Title Supply runs in a job, scoped by their dinner names

archive_title's single-flight scope was <weekStart>@<plan revision>, but
renaming a planned dinner changes the names to title without changing
the plan revision, so two overlapping generations across a rename could
share one model result. The scope is now
<weekStart>@<plan revision>/<sha256 of the ordered dinner names>, the
same list the skill is given, through the harness's own guard.

Push to Calendar and POST /shopping/{weekStart}/generate also waited
for the title call. Generation now enqueues a title_supply_run job
(service-only, in the generation's transaction) for a list still
untitled and returns without waiting; the list reads untitled until the
job stores its title. A failed title still leaves the list untitled, is
logged, recorded in ai_runs, fails the job title_failed, and is retried
by the week's next generation. A titled list enqueues no job.

Maestro task fa4b94c9-6623-41ab-8d2a-0ca7d1e6401a.

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

cmd/server/main.go

@@ -133,7 +133,7 @@ func run(cfg config.Config, logger *slog.Logger) error {
 		return err
 	}
 
-	shopSvc, err := shopping.NewService(db, archiveTitler(ai, guard), logger)
+	shopSvc, err := shopping.NewService(db, archiveTitler(ai, guard), runner, logger)
 	if err != nil {
 		return err
 	}
@@ -280,7 +280,7 @@ func newJobRunner(db *store.Store, logger *slog.Logger) (*jobs.Runner, *jobKinds
 // service registers its own kinds when it is built, before the runner
 // starts (dinners.NewService registers dinners.KindGroundDinner and
 // suggest.NewService suggest.KindSuggestionBatch, plan.NewService
-// plan.KindDraftWeek).
+// plan.KindDraftWeek, shopping.NewService shopping.KindTitleSupplyRun).
 func registerJobKinds(runner *jobs.Runner) (*jobKinds, error) {
 	builtins, err := jobs.RegisterBuiltins(runner)
 	if err != nil {

docs/ARCHITECTURE.md

@@ -476,14 +476,20 @@ automatic** (D-021).
   household temperature with no household context. A title must be 1–48
   characters on one line, with no emoji and no surrounding quotation
   marks; a reply breaking a rule gets the one repair turn, never a
-  truncation. `shopping.Generate` (and `GeneratePushed`) runs it after
+  truncation. `shopping.Generate` (and `GeneratePushed`), on storing a
-  storing a list that is still untitled — a new list, or one a failed
+  list that is still untitled — a new list, or one a failed title left
-  title left untitled — outside the generation's transaction, and writes
+  untitled — enqueues a `title_supply_run` job in the generation's
-  `shopping_lists.title` only while the list is untitled and not frozen.
+  transaction and returns without waiting for it, so neither Push to
-  A title is written once; a remake keeps it. A failed title never fails
+  Calendar nor `POST /shopping/{weekStart}/generate` waits for a model
-  the generation: the list stays untitled (the UI shows the week label),
+  call; the list reads untitled until the job stores its title. The job's
-  the failure is logged as a warning and recorded in `ai_runs`, and the
+  scope is `<weekStart>@<plan revision>/<sha256 of the dinner names in
-  week's next generation tries again.
+  order>`, so runs share a title only for the same names (a renamed dinner
+  changes the names, not the revision). It writes `shopping_lists.title`
+  only while the list is untitled and not frozen. A title is written once;
+  a remake keeps it and enqueues no job. A failed title never fails the
+  generation: the list stays untitled (the UI shows the week label), the
+  failure is logged as a warning and recorded in `ai_runs`, the job fails
+  `title_failed`, and the week's next generation tries again.
 
 ## Recipe grounding
 

internal/server/plans_test.go

@@ -37,6 +37,7 @@ type plansEnv struct {
 	h        http.Handler
 	st       *store.Store
 	svc      *plan.Service
+	runner   *jobs.Runner
 	questLog string
 	// google is the fake Google the plan service pushes to; it starts
 	// unconnected.
@@ -47,6 +48,13 @@ type plansEnv struct {
 }
 
 func newPlansRouter(t *testing.T) plansEnv {
+	t.Helper()
+	return newPlansRouterTitled(t, untitled)
+}
+
+// newPlansRouterTitled is newPlansRouter whose Supply runs are titled by
+// title.
+func newPlansRouterTitled(t *testing.T, title shopping.Titler) plansEnv {
 	t.Helper()
 	st := newTestStore(t)
 	ctx := t.Context()
@@ -80,7 +88,7 @@ func newPlansRouter(t *testing.T) plansEnv {
 	if err != nil {
 		t.Fatal(err)
 	}
-	shop, err := shopping.NewService(st, untitled, logger)
+	shop, err := shopping.NewService(st, title, runner, logger)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -119,7 +127,7 @@ func newPlansRouter(t *testing.T) plansEnv {
 			t.Fatal(err)
 		}
 	}
-	return plansEnv{h: h, st: st, svc: svc, questLog: dinner("Pad Thai", "quest_log", "stovetop", 35),
+	return plansEnv{h: h, st: st, svc: svc, runner: runner, questLog: dinner("Pad Thai", "quest_log", "stovetop", 35),
 		google: google, gcal: googleSvc, logs: logs}
 }
 

