Add the archive_title skill and title Supply runs on generation

archive_title v1 writes a Supply run's post title for the Supply archive
from the week's dinner names in day order. Validation requires 1-48
characters on one line, no emoji and no surrounding quotation marks; a
reply breaking a rule gets the harness's one repair turn.

shopping.Generate and GeneratePushed run it, outside the generation's
transaction, whenever the stored list is still untitled, and store
shopping_lists.title only while the list is untitled and not frozen. A
title failure never fails the generation: the list stays untitled, the
failure is logged and recorded in ai_runs, and the week's next
generation tries again. A titled list keeps its title on remakes.

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

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

internal/ai/skills/archive_title.go

@@ -0,0 +1,148 @@
+package skills
+
+import (
+	"context"
+	"encoding/json"
+	"errors"
+	"fmt"
+	"strings"
+	"time"
+	"unicode/utf8"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/harness"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm"
+)
+
+// TitleLimit is the most characters a Supply run's title may have.
+const TitleLimit = 48
+
+// ArchiveTitleRequest is what archive_title reads.
+type ArchiveTitleRequest struct {
+	// Dinners are the names of the week's planned dinners in day order,
+	// Monday first. It must hold at least one, none blank.
+	Dinners []string
+}
+
+// ArchiveTitle is archive_title's output.
+type ArchiveTitle struct {
+	// Title is the Supply run's post title in the Supply archive: 1 to
+	// TitleLimit characters on one line, with no emoji and no surrounding
+	// quotation marks.
+	Title string `json:"title"`
+}
+
+// TitleArchive runs archive_title v1 on in and returns the title of the
+// week's Supply run, written from its dinners. A request with no dinners,
+// or a blank one, fails before any LLM call. scope names the week and its
+// dinners (see harness.Run).
+func TitleArchive(ctx context.Context, cfg harness.Config, scope string, in ArchiveTitleRequest) (ArchiveTitle, error) {
+	return harness.Run(ctx, cfg, archiveTitle{}, scope, in)
+}
+
+// archiveTitle is the skill.
+type archiveTitle struct{}
+
+var _ harness.Skill[ArchiveTitleRequest, ArchiveTitle] = archiveTitle{}
+
+func (archiveTitle) Name() string { return "archive_title" }
+
+func (archiveTitle) Version() int { return 1 }
+
+func (archiveTitle) Timeout() time.Duration { return harness.DefaultTimeout }
+
+// archiveTitlePrompt is the template data of archive_title.v1.tmpl.
+type archiveTitlePrompt struct {
+	// Dinners are the week's dinner names in day order, each on one line.
+	Dinners []string
+}
+
+func (archiveTitle) PromptInput(in ArchiveTitleRequest) (harness.PromptInput, error) {
+	if len(in.Dinners) == 0 {
+		return harness.PromptInput{}, errors.New("the week has no dinners to title it from")
+	}
+	var p archiveTitlePrompt
+	for i, name := range in.Dinners {
+		name = oneLine(name)
+		if name == "" {
+			return harness.PromptInput{}, fmt.Errorf("dinner %d has a blank name", i+1)
+		}
+		p.Dinners = append(p.Dinners, name)
+	}
+	return harness.PromptInput{Data: p}, nil
+}
+
+func (archiveTitle) Schema() llm.JSONSchema {
+	return llm.JSONSchema{Name: "archive_title", Schema: json.RawMessage(`{
+		"type": "object",
+		"properties": {
+			"title": {"type": "string"}
+		},
+		"required": ["title"],
+		"additionalProperties": false
+	}`)}
+}
+
+// UnmarshalJSON decodes the output, requiring its field as the schema
+// does.
+func (t *ArchiveTitle) UnmarshalJSON(data []byte) error {
+	if err := requireFields(data, nil, "title"); err != nil {
+		return fmt.Errorf("output %s", err)
+	}
+	type plain ArchiveTitle
+	return json.Unmarshal(data, (*plain)(t))
+}
+
+// quotes are the quotation marks a title may not start or end with.
+const quotes = `"'` + "`" + "“”‘’„‚«»‹›「」『』"
+
+// Validate finds every broken rule of the title as PostProcess will store
+// it, on one line: empty, over TitleLimit characters, holding an emoji, or
+// starting or ending with a quotation mark.
+func (archiveTitle) Validate(out ArchiveTitle) []string {
+	var problems []string
+	title := oneLine(out.Title)
+	switch n := utf8.RuneCountInString(title); {
+	case n == 0:
+		problems = append(problems, fmt.Sprintf("title is empty; give a title of 1 to %d characters", TitleLimit))
+	case n > TitleLimit:
+		problems = append(problems, fmt.Sprintf("title %q has %d characters; shorten it to at most %d", title, n, TitleLimit))
+	}
+	for _, r := range title {
+		if isEmoji(r) {
+			problems = append(problems, fmt.Sprintf("title %q has an emoji (%U); use words only", title, r))
+			break
+		}
+	}
+	if first, _ := utf8.DecodeRuneInString(title); title != "" && strings.ContainsRune(quotes, first) {
+		problems = append(problems, fmt.Sprintf("title %q starts with a quotation mark; give the title without quotation marks around it", title))
+	} else if last, _ := utf8.DecodeLastRuneInString(title); title != "" && strings.ContainsRune(quotes, last) {
+		problems = append(problems, fmt.Sprintf("title %q ends with a quotation mark; give the title without quotation marks around it", title))
+	}
+	return problems
+}
+
+// isEmoji reports whether r is an emoji or a part of one: a pictograph,
+// a symbol from the emoji blocks, a regional indicator, a keycap, a skin
+// tone, an emoji variation selector or the zero-width joiner.
+func isEmoji(r rune) bool {
+	switch {
+	case r >= 0x1F000 && r <= 0x1FAFF: // tiles, cards, enclosed, pictographs, emoticons, transport, supplemental symbols
+		return true
+	case r >= 0x2600 && r <= 0x27BF: // miscellaneous symbols and dingbats
+		return true
+	case r >= 0x2B00 && r <= 0x2BFF: // arrows and stars such as ⭐ and ⬛
+		return true
+	case r >= 0x2300 && r <= 0x23FF: // technical symbols such as ⌚ and ⏰
+		return true
+	case r >= 0xE0020 && r <= 0xE007F: // tag sequences of flags
+		return true
+	case r == 0x200D, r == 0x20E3, r == 0xFE0F: // joiner, keycap, emoji presentation
+		return true
+	}
+	return false
+}
+
+// PostProcess puts the title on one line, collapsing its white space.
+func (archiveTitle) PostProcess(out ArchiveTitle) (ArchiveTitle, error) {
+	return ArchiveTitle{Title: oneLine(out.Title)}, nil
+}

