Read the plan service's today from the scheduler's clock

The plan service read "today" from time.Now, so the plan-draft schedule
tests could not pin the plan_ready title on the fake clock. NewService now
takes a clock; the server passes the scheduler's Now. The plan-draft tests
read the started scheduler's fake clock and assert each plan_ready row's
title and channel alongside the existing key assertions.

Maestro task ece60217-04d0-43a4-9690-4aba2a00d420

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

cmd/server/main.go

@@ -158,7 +158,7 @@ func run(cfg config.Config, logger *slog.Logger) error {
 		return err
 	}
 
-	planSvc, err := plan.NewService(db, weekDrafter(ai, guard), runner, googleSvc, notifier, sched.Wake, cfg.PublicURL, logger)
+	planSvc, err := plan.NewService(db, weekDrafter(ai, guard), runner, googleSvc, notifier, sched.Wake, cfg.PublicURL, sched.Now, logger)
 	if err != nil {
 		return err
 	}

docs/ARCHITECTURE.md

@@ -1120,7 +1120,10 @@ Fake-clock tests of a schedule live in `internal/scheduler`, where
   - The week's Supply run (Feature 17) is made from a pushed plan: after
     a successful `Push`, the handler runs `shopping.GeneratePushed` for
     the week at the plan revision `Push` pushed, and the 200 answer
-    carries `supply_run: {status, error}`. `status` is `generated`;
+    carries `supply_run: {status, error, title_job_id}`. `title_job_id` is
+    the `title_supply_run` job titling a generated list, as for `POST
+    /shopping/{weekStart}/generate`; null when the list already has its
+    title or was not generated. `status` is `generated`;
     `archived` when the week's Supply run is in the Supply archive and was
     left as it was; or `failed` — error `plan_changed` (retryable, logged
     as a warning) when the plan was edited between the push and
@@ -1143,8 +1146,12 @@ Fake-clock tests of a schedule live in `internal/scheduler`, where
   when the week has no Supply run, 400 `invalid_week`.
 - `POST /api/v1/shopping/{weekStart}/generate` makes or remakes the list
   through `shopping.Generate` and answers with the same shape plus
-  `skipped: [{date, dinner_id, dinner_name, reason}]`. 404 when the week
-  has no plan, 409 `archived` when its list is in the Supply archive.
+  `skipped: [{date, dinner_id, dinner_name, reason}]` and
+  `title_job_id`, the `title_supply_run` job titling the list, which
+  `GET /api/v1/jobs/{id}` reports on (failed `title_failed` when the title
+  could not be written); null when the list already has its title. 404
+  when the week has no plan, 409 `archived` when its list is in the Supply
+  archive.
 - `POST /api/v1/shopping/{weekStart}/send-chat` (CSRF-checked) takes
   `{}` or `{"resend": true}` and posts the Supply run to Google Chat
   through `chat.PostSupplyRun`, in the week's thread: "Supply run · " and

internal/auth/auth.go

@@ -79,6 +79,7 @@ type Auth struct {
 	provider *oidc.Provider
 	client   *http.Client
 	cookie   loginCookie
+	pending  *PendingStates
 	sessions Sessions
 	allowed  []string
 	// endSessionURL is the provider's end_session_endpoint; logout ends
@@ -157,6 +158,7 @@ func New(ctx context.Context, cfg Config, sessions Sessions, logger *slog.Logger
 		client:        client,
 		allowed:       slices.Clone(cfg.AllowedGroups),
 		cookie:        newLoginCookie(cfg.SecretKey),
+		pending:       NewPendingStates(loginCookieTTL),
 		sessions:      sessions,
 		endSessionURL: discovered.EndSessionURI,
 		logger:        logger,
@@ -250,7 +252,13 @@ func (a *Auth) login(w http.ResponseWriter, r *http.Request) {
 		Verifier: oauth2.GenerateVerifier(),
 		Return:   returnTo,
 	}
-	if err := a.cookie.set(w, state, time.Now()); err != nil {
+	now := time.Now()
+	if err := a.pending.Add(state.State, now); err != nil {
+		a.logger.WarnContext(r.Context(), "login refused", "error", err)
+		http.Error(w, "too many sign-ins in progress; try again later", http.StatusServiceUnavailable)
+		return
+	}
+	if err := a.cookie.set(w, state, now); err != nil {
 		a.logger.ErrorContext(r.Context(), "set login cookie", "error", err)
 		http.Error(w, "internal error", http.StatusInternalServerError)
 		return
@@ -262,7 +270,7 @@ func (a *Auth) login(w http.ResponseWriter, r *http.Request) {
 }
 
 // callback completes the flow: it checks state against the login cookie,
-// exchanges the code, verifies the ID token and nonce, then starts a session
+// consumes it, exchanges the code, verifies the ID token and nonce, then starts a session
 // if the account is in an allowed group. Membership is checked on every
 // login, so an account removed from the group is refused at its next one.
 func (a *Auth) callback(w http.ResponseWriter, r *http.Request) {
@@ -283,6 +291,13 @@ func (a *Auth) callback(w http.ResponseWriter, r *http.Request) {
 		http.Error(w, "sign-in state mismatch; start again", http.StatusBadRequest)
 		return
 	}
+	// A copy of the cookie verifies until it expires, so the state is
+	// single-use only because it is consumed here.
+	if !a.pending.Consume(state.State) {
+		a.logger.WarnContext(ctx, "login callback state already used")
+		http.Error(w, "sign-in state mismatch; start again", http.StatusBadRequest)
+		return
+	}
 	if q.Get("error") != "" {
 		// error and error_description are provider-supplied text; only the
 		// fixed category is logged.

internal/auth/auth_test.go

@@ -497,6 +497,59 @@ func TestCallbackDefaultReturnPath(t *testing.T) {
 	}
 }
 
+// A saved copy of the login cookie still verifies until it expires, so a
+// replay with a second valid code is refused only because the server
+// consumed the state on first use.
+func TestCallbackRefusesReplayedLoginState(t *testing.T) {
+	t.Parallel()
+	h := newHarness(t)
+	l := h.login(t, LoginPath)
+	idToken := h.provider.signRS256(h.provider.claims(l.query.Get("nonce")))
+
+	if resp := h.callback(l, l.query.Get("state"), idToken); resp.StatusCode != http.StatusSeeOther {
+		t.Fatalf("first callback status = %d, want 303", resp.StatusCode)
+	}
+	resp := h.callback(l, l.query.Get("state"), idToken)
+	if resp.StatusCode != http.StatusBadRequest {
+		t.Errorf("replayed callback status = %d, want 400", resp.StatusCode)
+	}
+	if n := len(h.sessions.started()); n != 1 {
+		t.Errorf("%d sessions started, want 1", n)
+	}
+	assertLoginCookieCleared(t, resp)
+}
+
+// Pending login states live in memory, so a login started before a restart
+// fails closed after it even though its cookie still verifies.
+func TestCallbackRefusesLoginStartedBeforeRestart(t *testing.T) {
+	t.Parallel()
+	h := newHarness(t)
+	l := h.login(t, LoginPath)
+
+	restarted, err := New(context.Background(), Config{
+		Issuer:        h.provider.issuer(),
+		ClientID:      testClientID,
+		ClientSecret:  testClientSecret,
+		PublicURL:     testPublicURL,
+		SecretKey:     []byte("server-secret-key"),
+		AllowedGroups: testAllowedGroups,
+	}, h.sessions, slog.New(slog.DiscardHandler))
+	if err != nil {
+		t.Fatal(err)
+	}
+	r := chi.NewRouter()
+	restarted.Mount(r)
+	h.router = r
+
+	resp := h.callback(l, l.query.Get("state"), h.provider.signRS256(h.provider.claims(l.query.Get("nonce"))))
+	if resp.StatusCode != http.StatusBadRequest {
+		t.Errorf("callback after restart status = %d, want 400", resp.StatusCode)
+	}
+	if n := len(h.sessions.started()); n != 0 {
+		t.Errorf("%d sessions started, want none", n)
+	}
+}
+
 func TestCallbackRejected(t *testing.T) {
 	t.Parallel()
 
@@ -819,6 +872,44 @@ func TestLoginCookieExpires(t *testing.T) {
 	}
 }
 
+func TestPendingStates(t *testing.T) {
+	t.Parallel()
+	p := NewPendingStates(time.Minute)
+	now := time.Now()
+	if err := p.Add("first", now); err != nil {
+		t.Fatal(err)
+	}
+	if !p.Consume("first") {
+		t.Error("Consume of a pending state = false")
+	}
+	if p.Consume("first") {
+		t.Error("second Consume of a state = true")
+	}
+	if p.Consume("never-added") {
+		t.Error("Consume of an unknown state = true")
+	}
+
+	for i := range maxPendingStates - 1 {
+		if err := p.Add(fmt.Sprint("s", i), now); err != nil {
+			t.Fatalf("Add %d: %v", i, err)
+		}
+	}
+	// "first" was consumed but has not expired, so it still counts.
+	if err := p.Add("over", now); !errors.Is(err, ErrTooManyPending) {
+		t.Errorf("Add past the bound = %v, want ErrTooManyPending", err)
+	}
+	// Once the earlier states expire, they are forgotten and a new one fits.
+	if err := p.Add("later", now.Add(time.Minute)); err != nil {
+		t.Errorf("Add after expiry: %v", err)
+	}
+	if p.Consume("s0") {
+		t.Error("an expired state was still pending")
+	}
+	if !p.Consume("later") {
+		t.Error("the state added after expiry is not pending")
+	}
+}
+
 func TestLoginRejectsOffOriginReturn(t *testing.T) {
 	t.Parallel()
 	h := newHarness(t)

internal/auth/cookie.go

@@ -10,6 +10,7 @@ import (
 	"net/http"
 	"net/url"
 	"strings"
+	"sync"
 	"time"
 )
 
@@ -153,6 +154,73 @@ func (c FlowCookie) Read(r *http.Request, v flowValue, now time.Time) error {
 	return nil
 }
 
+// maxPendingStates bounds each flow's pending states. The login route is
+// unauthenticated, so without a bound anyone could grow the set without
+// limit; one household never has close to this many flows in progress.
+const maxPendingStates = 10000
+
+// ErrTooManyPending means a flow's pending states are at maxPendingStates,
+// so a new flow is refused until older ones expire.
+var ErrTooManyPending = errors.New("too many sign-in flows in progress")
+
+// PendingStates holds the state of every redirect flow started and not yet
+// completed, until its flow cookie expires. A copy of a flow cookie verifies
+// until it expires, so a flow is single-use only because its callback
+// consumes the state here. The states live in memory — MealQuest runs as one
+// process — so a flow started before a restart fails closed after it.
+type PendingStates struct {
+	ttl    time.Duration
+	mu     sync.Mutex
+	states map[string]time.Time
+	// order is every added state in the order added. Every state is pending
+	// for the same ttl, so it is also expiry order and Add forgets expired
+	// states from its front.
+	order []pendingState
+}
+
+type pendingState struct {
+	state   string
+	expires time.Time
+}
+
+// NewPendingStates returns an empty set whose states are pending for ttl,
+// the flow cookie's lifetime.
+func NewPendingStates(ttl time.Duration) *PendingStates {
+	return &PendingStates{ttl: ttl, states: map[string]time.Time{}}
+}
+
+// Add records state, started at now, as pending and forgets expired ones.
+// It fails with ErrTooManyPending when maxPendingStates are pending.
+func (p *PendingStates) Add(state string, now time.Time) error {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	expired := 0
+	for expired < len(p.order) && !now.Before(p.order[expired].expires) {
+		delete(p.states, p.order[expired].state)
+		expired++
+	}
+	p.order = p.order[expired:]
+	// The bound counts every unexpired state, consumed or not: a consumed
+	// state leaves states at once but order only when it expires.
+	if len(p.order) >= maxPendingStates {
+		return ErrTooManyPending
+	}
+	expires := now.Add(p.ttl)
+	p.states[state] = expires
+	p.order = append(p.order, pendingState{state: state, expires: expires})
+	return nil
+}
+
+// Consume removes state from the pending states, reporting whether it was
+// there.
+func (p *PendingStates) Consume(state string) bool {
+	p.mu.Lock()
+	defer p.mu.Unlock()
+	_, ok := p.states[state]
+	delete(p.states, state)
+	return ok
+}
+
 // returnPath validates the optional post-login return path. Empty means "/".
 // Only same-origin absolute paths are allowed: no scheme, host, protocol-
 // relative "//" prefix, backslashes or control characters.