internal/server/server_test.go

@@ -214,7 +214,13 @@ func newTestPlan(t *testing.T) *plan.Service {
 // database, whose Supply runs stay untitled.
 func newTestShopping(t *testing.T) *shopping.Service {
 	t.Helper()
-	svc, err := shopping.NewService(newTestStore(t), untitled, slog.New(slog.NewTextHandler(io.Discard, nil)))
+	st := newTestStore(t)
+	logger := slog.New(slog.NewTextHandler(io.Discard, nil))
+	runner, err := jobs.NewRunner(st, logger, 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	svc, err := shopping.NewService(st, untitled, runner, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/shopping_test.go

@@ -1,6 +1,7 @@
 package server
 
 import (
+	"context"
 	"database/sql"
 	"encoding/json"
 	"net/http"
@@ -8,7 +9,9 @@ import (
 	"slices"
 	"strings"
 	"testing"
+	"time"
 
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/skills"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/plan"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
@@ -378,6 +381,128 @@ func TestPushPlanMakesSupplyRun(t *testing.T) {
 	}
 }
 
+// heldTitler is a shopping.Titler that reports each call on entered and
+// answers title only once release is closed.
+type heldTitler struct {
+	entered chan struct{}
+	release chan struct{}
+}
+
+func newHeldTitler() heldTitler {
+	return heldTitler{entered: make(chan struct{}, 4), release: make(chan struct{})}
+}
+
+func (h heldTitler) title(ctx context.Context, _ string, _ skills.ArchiveTitleRequest) (skills.ArchiveTitle, error) {
+	h.entered <- struct{}{}
+	select {
+	case <-h.release:
+		return skills.ArchiveTitle{Title: "Chili and Friends"}, nil
+	case <-ctx.Done():
+		return skills.ArchiveTitle{}, ctx.Err()
+	}
+}
+
+// startRunner starts e's job runner, stopping it when the test ends. e's
+// logs must not be read while it runs.
+func (e plansEnv) startRunner(t *testing.T) {
+	t.Helper()
+	ctx, cancel := context.WithCancel(context.Background())
+	if err := e.runner.Start(ctx); err != nil {
+		cancel()
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		cancel()
+		e.runner.Wait()
+	})
+}
+
+// waitEntered waits for the title call to begin.
+func (h heldTitler) waitEntered(t *testing.T) {
+	t.Helper()
+	select {
+	case <-h.entered:
+	case <-time.After(10 * time.Second):
+		t.Fatal("archive_title was never called")
+	}
+}
+
+// waitTitled waits for the week's Supply run to have a title through GET
+// and returns it.
+func (e plansEnv) waitTitled(t *testing.T) string {
+	t.Helper()
+	deadline := time.Now().Add(10 * time.Second)
+	for {
+		var l supplyRunJSON
+		callShopping(t, e, http.MethodGet, shoppingPath+"2026-10-12", "", &l)
+		if l.Title != nil {
+			return *l.Title
+		}
+		if time.Now().After(deadline) {
+			t.Fatal("the Supply run was never titled")
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+}
+
+// TestPushPlanDoesNotWaitForTitle: Push to Calendar answers while the
+// Supply run's title is still being written; the list reads untitled until
+// the title job stores it.
+func TestPushPlanDoesNotWaitForTitle(t *testing.T) {
+	t.Parallel()
+	held := newHeldTitler()
+	e := newPlansRouterTitled(t, held.title)
+	e.groundWeek(t)
+	e.connectCalendar(t, true)
+	e.startRunner(t)
+
+	rec, body := callDinners(t, e.h, http.MethodPost, plansPath+"2026-10-12/push-calendar", "")
+	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)
+	}
+	held.waitEntered(t)
+	var l supplyRunJSON
+	callShopping(t, e, http.MethodGet, shoppingPath+"2026-10-12", "", &l)
+	if l.Title != nil {
+		t.Errorf("title = %q while archive_title is still running, want null", *l.Title)
+	}
+
+	close(held.release)
+	if got := e.waitTitled(t); got != "Chili and Friends" {
+		t.Errorf("title = %q, want the title job's", got)
+	}
+}
+
+// TestSupplyRunGenerateDoesNotWaitForTitle: POST generate answers with the
+// list untitled while its title is still being written.
+func TestSupplyRunGenerateDoesNotWaitForTitle(t *testing.T) {
+	t.Parallel()
+	held := newHeldTitler()
+	e := newPlansRouterTitled(t, held.title)
+	e.groundWeek(t)
+	e.startRunner(t)
+
+	var l supplyRunJSON
+	if status, body := callShopping(t, e, http.MethodPost, shoppingPath+"2026-10-12/generate", "", &l); status != http.StatusOK {
+		t.Fatalf("generate = %d %v", status, body)
+	}
+	if l.Title != nil {
+		t.Errorf("title = %q while archive_title is still running, want null", *l.Title)
+	}
+	if !reflect.DeepEqual(l.render(), weekLines) {
+		t.Errorf("generated = %v, want %v", l.render(), weekLines)
+	}
+	held.waitEntered(t)
+
+	close(held.release)
+	if got := e.waitTitled(t); got != "Chili and Friends" {
+		t.Errorf("title = %q, want the title job's", got)
+	}
+}
+
 // TestFailedPushMakesNoSupplyRun: a push Calendar refused makes no Supply
 // run.
 func TestFailedPushMakesNoSupplyRun(t *testing.T) {