internal/ai/skills/archive_title_test.go

@@ -0,0 +1,170 @@
+package skills
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"slices"
+	"strings"
+	"testing"
+
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/harness"
+	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/ai/llm"
+)
+
+// titleWeek is a week of seven dinners, Monday first.
+var titleWeek = ArchiveTitleRequest{Dinners: []string{
+	"Beef Chili", "Pot Roast", "Chicken  Fajitas", "Spaghetti Bolognese", "Sheet Pan Salmon", "Pad Thai", "Fish Tacos",
+}}
+
+func titleReply(title string) llm.GenerateResult {
+	return reply(fmt.Sprintf(`{"title":%q}`, title))
+}
+
+// title runs TitleArchive on in with f and checks f was called exactly
+// calls times, each at the household temperature with the archive_title
+// schema.
+func title(t *testing.T, f *llm.Fake, in ArchiveTitleRequest, calls int) (ArchiveTitle, []llm.Request, error) {
+	t.Helper()
+	out, err := TitleArchive(context.Background(), testConfig(t, f), "2026-10-12", in)
+	reqs := f.Requests()
+	if len(reqs) != calls {
+		t.Fatalf("Generate called %d times, want %d", len(reqs), calls)
+	}
+	if g, _, _ := f.Remaining(); g != 0 {
+		t.Fatalf("%d scripted Generate results unused", g)
+	}
+	for i, req := range reqs {
+		if req.Temperature == nil || *req.Temperature != 0.7 {
+			t.Fatalf("request %d temperature = %v, want 0.7", i+1, req.Temperature)
+		}
+		if req.Schema == nil || req.Schema.Name != "archive_title" {
+			t.Fatalf("request %d schema = %v, want archive_title", i+1, req.Schema)
+		}
+	}
+	return out, reqs, err
+}
+
+func TestArchiveTitleValid(t *testing.T) {
+	var f llm.Fake
+	f.QueueGenerate(titleReply("  Slow Simmers\nand Taco Night "))
+	out, reqs, err := title(t, &f, titleWeek, 1)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out.Title != "Slow Simmers and Taco Night" {
+		t.Fatalf("title = %q", out.Title)
+	}
+	system, user := reqs[0].System, reqs[0].Messages[0].Content
+	golden(t, "archive_title_valid.system.golden", system)
+	golden(t, "archive_title_valid.user.golden", user)
+	want := "Title the week whose dinners are, in day order from Monday:\n" +
+		"- Beef Chili\n- Pot Roast\n- Chicken Fajitas\n- Spaghetti Bolognese\n- Sheet Pan Salmon\n- Pad Thai\n- Fish Tacos"
+	if user != want {
+		t.Errorf("user message = %q, want %q", user, want)
+	}
+	if !strings.Contains(system, "## Output contract") || !strings.Contains(system, `"title"`) {
+		t.Error("system prompt lacks the output contract")
+	}
+}
+
+// titleRepaired checks a first reply is repaired once, quoting it and the
+// problem wanted.
+func titleRepaired(t *testing.T, first, want string) {
+	t.Helper()
+	var f llm.Fake
+	f.QueueGenerate(titleReply(first), titleReply("Chili, Roast and Taco Night"))
+	out, reqs, err := title(t, &f, titleWeek, 2)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if out.Title != "Chili, Roast and Taco Night" {
+		t.Fatalf("title = %q", out.Title)
+	}
+	repair := reqs[1].Messages
+	if len(repair) != 3 || repair[1].Content != fmt.Sprintf(`{"title":%q}`, first) {
+		t.Fatalf("repair turn does not quote the first reply: %+v", repair)
+	}
+	if !strings.Contains(repair[2].Content, want) {
+		t.Fatalf("repair message = %q, want it to contain %q", repair[2].Content, want)
+	}
+}
+
+func TestArchiveTitleTooLongRepaired(t *testing.T) {
+	long := "A Week of Slow Simmers, Sizzling Fajitas and Taco Night" // 55 characters