internal/gcal/connect.go

@@ -137,10 +137,9 @@ type Service struct {
 	account sync.Mutex
 
 	// pending holds the state of every connect started and not yet
-	// completed, with when it expires. Complete consumes a state once, so a
-	// replayed cookie finds it gone.
-	pendingMu sync.Mutex
-	pending   map[string]time.Time
+	// completed. Complete consumes a state once, so a replayed cookie finds
+	// it gone.
+	pending *auth.PendingStates
 }
 
 // NewService returns the service over st, sealing refresh tokens with box.
@@ -175,7 +174,7 @@ func NewService(st *store.Store, box *secretbox.Box, cfg Config) (*Service, erro
 		cookie:      auth.NewFlowCookie(connectCookieName, connectCookieKeyLabel, connectCookieTTL, cfg.SecretKey),
 		retryDelay:  firstRetryDelay,
 		now:         time.Now,
-		pending:     map[string]time.Time{},
+		pending:     auth.NewPendingStates(connectCookieTTL),
 	}, nil
 }
 
@@ -210,10 +209,12 @@ func (s *Service) Connect(w http.ResponseWriter, session auth.Session) (string,
 		Session:  sessionBinding(session),
 	}
 	now := s.now()
+	if err := s.pending.Add(state.State, now); err != nil {
+		return "", fmt.Errorf("gcal: %w", err)
+	}
 	if err := s.cookie.Set(w, &state, now); err != nil {
 		return "", fmt.Errorf("gcal: set connect cookie: %w", err)
 	}
-	s.addPending(state.State, now)
 	return s.oauth.AuthCodeURL(state.State,
 		oauth2.AccessTypeOffline,
 		oauth2.ApprovalForce,
@@ -243,7 +244,7 @@ func (s *Service) Complete(w http.ResponseWriter, r *http.Request, session auth.
 	}
 	// A copy of the cookie verifies until it expires, so the state is
 	// single-use only because it is consumed here.
-	if !s.consumePending(state.State) {
+	if !s.pending.Consume(state.State) {
 		return fmt.Errorf("%w: already used", ErrBadState)
 	}
 	if q.Get("error") != "" {
@@ -276,29 +277,6 @@ func (s *Service) Complete(w http.ResponseWriter, r *http.Request, session auth.
 	return s.store(ctx, sealed)
 }
 
-// addPending records state, started at now, as pending until the connect
-// cookie expires, and forgets expired ones.
-func (s *Service) addPending(state string, now time.Time) {
-	s.pendingMu.Lock()
-	defer s.pendingMu.Unlock()
-	for k, expires := range s.pending {
-		if !now.Before(expires) {
-			delete(s.pending, k)
-		}
-	}
-	s.pending[state] = now.Add(connectCookieTTL)
-}
-
-// consumePending removes state from the pending states, reporting whether
-// it was there.
-func (s *Service) consumePending(state string) bool {
-	s.pendingMu.Lock()
-	defer s.pendingMu.Unlock()
-	_, ok := s.pending[state]
-	delete(s.pending, state)
-	return ok
-}
-
 // checkScopes fails with ErrScopes unless token's granted scopes include
 // every scope in Scopes. Google lets the household untick a permission on
 // the consent screen and reports what was granted in "scope".

internal/home/home_test.go

@@ -94,7 +94,7 @@ func newEnv(t *testing.T) *env {
 	draft := func(context.Context, string, skills.WeekRequest) (skills.Week, error) {
 		return skills.Week{}, errors.New("no model in this test")
 	}
-	plans, err := plan.NewService(st, draft, runner, googleSvc, notifier, func() {}, pub, logger)
+	plans, err := plan.NewService(st, draft, runner, googleSvc, notifier, func() {}, pub, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/plan/draft.go

@@ -96,7 +96,7 @@ func (s *Service) revision(ctx context.Context, weekStart store.LocalDate) (int6
 // the household context, the pool, last week's dinners and the dinner
 // time.
 func (s *Service) request(ctx context.Context, weekStart store.LocalDate) (skills.WeekRequest, error) {
-	hctx, err := harness.BuildContext(ctx, s.st, time.Now(), ContextBudget)
+	hctx, err := harness.BuildContext(ctx, s.st, s.now(), ContextBudget)
 	if err != nil {
 		return skills.WeekRequest{}, fmt.Errorf("plan: %w", err)
 	}

internal/plan/plan.go

@@ -149,16 +149,19 @@ type Service struct {
 	// publicURL is MEALQUEST_PUBLIC_URL, under which a pushed event links
 	// to its dinner.
 	publicURL *url.URL
+	// now is the clock today is read from: the scheduler's.
+	now func() time.Time
 }
 
 // NewService returns a service over st that drafts with draft, pushes to
 // cal with links under publicURL, tells the household through notifier,
 // which must be over st, calls wake (the scheduler's Wake) after every
-// committed change to a plan's days, and registers the KindDraftWeek job on
-// runner, which must not have started yet. The kind is service-only:
+// committed change to a plan's days, reads today from now (the scheduler's
+// Now) and registers the KindDraftWeek job on runner, which must not have
+// started yet. The kind is service-only:
 // StartDraft and StartScheduledDraft, which keep one draft in flight per
 // week, are the only way to enqueue it.
-func NewService(st *store.Store, draft Drafter, runner *jobs.Runner, cal Calendar, notifier *notify.Service, wake func(), publicURL *url.URL, logger *slog.Logger) (*Service, error) {
+func NewService(st *store.Store, draft Drafter, runner *jobs.Runner, cal Calendar, notifier *notify.Service, wake func(), publicURL *url.URL, now func() time.Time, logger *slog.Logger) (*Service, error) {
 	switch {
 	case st == nil:
 		return nil, errors.New("plan: nil store")
@@ -174,10 +177,12 @@ func NewService(st *store.Store, draft Drafter, runner *jobs.Runner, cal Calenda
 		return nil, errors.New("plan: nil wake")
 	case publicURL == nil:
 		return nil, errors.New("plan: nil public URL")
+	case now == nil:
+		return nil, errors.New("plan: nil clock")
 	case logger == nil:
 		return nil, errors.New("plan: nil logger")
 	}
-	s := &Service{st: st, draft: draft, cal: cal, notifier: notifier, wake: wake, logger: logger, publicURL: publicURL}
+	s := &Service{st: st, draft: draft, cal: cal, notifier: notifier, wake: wake, logger: logger, publicURL: publicURL, now: now}
 	kind, err := jobs.Register(runner, KindDraftWeek, s.runDraft, Reasons...)
 	if err != nil {
 		return nil, err
@@ -501,7 +506,7 @@ func (s *Service) Tonight(ctx context.Context) (week, today store.LocalDate, err
 	if err != nil {
 		return store.LocalDate{}, store.LocalDate{}, fmt.Errorf("plan: household settings: %w", err)
 	}
-	today = household.Today(time.Now(), zone)
+	today = household.Today(s.now(), zone)
 	week = household.WeekStart(today)
 	_, err = q.GetWeekPlan(ctx, week.String())
 	if errors.Is(err, sql.ErrNoRows) {

internal/plan/plan_test.go

@@ -146,7 +146,7 @@ func newEnv(t *testing.T) *env {
 	if err != nil {
 		t.Fatal(err)
 	}
-	e.svc, err = plan.NewService(st, drafter, e.runner, e.gcal, notifytest.New(t, st), func() {}, publicURL, logger)
+	e.svc, err = plan.NewService(st, drafter, e.runner, e.gcal, notifytest.New(t, st), func() {}, publicURL, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/scheduler/plan_draft_test.go

@@ -7,6 +7,7 @@ import (
 	"fmt"
 	"log/slog"
 	"net/url"
+	"slices"
 	"strings"
 	"sync"
 	"testing"
@@ -85,7 +86,21 @@ func (c noCalendar) PushEvents(context.Context, []gcal.Event, func() error) erro
 // pass the fake clock's waits do not expect.
 func (e *env) plans(ids map[string]string) *planEnv {
 	e.t.Helper()
-	return e.newPlans(ids, func() {})
+	return e.newPlans(ids, func() {}, time.Now)
+}
+
+// scheduledPlans is plans whose today is read from the clock of the
+// scheduler start last started, as in the server, so a draft's plan_ready
+// title follows the fake clock. It drafts only once a scheduler started.
+func (e *env) scheduledPlans(ids map[string]string) *planEnv {
+	e.t.Helper()
+	return e.newPlans(ids, func() {}, func() time.Time {
+		s := e.sched.Load()
+		if s == nil {
+			panic("plan service read the clock before a scheduler started")
+		}
+		return s.Now()
+	})
 }
 
 // wakingPlans is plans whose changes wake the scheduler, as in the server.
@@ -93,11 +108,12 @@ func (e *env) plans(ids map[string]string) *planEnv {
 // the wake's pass with changed.
 func (e *env) wakingPlans(ids map[string]string) *planEnv {
 	e.t.Helper()
-	return e.newPlans(ids, e.wake)
+	return e.newPlans(ids, e.wake, time.Now)
 }
 
-// newPlans is plans whose service calls wake after a plan change.
-func (e *env) newPlans(ids map[string]string, wake func()) *planEnv {
+// newPlans is plans whose service calls wake after a plan change and reads
+// today from now.
+func (e *env) newPlans(ids map[string]string, wake func(), now func() time.Time) *planEnv {
 	e.t.Helper()
 	p := &planEnv{e: e, model: &llm.Fake{}, ids: ids, logs: &syncBuffer{}}
 	guard, err := harness.NewGuard(harness.DefaultMaxCalls)
@@ -118,7 +134,7 @@ func (e *env) newPlans(ids map[string]string, wake func()) *planEnv {
 	if err != nil {
 		e.t.Fatal(err)
 	}
-	p.svc, err = plan.NewService(e.st, drafter, runner, noCalendar{e.t}, notifytest.New(e.t, e.st), wake, publicURL, logger)
+	p.svc, err = plan.NewService(e.st, drafter, runner, noCalendar{e.t}, notifytest.New(e.t, e.st), wake, publicURL, now, logger)
 	if err != nil {
 		e.t.Fatal(err)
 	}
@@ -235,6 +251,41 @@ func (e *env) planReady() []string {
 	return keys
 }
 
+// readyRow is a stored plan_ready notification as these tests check it.
+type readyRow struct {
+	Key     string
+	Channel notify.Channel
+	Title   string
+}
+
+// planReadyRows returns every plan_ready notification stored, oldest
+// first, each week's Google Chat row before its push row.
+func (e *env) planReadyRows() []readyRow {
+	e.t.Helper()
+	var out []readyRow
+	for _, r := range notifytest.Rows(e.t, e.st, notify.PlanReady) {
+		out = append(out, readyRow{Key: r.Key, Channel: r.Channel, Title: r.Payload.Title})
+	}
+	return out
+}
+
+// nextWeekReady is the plan_ready rows of a draft of the week starting
+// week, drafted the week before: one to Google Chat and one to push.
+func nextWeekReady(week string) []readyRow {
+	const title = "Next week's plan is ready"
+	key := string(notify.PlanReady) + ":" + week
+	return []readyRow{{key, notify.ChannelChat, title}, {key, notify.ChannelPush, title}}
+}
+
+// wantReady fails unless the plan_ready rows are got.
+func wantReady(t *testing.T, what string, got []readyRow, want ...[]readyRow) {
+	t.Helper()
+	all := slices.Concat(want...)
+	if !slices.Equal(got, all) {
+		t.Fatalf("%s: plan_ready rows = %+v, want %+v", what, got, all)
+	}
+}
+
 var (
 	succeeded = draftJob{Status: string(jobs.StatusSucceeded)}
 	aiFailed  = draftJob{Status: string(jobs.StatusFailed), Error: plan.ReasonAIFailed}
@@ -257,7 +308,7 @@ func mustLocalDate(s string) store.LocalDate {
 // by its Monday once.
 func TestPlanDraftDraftsNextWeek(t *testing.T) {
 	e := newEnv(t)
-	p := e.plans(e.pool())
+	p := e.scheduledPlans(e.pool())
 	p.reply(w43)
 	p.reply(w44)
 