internal/shopping/shopping.go

@@ -6,12 +6,15 @@
 // the plan changes. It is deterministic and runs no model: an item is one
 // ingredient of the dinner's recipe exactly as recipe grounding stored it
 // (see Generate). The one model call is the Supply run's title, written by
-// archive_title when the list is generated untitled (see Generate).
+// archive_title in a KindTitleSupplyRun job when the list is generated
+// untitled (see Generate).
 package shopping
 
 import (
 	"context"
+	"crypto/sha256"
 	"database/sql"
+	"encoding/json"
 	"errors"
 	"fmt"
 	"log/slog"
@@ -21,6 +24,7 @@ import (
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/dinners"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/household"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/store"
 )
 
@@ -39,6 +43,15 @@ const (
 	SkipNoIngredients = "no_ingredients"
 )
 
+// KindTitleSupplyRun is the job kind that titles a Supply run with
+// archive_title. Only Generate and GeneratePushed enqueue it.
+const KindTitleSupplyRun = "title_supply_run"
+
+// ReasonTitleFailed is the failure code of a KindTitleSupplyRun job that
+// stored no title: archive_title failed, or the Supply run was frozen or
+// replaced first. The Supply run stays untitled.
+const ReasonTitleFailed = "title_failed"
+
 // ErrPlanNotFound is a generation for a week with no plan.
 var ErrPlanNotFound = errors.New("the week has no plan")
 
@@ -57,30 +70,44 @@ var ErrListNotFound = errors.New("the week has no Supply run")
 // ErrItemNotFound is a change to an item on no Supply run.
 var ErrItemNotFound = errors.New("no Supply run has that item")
 
-// Titler runs archive_title on in; scope names the week and its dinners.
+// Titler runs archive_title on in; scope names the week, its plan revision
+// and its dinners.
 // In production it is skills.TitleArchive with the household's
 // harness.Config.
 type Titler func(ctx context.Context, scope string, in skills.ArchiveTitleRequest) (skills.ArchiveTitle, error)
 
 // Service generates Supply runs.
 type Service struct {
-	st     *store.Store
+	st       *store.Store
-	title  Titler
+	title    Titler
-	logger *slog.Logger
+	titleJob *jobs.Kind[TitleJob]
+	logger   *slog.Logger
 }
 
 // NewService returns a service over st that titles Supply runs with title
-// and logs to logger.
+// in KindTitleSupplyRun jobs, which it registers on runner, and logs to
-func NewService(st *store.Store, title Titler, logger *slog.Logger) (*Service, error) {
+// logger. runner must not have started yet.
+func NewService(st *store.Store, title Titler, runner *jobs.Runner, logger *slog.Logger) (*Service, error) {
 	switch {
 	case st == nil:
 		return nil, errors.New("shopping: nil store")
 	case title == nil:
 		return nil, errors.New("shopping: nil titler")
+	case runner == nil:
+		return nil, errors.New("shopping: nil job runner")
 	case logger == nil:
 		return nil, errors.New("shopping: nil logger")
 	}
-	return &Service{st: st, title: title, logger: logger}, nil
+	s := &Service{st: st, title: title, logger: logger}
+	kind, err := jobs.Register(runner, KindTitleSupplyRun, s.runTitleJob, ReasonTitleFailed)
+	if err != nil {
+		return nil, err
+	}
+	if err := kind.ServiceOnly(); err != nil {
+		return nil, err
+	}
+	s.titleJob = kind
+	return s, nil
 }
 