+	titleRepaired(t, long, fmt.Sprintf("title %q has 55 characters; shorten it to at most 48", long))
+}
+
+func TestArchiveTitleEmojiRepaired(t *testing.T) {
+	titleRepaired(t, "Taco Night 🌮", `title "Taco Night 🌮" has an emoji (U+1F32E); use words only`)
+}
+
+func TestArchiveTitleQuotedRepaired(t *testing.T) {
+	titleRepaired(t, `"Taco Night"`, `title "\"Taco Night\"" starts with a quotation mark; give the title without quotation marks around it`)
+}
+
+func TestArchiveTitleEmojiTwiceFails(t *testing.T) {
+	var f llm.Fake
+	f.QueueGenerate(titleReply("Chili Week 🔥"), titleReply("Chili Week ❤️"))
+	out, _, err := title(t, &f, titleWeek, 2)
+	var bad *harness.BadOutputError
+	if !errors.As(err, &bad) || !errors.Is(err, llm.ErrBadOutput) {
+		t.Fatalf("err = %v, want a BadOutputError", err)
+	}
+	if !slices.Equal(bad.Repair, []string{`title "Chili Week ❤️" has an emoji (U+2764); use words only`}) {
+		t.Fatalf("repair problems = %q", bad.Repair)
+	}
+	if out.Title != "" {
+		t.Fatalf("title = %q, want none", out.Title)
+	}
+}
+
+func TestArchiveTitleRules(t *testing.T) {
+	s := archiveTitle{}
+	for _, tc := range []struct {
+		title string
+		want  []string
+	}{
+		{"Taco Night", nil},
+		{strings.Repeat("a", TitleLimit), nil},
+		{"Crème Brûlée & Co.", nil},
+		{"Fajitas — Then Tacos", nil},
+		{"Mom's Pot Roast Week", nil},
+		{"  Spaced   out  ", nil},
+		{"", []string{"title is empty; give a title of 1 to 48 characters"}},
+		{" \n ", []string{"title is empty; give a title of 1 to 48 characters"}},
+		{strings.Repeat("é", TitleLimit+1), []string{fmt.Sprintf("title %q has 49 characters; shorten it to at most 48", strings.Repeat("é", TitleLimit+1))}},
+		{"Hot ☕ Week", []string{`title "Hot ☕ Week" has an emoji (U+2615); use words only`}},
+		{"Star ⭐ Week", []string{`title "Star ⭐ Week" has an emoji (U+2B50); use words only`}},
+		{"Go 🇮🇹", []string{`title "Go 🇮🇹" has an emoji (U+1F1EE); use words only`}},
+		{"‘Taco Night’", []string{`title "‘Taco Night’" starts with a quotation mark; give the title without quotation marks around it`}},
+		{"Taco Night”", []string{`title "Taco Night”" ends with a quotation mark; give the title without quotation marks around it`}},
+		{"«Pasta» 🍝 " + strings.Repeat("x", 45), []string{
+			fmt.Sprintf("title %q has 55 characters; shorten it to at most 48", "«Pasta» 🍝 "+strings.Repeat("x", 45)),
+			fmt.Sprintf("title %q has an emoji (U+1F35D); use words only", "«Pasta» 🍝 "+strings.Repeat("x", 45)),
+			fmt.Sprintf("title %q starts with a quotation mark; give the title without quotation marks around it", "«Pasta» 🍝 "+strings.Repeat("x", 45)),
+		}},
+	} {
+		if got := s.Validate(ArchiveTitle{Title: tc.title}); !slices.Equal(got, tc.want) {
+			t.Errorf("Validate(%q) =\n%q\nwant\n%q", tc.title, got, tc.want)
+		}
+	}
+}
+
+func TestArchiveTitleBadRequestFailsBeforeCall(t *testing.T) {
+	for name, tc := range map[string]struct {
+		in   ArchiveTitleRequest
+		want string
+	}{
+		"no dinners":   {ArchiveTitleRequest{}, "the week has no dinners to title it from"},
+		"blank dinner": {ArchiveTitleRequest{Dinners: []string{"Pad Thai", " \n"}}, "dinner 2 has a blank name"},
+	} {
+		t.Run(name, func(t *testing.T) {
+			var f llm.Fake
+			_, _, err := title(t, &f, tc.in, 0)
+			if err == nil || !strings.Contains(err.Error(), tc.want) {
+				t.Fatalf("err = %v, want one containing %q", err, tc.want)
+			}
+		})
+	}
+}