@@ -271,6 +322,7 @@ func TestPlanDraftDraftsNextWeek(t *testing.T) {
 	wantDrafts(t, "at Friday 09:00", e.drafts(), succeeded)
 	wantKeys(t, "plans at Friday 09:00", e.weekPlans(), []string{"2026-10-19"})
 	wantKeys(t, "plan_ready of W43", e.planReady(), []string{"plan_ready:2026-10-19"})
+	wantReady(t, "plan_ready rows of W43", e.planReadyRows(), nextWeekReady("2026-10-19"))
 	got, err := p.svc.Get(context.Background(), w43)
 	if err != nil {
 		t.Fatal(err)
@@ -283,6 +335,7 @@ func TestPlanDraftDraftsNextWeek(t *testing.T) {
 	wantDrafts(t, "W44", e.drafts(), succeeded, succeeded)
 	wantKeys(t, "plans", e.weekPlans(), []string{"2026-10-19", "2026-10-26"})
 	wantKeys(t, "plan_ready of W43 and W44", e.planReady(), []string{"plan_ready:2026-10-19", "plan_ready:2026-10-26"})
+	wantReady(t, "plan_ready rows of W43 and W44", e.planReadyRows(), nextWeekReady("2026-10-19"), nextWeekReady("2026-10-26"))
 	wantKeys(t, "schedule_runs", e.claimed(scheduler.PlanDraft), []string{"2026-W42", "2026-W43", "2026-W44"})
 }
 
@@ -291,23 +344,25 @@ func TestPlanDraftDraftsNextWeek(t *testing.T) {
 // notifies no one and says so.
 func TestPlanDraftLeavesAnExistingPlan(t *testing.T) {
 	e := newEnv(t)
-	p := e.plans(e.pool())
+	p := e.scheduledPlans(e.pool())
 	p.reply(w43)
 	p.reply(w43) // a second draft would succeed too
+	r := e.start(at(2026, 10, 16, 8, 0), p.svc.DraftSchedule())
 	if _, err := p.svc.StartDraft(context.Background(), w43, false); err != nil {
 		t.Fatal(err)
 	}
 	wantDrafts(t, "manual draft", e.drafts(), succeeded)
 	wantKeys(t, "plan_ready of the manual draft", e.planReady(), []string{"plan_ready:2026-10-19"})
+	wantReady(t, "plan_ready rows of the manual draft", e.planReadyRows(), nextWeekReady("2026-10-19"))
 	before, err := p.svc.Get(context.Background(), w43)
 	if err != nil {
 		t.Fatal(err)
 	}
 
-	r := e.start(at(2026, 10, 16, 8, 0), p.svc.DraftSchedule())
 	r.runUntil(at(2026, 10, 16, 9, 0))
 	wantDrafts(t, "with a plan", e.drafts(), succeeded)
 	wantKeys(t, "plan_ready with a plan", e.planReady(), []string{"plan_ready:2026-10-19"})
+	wantReady(t, "plan_ready rows with a plan", e.planReadyRows(), nextWeekReady("2026-10-19"))
 	wantKeys(t, "schedule_runs", e.claimed(scheduler.PlanDraft), []string{"2026-W42", "2026-W43"})
 	after, err := p.svc.Get(context.Background(), w43)
 	if err != nil {
@@ -327,23 +382,25 @@ func TestPlanDraftLeavesAnExistingPlan(t *testing.T) {
 func TestPlanDraftNoDuplicateAfterRestart(t *testing.T) {
 	e := newEnv(t)
 	ids := e.pool()
-	p := e.plans(ids)
+	p := e.scheduledPlans(ids)
 	p.reply(w43)
 	r := e.start(at(2026, 10, 16, 8, 0), p.svc.DraftSchedule())
 	r.runUntil(at(2026, 10, 16, 9, 0))
 	wantDrafts(t, "first process", e.drafts(), succeeded)
+	wantReady(t, "plan_ready rows of the first process", e.planReadyRows(), nextWeekReady("2026-10-19"))
 	r.stop()
 	p.stop()
 
 	// The restarted process has a new job runner, plan service and
 	// scheduler; it would answer a second draft if one were started.
-	p2 := e.plans(ids)
+	p2 := e.scheduledPlans(ids)
 	p2.reply(w43)
 	r2 := e.start(at(2026, 10, 16, 10, 0), p2.svc.DraftSchedule())
 	r2.runUntil(at(2026, 10, 23, 8, 59))
 	wantDrafts(t, "after restart", e.drafts(), succeeded)
 	wantKeys(t, "plans after restart", e.weekPlans(), []string{"2026-10-19"})
 	wantKeys(t, "plan_ready after restart", e.planReady(), []string{"plan_ready:2026-10-19"})
+	wantReady(t, "plan_ready rows after restart", e.planReadyRows(), nextWeekReady("2026-10-19"))
 	wantKeys(t, "schedule_runs", e.claimed(scheduler.PlanDraft), []string{"2026-W42", "2026-W43"})
 }
 
@@ -354,7 +411,7 @@ func TestPlanDraftNoDuplicateAfterRestart(t *testing.T) {
 func TestPlanDraftAIFailureEmitsNothing(t *testing.T) {
 	e := newEnv(t)
 	ids := e.pool()
-	p := e.plans(ids)
+	p := e.scheduledPlans(ids)
 	p.model.QueueGenerate(llm.GenerateResult{Err: errors.New("provider down")})
 
 	r := e.start(at(2026, 10, 16, 8, 0), p.svc.DraftSchedule())
@@ -362,6 +419,7 @@ func TestPlanDraftAIFailureEmitsNothing(t *testing.T) {
 	wantDrafts(t, "after the AI failed", e.drafts(), aiFailed)
 	wantKeys(t, "plans after the AI failed", e.weekPlans(), nil)
 	wantKeys(t, "plan_ready after the AI failed", e.planReady(), nil)
+	wantReady(t, "plan_ready rows after the AI failed", e.planReadyRows())
 	wantKeys(t, "schedule_runs", e.claimed(scheduler.PlanDraft), []string{"2026-W42", "2026-W43"})
 
 	var status, msg string
@@ -377,11 +435,12 @@ func TestPlanDraftAIFailureEmitsNothing(t *testing.T) {
 
 	r.stop()
 	p.stop()
-	p2 := e.plans(ids)
+	p2 := e.scheduledPlans(ids)
 	p2.reply(w43)
 	e.start(at(2026, 10, 16, 10, 0), p2.svc.DraftSchedule())
 	wantDrafts(t, "after restart", e.drafts(), aiFailed)
 	wantKeys(t, "plan_ready after restart", e.planReady(), nil)
+	wantReady(t, "plan_ready rows after restart", e.planReadyRows())
 }
 
 // TestPlanDraftFollowsSettingsWithoutRestart: a plan_draft_dow and
@@ -390,7 +449,7 @@ func TestPlanDraftAIFailureEmitsNothing(t *testing.T) {
 // week.
 func TestPlanDraftFollowsSettingsWithoutRestart(t *testing.T) {
 	e := newEnv(t)
-	p := e.plans(e.pool())
+	p := e.scheduledPlans(e.pool())
 	p.reply(w43)
 
 	r := e.start(at(2026, 10, 12, 12, 0), p.svc.DraftSchedule()) // Monday
@@ -401,6 +460,7 @@ func TestPlanDraftFollowsSettingsWithoutRestart(t *testing.T) {
 	r.runUntil(at(2026, 10, 14, 18, 30))
 	wantDrafts(t, "at Wednesday 18:30", e.drafts(), succeeded)
 	wantKeys(t, "plan_ready", e.planReady(), []string{"plan_ready:2026-10-19"})
+	wantReady(t, "plan_ready rows", e.planReadyRows(), nextWeekReady("2026-10-19"))
 
 	// Friday 09:00, the old fire time, drafts nothing more.
 	r.runUntil(at(2026, 10, 16, 9, 0))

internal/scheduler/scheduler.go

@@ -378,6 +378,11 @@ func (s *Scheduler) Wake() {
 	s.signal()
 }
 
+// Now is the time on the scheduler's clock, by which its schedules fire.
+func (s *Scheduler) Now() time.Time {
+	return s.now()
+}
+
 // signal leaves one token in wake for the loop.
 func (s *Scheduler) signal() {
 	select {

internal/server/ideaactions_test.go

@@ -73,7 +73,7 @@ func newIdeaActionsRouter(t *testing.T, model, normalize *llm.Fake, search *reci
 		t.Error("draft_week ran: an idea action must never draft a plan")
 		return skills.Week{}, context.Canceled
 	}
-	planSvc, err := plan.NewService(st, draft, runner, newTestGoogle(t), notifytest.New(t, st), func() {}, &url.URL{Scheme: "https", Host: "mealquest.example"}, logger)
+	planSvc, err := plan.NewService(st, draft, runner, newTestGoogle(t), notifytest.New(t, st), func() {}, &url.URL{Scheme: "https", Host: "mealquest.example"}, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/plans.go

@@ -111,10 +111,13 @@ type pushedPlan struct {
 // plan Calendar does not show and pushing again makes it; or
 // supply_run_failed when it could not be made, and POST
 // /shopping/{weekStart}/generate makes it again. error is null when status
-// is generated.
+// is generated. title_job_id is the job titling a generated Supply run,
+// which GET /jobs/{id} reports on; null when it already has its title or
+// was not generated.
 type pushedSupplyRun struct {
-	Status string    `json:"status"`
-	Error  *apiError `json:"error"`
+	Status     string    `json:"status"`
+	Error      *apiError `json:"error"`
+	TitleJobID *string   `json:"title_job_id"`
 }
 
 // postPlanPush pushes the week's plan to the chosen Google calendar
@@ -143,7 +146,9 @@ func postPlanPush(logger *slog.Logger, svc *plan.Service, shop *shopping.Service
 		// gone.
 		ctx := context.WithoutCancel(r.Context())
 		run := pushedSupplyRun{Status: "generated"}
-		if _, err := shop.GeneratePushed(ctx, week, revision); errors.Is(err, shopping.ErrFrozen) {
+		if g, err := shop.GeneratePushed(ctx, week, revision); err == nil {
+			run.TitleJobID = g.TitleJobID
+		} else if errors.Is(err, shopping.ErrFrozen) {
 			logger.InfoContext(ctx, "Supply run in the Supply archive left as it was after Push to Calendar", "week", week.String())
 			run = pushedSupplyRun{Status: "archived", Error: &apiError{Code: "archived", Message: err.Error()}}
 		} else if errors.Is(err, shopping.ErrPlanChanged) {
@@ -153,7 +158,7 @@ func postPlanPush(logger *slog.Logger, svc *plan.Service, shop *shopping.Service
 				Message:   "the plan is on Calendar as pushed, but it was edited before its Supply run was made, so no Supply run was made from it; push again",
 				Retryable: true,
 			}}
-		} else if err != nil {
+		} else {
 			logger.ErrorContext(ctx, "generate Supply run after Push to Calendar", "week", week.String(), "error", err)
 			run = pushedSupplyRun{Status: "failed", Error: &apiError{
 				Code:      "supply_run_failed",

internal/server/plans_test.go

@@ -14,6 +14,7 @@ import (
 	"sync"
 	"testing"
 	"testing/fstest"
+	"time"
 