 // List is a Supply run.
@@ -158,6 +185,9 @@ type Generated struct {
 	// Skipped are the plan days whose dinner has no ingredients to shop
 	// for, by date.
 	Skipped []SkippedDay `json:"skipped"`
+	// TitleJobID is the KindTitleSupplyRun job titling the list; nil when
+	// the list already has its title.
+	TitleJobID *string `json:"title_job_id"`
 }
 
 // Generate makes the Supply run of the week starting weekStart from the
@@ -182,12 +212,15 @@ type Generated struct {
 // new and needed; an item no longer on the plan is removed, and with it a
 // group no longer on the plan.
 //
-// A list still untitled once it is stored, as a new list always is, is
+// A list still untitled once it is stored, as a new list always is, gets a
-// then titled by archive_title from the names of the plan's dinners in day
+// KindTitleSupplyRun job, enqueued in the same transaction, that titles it
-// order, outside the transaction. A title is written once: a remake keeps
+// with archive_title from the names of the plan's dinners in day order.
-// it. Titling never fails the generation: a title that cannot be written
+// Generate returns without waiting for the job: the list is returned
-// leaves the list untitled, as it is returned, the failure is logged, and
+// untitled, with the job's id. A title is written once: a remake keeps it
-// the next generation of the week, Generate or GeneratePushed, tries again.
+// and enqueues no job. Titling never fails the generation: a title that
+// cannot be written leaves the list untitled, the failure is logged and
+// the job failed with ReasonTitleFailed, and the next generation of the
+// week, Generate or GeneratePushed, tries again.
 //
 // A week with no plan is ErrPlanNotFound; a list frozen into the Supply
 // archive is ErrFrozen. A fetched recipe's ingredient without a name is an
@@ -216,11 +249,7 @@ func (s *Service) generate(ctx context.Context, weekStart store.LocalDate, check
 	if _, err := household.WeekDays(weekStart); err != nil {
 		return Generated{}, fmt.Errorf("shopping: generate: %w", err)
 	}
-	var (
+	var out Generated
-		out      Generated
-		revision int64
-		names    []string // the plan's dinners, in day order
-	)
 	err := s.st.WithTx(ctx, func(tx *sql.Tx) error {
 		q := db.New(tx)
 		plan, err := q.GetWeekPlan(ctx, weekStart.String())
@@ -237,7 +266,6 @@ func (s *Service) generate(ctx context.Context, weekStart store.LocalDate, check
 		if err != nil {
 			return err
 		}
-		revision, names = plan.Revision, dinnerNames
 		now := store.Now().String()
 		list, err := q.GetShoppingList(ctx, weekStart.String())
 		if err != nil && !errors.Is(err, sql.ErrNoRows) {
@@ -263,43 +291,77 @@ func (s *Service) generate(ctx context.Context, weekStart store.LocalDate, check
 			return err
 		}
 		out = Generated{List: listOf(list, groups), Skipped: skipped}
+		if list.Title.Valid {
+			return nil
+		}
+		id, err := s.titleJob.EnqueueTx(ctx, tx, TitleJob{
+			ListID: list.ID, WeekStart: list.WeekStart, Revision: plan.Revision, Dinners: dinnerNames,
+		})
+		if err != nil {
+			return fmt.Errorf("shopping: enqueue title: %w", err)
+		}
+		out.TitleJobID = &id
 		return nil
 	})
 	if err != nil {
 		return Generated{}, err
 	}
-	if out.List.Title == nil {
+	if out.TitleJobID != nil {
-		s.titleList(ctx, &out.List, revision, names)
+		s.titleJob.Wake()
 	}
 	return out, nil
 }
 
-// titleList titles l, an untitled Supply run made from dinners, the names
+// TitleJob is a KindTitleSupplyRun job's payload: the untitled Supply run
-// of its plan's dinners in day order at plan revision, with archive_title,
+// ListID of the week WeekStart, made from the plan at Revision, whose
-// and stores the title on it. A title that cannot be written leaves l
+// dinners in day order are Dinners.
-// untitled; the failure is logged, never returned.
+type TitleJob struct {
-func (s *Service) titleList(ctx context.Context, l *List, revision int64, dinners []string) {
+	ListID    string   `json:"list_id"`
-	title, err := s.writeTitle(ctx, l, revision, dinners)
+	WeekStart string   `json:"week_start"`
-	if err != nil {
+	Revision  int64    `json:"revision"`
-		s.logger.WarnContext(ctx, "Supply run left untitled; its next generation titles it again",
+	Dinners   []string `json:"dinners"`
-			"week", l.WeekStart, "list", l.ID, "error", err)
-		return
-	}
-	l.Title = &title
 }
 
