashboard

tests/test_workspace_bootstrap.py

@@ -25,16 +25,23 @@ const status={textContent:''};
 const document={
   querySelector(selector) {
     if (selector === 'meta[name="stackchain-feature-today-timer"]') return {content:'feature-workspace-abc.js'};
+    if (selector === 'meta[name="stackchain-feature-planning"]') return {content:'feature-planning-def.js'};
     if (selector === '#my-work-action-status') return status;
     return null;
   }
 };
-let requested='';
-const createLoader=options=>({load:async name=>{requested=name + ':' + options.urls[name];}});
+const requested=[];
+const createLoader=options=>({load:async name=>{requested.push(name + ':' + options.urls[name]);}});
 await loadWorkspace({document,createLoader});
 console.log(JSON.stringify({requested,status:status.textContent}));
 """)
-    assert result == {"requested": "today-timer:feature-workspace-abc.js", "status": ""}
+    assert result == {
+        "requested": [
+            "today-timer:feature-workspace-abc.js",
+            "planning:feature-planning-def.js",
+        ],
+        "status": "",
+    }
 
 
 def test_workspace_bootstrap_recovers_one_transient_failure_in_place():
@@ -51,7 +58,7 @@ const schedule=callback=>{callback();};
 await loadWorkspace({document,createLoader,schedule});
 console.log(JSON.stringify({attempts,status:status.textContent,retryHidden:retry.hidden}));
 """)
-    assert result == {"attempts": 2, "status": "", "retryHidden": True}
+    assert result == {"attempts": 4, "status": "", "retryHidden": True}
 
 
 def test_workspace_bootstrap_offers_single_flight_manual_retry_without_reloading():
@@ -65,7 +72,7 @@ const document={querySelector(selector) {
   return null;
 }};
 const window={location:{reload(){reloads++;}},addEventListener(){},removeEventListener(){}};
-const createLoader=()=>({load:async()=>{attempts++; if (attempts < 3) throw new Error('offline');}});
+const createLoader=()=>({load:async()=>{attempts++; if (attempts < 5) throw new Error('offline');}});
 const loading=loadWorkspace({document,window,createLoader,schedule:callback=>callback()});
 await new Promise(resolve=>setImmediate(resolve));
 const offered={hidden:retry.hidden,disabled:retry.disabled,status:status.textContent};
@@ -74,7 +81,7 @@ await Promise.all([first,second,loading]);
 console.log(JSON.stringify({attempts,reloads,offered,status:status.textContent,retryHidden:retry.hidden}));
 """)
     assert result == {
-        "attempts": 3,
+        "attempts": 6,
         "reloads": 0,
         "offered": {
             "hidden": False,
@@ -109,7 +116,7 @@ const window={
   addEventListener(name,callback) { listeners[name]=callback; },
   removeEventListener(name,callback) { if (listeners[name] === callback) delete listeners[name]; },
 };
-const createLoader=()=>({load:async()=>{attempts++; if (attempts < 3) throw new Error('offline');}});
+const createLoader=()=>({load:async()=>{attempts++; if (attempts < 5) throw new Error('offline');}});
 const loading=loadWorkspace({document,window,createLoader,schedule:callback=>callback()});
 await new Promise(resolve=>setImmediate(resolve));
 const waiting=Boolean(listeners.online);
@@ -118,7 +125,7 @@ await loading;
 console.log(JSON.stringify({attempts,waiting,reloads,status:status.textContent}));
 """)
     assert result == {
-        "attempts": 3,
+        "attempts": 6,
         "waiting": True,
         "reloads": 0,
         "status": "",