internal/ai/skills/prompts/archive_title.v1.tmpl

@@ -0,0 +1,22 @@
+{{/* archive_title titles a week's Supply run for the Supply archive, from the week's dinners. */}}
+{{define "instructions" -}}
+You title the household's Supply run, the week's shopping list, as it is filed in the Supply archive: a blog-style history of the household's weeks of dinners. Write one short, warm, playful post title for the week, drawn from its dinners.
+
+Rules:
+- At most 48 characters, on one line.
+- Words only: no emoji.
+- No quotation marks around the title.
+- Do not name a date or week number; the archive shows those.
+
+Give:
+- title: the title.
+
+One valid reply, for a week of Beef Chili, Pot Roast and Fish Tacos (an example only, not about this household):
+{"title": "Slow Simmers and Taco Night"}
+{{- end}}
+{{define "user" -}}
+Title the week whose dinners are, in day order from Monday:
+{{- range .Dinners}}
+- {{.}}
+{{- end}}
+{{- end}}

internal/ai/skills/prompts/checksums.txt

@@ -5,3 +5,4 @@ echo v1 ab5d7884f5c7a2261c06b0c9353bb9597070c001420bd4cbb6ec6272c093fdce
 normalize_recipe v1 7174e5479fc020f3b2b39953d85411381aea26defb9943145e7864c5b752d7ee
 suggest_side_quests v1 bd54d7bf9aea0980059a346e5f40ff4c866b80ef9bb9f74e7cbd413be0911c8a
 draft_week v1 e637419690d9532bab53cb8ca01b73a079ecfe8e3022522c05188d18e9740f32
+archive_title v1 b4f30562a8614dac09a69d512dc361883b917ee4228a0ce3b4583c7fd3f6101a

internal/ai/skills/testdata/archive_title_valid.system.golden

@@ -0,0 +1,33 @@
+## Instructions
+You title the household's Supply run, the week's shopping list, as it is filed in the Supply archive: a blog-style history of the household's weeks of dinners. Write one short, warm, playful post title for the week, drawn from its dinners.
+
+Rules:
+- At most 48 characters, on one line.
+- Words only: no emoji.
+- No quotation marks around the title.
+- Do not name a date or week number; the archive shows those.
+
+Give:
+- title: the title.
+
+One valid reply, for a week of Beef Chili, Pot Roast and Fish Tacos (an example only, not about this household):
+{"title": "Slow Simmers and Taco Night"}
+
+## Household context
+No household context.
+
+## Output contract
+This contract overrides any earlier instruction about the form of your reply. Reply with one JSON value matching the JSON Schema "archive_title" below, and nothing else: no prose and no Markdown code fences.
+
+{
+  "type": "object",
+  "properties": {
+    "title": {
+      "type": "string"
+    }
+  },
+  "required": [
+    "title"
+  ],
+  "additionalProperties": false
+}

internal/ai/skills/testdata/archive_title_valid.user.golden

@@ -0,0 +1,8 @@
+Title the week whose dinners are, in day order from Monday:
+- Beef Chili
+- Pot Roast
+- Chicken Fajitas
+- Spaghetti Bolognese
+- Sheet Pan Salmon
+- Pad Thai
+- Fish Tacos

internal/db/querier.go

@@ -243,6 +243,9 @@ type Querier interface {
 	SetPlanDayCalendarEvent(ctx context.Context, arg SetPlanDayCalendarEventParams) (int64, error)
 	// Marks item id needed (1) or "have it" (0).
 	SetShoppingItemNeeded(ctx context.Context, arg SetShoppingItemNeededParams) error
+	// Titles list id, unless it has a title already or is frozen into the
+	// Supply archive.
+	SetShoppingListTitle(ctx context.Context, arg SetShoppingListTitleParams) (int64, error)
 	// Marks a pending batch running; a batch in any other status is left as
 	// it is (0 rows).
 	StartSuggestionBatch(ctx context.Context, arg StartSuggestionBatchParams) (int64, error)

