feat(logistics): external attendees self-select lunch dish via tokenized page

External lunch attendees had no way to pick their own dish — an admin had to set
it inline and no email was ever sent. (Marine added herself as an external
expecting a dish-selection link and never received one.)

Adds:
- ExternalAttendee.inviteSentAt + additive migration
- HMAC-signed external lunch token (mirrors finalist-token)
- Public no-login picker page /lunch/pick/[token] — dish + allergens + notes,
  gated by the lunch change deadline, read-only after
- tRPC getExternalByToken / setExternalPick (public) + sendExternalInvite (admin)
- Auto-send invite on createExternal when an email is present; per-row resend
  button + status chip (Invited / Picked / no email) in the logistics screen
- Unpicked externals chased by the lunch reminder cron + manual "Send reminders"
- sendExternalDishInviteEmail (branded). Page + email title use the configurable
  venue ("Lunch at {venue}") rather than "grand finale"

Tests: token roundtrip/tamper/expiry, selectUnpickedExternals filter,
get/set-by-token happy + deadline + bad-token, createExternal auto-send,
cron external reminders. Full suite 303 passing; build clean.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/app/(public)/lunch/pick/[token]/page.tsx

@@ -0,0 +1,327 @@
+'use client'
+
+import { Suspense, use, useEffect, useState } from 'react'
+import { trpc } from '@/lib/trpc/client'
+import { Card, CardContent, CardHeader, CardTitle } from '@/components/ui/card'
+import { Button } from '@/components/ui/button'
+import { Checkbox } from '@/components/ui/checkbox'
+import { RadioGroup, RadioGroupItem } from '@/components/ui/radio-group'
+import { Skeleton } from '@/components/ui/skeleton'
+import { Textarea } from '@/components/ui/textarea'
+import { Badge } from '@/components/ui/badge'
+import { Label } from '@/components/ui/label'
+import { AlertCircle, CheckCircle2, Loader2, Salad, UtensilsCrossed } from 'lucide-react'
+
+const ALLERGENS = [
+  'GLUTEN', 'CRUSTACEANS', 'EGGS', 'FISH', 'PEANUTS', 'SOYBEANS', 'MILK',
+  'TREE_NUTS', 'CELERY', 'MUSTARD', 'SESAME', 'SULPHITES', 'LUPIN', 'MOLLUSCS',
+] as const
+type Allergen = (typeof ALLERGENS)[number]
+
+interface PageProps {
+  params: Promise<{ token: string }>
+}
+
+function formatTag(t: string): string {
+  return t.replace('_', ' ').toLowerCase()
+}
+
+function formatWhen(d: Date): string {
+  return new Intl.DateTimeFormat(undefined, {
+    dateStyle: 'long',
+    timeStyle: 'short',
+  }).format(d)
+}
+
+function CountdownLabel({ deadline }: { deadline: Date }) {
+  const [now, setNow] = useState<number>(Date.now())
+  useEffect(() => {
+    const id = setInterval(() => setNow(Date.now()), 1000)
+    return () => clearInterval(id)
+  }, [])
+  const ms = deadline.getTime() - now
+  if (ms <= 0) return <span className="text-destructive font-medium">closed</span>
+  const totalSec = Math.floor(ms / 1000)
+  const hours = Math.floor(totalSec / 3600)
+  const minutes = Math.floor((totalSec % 3600) / 60)
+  const seconds = totalSec % 60
+  if (hours >= 24) {
+    const days = Math.floor(hours / 24)
+    return (
+      <span className="font-medium tabular-nums">
+        {days}d {hours % 24}h remaining
+      </span>
+    )
+  }
+  return (
+    <span className="font-medium tabular-nums">
+      {hours.toString().padStart(2, '0')}:{minutes.toString().padStart(2, '0')}:
+      {seconds.toString().padStart(2, '0')} remaining
+    </span>
+  )
+}
+
+function FriendlyError({ title, message }: { title: string; message: string }) {
+  return (
+    <Card className="mx-auto max-w-xl">
+      <CardHeader>
+        <div className="flex items-center gap-2">
+          <AlertCircle className="text-muted-foreground h-5 w-5" />
+          <CardTitle>{title}</CardTitle>
+        </div>
+      </CardHeader>
+      <CardContent>
+        <p className="text-muted-foreground">{message}</p>
+      </CardContent>
+    </Card>
+  )
+}
+
+function DishPickContent({ token }: { token: string }) {
+  const { data, isLoading, error } = trpc.lunch.getExternalByToken.useQuery(