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/harness"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/skills"
@@ -93,7 +94,7 @@ func newPlansRouterTitled(t *testing.T, title shopping.Titler) plansEnv {
 		t.Fatal(err)
 	}
 	notifier := notifytest.New(t, st)
-	svc, err := plan.NewService(st, fail, runner, googleSvc, notifier, func() {}, pub, logger)
+	svc, err := plan.NewService(st, fail, runner, googleSvc, notifier, func() {}, pub, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/server_test.go

@@ -15,6 +15,7 @@ import (
 	"strings"
 	"testing"
 	"testing/fstest"
+	"time"
 
 	"github.com/go-chi/chi/v5"
 	"golang.org/x/oauth2"
@@ -240,7 +241,7 @@ func newTestPlan(t *testing.T) *plan.Service {
 	fail := func(context.Context, string, skills.WeekRequest) (skills.Week, error) {
 		return skills.Week{}, errors.New("no model in this test")
 	}
-	svc, err := plan.NewService(st, fail, runner, newTestGoogle(t), notifytest.New(t, st), func() {}, &url.URL{Scheme: "https", Host: "mealquest.example"}, logger)
+	svc, err := plan.NewService(st, fail, runner, newTestGoogle(t), notifytest.New(t, st), func() {}, &url.URL{Scheme: "https", Host: "mealquest.example"}, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -303,7 +304,7 @@ func newTestHomeOn(t *testing.T, st *store.Store) *home.Service {
 	if err != nil {
 		t.Fatal(err)
 	}
-	planSvc, err := plan.NewService(st, draft, runner, googleSvc, notifier, func() {}, pub, logger)
+	planSvc, err := plan.NewService(st, draft, runner, googleSvc, notifier, func() {}, pub, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/shopping.go

@@ -60,10 +60,13 @@ type supplyRunItem struct {
 }
 
 // generatedSupplyRun is the POST /shopping/{weekStart}/generate answer:
-// the Supply run as made, and the plan days with nothing to shop for.
+// the Supply run as made, the plan days with nothing to shop for, and the
+// title_job_id of the job titling it, which GET /jobs/{id} reports on;
+// null when the Supply run already has its title.
 type generatedSupplyRun struct {
 	supplyRun
-	Skipped []shopping.SkippedDay `json:"skipped"`
+	Skipped    []shopping.SkippedDay `json:"skipped"`
+	TitleJobID *string               `json:"title_job_id"`
 }
 
 // sendChatRequest is the POST /shopping/{weekStart}/send-chat body:
@@ -108,7 +111,7 @@ func getSupplyRun(logger *slog.Logger, svc *shopping.Service) http.HandlerFunc {
 }
 
 // postSupplyRunGenerate makes, or remakes, the week's Supply run from its
-// plan and answers with it and the plan days it skipped.
+// plan and answers with it, the plan days it skipped and its title job.
 func postSupplyRunGenerate(logger *slog.Logger, svc *shopping.Service) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		week, ok := weekStartOrFail(w, r, logger)
@@ -129,7 +132,7 @@ func postSupplyRunGenerate(logger *slog.Logger, svc *shopping.Service) http.Hand
 		if skipped == nil {
 			skipped = []shopping.SkippedDay{}
 		}
-		writeJSON(w, r, logger, http.StatusOK, generatedSupplyRun{supplyRun: out, Skipped: skipped})
+		writeJSON(w, r, logger, http.StatusOK, generatedSupplyRun{supplyRun: out, Skipped: skipped, TitleJobID: g.TitleJobID})
 	}
 }
 

internal/server/shopping_test.go

@@ -186,7 +186,7 @@ func TestSupplyRunShape(t *testing.T) {
 	if status != http.StatusOK {
 		t.Fatalf("generate = %d %v", status, raw)
 	}
-	wantTop := []string{"chat_send_unconfirmed_at", "groups", "label", "needed_count", "sent_to_chat_at", "skipped", "status", "title", "total_count", "weekStart"}
+	wantTop := []string{"chat_send_unconfirmed_at", "groups", "label", "needed_count", "sent_to_chat_at", "skipped", "status", "title", "title_job_id", "total_count", "weekStart"}
 	if got := keys(raw); !reflect.DeepEqual(got, wantTop) {
 		t.Errorf("generate fields = %v, want %v", got, wantTop)
 	}
@@ -199,7 +199,7 @@ func TestSupplyRunShape(t *testing.T) {
 	if status != http.StatusOK {
 		t.Fatalf("GET = %d %v", status, raw)
 	}
-	if k := keys(raw); !reflect.DeepEqual(k, slices.DeleteFunc(slices.Clone(wantTop), func(s string) bool { return s == "skipped" })) {
+	if k := keys(raw); !reflect.DeepEqual(k, slices.DeleteFunc(slices.Clone(wantTop), func(s string) bool { return s == "skipped" || s == "title_job_id" })) {
 		t.Errorf("GET fields = %v", k)
 	}
 	group := raw["groups"].([]any)[0].(map[string]any)
@@ -376,8 +376,12 @@ func TestPushPlanMakesSupplyRun(t *testing.T) {
 	if rec.Code != http.StatusOK || body["status"] != "synced" {
 		t.Fatalf("push = %d %s", rec.Code, rec.Body)
 	}
-	if want := map[string]any{"status": "generated", "error": nil}; !reflect.DeepEqual(body["supply_run"], want) {
-		t.Errorf("supply_run = %v, want %v", body["supply_run"], want)
+	run, _ := body["supply_run"].(map[string]any)
+	if k := keys(run); run["status"] != "generated" || run["error"] != nil || !reflect.DeepEqual(k, []string{"error", "status", "title_job_id"}) {
+		t.Errorf("supply_run = %v, want generated with no error", run)
+	}
+	if job := titleJob(t, e, run["title_job_id"]); job["status"] != "queued" {
+		t.Errorf("title job = %v, want queued: no runner in this test", job)
 	}
 	var l supplyRunJSON
 	if status, got := callShopping(t, e, http.MethodGet, shoppingPath+"2026-10-12", "", &l); status != http.StatusOK {
@@ -467,9 +471,11 @@ func TestPushPlanDoesNotWaitForTitle(t *testing.T) {
 	if rec.Code != http.StatusOK || body["status"] != "synced" {
 		t.Fatalf("push = %d %s", rec.Code, rec.Body)
 	}
-	if want := map[string]any{"status": "generated", "error": nil}; !reflect.DeepEqual(body["supply_run"], want) {
-		t.Errorf("supply_run = %v, want %v", body["supply_run"], want)
+	run, _ := body["supply_run"].(map[string]any)
+	if run["status"] != "generated" || run["error"] != nil {
+		t.Errorf("supply_run = %v, want generated with no error", run)
 	}
+	titleJobID, _ := run["title_job_id"].(string)
 	held.waitEntered(t)
 	var l supplyRunJSON
 	callShopping(t, e, http.MethodGet, shoppingPath+"2026-10-12", "", &l)
@@ -478,6 +484,7 @@ func TestPushPlanDoesNotWaitForTitle(t *testing.T) {
 	}
 
 	close(held.release)
+	wantTitleJobSucceeded(t, e, titleJobID)
 	if got := e.waitTitled(t); got != "Chili and Friends" {
 		t.Errorf("title = %q, want the title job's", got)
 	}
@@ -493,7 +500,8 @@ func TestSupplyRunGenerateDoesNotWaitForTitle(t *testing.T) {
 	e.startRunner(t)
 
 	var l supplyRunJSON
-	if status, body := callShopping(t, e, http.MethodPost, shoppingPath+"2026-10-12/generate", "", &l); status != http.StatusOK {
+	status, body := callShopping(t, e, http.MethodPost, shoppingPath+"2026-10-12/generate", "", &l)
+	if status != http.StatusOK {
 		t.Fatalf("generate = %d %v", status, body)
 	}
 	if l.Title != nil {
@@ -502,12 +510,66 @@ func TestSupplyRunGenerateDoesNotWaitForTitle(t *testing.T) {
 	if !reflect.DeepEqual(l.render(), weekLines) {
 		t.Errorf("generated = %v, want %v", l.render(), weekLines)
 	}
+	titleJobID, _ := body["title_job_id"].(string)
 	held.waitEntered(t)
 
 	close(held.release)
+	wantTitleJobSucceeded(t, e, titleJobID)
 	if got := e.waitTitled(t); got != "Chili and Friends" {
 		t.Errorf("title = %q, want the title job's", got)
 	}
+	if _, body := callShopping(t, e, http.MethodPost, shoppingPath+"2026-10-12/generate", "", nil); body["title_job_id"] != nil {
+		t.Errorf("remake title_job_id = %v, want null: the Supply run has its title", body["title_job_id"])
+	}
+}
+
+// TestSupplyRunGenerateTitleJobFails: a title job that cannot title the
+// Supply run is reported failed with title_failed by GET /jobs/{id}, and
+// the week's next generation answers with a new title job.
+func TestSupplyRunGenerateTitleJobFails(t *testing.T) {
+	t.Parallel()
+	e := newPlansRouter(t)
+	e.groundWeek(t)
+	e.startRunner(t)
+
+	_, body := callShopping(t, e, http.MethodPost, shoppingPath+"2026-10-12/generate", "", nil)
+	first := titleJob(t, e, body["title_job_id"])
+	job := waitJob(t, e.h, first["id"].(string))
+	if job["status"] != "failed" || job["error"] != shopping.ReasonTitleFailed {
+		t.Errorf("title job = %v, want failed %s", job, shopping.ReasonTitleFailed)
+	}
+
+	_, body = callShopping(t, e, http.MethodPost, shoppingPath+"2026-10-12/generate", "", nil)
+	if second := titleJob(t, e, body["title_job_id"]); second["id"] == first["id"] {
+		t.Errorf("retry title_job_id = %v, want a new job", second["id"])
+	}
+}
+
+// titleJob returns the title_supply_run job id, as GET /jobs/{id} reports
+// it; id must be a job id string.
+func titleJob(t *testing.T, e plansEnv, id any) map[string]any {
+	t.Helper()
+	s, ok := id.(string)
+	if !ok || s == "" {
+		t.Fatalf("title_job_id = %v, want a job id", id)
+	}
+	rec, job := callDinners(t, e.h, http.MethodGet, "/api/v1/jobs/"+s, "")
+	if rec.Code != http.StatusOK || job["kind"] != shopping.KindTitleSupplyRun {
+		t.Fatalf("GET title job = %d %s, want a %s job", rec.Code, rec.Body, shopping.KindTitleSupplyRun)
+	}
+	return job
+}
+
+// wantTitleJobSucceeded waits for title job id to finish and fails t
+// unless GET /jobs/{id} reports it succeeded with the title written.
+func wantTitleJobSucceeded(t *testing.T, e plansEnv, id string) {
+	t.Helper()
+	titleJob(t, e, id)
+	job := waitJob(t, e.h, id)
+	result, _ := job["result"].(map[string]any)
+	if job["status"] != "succeeded" || result["title"] != "Chili and Friends" {
+		t.Errorf("title job = %v, want succeeded with the title", job)
+	}
 }
 