-// writeTitle runs archive_title for l and stores its title. When l was
+// titleResult is a KindTitleSupplyRun job's result: the Supply run and the
-// titled by another generation meanwhile, that title stands and is
+// title it has.
-// returned.
+type titleResult struct {
-func (s *Service) writeTitle(ctx context.Context, l *List, revision int64, dinners []string) (string, error) {
+	ListID string `json:"list_id"`
-	scope := fmt.Sprintf("%s@%d", l.WeekStart, revision)
+	Title  string `json:"title"`
-	out, err := s.title(ctx, scope, skills.ArchiveTitleRequest{Dinners: dinners})
+}
+
+// PublicJSON returns the Supply run's id and title.
+func (r titleResult) PublicJSON() ([]byte, error) { return json.Marshal(r) }
+
+// runTitleJob titles the Supply run of p with archive_title and stores the
+// title. A title that cannot be stored leaves the list untitled: the
+// failure is logged and the job fails with ReasonTitleFailed.
+func (s *Service) runTitleJob(ctx context.Context, p TitleJob, _ func(titleResult) error) (titleResult, error) {
+	title, err := s.writeTitle(ctx, p)
+	if err != nil {
+		s.logger.WarnContext(ctx, "Supply run left untitled; its next generation titles it again",
+			"week", p.WeekStart, "list", p.ListID, "error", err)
+		return titleResult{}, &jobs.Failure{Code: ReasonTitleFailed}
+	}
+	return titleResult{ListID: p.ListID, Title: title}, nil
+}
+
+// writeTitle runs archive_title for p's Supply run and stores its title.
+// When the list was titled by another job, before this one ran or
+// meanwhile, that title stands and is returned.
+func (s *Service) writeTitle(ctx context.Context, p TitleJob) (string, error) {
+	q := db.New(s.st.Writer)
+	title, err := s.currentTitle(ctx, q, p)
+	if err != nil || title != "" {
+		return title, err
+	}
+	out, err := s.title(ctx, titleScope(p), skills.ArchiveTitleRequest{Dinners: p.Dinners})
 	if err != nil {
 		return "", fmt.Errorf("shopping: title: %w", err)
 	}
-	q := db.New(s.st.Writer)
+	write, cancel := jobs.FinalWriteContext(ctx)
-	n, err := q.SetShoppingListTitle(ctx, db.SetShoppingListTitleParams{
+	defer cancel()
-		Title: sql.NullString{String: out.Title, Valid: true}, UpdatedAt: store.Now().String(), ID: l.ID,
+	n, err := q.SetShoppingListTitle(write, db.SetShoppingListTitleParams{
+		Title: sql.NullString{String: out.Title, Valid: true}, UpdatedAt: store.Now().String(), ID: p.ListID,
 	})
 	if err != nil {
 		return "", fmt.Errorf("shopping: store title: %w", err)
@@ -307,14 +369,37 @@ func (s *Service) writeTitle(ctx context.Context, l *List, revision int64, dinne
 	if n == 1 {
 		return out.Title, nil
 	}
-	list, err := q.GetShoppingList(ctx, l.WeekStart)
+	title, err = s.currentTitle(write, q, p)
-	if err != nil {
+	if err == nil && title == "" {
-		return "", fmt.Errorf("shopping: store title: read list: %w", err)
+		err = errors.New("shopping: store title: the Supply run is still untitled")
 	}
-	if list.ID != l.ID || !list.Title.Valid {
+	return title, err
+}
+
+// currentTitle returns the title of p's Supply run, or "" while it is
+// untitled. A list frozen or replaced untitled is an error: it can no
+// longer be titled.
+func (s *Service) currentTitle(ctx context.Context, q *db.Queries, p TitleJob) (string, error) {
+	list, err := q.GetShoppingList(ctx, p.WeekStart)
+	if err != nil && !errors.Is(err, sql.ErrNoRows) {
+		return "", fmt.Errorf("shopping: title: read list: %w", err)
+	}
+	switch {
+	case err == nil && list.ID == p.ListID && list.Title.Valid:
+		return list.Title.String, nil
+	case err != nil || list.ID != p.ListID || frozen(list):
 		return "", errors.New("shopping: store title: the Supply run was frozen or replaced before its title was stored")
 	}
-	return list.Title.String, nil
+	return "", nil
+}
+
+// titleScope is the archive_title scope of p: its week and plan revision,
+// and a fingerprint of its dinners in day order, so runs share a title only
+// when they title the same dinner names. A renamed dinner changes the
+// names but not the plan revision.
+func titleScope(p TitleJob) string {
+	names, _ := json.Marshal(p.Dinners) // a []string always encodes
+	return fmt.Sprintf("%s@%d/%x", p.WeekStart, p.Revision, sha256.Sum256(names))
 }
 
 // Get returns the Supply run of the week starting weekStart, as stored: a

internal/shopping/shopping_test.go

@@ -12,6 +12,7 @@ import (
 	"strings"
 	"sync"
 	"testing"
+	"time"
 