+    { token },
+    { retry: false },
+  )
+  const setPick = trpc.lunch.setExternalPick.useMutation()
+
+  const [dishId, setDishId] = useState<string>('')
+  const [allergens, setAllergens] = useState<Allergen[]>([])
+  const [allergenOther, setAllergenOther] = useState<string>('')
+  const [hydrated, setHydrated] = useState(false)
+  const [saved, setSaved] = useState(false)
+  const [submitError, setSubmitError] = useState<string | null>(null)
+
+  useEffect(() => {
+    if (!hydrated && data) {
+      setDishId(data.external.dishId ?? '')
+      setAllergens((data.external.allergens as Allergen[]) ?? [])
+      setAllergenOther(data.external.allergenOther ?? '')
+      setHydrated(true)
+    }
+  }, [data, hydrated])
+
+  if (isLoading) {
+    return (
+      <div className="mx-auto max-w-xl space-y-4">
+        <Skeleton className="h-8 w-2/3" />
+        <Skeleton className="h-32 w-full" />
+        <Skeleton className="h-48 w-full" />
+      </div>
+    )
+  }
+
+  if (error) {
+    const msg = error.message ?? ''
+    if (/expired/i.test(msg)) {
+      return (
+        <FriendlyError
+          title="This link has expired"
+          message="Please contact us at info@monaco-opc.com and we'll sort out your lunch."
+        />
+      )
+    }
+    if (/signature|malformed|parseable/i.test(msg)) {
+      return (
+        <FriendlyError
+          title="This link is not valid"
+          message="Please check your email or contact us at info@monaco-opc.com."
+        />
+      )
+    }
+    return (
+      <FriendlyError
+        title="Something went wrong"
+        message={msg || 'Please try again or contact us at info@monaco-opc.com.'}
+      />
+    )
+  }
+  if (!data) {
+    return (
+      <FriendlyError
+        title="Not found"
+        message="Please check your email link or contact us at info@monaco-opc.com."
+      />
+    )
+  }
+
+  const deadline = data.changeDeadline ? new Date(data.changeDeadline) : null
+  const deadlinePassed = deadline ? new Date() > deadline : false
+  const eventAt = data.event.eventAt ? new Date(data.event.eventAt) : null
+
+  const handleSave = async () => {
+    setSubmitError(null)
+    try {
+      await setPick.mutateAsync({
+        token,
+        dishId: dishId || null,
+        allergens,
+        allergenOther: allergenOther.trim() || null,
+      })
+      setSaved(true)
+    } catch (err) {
+      setSubmitError(err instanceof Error ? err.message : 'Failed to save')
+    }
+  }
+
+  const eventCard = (
+    <Card className="border-primary/40 bg-primary/5">
+      <CardHeader>
+        <div className="flex items-center gap-2">
+          <UtensilsCrossed className="text-primary h-5 w-5" />
+          <CardTitle>
+            {data.event.venue ? `Lunch at ${data.event.venue}` : 'Lunch'}
+          </CardTitle>
+        </div>
+      </CardHeader>
+      <CardContent className="space-y-1 text-sm">
+        <p>
+          Hi <strong>{data.external.name}</strong>, please choose your dish below.
+        </p>
+        {eventAt && (
+          <p className="text-muted-foreground">
+            <strong>When:</strong> {formatWhen(eventAt)}
+          </p>
+        )}
+        {data.event.notes && (
+          <p className="text-muted-foreground">{data.event.notes}</p>
+        )}
+        {deadline && !deadlinePassed && (
+          <p className="text-muted-foreground pt-1">
+            Choose by {formatWhen(deadline)} · <CountdownLabel deadline={deadline} />
+          </p>
+        )}
+      </CardContent>
+    </Card>
+  )
+
+  // Past the change deadline → read-only.
+  if (deadlinePassed) {
+    const chosen = data.dishes.find((d) => d.id === data.external.dishId)
+    return (
+      <div className="mx-auto max-w-xl space-y-6">
+        {eventCard}
+        <FriendlyError
+          title="Dish selection is now closed"
+          message={
+            chosen
+              ? `Your choice is "${chosen.name}". To change it, please contact us at info@monaco-opc.com.`