 // TestFailedPushMakesNoSupplyRun: a push Calendar refused makes no Supply
@@ -546,7 +608,7 @@ func TestPushPlanSupplyRunFails(t *testing.T) {
 		"code":      "supply_run_failed",
 		"message":   "the plan is on Calendar, but its Supply run could not be made; make it again from the Supply run",
 		"retryable": true,
-	}}
+	}, "title_job_id": nil}
 	if !reflect.DeepEqual(body["supply_run"], want) {
 		t.Errorf("supply_run = %v, want %v", body["supply_run"], want)
 	}
@@ -599,7 +661,7 @@ func TestPushPlanEditedBeforeSupplyRun(t *testing.T) {
 		"code":      "plan_changed",
 		"message":   "the plan is on Calendar as pushed, but it was edited before its Supply run was made, so no Supply run was made from it; push again",
 		"retryable": true,
-	}}
+	}, "title_job_id": nil}
 	if !reflect.DeepEqual(body["supply_run"], want) {
 		t.Errorf("supply_run = %v, want %v", body["supply_run"], want)
 	}
@@ -632,7 +694,7 @@ func TestPushPlanLeavesArchivedSupplyRun(t *testing.T) {
 		t.Fatalf("push = %d %s", rec.Code, rec.Body)
 	}
 	run, _ := body["supply_run"].(map[string]any)
-	if apiErr, _ := run["error"].(map[string]any); run["status"] != "archived" || apiErr["code"] != "archived" {
+	if apiErr, _ := run["error"].(map[string]any); run["status"] != "archived" || apiErr["code"] != "archived" || run["title_job_id"] != nil {
 		t.Errorf("supply_run = %v, want archived", body["supply_run"])
 	}
 	var l supplyRunJSON

internal/shopping/title_test.go

@@ -311,3 +311,38 @@ func TestGenerateTitleOverlapAcrossRename(t *testing.T) {
 		t.Errorf("stored title = %v, want one of the two titles", deref(got))
 	}
 }
+
+// TestGenerateTitleNotStoredOnReplacedList: a list replaced by a new
+// untitled list of the same week once archive_title has answered, before
+// its title is stored, keeps the replacement untitled; the old list's
+// title job fails, and the failure is logged.
+func TestGenerateTitleNotStoredOnReplacedList(t *testing.T) {
+	e := titleWeek(t)
+	e.model.QueueGenerate(titled("Noodles, Tacos and Chili"))
+	e.afterTitle = func() {
+		for _, stmt := range []string{
+			`DELETE FROM shopping_items WHERE group_id IN (SELECT id FROM shopping_groups WHERE list_id IN (SELECT id FROM shopping_lists WHERE week_start = ?1))`,
+			`DELETE FROM shopping_groups WHERE list_id IN (SELECT id FROM shopping_lists WHERE week_start = ?1)`,
+			`UPDATE shopping_lists SET id = 'replacement' WHERE week_start = ?1`,
+		} {
+			if _, err := e.st.Writer.Exec(stmt, week.String()); err != nil {
+				t.Error(err)
+			}
+		}
+	}
+
+	g := e.generate(t)
+	wantJob(t, e.waitTitle(t, g), jobs.StatusFailed, shopping.ReasonTitleFailed)
+
+	var id string
+	if err := e.st.Reader.QueryRow(`SELECT id FROM shopping_lists WHERE week_start = ?`, week.String()).Scan(&id); err != nil {
+		t.Fatal(err)
+	}
+	if id != "replacement" || id == g.List.ID {
+		t.Fatalf("week's list = %s, want the replacement of %s", id, g.List.ID)
+	}
+	wantUntitled(t, "replacement's title", e.storedTitle(t))
+	if !strings.Contains(e.log.String(), "the Supply run was frozen or replaced before its title was stored") {
+		t.Errorf("log lacks the failure:\n%s", e.log.String())
+	}
+}

internal/suggest/suggest_test.go

@@ -1157,7 +1157,7 @@ func TestLaterBatchNeverResuggestsRenamedDrop(t *testing.T) {
 	fail := func(context.Context, string, skills.WeekRequest) (skills.Week, error) {
 		return skills.Week{}, errors.New("no draft in this test")
 	}
-	planSvc, err := plan.NewService(e.st, fail, e.runner, noCalendar{}, notifytest.New(t, e.st), func() {}, &url.URL{Scheme: "https", Host: "meals.example.com"}, logger)
+	planSvc, err := plan.NewService(e.st, fail, e.runner, noCalendar{}, notifytest.New(t, e.st), func() {}, &url.URL{Scheme: "https", Host: "meals.example.com"}, time.Now, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

web/src/plan/PlanPage.test.tsx

@@ -1392,6 +1392,64 @@ describe('PlanPage', () => {
       expect(within(tile('FRI')).getByText('Pizza night')).toBeInTheDocument()
     })
 
+    it("still shows a swap's failure on coming back to the week, through another, and asks for the swap again only on Retry", async () => {
+      const fetchMock = stubServer({
+        [`GET ${THIS_WEEK}`]: () => jsonResponse(200, planBody('draft')),
+        [`GET ${NEXT_WEEK}`]: () => errorResponse(404, 'not_found'),
+        [`GET /api/v1/plans/2026-10-19`]: () => errorResponse(404, 'not_found'),
+        ...lists,
+        [`PUT ${FRIDAY}`]: () => errorResponse(409, 'dinner_not_plannable'),
+      })
+      await renderPage()
+
+      fireEvent.click(await within(await openFriday()).findByRole('button', { name: /Lemon orzo/ }))
+      expect(await screen.findByRole('alert')).toHaveTextContent("Couldn't swap Friday's dinner. dinner_not_plannable message")
+      fireEvent.click(screen.getByRole('button', { name: 'Next week' }))
+      expect(await screen.findByRole('button', { name: 'Draft this week' })).toBeInTheDocument()
+      fireEvent.click(screen.getByRole('button', { name: 'Next week' }))
+      await waitFor(() => expect(screen.getByTestId('search')).toHaveTextContent('?week=2026-10-19'))
+      expect(await screen.findByRole('button', { name: 'Draft this week' })).toBeInTheDocument()
+      fireEvent.click(screen.getByRole('button', { name: 'Previous week' }))
+      await waitFor(() => expect(screen.getByTestId('search')).toHaveTextContent('?week=2026-10-12'))
+      fireEvent.click(screen.getByRole('button', { name: 'Previous week' }))
+
+      expect(await screen.findByRole('alert')).toHaveTextContent("Couldn't swap Friday's dinner. dinner_not_plannable message")
+      expect(within(tile('FRI')).getByText('Pizza night')).toBeInTheDocument()
+      expect(puts(fetchMock)).toHaveLength(1)
+    })
+
+    it('reads the plan again when the dinner is already on another day, and offers to choose another rather than send it again', async () => {
+      // Meanwhile lemon orzo was planned on Wednesday.
+      let read = planBody('draft')
+      const fetchMock = stubServer({
+        [`GET ${THIS_WEEK}`]: () => jsonResponse(200, read),
+        ...lists,
+        [`PUT ${FRIDAY}`]: () => errorResponse(409, 'dinner_already_planned'),
+      })
+      await renderPage()
+
+      const sheet = await openFriday()
+      read = planBody('draft')
+      read.days[2] = { ...read.days[2]!, dinner: { ...read.days[2]!.dinner, id: 'q1', name: 'Lemon orzo' }, is_new: true }
+      fireEvent.click(await within(sheet).findByRole('button', { name: /Lemon orzo/ }))
+
+      const alert = await screen.findByRole('alert')
+      expect(alert).toHaveTextContent("Couldn't swap Friday's dinner. Lemon orzo is already on another day this week.")
+      expect(within(alert).queryByRole('button', { name: 'Retry' })).not.toBeInTheDocument()
+      await waitFor(() => expect(within(tile('WED · NEW')).getByText('Lemon orzo')).toBeInTheDocument())
+      expect(within(tile('FRI')).getByText('Pizza night')).toBeInTheDocument()
+
+      // Choosing again opens Friday's sheet on the plan read, where lemon
+      // orzo is already this week; nothing is sent again.
+      fireEvent.click(within(alert).getByRole('button', { name: 'Choose another dinner' }))
+      const again = screen.getByRole('dialog', { name: 'Swap Friday' })
+      expect(screen.queryByRole('alert')).not.toBeInTheDocument()
+      const orzo = within(within(again).getByRole('list', { name: 'Quest log' })).getByRole('listitem')
+      expect(within(orzo).getByText('Already this week')).toBeInTheDocument()
+      expect(within(orzo).queryByRole('button')).not.toBeInTheDocument()
+      expect(puts(fetchMock)).toHaveLength(1)
+    })
+
     it('waits for a pending swap before Rebuild week, keeping its failure', async () => {
       let refuse!: () => void
       const fetchMock = stubServer({

web/src/plan/PlanPage.tsx

@@ -127,6 +127,12 @@ export function ago(at: Date, now: Date): string {
   return days === 1 ? '1 day ago' : `${days} days ago`
 }
 
+// alreadyPlanned says whether a swap was refused because its dinner is
+// already on another day of the week: sending it again cannot succeed.
+function alreadyPlanned(error: Error): boolean {
+  return error instanceof ApiError && error.code === 'dinner_already_planned'
+}
+
 // pushedToCalendar says whether drafting over a plan of this status needs
 // confirm: it was pushed to Calendar.
 function pushedToCalendar(status: PlanStatus): boolean {
@@ -398,9 +404,18 @@ function WeekBoard({
       </ErrorBanner>
     )
   ) : swap.failed !== null ? (
-    <ErrorBanner onRetry={() => swapIn(swap.failed!.swap)}>
-      Couldn't swap {weekdayName(swap.failed.swap.date)}'s dinner. {swap.failed.error.message}
-    </ErrorBanner>
+    alreadyPlanned(swap.failed.error) ? (
+      // The plan is read again (useSwapDay): the household chooses another
+      // dinner from it rather than sending the refused swap again.
+      <ErrorBanner onRetry={() => openSwap(swap.failed!.swap.date)} retryLabel="Choose another dinner">
+        Couldn't swap {weekdayName(swap.failed.swap.date)}'s dinner. {swap.failed.swap.dinner.name} is already on another day
+        this week.
+      </ErrorBanner>
+    ) : (
+      <ErrorBanner onRetry={() => swapIn(swap.failed!.swap)}>
+        Couldn't swap {weekdayName(swap.failed.swap.date)}'s dinner. {swap.failed.error.message}
+      </ErrorBanner>
+    )
   ) : startDraft.isError ? (
     <ErrorBanner onRetry={rebuild}>Couldn't start drafting this week. {startDraft.error.message}</ErrorBanner>
   ) : result.error !== null ? (

web/src/plan/api.test.tsx

@@ -127,6 +127,17 @@ describe('usePlan', () => {
     ['a method it does not know', (body: ReturnType<typeof planBody>) => (body.days[0]!.dinner.method = 'microwave'), 'method "microwave"'],
     ['no method', (body: ReturnType<typeof planBody>) => Reflect.deleteProperty(body.days[0]!.dinner, 'method'), 'method undefined'],
     ['a sync time that is no instant', (body: ReturnType<typeof planBody>) => (body.calendar_synced_at = 'yesterday'), 'calendar_synced_at "yesterday"'],
+    // Date reads both, in this device's zone: neither says which instant.
+    [
+      'a sync time with no offset',
+      (body: ReturnType<typeof planBody>) => (body.calendar_synced_at = '2026-10-07T15:58:00'),
+      'calendar_synced_at "2026-10-07T15:58:00" is not an instant',
+    ],
+    [
+      'a sync date with no time',
+      (body: ReturnType<typeof planBody>) => (body.calendar_synced_at = '2026-10-07'),
+      'calendar_synced_at "2026-10-07" is not an instant',
+    ],
   ])('refuses a plan with %s', async (_, change, said) => {
     const body = planBody()
     change(body)
@@ -208,6 +219,72 @@ describe('useSwapDay', () => {
     expect(result.current.swap.failed?.error.message).toBe('dinner_not_plannable message')
   })
 