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/harness"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm"
@@ -46,11 +47,15 @@ type env struct {
 	planID  string
 	// ids are the dinners' ids by name.
 	ids map[string]string
+	// runner runs the title jobs, two at a time, once start starts it.
+	runner *jobs.Runner
 	// model answers archive_title, which titles the Supply runs; with
 	// nothing queued it fails, and the lists stay untitled.
 	model *llm.Fake
 	// beforeTitle, when set, runs as archive_title is asked for a title.
 	beforeTitle func()
+	// beforeModel, when set, runs as the model is sent a request.
+	beforeModel func(llm.Request)
 	// log holds what the service logged.
 	log *syncBuffer
 }
@@ -95,7 +100,7 @@ func newEnv(t *testing.T) *env {
 	}
 	cfg := harness.Config{
 		Settings:    llm.Settings{Provider: "anthropic", Model: "claude-test", Temperature: 0.7},
-		NewProvider: func(llm.Settings, string) (llm.Provider, error) { return e.model, nil },
+		NewProvider: func(llm.Settings, string) (llm.Provider, error) { return hookedModel{e}, nil },
 		Store:       st,
 		Guard:       guard,
 	}
@@ -105,13 +110,70 @@ func newEnv(t *testing.T) *env {
 		}
 		return skills.TitleArchive(ctx, cfg, scope, in)
 	}
-	e.svc, err = shopping.NewService(st, title, slog.New(slog.NewTextHandler(e.log, nil)))
+	logger := slog.New(slog.NewTextHandler(e.log, nil))
+	e.runner, err = jobs.NewRunner(st, logger, 2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	e.svc, err = shopping.NewService(st, title, e.runner, logger)
 	if err != nil {
 		t.Fatal(err)
 	}
 	return e
 }
 
+// hookedModel is the env's model, running beforeModel first.
+type hookedModel struct{ e *env }
+
+func (m hookedModel) Generate(ctx context.Context, req llm.Request) (llm.Response, error) {
+	if m.e.beforeModel != nil {
+		m.e.beforeModel(req)
+	}
+	return m.e.model.Generate(ctx, req)
+}
+
+func (m hookedModel) ListModels(ctx context.Context) ([]llm.Model, error) {
+	return m.e.model.ListModels(ctx)
+}
+
+func (m hookedModel) Verify(ctx context.Context) error { return m.e.model.Verify(ctx) }
+
+// start starts the env's job runner, stopping it when the test ends.
+func (e *env) start(t *testing.T) {
+	t.Helper()
+	ctx, cancel := context.WithCancel(context.Background())
+	if err := e.runner.Start(ctx); err != nil {
+		cancel()
+		t.Fatal(err)
+	}
+	t.Cleanup(func() {
+		cancel()
+		e.runner.Wait()
+	})
+}
+
+// waitTitle waits for g's title job to finish and returns it.
+func (e *env) waitTitle(t *testing.T, g shopping.Generated) jobs.Job {
+	t.Helper()
+	if g.TitleJobID == nil {
+		t.Fatal("generation enqueued no title job")
+	}
+	deadline := time.Now().Add(10 * time.Second)
+	for {
+		job, err := e.runner.Get(t.Context(), *g.TitleJobID)
+		if err != nil {
+			t.Fatal(err)
+		}
+		if job.Status == jobs.StatusSucceeded || job.Status == jobs.StatusFailed {
+			return job
+		}
+		if time.Now().After(deadline) {
+			t.Fatalf("title job %s still %s", job.ID, job.Status)
+		}
+		time.Sleep(5 * time.Millisecond)
+	}
+}
+
 // ing is a recipe ingredient as recipe grounding stores it: an empty
 // qty or unit is NULL.
 type ing struct {
@@ -395,8 +457,13 @@ func TestGenerateSevenDayPlan(t *testing.T) {
 	}
 
 	// Generating again from the same plan changes nothing: same rows, same
-	// ids, no extra rows.
+	// ids, no extra rows. The list is still untitled, so it gets another
+	// title job.
 	again := e.generate(t)
+	if again.TitleJobID == nil || g.TitleJobID == nil || *again.TitleJobID == *g.TitleJobID {
+		t.Errorf("title jobs = %v then %v, want one per generation of the untitled list", deref(g.TitleJobID), deref(again.TitleJobID))
+	}
+	again.TitleJobID = g.TitleJobID
 	if !reflect.DeepEqual(again, g) {
 		t.Errorf("second generation =\n %+v\nwant the first\n %+v", again, g)
 	}

internal/shopping/title_test.go

@@ -4,12 +4,16 @@ import (
 	"database/sql"
 	"encoding/json"
 	"fmt"
+	"slices"
 	"strings"
+	"sync"
 	"testing"
+	"time"
 