internal/db/shopping.sql.go

@@ -378,3 +378,25 @@ func (q *Queries) SetShoppingItemNeeded(ctx context.Context, arg SetShoppingItem
 	_, err := q.db.ExecContext(ctx, setShoppingItemNeeded, arg.Needed, arg.UpdatedAt, arg.ID)
 	return err
 }
+
+const setShoppingListTitle = `-- name: SetShoppingListTitle :execrows
+UPDATE shopping_lists
+SET title = ?, updated_at = ?
+WHERE id = ? AND title IS NULL AND status = 'current' AND frozen_at IS NULL
+`
+
+type SetShoppingListTitleParams struct {
+	Title     sql.NullString
+	UpdatedAt string
+	ID        string
+}
+
+// Titles list id, unless it has a title already or is frozen into the
+// Supply archive.
+func (q *Queries) SetShoppingListTitle(ctx context.Context, arg SetShoppingListTitleParams) (int64, error) {
+	result, err := q.db.ExecContext(ctx, setShoppingListTitle, arg.Title, arg.UpdatedAt, arg.ID)
+	if err != nil {
+		return 0, err
+	}
+	return result.RowsAffected()
+}

internal/server/plans_test.go

@@ -80,7 +80,7 @@ func newPlansRouter(t *testing.T) plansEnv {
 	if err != nil {
 		t.Fatal(err)
 	}
-	shop, err := shopping.NewService(st)
+	shop, err := shopping.NewService(st, untitled, logger)
 	if err != nil {
 		t.Fatal(err)
 	}

internal/server/server_test.go

@@ -211,16 +211,22 @@ func newTestPlan(t *testing.T) *plan.Service {
 }
 
 // newTestShopping returns a shopping service over a migrated temp
-// database.
+// database, whose Supply runs stay untitled.
 func newTestShopping(t *testing.T) *shopping.Service {
 	t.Helper()
-	svc, err := shopping.NewService(newTestStore(t))
+	svc, err := shopping.NewService(newTestStore(t), untitled, slog.New(slog.NewTextHandler(io.Discard, nil)))
 	if err != nil {
 		t.Fatal(err)
 	}
 	return svc
 }
 
+// untitled is a shopping.Titler with no model: every Supply run it is
+// asked to title stays untitled.
+func untitled(context.Context, string, skills.ArchiveTitleRequest) (skills.ArchiveTitle, error) {
+	return skills.ArchiveTitle{}, errors.New("no model in this test")
+}
+
 // newTestBox returns a secret box under a random key.
 func newTestBox(t *testing.T) *secretbox.Box {
 	t.Helper()

internal/shopping/shopping.go

@@ -5,7 +5,8 @@
 // Generate makes a week's Supply run from its plan, and remakes it after
 // 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).
+// (see Generate). The one model call is the Supply run's title, written by
+// archive_title when the list is generated untitled (see Generate).
 package shopping
 
 import (
@@ -13,8 +14,10 @@ import (
 	"database/sql"
 	"errors"
 	"fmt"
+	"log/slog"
 	"strings"
 
+	"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/dinners"
 	"code.cubecraftlabs.com/Maniacs_Mansion/Meal-Quest/internal/household"
@@ -54,17 +57,30 @@ 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.
+// 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
+	logger *slog.Logger
 }
 
-// NewService returns a service over st.
-func NewService(st *store.Store) (*Service, error) {
-	if st == nil {
+// NewService returns a service over st that titles Supply runs with title
+// and logs to logger.
+func NewService(st *store.Store, title Titler, 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 logger == nil:
+		return nil, errors.New("shopping: nil logger")
 	}
-	return &Service{st: st}, nil
+	return &Service{st: st, title: title, logger: logger}, nil
 }
 
 // List is a Supply run.
@@ -166,6 +182,13 @@ 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
+// then titled by archive_title from the names of the plan's dinners in day
+// order, outside the transaction. A title is written once: a remake keeps
+// it. Titling never fails the generation: a title that cannot be written
+// leaves the list untitled, as it is returned, the failure is logged, 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
 // error: grounding always names one.
@@ -193,7 +216,11 @@ 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 out Generated
+	var (
+		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())
@@ -206,10 +233,11 @@ func (s *Service) generate(ctx context.Context, weekStart store.LocalDate, check
 		if err := check(plan); err != nil {
 			return err
 		}
-		want, skipped, err := wanted(ctx, q, plan.ID)
+		want, skipped, dinnerNames, err := wanted(ctx, q, plan.ID)
 		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) {
@@ -240,9 +268,55 @@ func (s *Service) generate(ctx context.Context, weekStart store.LocalDate, check
 	if err != nil {
 		return Generated{}, err
 	}
+	if out.List.Title == nil {
+		s.titleList(ctx, &out.List, revision, names)
+	}
 	return out, nil
 }
 