+  it('leaves a day a later plan read landed, the very day the swap wrote, when the swap of it fails', async () => {
+    const friday = deferred()
+    let read = planBody()
+    stubServer({
+      [`GET ${PLAN}`]: () => jsonResponse(200, read),
+      [`PUT ${FRIDAY}`]: () => friday.reply,
+    })
+    const { result, plan, queryClient } = await renderSwaps()
+
+    // The read finds Friday lemon orzo, field for field the day the swap
+    // wrote: the server has it, whatever this swap's PUT is answered with.
+    const swapped = { date: '2026-10-09', dinner: ORZO.dinner, is_new: true, start_by: null }
+    act(() => result.current.swap.mutate(ORZO))
+    await waitFor(() => expect(plan().days[4]).toEqual(swapped))
+    read = planBody({ 4: { id: 'q1', name: 'Lemon orzo', is_new: true } })
+    await act(() => result.current.plan.refetch())
+    await act(async () => friday.send(errorResponse(500, 'internal')))
+
+    await waitFor(() => expect(queryClient.isMutating()).toBe(0))
+    expect(plan().days[4]).toEqual(swapped)
+    expect(result.current.swap.failed?.error.message).toBe('internal message')
+  })
+
+  it('puts the day back when the swap of it fails with no plan read since, after a later swap of another day', async () => {
+    const friday = deferred()
+    const monday = deferred()
+    stubServer({
+      [`GET ${PLAN}`]: () => jsonResponse(200, planBody()),
+      [`PUT ${FRIDAY}`]: () => friday.reply,
+      [`PUT ${MONDAY}`]: () => monday.reply,
+    })
+    const { result, plan, queryClient } = await renderSwaps()
+
+    act(() => result.current.swap.mutate(ORZO))
+    act(() => result.current.swap.mutate(FISH))
+    await waitFor(() => expect(plan().days[0]!.dinner.name).toBe('Fish tacos'))
+    await act(async () => friday.send(errorResponse(500, 'internal')))
+
+    await waitFor(() => expect(plan().days[4]!.dinner.name).toBe('Dinner 4'))
+    expect(plan().days[0]!.dinner.name).toBe('Fish tacos')
+    await act(async () => monday.send(errorResponse(500, 'internal')))
+    await waitFor(() => expect(queryClient.isMutating()).toBe(0))
+    expect(plan().days.map((day) => day.dinner.name)).toEqual(planBody().days.map((day) => day.dinner.name))
+  })
+
+  it('reads the plan again when the dinner is already on another day of the week, and sends the swap only once', async () => {
+    let read = planBody()
+    stubServer({
+      [`GET ${PLAN}`]: () => jsonResponse(200, read),
+      [`PUT ${FRIDAY}`]: () => errorResponse(409, 'dinner_already_planned'),
+    })
+    const { result, plan, queryClient } = await renderSwaps()
+
+    // Meanwhile lemon orzo was planned on Wednesday.
+    read = planBody({ 2: { id: 'q1', name: 'Lemon orzo', is_new: true } })
+    act(() => result.current.swap.mutate(ORZO))
+
+    await waitFor(() => expect(plan().days[2]!.dinner.name).toBe('Lemon orzo'))
+    expect(plan().days[4]!.dinner.name).toBe('Dinner 4')
+    await waitFor(() => expect(queryClient.isMutating()).toBe(0))
+    expect(result.current.swap.failed?.error.message).toBe('dinner_already_planned message')
+    const sent = vi.mocked(fetch).mock.calls.map(([input, init]) => `${init?.method ?? 'GET'} ${String(input)}`)
+    expect(sent.filter((call) => call === `PUT ${FRIDAY}`)).toHaveLength(1)
+    expect(sent.filter((call) => call === `GET ${PLAN}`)).toHaveLength(2)
+  })
+
   it('refuses to dismiss a pending swap', async () => {
     const friday = deferred()
     stubServer({ [`GET ${PLAN}`]: () => jsonResponse(200, planBody()), [`PUT ${FRIDAY}`]: () => friday.reply })
@@ -353,6 +430,61 @@ describe('week mutations', () => {
     expect(weekMutations(queryClient, LATER)).toEqual([])
   })
 
+  it("leaves behind a week's settled swaps but for the failure that speaks for it, which stays until its week leaves it behind", async () => {
+    let refuse = true
+    stubServer({
+      [`GET ${PLAN}`]: () => jsonResponse(200, planBody()),
+      [`PUT ${FRIDAY}`]: () => (refuse ? errorResponse(409, 'dinner_not_plannable') : jsonResponse(200, planBody())),
+      [`PUT ${MONDAY}`]: () => jsonResponse(200, planBody({ 0: { id: 'r1', name: 'Fish tacos' } })),
+      [`GET /api/v1/plans/${NEXT}`]: () => errorResponse(404, 'not_found'),
+      [`GET /api/v1/plans/${LATER}`]: () => errorResponse(404, 'not_found'),
+    })
+    const api = createApiClient(fakeLocation('/plan'), createNetworkStatus(window), createVerifiedSession(localStorage))
+    await api.loadMe()
+    const queryClient = createQueryClient()
+    const wrapper = ({ children }: { children: ReactNode }) => (
+      <ApiProvider client={api}>
+        <QueryClientProvider client={queryClient}>{children}</QueryClientProvider>
+      </ApiProvider>
+    )
+    const hook = renderHook(({ week }) => ({ plan: usePlan(week), swap: useSwapDay(week) }), {
+      wrapper,
+      initialProps: { week: WEEK },
+    })
+    await waitFor(() => expect(hook.result.current.plan.isSuccess).toBe(true))
+
+    // Two swaps settle while the week is shown: the earlier is needed for
+    // ordering no longer, and only the latest stays.
+    act(() => hook.result.current.swap.mutate(FISH))
+    act(() => hook.result.current.swap.mutate(ORZO))
+    await waitFor(() => expect(weekMutations(queryClient, WEEK)).toEqual(['swap error']))
+
+    // Leaving the week, through two others, keeps the failure alone.
+    for (const week of [NEXT, LATER, NEXT]) {
+      hook.rerender({ week })
+      await waitFor(() => expect(hook.result.current.plan.isSuccess).toBe(true))
+      expect(weekMutations(queryClient, WEEK)).toEqual(['swap error'])
+    }
+
+    // Coming back shows it; it fails again, and again one stays.
+    hook.rerender({ week: WEEK })
+    expect(hook.result.current.swap.failed?.error.message).toBe('dinner_not_plannable message')
+    act(() => hook.result.current.swap.dismiss())
+    act(() => hook.result.current.swap.mutate(ORZO))
+    await waitFor(() => expect(hook.result.current.swap.failed).not.toBeNull())
+    expect(weekMutations(queryClient, WEEK)).toEqual(['swap error'])
+
+    // A swap that succeeds is left behind once the week is.
+    refuse = false
+    act(() => hook.result.current.swap.dismiss())
+    act(() => hook.result.current.swap.mutate(ORZO))
+    await waitFor(() => expect(hook.result.current.swap.succeeded).not.toBeNull())
+    expect(weekMutations(queryClient, WEEK)).toEqual(['swap success'])
+    hook.rerender({ week: NEXT })
+    await waitFor(() => expect(hook.result.current.plan.isSuccess).toBe(true))
+    expect(weekMutations(queryClient, WEEK)).toEqual([])
+  })
+
   it('keeps a push whose Supply run was not made, settled in a week no longer shown, to be shown on coming back', async () => {
     const nextPush = deferred()
     stubServer({

web/src/plan/api.ts

@@ -1,5 +1,14 @@
 import { useEffect } from 'react'
-import { useMutation, useMutationState, useQuery, useQueryClient, type Mutation, type QueryClient } from '@tanstack/react-query'
+import {
+  useMutation,
+  useMutationState,
+  useQuery,
+  useQueryClient,
+  type Mutation,
+  type Query,
+  type QueryClient,
+  type QueryKey,
+} from '@tanstack/react-query'
 import { ApiError, useApi, type ApiRead } from '../api/index.ts'
 import { isRecord } from '../api/errors.ts'
 import { METHODS, oneOf, photoId, type Method } from '../dinners/api.ts'
@@ -83,10 +92,16 @@ function parseDay(where: string, body: unknown): PlanDay {
   return { date: body.date, dinner, is_new: body.is_new, start_by: body.start_by }
 }
 
+// RFC3339 is an RFC 3339 instant as the server writes it: a full date and
+// time, to the second or finer, and its offset, Z or ±hh:mm. A date alone,
+// or a time with no offset, which Date would read in this device's zone, is
+// not one.
+const RFC3339 = /^\d{4}-\d{2}-\d{2}T\d{2}:\d{2}:\d{2}(?:\.\d+)?(?:Z|[+-]\d{2}:\d{2})$/
+
 // syncedAt reads calendar_synced_at, an RFC 3339 instant or null.
 function syncedAt(where: string, value: unknown): Date | null {
   if (value === null) return null
-  const at = typeof value === 'string' ? new Date(value) : null
+  const at = typeof value === 'string' && RFC3339.test(value) ? new Date(value) : null
   if (at === null || Number.isNaN(at.getTime())) {
     throw new Error(`${where}: calendar_synced_at ${JSON.stringify(value)} is not an instant`)
   }
@@ -264,38 +279,54 @@ const weeksShown = new WeakMap<QueryClient, WeeksShown>()
 // time a week is shown, and is never removed, so a swap or push that settles
 // after its Draft board, or the whole Plan, is gone is still collected.
 //
-// When a week is shown, the settled ones of every other week are removed,
-// unless that week still has one pending: a pending one, and those an
-// earlier pending one must see, stay across leaving its week and coming
-// back. When one settles, the same is done, except that a week's latest,
-// when it failed, stays until a week is next shown, so that coming straight
-// back to it shows the failure. A week's latest push whose Supply run was
-// not made stays whatever is shown: the week has no shopping list until one
-// is made, which settles the push, or a push sent since replaces it, and
-// making it may still be under way when the week is left. The cache holds
-// at most the weeks shown's, those of weeks left pending, one push of each
-// week whose Supply run was not made, and one failure of each week whose
-// last pending one settled since a week was last shown.
+// A swap or push pending is kept, with every other of its kind and week:
+// an earlier pending one must see those sent after it, across leaving its
+// week and coming back. Once none of a kind and week is pending, only the
+// latest is needed, and the rest are removed, whenever a week is shown or
+// one settles. The latest itself stays while its week is shown. In a week
+// not shown it is removed, unless:
+//
+//   - it is a failed swap: it stays, whatever is shown, until the week's
+//     board leaves it behind (useWeekSwap, Rebuild week, Push to Calendar),
+//     so coming back to the week shows the failure;
+//   - it is a push whose Supply run was not made: the week has no shopping
+//     list until one is made, which settles the push, or a push sent since
+//     replaces it, and making it may still be under way when the week is
+//     left;
+//   - it is a failed push that settled after its week was left: it stays
+//     until a week is next shown, so coming straight back shows it.
+//
+// So once none of its kind is pending, a week keeps at most one settled
+// swap and one settled push, and a week left keeps none but those above:
+// settled swaps and pushes never accumulate.
 function keepWeekMutations(queryClient: QueryClient): WeeksShown {
   const kept = weeksShown.get(queryClient)
   if (kept !== undefined) return kept
   const mutations = queryClient.getMutationCache()
   // How many times each week is shown at once.
   const shown = new Map<string, number>()
+  // keep says whether the latest of its kind and week, none of which is
+  // pending, stays; settled says a mutation settling swept, not a week
+  // shown.
+  function keep(mutation: Mutation, of: { kind: 'swap' | 'push'; week: string }, settled: boolean): boolean {
+    if (shown.has(of.week)) return true
+    if (of.kind === 'swap') return failed(mutation)
+    return unmade(mutation) || (settled && failed(mutation))
+  }
   function sweep(settled: boolean) {
-    // The mutations of each kind of each week not shown, in the order sent.
-    const left = new Map<string, Mutation[]>()
+    // The mutations of each kind of each week, in the order sent.
+    const sent = new Map<string, { of: { kind: 'swap' | 'push'; week: string }; week: Mutation[] }>()
     for (const mutation of mutations.getAll()) {
       const of = weekMutation(mutation)
-      if (of === null || shown.has(of.week)) continue
+      if (of === null) continue
       const id = `${of.kind} ${of.week}`
-      left.set(id, [...(left.get(id) ?? []), mutation])
+      sent.set(id, { of, week: [...(sent.get(id)?.week ?? []), mutation] })
     }
-    for (const week of left.values()) {
+    for (const { of, week } of sent.values()) {
       if (week.some((mutation) => mutation.state.status === 'pending')) continue
       const latest = week.at(-1)
       for (const mutation of week) {
-        if (mutation === latest && (unmade(mutation) || (settled && failed(mutation)))) continue
+        if (mutation === latest && keep(mutation, of, settled)) continue
         mutations.remove(mutation)
       }
     }
@@ -324,6 +355,30 @@ function useWeekShown(weekStart: string) {
   useEffect(() => keepWeekMutations(queryClient).show(weekStart), [queryClient, weekStart])
 }
 