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/harness"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/db"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/jobs"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/shopping"
 )
 
@@ -20,10 +24,11 @@ func titled(title string) llm.GenerateResult {
 }
 
 // titleWeek stores three dinners, one with no recipe, and plans them on
-// the week's first three days.
+// the week's first three days; its job runner is started.
 func titleWeek(t *testing.T) *env {
 	t.Helper()
 	e := newEnv(t)
+	e.start(t)
 	e.dinner(t, "Beef Chili", ing{"ground beef", "1", "lb"})
 	e.dinner(t, "Fish Tacos")
 	e.dinner(t, "Pad Thai", ing{"rice noodles", "8", "oz"})
@@ -88,16 +93,29 @@ func deref(s *string) any {
 	return *s
 }
 
-// TestGenerateTitlesNewList: a new list is titled by archive_title from
+// wantJob fails t unless job ended with status and, when failed, code.
-// the plan's dinners in day order, a dinner with no group included, and
+func wantJob(t *testing.T, job jobs.Job, status jobs.Status, code string) {
-// the title is stored and returned.
+	t.Helper()
+	if job.Status != status || (code != "" && (job.Error == nil || *job.Error != code)) {
+		t.Errorf("title job = %s %v, want %s %s", job.Status, deref(job.Error), status, code)
+	}
+}
+
+// TestGenerateTitlesNewList: a new list is returned untitled with a title
+// job, which titles it by archive_title from the plan's dinners in day
+// order, a dinner with no group included, and stores the title.
 func TestGenerateTitlesNewList(t *testing.T) {
 	e := titleWeek(t)
 	e.model.QueueGenerate(titled("Noodles, Tacos and Chili"))
 
 	g := e.generate(t)
+	wantUntitled(t, "returned title", g.List.Title)
+	job := e.waitTitle(t, g)
 
-	wantTitle(t, "returned title", g.List.Title, "Noodles, Tacos and Chili")
+	wantJob(t, job, jobs.StatusSucceeded, "")
+	if want := `{"list_id":"` + g.List.ID + `","title":"Noodles, Tacos and Chili"}`; string(job.Result) != want {
+		t.Errorf("job result = %s, want %s", job.Result, want)
+	}
 	wantTitle(t, "stored title", e.storedTitle(t), "Noodles, Tacos and Chili")
 	got, err := e.svc.Get(t.Context(), week)
 	if err != nil {
@@ -125,9 +143,8 @@ func TestGenerateTitleTooLongRepaired(t *testing.T) {
 	long := "Pad Thai Monday, Fish Taco Tuesday and Chili Wednesday"
 	e.model.QueueGenerate(titled(long), titled("Noodles, Tacos and Chili"))
 
-	g := e.generate(t)
+	wantJob(t, e.waitTitle(t, e.generate(t)), jobs.StatusSucceeded, "")
 
-	wantTitle(t, "returned title", g.List.Title, "Noodles, Tacos and Chili")
 	wantTitle(t, "stored title", e.storedTitle(t), "Noodles, Tacos and Chili")
 	reqs := e.model.Requests()
 	if len(reqs) != 2 || !strings.Contains(reqs[1].Messages[2].Content, "has 54 characters; shorten it to at most 48") {
@@ -140,7 +157,7 @@ func TestGenerateTitleTooLongRepaired(t *testing.T) {
 
 // TestGenerateTitleFailureKeepsList: archive_title giving an emoji twice
 // fails, and the list is still made, whole and untitled, with the failure
-// logged and recorded in ai_runs.
+// logged, recorded in ai_runs and failing the title job.
 func TestGenerateTitleFailureKeepsList(t *testing.T) {
 	e := titleWeek(t)
 	e.model.QueueGenerate(titled("Taco Week 🌮"), titled("Taco Week 🌮"))
@@ -159,6 +176,7 @@ func TestGenerateTitleFailureKeepsList(t *testing.T) {
 	if len(g.Skipped) != 1 || g.Skipped[0].DinnerName != "Fish Tacos" {
 		t.Errorf("skipped = %+v, want Fish Tacos", g.Skipped)
 	}
+	wantJob(t, e.waitTitle(t, g), jobs.StatusFailed, shopping.ReasonTitleFailed)
 	wantUntitled(t, "returned title", g.List.Title)
 	wantUntitled(t, "stored title", e.storedTitle(t))
 	if g.List.Status != shopping.StatusCurrent {
@@ -182,7 +200,8 @@ func TestGenerateRetriesTitle(t *testing.T) {
 	e := titleWeek(t)
 	e.model.QueueGenerate(llm.GenerateResult{Err: fmt.Errorf("%w: model down", llm.ErrProvider)})
 	first := e.generate(t)
-	wantUntitled(t, "first title", first.List.Title)
+	wantJob(t, e.waitTitle(t, first), jobs.StatusFailed, shopping.ReasonTitleFailed)
+	wantUntitled(t, "first title", e.storedTitle(t))
 	if !strings.Contains(e.log.String(), "model down") {
 		t.Errorf("log lacks the failure:\n%s", e.log.String())
 	}
@@ -199,12 +218,15 @@ func TestGenerateRetriesTitle(t *testing.T) {
 	if second.List.ID != first.List.ID {
 		t.Fatalf("second generation made list %s, want list %s again", second.List.ID, first.List.ID)
 	}
-	wantTitle(t, "retried title", second.List.Title, "Noodles, Tacos and Chili")
+	wantJob(t, e.waitTitle(t, second), jobs.StatusSucceeded, "")
-	wantTitle(t, "stored title", e.storedTitle(t), "Noodles, Tacos and Chili")
+	wantTitle(t, "retried title", e.storedTitle(t), "Noodles, Tacos and Chili")
 