+              : 'The deadline to choose a dish has passed. Please contact us at info@monaco-opc.com.'
+          }
+        />
+      </div>
+    )
+  }
+
+  return (
+    <div className="mx-auto max-w-xl space-y-6">
+      {eventCard}
+
+      <Card>
+        <CardHeader>
+          <CardTitle className="flex items-center gap-2 text-base">
+            <Salad className="h-4 w-4 text-emerald-600" /> Your dish
+          </CardTitle>
+        </CardHeader>
+        <CardContent className="space-y-6">
+          <RadioGroup value={dishId} onValueChange={setDishId} className="gap-2">
+            {data.dishes.map((d) => (
+              <label
+                key={d.id}
+                htmlFor={`dish-${d.id}`}
+                className="hover:bg-muted/50 flex cursor-pointer items-start gap-3 rounded-md border p-3"
+              >
+                <RadioGroupItem id={`dish-${d.id}`} value={d.id} className="mt-0.5" />
+                <div>
+                  <div className="font-medium">{d.name}</div>
+                  {d.dietaryTags.length > 0 && (
+                    <div className="mt-1 flex flex-wrap gap-1">
+                      {d.dietaryTags.map((t) => (
+                        <Badge key={t} variant="secondary" className="text-xs">
+                          {formatTag(t)}
+                        </Badge>
+                      ))}
+                    </div>
+                  )}
+                </div>
+              </label>
+            ))}
+            {data.dishes.length === 0 && (
+              <p className="text-muted-foreground text-sm">
+                No dishes have been published yet. Please check back later.
+              </p>
+            )}
+          </RadioGroup>
+
+          <div>
+            <Label className="text-sm">Allergens</Label>
+            <div className="mt-2 grid grid-cols-2 gap-2 sm:grid-cols-3">
+              {ALLERGENS.map((a) => (
+                <label key={a} className="flex items-center gap-2 text-sm">
+                  <Checkbox
+                    checked={allergens.includes(a)}
+                    onCheckedChange={(v) =>
+                      setAllergens(
+                        v ? [...allergens, a] : allergens.filter((x) => x !== a),
+                      )
+                    }
+                  />
+                  {formatTag(a)}
+                </label>
+              ))}
+            </div>
+          </div>
+
+          <div>
+            <Label className="text-sm">Other allergens / dietary notes</Label>
+            <Textarea
+              value={allergenOther}
+              onChange={(e) => {
+                setAllergenOther(e.target.value)
+                setSaved(false)
+              }}
+              rows={2}
+              className="mt-1"
+              placeholder="e.g. severe nut allergy, no shellfish"
+            />
+          </div>
+        </CardContent>
+      </Card>
+
+      {submitError && (
+        <div className="border-destructive bg-destructive/10 text-destructive rounded-md border p-3 text-sm">
+          {submitError}
+        </div>
+      )}
+
+      <div className="flex items-center justify-between gap-4">
+        {saved && !setPick.isPending ? (
+          <span className="flex items-center gap-2 text-sm text-emerald-600">
+            <CheckCircle2 className="h-4 w-4" /> Saved — you can change it until the deadline.
+          </span>
+        ) : (
+          <span />
+        )}
+        <Button size="lg" onClick={handleSave} disabled={setPick.isPending}>
+          {setPick.isPending ? (
+            <>
+              <Loader2 className="mr-2 h-4 w-4 animate-spin" /> Saving…
+            </>
+          ) : (
+            <>
+              <CheckCircle2 className="mr-2 h-4 w-4" /> Save my choice
+            </>
+          )}
+        </Button>
+      </div>
+    </div>
+  )
+}
+
+export default function LunchPickPage({ params }: PageProps) {
+  const { token } = use(params)
+  return (
+    <Suspense fallback={<Skeleton className="h-64 w-full" />}>
+      <DishPickContent token={token} />
+    </Suspense>
+  )
+}