+// swapWrites counts, for each plan query, its updates that were a swap's
+// own optimistic write or rollback, not a plan read from the server.
+const swapWrites = new WeakMap<Query, number>()
+
+// serverReads is how many plans read from the server have landed in the
+// plan query: its updates, less the swaps' own writes. A plan read lands
+// whether or not it differs from the plan shown.
+function serverReads(query: Query): number {
+  return query.state.dataUpdateCount - (swapWrites.get(query) ?? 0)
+}
+
+// writeSwap updates the plan query as a swap's own write, which serverReads
+// does not count.
+function writeSwap(queryClient: QueryClient, query: Query, update: (plan: Plan | null | undefined) => Plan | null | undefined) {
+  const before = query.state.dataUpdateCount
+  queryClient.setQueryData<Plan | null>(query.queryKey, update)
+  swapWrites.set(query, (swapWrites.get(query) ?? 0) + query.state.dataUpdateCount - before)
+}
+
+// planQuery is the plan query keyed key, if the query cache has it.
+function planQuery(queryClient: QueryClient, key: QueryKey): Query | undefined {
+  return queryClient.getQueryCache().find({ queryKey: key, exact: true })
+}
+
 // swapKey keys the swaps of the week starting on weekStart in the mutation
 // cache, where they outlive the Draft board that sent them.
 function swapKey(weekStart: string) {
@@ -345,9 +400,13 @@ export type SwapDay = {
 // (PUT /api/v1/plans/{weekStart}/days/{date}). The day shows the dinner at
 // once, NEW when it came from the Quest log, with no start-by time until the
 // server answers with the plan as swapped, which then replaces it. A refused
-// swap puts the day back as it was, unless it has changed again meanwhile.
-// However the swap ends, the Quest log is read again: the server leaves a
-// dinner on the plan out of it.
+// swap puts the day back as it was, unless it has changed again meanwhile:
+// another swap wrote over it, or any plan read from the server landed
+// since, even one with the very day the swap wrote. A swap refused because
+// the dinner is already on another day of the week (409
+// dinner_already_planned) reads the plan again, so the household chooses
+// again from the plan as it is. However the swap ends, the Quest log is
+// read again: the server leaves a dinner on the plan out of it.
 //
 // The week's swaps live in the mutation cache, not in the component, so
 // leaving the week and coming back keeps them: pending and failed are read
@@ -374,7 +433,7 @@ export function useSwapDay(weekStart: string): SwapDay {
   function mutate(chosen: Swap) {
     // isLatest says whether no swap of the week was sent after this one.
     const isLatest = () => mutations.findAll({ mutationKey }).every((other) => other.mutationId <= mutation.mutationId)
-    const mutation = mutations.build<Plan, Error, Swap, { previous: PlanDay; swapped: PlanDay }>(queryClient, {
+    const mutation = mutations.build<Plan, Error, Swap, { previous: PlanDay; swapped: PlanDay; query: Query; reads: number }>(queryClient, {
       mutationKey,
       // Kept until dismissed or settled in a week not shown
       // (keepWeekMutations): a later swap must stay in the cache while an
@@ -387,24 +446,32 @@ export function useSwapDay(weekStart: string): SwapDay {
       },
       onMutate: async ({ date, dinner, fromQuestLog }) => {
         await queryClient.cancelQueries({ queryKey: key })
-        const plan = queryClient.getQueryData<Plan | null>(key)
+        const query = planQuery(queryClient, key)
+        const plan = query?.state.data as Plan | null | undefined
         const previous = plan?.days.find((day) => day.date === date)
-        if (!plan || previous === undefined) throw new Error(`The week of ${weekStart} has no plan day ${date} to swap.`)
+        if (query === undefined || !plan || previous === undefined) {
+          throw new Error(`The week of ${weekStart} has no plan day ${date} to swap.`)
+        }
         const swapped: PlanDay = { date, dinner, is_new: fromQuestLog, start_by: null }
-        queryClient.setQueryData<Plan>(key, { ...plan, days: plan.days.map((day) => (day.date === date ? swapped : day)) })
-        return { previous, swapped }
+        writeSwap(queryClient, query, () => ({ ...plan, days: plan.days.map((day) => (day.date === date ? swapped : day)) }))
+        return { previous, swapped, query, reads: serverReads(query) }
       },
       onSuccess: (plan) => {
         if (isLatest()) queryClient.setQueryData<Plan>(key, plan)
       },
       // The day goes back only while it is still, field for field, the day
-      // this swap wrote: a later swap or plan read that replaced it is left
-      // alone.
-      onError: (_error, _swap, context) => {
-        if (context === undefined) return
-        queryClient.setQueryData<Plan | null>(key, (plan) =>
-          plan && { ...plan, days: plan.days.map((day) => (sameDay(day, context.swapped) ? context.previous : day)) },
-        )
+      // this swap wrote, and no plan read from the server has landed since
+      // (serverReads): a later swap that replaced it, or a read that did,
+      // even with the same day, is left alone.
+      onError: (error, _swap, context) => {
+        if (context !== undefined && planQuery(queryClient, key) === context.query && serverReads(context.query) === context.reads) {
+          writeSwap(queryClient, context.query, (plan) =>
+            plan && { ...plan, days: plan.days.map((day) => (sameDay(day, context.swapped) ? context.previous : day)) },
+          )
+        }
+        if (error instanceof ApiError && error.code === 'dinner_already_planned') {
+          void queryClient.invalidateQueries({ queryKey: key })
+        }
       },
       onSettled: () => queryClient.invalidateQueries({ queryKey: QUEST_LOG_KEY }),
     })

web/src/settings/RegularsSettingsPage.tsx

@@ -80,7 +80,10 @@ export function RegularsSettingsPage() {
 // Which sheet is open, for which Regular.
 type Open = { sheet: 'edit' | 'fix'; id: string } | null
 
-function RegularsManager() {
+// RegularsManager lists, adds, edits and fixes the recipes of the
+// household's Regulars: this page's body, and the Settings "Regular
+// dinners" sub-tab at tablet and desktop widths.
+export function RegularsManager() {
   const regulars = useRegulars()
   const add = useAddRegular()
   const remove = useRemoveRegular()

web/src/settings/SettingsPage.test.tsx

@@ -104,7 +104,10 @@ describe('SettingsPage', () => {
     expect(await screen.findByText('America/New_York · Dinner at 5:30 pm')).toBeInTheDocument()
     expect(within(row('AI assistant')).getByText('Anthropic · Claude Sonnet')).toBeInTheDocument()
     expect(within(row('Household')).getByText('America/New_York · Dinner at 5:30 pm')).toBeInTheDocument()
+    // The rotation count and the hidden Regular dinners sub-tab both read
+    // the Regulars.
     expect(fetchMock.mock.calls.map(([input]) => String(input)).sort()).toEqual([
+      REGULARS_PATH,
       REGULARS_PATH,
       CALENDAR_PATH,
       '/api/v1/settings/ai',
@@ -117,7 +120,7 @@ describe('SettingsPage', () => {
   })
 
   it('shows the not-yet-available states while the server has no endpoint for them', async () => {
-    stubSettings()
+    stubSettings({ [REGULARS_PATH]: () => errorResponse(404, 'not_found') })
     renderSettings()
     expect(await within(row('Regular dinners')).findByText('Rotation count unavailable')).toBeInTheDocument()
     expect(

web/src/settings/SettingsTabs.module.css

@@ -101,24 +101,3 @@
   padding: 24px;
   border-radius: 30px;
 }
-
-.placeholder {
-  display: flex;
-  flex-direction: column;
-  gap: 14px;
-}
-
-.cardTitle {
-  margin: 0;
-  font-family: var(--font-heading);
-  font-size: 22px;
-  font-weight: 400;
-}
-
-.hint {
-  margin: 0;
-  font-family: var(--font-body);
-  font-size: 14px;
-  line-height: 1.45;
-  color: var(--color-neutral-700);
-}

web/src/settings/SettingsTabs.test.tsx

@@ -11,9 +11,11 @@ import {
   HOUSEHOLD_SETTINGS,
   NOTIFICATION_SETTINGS,
   RECIPE_SEARCH_SETTINGS,
+  SETTINGS_REGULARS,
 } from '../test/ApiProviders.tsx'
 import { InDataRouter } from '../test/dataRouter.tsx'
-import { errorResponse, fakeLocation, jsonResponse, ME } from '../test/fetchStub.ts'
+import { dinnerBody, type DinnerBody } from '../test/dinners.ts'
+import { fakeLocation, jsonResponse, ME } from '../test/fetchStub.ts'
 import { expectMinHitArea } from '../test/hitArea.ts'
 import { mockViewport } from '../test/matchMedia.ts'
 import { SettingsPage } from './SettingsPage.tsx'
@@ -32,6 +34,7 @@ function stubAPI(responders: Record<string, Responder> = {}): Mock<typeof fetch>
     'GET /api/v1/settings/recipe-search': () => jsonResponse(200, RECIPE_SEARCH_SETTINGS),
     'GET /api/v1/settings/notifications': () => jsonResponse(200, NOTIFICATION_SETTINGS),
     'GET /api/v1/settings/chat-webhook': () => jsonResponse(200, CHAT_WEBHOOK),
+    'GET /api/v1/dinners?status=regular': () => jsonResponse(200, SETTINGS_REGULARS),
     ...responders,
   }
   const fetchMock = vi.fn<typeof fetch>((input, init) => {
@@ -121,7 +124,7 @@ describe.each([1440, 1180])('SettingsPage at %i px (mock 2e)', (width) => {
     expect(tab('Regular dinners')).toHaveAttribute('aria-selected', 'true')
     expect(tab('Regular dinners')).toHaveFocus()
     expect(panel('Regular dinners')).toBeVisible()
-    expect(within(panel('Regular dinners')).getByRole('region', { name: 'Regular dinners' })).toBeInTheDocument()
+    expect(await within(panel('Regular dinners')).findByRole('heading', { name: 'On rotation · 1' })).toBeInTheDocument()
     expect(panel('Household')).not.toBeVisible()
 
     fireEvent.keyDown(tab('Regular dinners'), { key: 'End' })
@@ -165,6 +168,123 @@ describe.each([1440, 1180])('SettingsPage at %i px (mock 2e)', (width) => {
   })
 })
 