+// titleList titles l, an untitled Supply run made from dinners, the names
+// of its plan's dinners in day order at plan revision, with archive_title,
+// and stores the title on it. A title that cannot be written leaves l
+// untitled; the failure is logged, never returned.
+func (s *Service) titleList(ctx context.Context, l *List, revision int64, dinners []string) {
+	title, err := s.writeTitle(ctx, l, revision, dinners)
+	if err != nil {
+		s.logger.WarnContext(ctx, "Supply run left untitled; its next generation titles it again",
+			"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
+// titled by another generation meanwhile, that title stands and is
+// returned.
+func (s *Service) writeTitle(ctx context.Context, l *List, revision int64, dinners []string) (string, error) {
+	scope := fmt.Sprintf("%s@%d", l.WeekStart, revision)
+	out, err := s.title(ctx, scope, skills.ArchiveTitleRequest{Dinners: dinners})
+	if err != nil {
+		return "", fmt.Errorf("shopping: title: %w", err)
+	}
+	q := db.New(s.st.Writer)
+	n, err := q.SetShoppingListTitle(ctx, db.SetShoppingListTitleParams{
+		Title: sql.NullString{String: out.Title, Valid: true}, UpdatedAt: store.Now().String(), ID: l.ID,
+	})
+	if err != nil {
+		return "", fmt.Errorf("shopping: store title: %w", err)
+	}
+	if n == 1 {
+		return out.Title, nil
+	}
+	list, err := q.GetShoppingList(ctx, l.WeekStart)
+	if err != nil {
+		return "", fmt.Errorf("shopping: store title: read list: %w", err)
+	}
+	if list.ID != l.ID || !list.Title.Valid {
+		return "", errors.New("shopping: store title: the Supply run was frozen or replaced before its title was stored")
+	}
+	return list.Title.String, nil
+}
+
 // Get returns the Supply run of the week starting weekStart, as stored: a
 // week with none is ErrListNotFound.
 func (s *Service) Get(ctx context.Context, weekStart store.LocalDate) (l List, err error) {
@@ -365,18 +439,21 @@ type wantItem struct {
 }
 
 // wanted reads plan planID's days and their dinners' ingredients: the
-// groups the list must have, by date, and the days that get none.
-func wanted(ctx context.Context, q *db.Queries, planID string) ([]wantGroup, []SkippedDay, error) {
+// groups the list must have, by date, the days that get none, and the
+// names of the plan's dinners in day order.
+func wanted(ctx context.Context, q *db.Queries, planID string) ([]wantGroup, []SkippedDay, []string, error) {
 	days, err := q.ListPlanDays(ctx, planID)
 	if err != nil {
-		return nil, nil, fmt.Errorf("shopping: read plan days: %w", err)
+		return nil, nil, nil, fmt.Errorf("shopping: read plan days: %w", err)
 	}
 	var (
 		groups  []wantGroup
 		skipped []SkippedDay
+		names   []string
 	)
 	for _, day := range days {
 		d := day.Dinner
+		names = append(names, d.Name)
 		skip := SkippedDay{Date: day.Date, DinnerID: d.ID, DinnerName: d.Name}
 		if !d.RecipeID.Valid {
 			skip.Reason = SkipNoRecipe
@@ -385,11 +462,11 @@ func wanted(ctx context.Context, q *db.Queries, planID string) ([]wantGroup, []S
 		}
 		recipe, err := q.GetRecipe(ctx, d.RecipeID.String)
 		if err != nil {
-			return nil, nil, fmt.Errorf("shopping: read recipe %s of dinner %s: %w", d.RecipeID.String, d.ID, err)
+			return nil, nil, nil, fmt.Errorf("shopping: read recipe %s of dinner %s: %w", d.RecipeID.String, d.ID, err)
 		}
 		ings, err := q.ListRecipeIngredients(ctx, recipe.ID)
 		if err != nil {
-			return nil, nil, fmt.Errorf("shopping: read ingredients of recipe %s: %w", recipe.ID, err)
+			return nil, nil, nil, fmt.Errorf("shopping: read ingredients of recipe %s: %w", recipe.ID, err)
 		}
 		if len(ings) == 0 {
 			skip.Reason = SkipNoIngredients
@@ -401,13 +478,13 @@ func wanted(ctx context.Context, q *db.Queries, planID string) ([]wantGroup, []S
 		for _, ing := range ings {
 			it, err := item(ing, manual)
 			if err != nil {
-				return nil, nil, fmt.Errorf("shopping: recipe %s: %w", recipe.ID, err)
+				return nil, nil, nil, fmt.Errorf("shopping: recipe %s: %w", recipe.ID, err)
 			}
 			g.items = append(g.items, it)
 		}
 		groups = append(groups, g)
 	}
-	return groups, skipped, nil
+	return groups, skipped, names, nil
 }
 