 	e.swap(t, "2026-10-12", "Beef Chili")
 	third := e.generate(t)
 	wantTitle(t, "title after a remake", third.List.Title, "Noodles, Tacos and Chili")
+	if third.TitleJobID != nil {
+		t.Errorf("a remake of a titled list enqueued title job %s", *third.TitleJobID)
+	}
 	if n := len(e.model.Requests()); n != 2 {
 		t.Errorf("%d model calls, want 2: a titled list is not titled again", n)
 	}
@@ -222,11 +244,70 @@ func TestGenerateTitleNotStoredOnFrozenList(t *testing.T) {
 		}
 	}
 
-	g := e.generate(t)
+	wantJob(t, e.waitTitle(t, e.generate(t)), jobs.StatusFailed, shopping.ReasonTitleFailed)
 
-	wantUntitled(t, "returned title", g.List.Title)
 	wantUntitled(t, "stored 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())
 	}
 }
+
+// TestGenerateTitleOverlapAcrossRename: a dinner renamed between two
+// generations of an untitled list changes the names to title but not the
+// plan revision. The two title jobs, running at once, each send the model
+// their own names; neither is given the other's title.
+func TestGenerateTitleOverlapAcrossRename(t *testing.T) {
+	e := titleWeek(t)
+	e.model.QueueGenerate(titled("Noodles, Tacos and Chili"), titled("Drunken Noodles Week"))
+	// Each model call waits for the other, so the runs overlap.
+	var arrived sync.WaitGroup
+	arrived.Add(2)
+	e.beforeModel = func(llm.Request) {
+		arrived.Done()
+		done := make(chan struct{})
+		go func() { arrived.Wait(); close(done) }()
+		select {
+		case <-done:
+		case <-time.After(5 * time.Second):
+			t.Error("the title runs did not overlap: one model call never came")
+		}
+	}
+	revision := func() int64 {
+		p, err := db.New(e.st.Reader).GetWeekPlan(t.Context(), week.String())
+		if err != nil {
+			t.Fatal(err)
+		}
+		return p.Revision
+	}
+
+	before := revision()
+	first := e.generate(t)
+	if _, err := e.st.Writer.Exec(`UPDATE dinners SET name = 'Drunken Noodles', normalized_name = 'drunken noodles' WHERE id = ?`, e.ids["Pad Thai"]); err != nil {
+		t.Fatal(err)
+	}
+	second := e.generate(t)
+	if revision() != before {
+		t.Fatalf("plan revision moved from %d to %d: the rename must leave it", before, revision())
+	}
+
+	wantJob(t, e.waitTitle(t, first), jobs.StatusSucceeded, "")
+	wantJob(t, e.waitTitle(t, second), jobs.StatusSucceeded, "")
+	var users []string
+	for _, r := range e.model.Requests() {
+		users = append(users, r.Messages[0].Content)
+	}
+	slices.Sort(users)
+	want := []string{
+		"Title the week whose dinners are, in day order from Monday:\n- Drunken Noodles\n- Fish Tacos\n- Beef Chili",
+		"Title the week whose dinners are, in day order from Monday:\n- Pad Thai\n- Fish Tacos\n- Beef Chili",
+	}
+	if !slices.Equal(users, want) {
+		t.Errorf("model was sent %q, want each generation's own names %q", users, want)
+	}
+	if s := e.runStatuses(t); len(s) != 2 {
+		t.Errorf("archive_title runs = %q, want two", s)
+	}
+	if got := e.storedTitle(t); got == nil || (*got != "Noodles, Tacos and Chili" && *got != "Drunken Noodles Week") {
+		t.Errorf("stored title = %v, want one of the two titles", deref(got))
+	}
+}