+const TACOS = dinnerBody('d1', 'Beef tacos', { method: 'stovetop', minutes_total: 40, difficulty: 'easy' })
+const PIZZA = dinnerBody('d3', 'Pizza night', { grounding_status: 'failed', grounding_error: 'no_recipe_found' })
+
+// stubRegulars answers the Regulars from server.regulars, so a write's
+// responder changes what the next read sees.
+function stubRegulars(regulars: DinnerBody[], responders: (server: { regulars: DinnerBody[] }) => Record<string, Responder>) {
+  const server = { regulars }
+  const fetchMock = stubAPI({
+    'GET /api/v1/dinners?status=regular': () => jsonResponse(200, { dinners: server.regulars }),
+    ...responders(server),
+  })
+  return { server, fetchMock }
+}
+
+// writes lists the requests other than GETs, as method, path and body.
+function writes(fetchMock: Mock<typeof fetch>) {
+  return fetchMock.mock.calls
+    .filter(([, init]) => (init?.method ?? 'GET') !== 'GET')
+    .map(([input, init]) => [init?.method, String(input), init?.body])
+}
+
+// openRegulars shows the Regular dinners tab once its Regulars have loaded.
+async function openRegulars() {
+  fireEvent.click(tab('Regular dinners'))
+  const regulars = within(panel('Regular dinners'))
+  await regulars.findByRole('heading', { level: 2, name: /^On rotation/ })
+  return regulars
+}
+
+function regularRow(name: string) {
+  const item = within(screen.getByRole('list', { name: 'Regulars' }))
+    .getAllByRole('listitem')
+    .find((li) => within(li).queryByText(name) !== null)
+  if (item === undefined) throw new Error(`no Regular row named ${name}`)
+  return within(item)
+}
+
+describe.each([1440, 1180])('SettingsPage Regular dinners tab at %i px (mock 2e)', (width) => {
+  it('lists the Regulars as /settings/regulars does, under the page title rather than its own', async () => {
+    stubRegulars([TACOS, PIZZA], () => ({}))
+    await renderAt(width)
+    const regulars = await openRegulars()
+    expect(regulars.getByRole('heading', { level: 2, name: 'On rotation · 2' })).toBeInTheDocument()
+    expect(regularRow('Beef tacos').getByText('Stovetop · 40 min')).toBeInTheDocument()
+    expect(regularRow('Beef tacos').getByText('Recipe found')).toBeInTheDocument()
+    expect(regularRow('Pizza night').getByText('Needs a recipe')).toBeInTheDocument()
+    expect(regulars.getByRole('textbox', { name: 'Add a Regular' })).toBeInTheDocument()
+    expect(screen.getAllByRole('heading', { level: 1 }).map((h) => h.textContent)).toEqual(['Settings'])
+    expect(regulars.queryByRole('button', { name: 'Back to Settings' })).not.toBeInTheDocument()
+  })
+
+  it('adds a Regular by name', async () => {
+    const { fetchMock } = stubRegulars([TACOS], (server) => ({
+      'POST /api/v1/dinners': (body) => {
+        const created = dinnerBody('d9', (body as { name: string }).name, { grounding_status: 'pending' })
+        server.regulars = [...server.regulars, created]
+        return jsonResponse(201, { ...created, grounding_job_id: 'job-1' })
+      },
+    }))
+    await renderAt(width)
+    const regulars = await openRegulars()
+    fireEvent.change(regulars.getByRole('textbox', { name: 'Add a Regular' }), { target: { value: 'Chicken enchiladas' } })
+    fireEvent.click(regulars.getByRole('button', { name: 'Add Regular' }))
+
+    expect(await regulars.findByRole('heading', { level: 2, name: 'On rotation · 2' })).toBeInTheDocument()
+    expect(regularRow('Chicken enchiladas').getByText('Finding recipe…')).toBeInTheDocument()
+    expect(writes(fetchMock)).toEqual([['POST', '/api/v1/dinners', JSON.stringify({ name: 'Chicken enchiladas' })]])
+  })
+
+  it('edits a Regular in its sheet', async () => {
+    const { fetchMock } = stubRegulars([TACOS], (server) => ({
+      'PATCH /api/v1/dinners/d1': (body) => {
+        const edited = { ...TACOS, ...(body as object) }
+        server.regulars = [edited]
+        return jsonResponse(200, edited)
+      },
+    }))
+    await renderAt(width)
+    await openRegulars()
+    fireEvent.click(regularRow('Beef tacos').getByRole('button', { name: /^Beef tacos/ }))
+    const sheet = within(screen.getByRole('dialog', { name: 'Edit Beef tacos' }))
+    fireEvent.change(sheet.getByLabelText('Minutes'), { target: { value: '25' } })
+    fireEvent.click(sheet.getByRole('button', { name: 'Save changes' }))
+
+    await waitFor(() => expect(screen.queryByRole('dialog')).not.toBeInTheDocument())
+    expect(writes(fetchMock)).toEqual([['PATCH', '/api/v1/dinners/d1', JSON.stringify({ minutes_total: 25 })]])
+    expect(await regularRow('Beef tacos').findByText('Stovetop · 25 min')).toBeInTheDocument()
+  })
+
+  it('fixes the recipe of a Regular that needs one', async () => {
+    const { fetchMock } = stubRegulars([PIZZA], (server) => ({
+      'GET /api/v1/dinners/d3/recipe-candidates': () =>
+        jsonResponse(200, {
+          candidates: [
+            { candidate_id: 'https://example.com/pizza', title: 'Weeknight pizza', site_name: 'Example Kitchen', photo_url: null, minutes: 45 },
+          ],
+        }),
+      'POST /api/v1/dinners/d3/ground': () => {
+        const fixed = { ...PIZZA, grounding_status: 'grounded', grounding_error: null }
+        server.regulars = [fixed]
+        return jsonResponse(200, fixed)
+      },
+    }))
+    await renderAt(width)
+    await openRegulars()
+    fireEvent.click(regularRow('Pizza night').getByRole('button', { name: /^Pizza night/ }))
+    const sheet = within(screen.getByRole('dialog', { name: 'Fix recipe' }))
+    fireEvent.click(await sheet.findByRole('button', { name: 'Use Weeknight pizza from Example Kitchen' }))
+
+    await waitFor(() => expect(screen.queryByRole('dialog')).not.toBeInTheDocument())
+    expect(writes(fetchMock)).toEqual([
+      ['POST', '/api/v1/dinners/d3/ground', JSON.stringify({ candidate_id: 'https://example.com/pizza' })],
+    ])
+    expect(await regularRow('Pizza night').findByText('Recipe found')).toBeInTheDocument()
+  })
+})
+
 describe('SettingsPage reminder time across tabs', () => {
   it('shows a reminder time saved on Notifications in the Household tab, keeping its draft', async () => {
     const saved = { ...HOUSEHOLD_SETTINGS }
@@ -195,10 +315,7 @@ describe('SettingsPage reminder time across tabs', () => {
 
 describe('SettingsPage across the 768 px breakpoint', () => {
   it('shows the mobile list below 768 px and the sub-tabs from 768 px', async () => {
-    stubAPI({
-      'GET /api/v1/dinners?status=regular': () => errorResponse(404, 'not_found'),
-      'GET /api/v1/integrations/google': () => jsonResponse(200, GOOGLE_NOT_CONNECTED),
-    })
+    stubAPI({ 'GET /api/v1/integrations/google': () => jsonResponse(200, GOOGLE_NOT_CONNECTED) })
     const resize = await renderAt(767)
     expect(screen.getByRole('link', { name: /^AI assistant/ })).toHaveAttribute('href', '/settings/ai')
     expect(screen.queryByRole('tablist')).not.toBeInTheDocument()
@@ -209,10 +326,7 @@ describe('SettingsPage across the 768 px breakpoint', () => {
   })
 
   it('keeps an unsaved draft and its leave guard across 1180 px, 390 px and back', async () => {
-    stubAPI({
-      'GET /api/v1/dinners?status=regular': () => errorResponse(404, 'not_found'),
-      'GET /api/v1/integrations/google': () => jsonResponse(200, GOOGLE_NOT_CONNECTED),
-    })
+    stubAPI({ 'GET /api/v1/integrations/google': () => jsonResponse(200, GOOGLE_NOT_CONNECTED) })
     const resize = await renderAt(1180)
     fireEvent.change(await screen.findByRole('textbox', { name: 'System prompt' }), {
       target: { value: 'A draft' },

web/src/settings/SettingsTabs.tsx

@@ -1,11 +1,11 @@
 import { useId, useRef, useState, type KeyboardEvent, type ReactNode } from 'react'
 import { useBreakpoint, useOrientation } from '../shell/useBreakpoint.ts'
-import { Card } from '../ui/Card.tsx'
 import { AIAssistantCard } from './AISettingsPage.tsx'
 import { HouseholdSettingsSections } from './HouseholdSettingsPage.tsx'
 import { LeaveGuard } from './LeaveGuard.tsx'
 import { ChatWebhookCard, NotificationsCard } from './NotificationsPage.tsx'
 import { RecipeSearchCard } from './RecipeSearchCard.tsx'
+import { RegularsManager } from './RegularsSettingsPage.tsx'
 import styles from './SettingsTabs.module.css'
 
 type Tab = 'household' | 'regulars' | 'notifications-ai'
@@ -101,13 +101,7 @@ export function SettingsTabs({ hidden = false }: { hidden?: boolean }) {
 
       {panel('household', styles.single, <HouseholdSettingsSections onDirtyChange={setHouseholdDirty} />)}
 
-      {panel(
-        'regulars',
-        styles.single,
-        // TODO(Feature 12): embed the Regular dinners screen here once Feature
-        // 12 builds it.
-        <Placeholder title="Regular dinners">Managing the household's Regulars arrives in a later update.</Placeholder>,
-      )}
+      {panel('regulars', styles.single, <RegularsManager />)}
 
       {panel(
         'notifications-ai',
@@ -128,17 +122,3 @@ export function SettingsTabs({ hidden = false }: { hidden?: boolean }) {
     </div>
   )
 }
-
-// Placeholder is a neutral card holding a section's place until the feature
-// that owns it renders it.
-function Placeholder({ title, children }: { title: string; children: ReactNode }) {
-  const titleId = useId()
-  return (
-    <Card className={styles.placeholder} aria-labelledby={titleId} role="region">
-      <h2 id={titleId} className={styles.cardTitle}>
-        {title}
-      </h2>
-      <p className={styles.hint}>{children}</p>
-    </Card>
-  )
-}

web/src/test/ApiProviders.tsx

@@ -2,7 +2,8 @@ import { QueryClientProvider } from '@tanstack/react-query'
 import { useState, type ReactNode } from 'react'
 import { ApiProvider, createApiClient, createQueryClient, createVerifiedSession } from '../api/index.ts'
 import { createNetworkStatus } from '../pwa/networkStatus.ts'
-import { errorResponse, fakeLocation, jsonResponse } from './fetchStub.ts'
+import { dinnerBody } from './dinners.ts'
+import { fakeLocation, jsonResponse } from './fetchStub.ts'
 
 // AI_SETTINGS is a GET /api/v1/settings/ai body: Anthropic with a verified key.
 export const AI_SETTINGS = {
@@ -99,12 +100,16 @@ export const CHAT_WEBHOOK = {
   last_test_status: null,
 }
 
+// SETTINGS_REGULARS is a GET /api/v1/dinners?status=regular body: one
+// Regular, its recipe found.
+export const SETTINGS_REGULARS = { dinners: [dinnerBody('r1', 'Beef tacos')] }
+
 // SETTINGS_API answers the settings home's requests, for stubFetchByPath, as
-// today's server does: the dinners endpoint does not exist yet, and neither
-// Google Calendar nor Google Chat is connected. The home's sub-tabs stay mounted on mobile, so
-// it also reads the AI models and recipe search settings.
+// today's server does: one Regular on rotation, and neither Google Calendar
+// nor Google Chat connected. The home's sub-tabs stay mounted on mobile, so
+// it also reads the Regulars list, the AI models and recipe search settings.
 export const SETTINGS_API = {
-  '/api/v1/dinners?status=regular': () => errorResponse(404, 'not_found'),
+  '/api/v1/dinners?status=regular': () => jsonResponse(200, SETTINGS_REGULARS),
   '/api/v1/integrations/google': () => jsonResponse(200, GOOGLE_NOT_CONNECTED),
   '/api/v1/settings/notifications': () => jsonResponse(200, NOTIFICATION_SETTINGS),
   '/api/v1/settings/chat-webhook': () => jsonResponse(200, CHAT_WEBHOOK_NONE),