 // item is the item for ingredient ing of a recipe entered by hand

internal/shopping/shopping_test.go

@@ -1,6 +1,8 @@
 package shopping_test
 
 import (
+	"bytes"
+	"context"
 	"database/sql"
 	"errors"
 	"fmt"
@@ -8,10 +10,12 @@ import (
 	"log/slog"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 
 	"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/ai/skills"
 	"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/jobs"
@@ -42,6 +46,31 @@ type env struct {
 	planID  string
 	// ids are the dinners' ids by name.
 	ids map[string]string
+	// 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()
+	// log holds what the service logged.
+	log *syncBuffer
+}
+
+// syncBuffer is a bytes.Buffer safe for concurrent use.
+type syncBuffer struct {
+	mu  sync.Mutex
+	buf bytes.Buffer
+}
+
+func (b *syncBuffer) Write(p []byte) (int, error) {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.buf.Write(p)
+}
+
+func (b *syncBuffer) String() string {
+	b.mu.Lock()
+	defer b.mu.Unlock()
+	return b.buf.String()
 }
 
 func newEnv(t *testing.T) *env {
@@ -59,11 +88,28 @@ func newEnv(t *testing.T) *env {
 	if err := store.Migrate(t.Context(), st.Writer, migrations.FS); err != nil {
 		t.Fatal(err)
 	}
-	svc, err := shopping.NewService(st)
+	e := &env{st: st, dataDir: dataDir, ids: map[string]string{}, model: &llm.Fake{}, log: &syncBuffer{}}
+	guard, err := harness.NewGuard(harness.DefaultMaxCalls)
 	if err != nil {
 		t.Fatal(err)
 	}
-	return &env{svc: svc, st: st, dataDir: dataDir, ids: map[string]string{}}
+	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 },
+		Store:       st,
+		Guard:       guard,
+	}
+	title := func(ctx context.Context, scope string, in skills.ArchiveTitleRequest) (skills.ArchiveTitle, error) {
+		if e.beforeTitle != nil {
+			e.beforeTitle()
+		}
+		return skills.TitleArchive(ctx, cfg, scope, in)
+	}
+	e.svc, err = shopping.NewService(st, title, slog.New(slog.NewTextHandler(e.log, nil)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	return e
 }
 
 // ing is a recipe ingredient as recipe grounding stores it: an empty

internal/shopping/title_test.go

@@ -0,0 +1,232 @@
+package shopping_test
+
+import (
+	"database/sql"
+	"encoding/json"
+	"fmt"
+	"strings"
+	"testing"
+
+	"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/shopping"
+)
+
+// titled is archive_title's reply giving title.
+func titled(title string) llm.GenerateResult {
+	js := fmt.Sprintf(`{"title":%q}`, title)
+	return llm.GenerateResult{Response: llm.Response{Text: js, JSON: json.RawMessage(js)}}
+}
+
+// titleWeek stores three dinners, one with no recipe, and plans them on
+// the week's first three days.
+func titleWeek(t *testing.T) *env {
+	t.Helper()
+	e := newEnv(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"})
+	e.plan(t, "Pad Thai", "Fish Tacos", "Beef Chili")
+	return e
+}
+
+// storedTitle returns the week's list's stored title; nil when NULL.
+func (e *env) storedTitle(t *testing.T) *string {
+	t.Helper()
+	var title sql.NullString
+	if err := e.st.Reader.QueryRow(`SELECT title FROM shopping_lists WHERE week_start = ?`, week.String()).Scan(&title); err != nil {
+		t.Fatal(err)
+	}
+	if !title.Valid {
+		return nil
+	}
+	return &title.String
+}
+
+// runStatuses returns the status of every archive_title run recorded in
+// ai_runs, oldest first.
+func (e *env) runStatuses(t *testing.T) []string {
+	t.Helper()
+	rows, err := e.st.Reader.Query(`SELECT status FROM ai_runs WHERE skill = 'archive_title' ORDER BY created_at, rowid`)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer rows.Close()
+	var out []string
+	for rows.Next() {
+		var s string
+		if err := rows.Scan(&s); err != nil {
+			t.Fatal(err)
+		}
+		out = append(out, s)
+	}
+	if err := rows.Err(); err != nil {
+		t.Fatal(err)
+	}
+	return out
+}
+
+func wantTitle(t *testing.T, what string, got *string, want string) {
+	t.Helper()
+	if got == nil || *got != want {
+		t.Errorf("%s = %v, want %q", what, deref(got), want)
+	}
+}
+
+func wantUntitled(t *testing.T, what string, got *string) {
+	t.Helper()
+	if got != nil {
+		t.Errorf("%s = %q, want none", what, *got)
+	}
+}
+
+func deref(s *string) any {
+	if s == nil {
+		return nil
+	}
+	return *s
+}
+
+// TestGenerateTitlesNewList: a new list is titled by archive_title from
+// the plan's dinners in day order, a dinner with no group included, and
+// the title is stored and returned.
+func TestGenerateTitlesNewList(t *testing.T) {
+	e := titleWeek(t)
+	e.model.QueueGenerate(titled("Noodles, Tacos and Chili"))
+
+	g := e.generate(t)
+
+	wantTitle(t, "returned title", g.List.Title, "Noodles, Tacos and Chili")
+	wantTitle(t, "stored title", e.storedTitle(t), "Noodles, Tacos and Chili")
+	got, err := e.svc.Get(t.Context(), week)
+	if err != nil {
+		t.Fatal(err)
+	}
+	wantTitle(t, "title read back", got.Title, "Noodles, Tacos and Chili")
+	reqs := e.model.Requests()
+	if len(reqs) != 1 {
+		t.Fatalf("%d model calls, want 1", len(reqs))
+	}
+	want := "Title the week whose dinners are, in day order from Monday:\n- Pad Thai\n- Fish Tacos\n- Beef Chili"
+	if user := reqs[0].Messages[0].Content; user != want {
+		t.Errorf("user message = %q, want %q", user, want)
+	}
+	if s := e.runStatuses(t); len(s) != 1 || s[0] != string(harness.StatusOK) {
+		t.Errorf("archive_title runs = %q, want one ok", s)
+	}
+}
+
+// TestGenerateTitleTooLongRepaired: a title over 48 characters is repaired
+// through the repair turn, and the repaired title is stored, not a
+// truncation of the first.
+func TestGenerateTitleTooLongRepaired(t *testing.T) {
+	e := titleWeek(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)
+
+	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") {
+		t.Fatalf("model calls = %+v, want a repair turn asking for a shorter title", reqs)
+	}
+	if s := e.runStatuses(t); len(s) != 1 || s[0] != string(harness.StatusRepaired) {
+		t.Errorf("archive_title runs = %q, want one repaired", s)
+	}
+}
+
+// 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.
+func TestGenerateTitleFailureKeepsList(t *testing.T) {
+	e := titleWeek(t)
+	e.model.QueueGenerate(titled("Taco Week 🌮"), titled("Taco Week 🌮"))
+
+	g, err := e.svc.Generate(t.Context(), week)
+	if err != nil {
+		t.Fatalf("Generate = %v, want the list made though its title failed", err)
+	}
+
+	want := []string{
+		"0 2026-10-12 Pad Thai: 0 rice noodles [8 oz] needed",
+		"1 2026-10-14 Beef Chili: 0 ground beef [1 lb] needed",
+	}
+	wantLines(t, "list", lines(g.List), want)
+	wantLines(t, "stored list", e.stored(t), want)
+	if len(g.Skipped) != 1 || g.Skipped[0].DinnerName != "Fish Tacos" {
+		t.Errorf("skipped = %+v, want Fish Tacos", g.Skipped)
+	}
+	wantUntitled(t, "returned title", g.List.Title)
+	wantUntitled(t, "stored title", e.storedTitle(t))
+	if g.List.Status != shopping.StatusCurrent {
+		t.Errorf("status = %q, want current", g.List.Status)
+	}
+	log := e.log.String()
+	for _, part := range []string{"level=WARN", "Supply run left untitled", "week=2026-10-12", "has an emoji (U+1F32E)"} {
+		if !strings.Contains(log, part) {
+			t.Errorf("log lacks %q:\n%s", part, log)
+		}
+	}
+	if s := e.runStatuses(t); len(s) != 1 || s[0] != string(harness.StatusBadOutput) {
+		t.Errorf("archive_title runs = %q, want one bad_output", s)
+	}
+}
+
+// TestGenerateRetriesTitle: a list left untitled is titled by the week's
+// next generation, Generate or GeneratePushed; once titled, a remake keeps
+// its title and asks for none.
+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)
+	if !strings.Contains(e.log.String(), "model down") {
+		t.Errorf("log lacks the failure:\n%s", e.log.String())
+	}
+
+	e.model.QueueGenerate(titled("Noodles, Tacos and Chili"))
+	plan, err := db.New(e.st.Reader).GetWeekPlan(t.Context(), week.String())
+	if err != nil {
+		t.Fatal(err)
+	}
+	second, err := e.svc.GeneratePushed(t.Context(), week, plan.Revision)
+	if err != nil {
+		t.Fatal(err)
+	}
+	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")
+	wantTitle(t, "stored 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 n := len(e.model.Requests()); n != 2 {
+		t.Errorf("%d model calls, want 2: a titled list is not titled again", n)
+	}
+}
+
+// TestGenerateTitleNotStoredOnFrozenList: a list frozen into the Supply
+// archive while its title is written keeps no title, and the failure is
+// logged.
+func TestGenerateTitleNotStoredOnFrozenList(t *testing.T) {
+	e := titleWeek(t)
+	e.model.QueueGenerate(titled("Noodles, Tacos and Chili"))
+	e.beforeTitle = func() {
+		if _, err := e.st.Writer.Exec(`UPDATE shopping_lists SET status = 'archived', frozen_at = '2026-10-19T04:05:00Z'`); err != nil {
+			t.Error(err)
+		}
+	}
+
+	g := e.generate(t)
+
+	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())
+	}
+}