src/app/api/cron/lunch-reminders/route.ts

@@ -1,7 +1,11 @@
 import { NextResponse, type NextRequest } from 'next/server'
 import { prisma } from '@/lib/prisma'
 import { sendLunchReminderEmail } from '@/lib/email'
-import { selectUnpickedAttendees } from '@/server/services/lunch-reminders'
+import {
+  selectUnpickedAttendees,
+  selectUnpickedExternals,
+} from '@/server/services/lunch-reminders'
+import { sendExternalDishInvite } from '@/server/services/lunch-external-invite'
 
 /**
  * Cron: send a single reminder email per attending member who hasn't picked
@@ -53,6 +57,19 @@ export async function GET(request: NextRequest): Promise<NextResponse> {
           console.error('[lunch-reminders] send failed for', am.user.email, e)
         }
       }
+
+      // External attendees: emailed + no dish yet → their tokenized pick page.
+      const externals = await selectUnpickedExternals(prisma, { id: event.id })
+      for (const ext of externals) {
+        if (!ext.email) continue
+        try {
+          await sendExternalDishInvite(prisma, ext, event)
+          sent++
+        } catch (e) {
+          console.error('[lunch-reminders] external send failed for', ext.email, e)
+        }
+      }
+
       await prisma.lunchEvent.update({
         where: { id: event.id },
         data: { reminderSentAt: new Date() },

src/components/admin/logistics/lunch-externals.tsx

@@ -22,7 +22,8 @@ import {
   DialogTitle,
   DialogFooter,
 } from '@/components/ui/dialog'
-import { Plus, Pencil, Trash2 } from 'lucide-react'
+import { Badge } from '@/components/ui/badge'
+import { Plus, Pencil, Trash2, Mail, MailCheck, Utensils } from 'lucide-react'
 import { toast } from 'sonner'
 
 const ALLERGENS = [
@@ -90,6 +91,13 @@ export const LunchExternals = forwardRef<
     onSuccess: invalidateAll,
     onError: (e) => toast.error(e.message),
   })
+  const sendInvite = trpc.lunch.sendExternalInvite.useMutation({
+    onSuccess: () => {
+      invalidateAll()
+      toast.success('Dish invite sent')
+    },
+    onError: (e) => toast.error(e.message),
+  })
 
   const editingRow =
     editing?.mode === 'edit'
@@ -123,7 +131,40 @@ export const LunchExternals = forwardRef<
                       {e.project?.title ?? 'Standalone'}
                     </td>
                     <td className="text-muted-foreground">{e.roleNote ?? ''}</td>
+                    <td>
+                      {e.dishId ? (
+                        <Badge variant="secondary" className="gap-1">
+                          <Utensils className="h-3 w-3" /> Picked
+                        </Badge>
+                      ) : !e.email ? (
+                        <Badge variant="outline" className="text-muted-foreground">
+                          No email
+                        </Badge>
+                      ) : e.inviteSentAt ? (
+                        <Badge variant="outline" className="gap-1">
+                          <MailCheck className="h-3 w-3" /> Invited
+                        </Badge>
+                      ) : (
+                        <Badge variant="outline" className="text-muted-foreground">
+                          Not invited
+                        </Badge>
+                      )}
+                    </td>
                     <td className="text-right">
+                      {e.email && !e.dishId && (
+                        <Button
+                          size="sm"
+                          variant="ghost"
+                          title={e.inviteSentAt ? 'Resend dish invite' : 'Send dish invite'}
+                          disabled={
+                            sendInvite.isPending &&
+                            sendInvite.variables?.externalId === e.id
+                          }
+                          onClick={() => sendInvite.mutate({ externalId: e.id })}
+                        >
+                          <Mail className="h-4 w-4" />
+                        </Button>
+                      )}
                       <Button
                         size="sm"
                         variant="ghost"

src/lib/email.ts

@@ -3650,6 +3650,73 @@ ${opts.pickUrl}`
   await sendEmail({ to: opts.to, subject, text, html })
 }
 
+/**
+ * Invite an external lunch attendee to choose their dish via a tokenized,
+ * no-login page. Used for the initial invite (auto on add + admin resend) and
+ * for reminder sweeps — one template serves both.
+ */
+export async function sendExternalDishInviteEmail(opts: {
+  to: string
+  name: string
+  eventAt: Date | null
+  venue: string | null
+  notes: string | null
+  changeDeadline: Date | null
+  pickUrl: string
+}): Promise<void> {
+  const fmt = new Intl.DateTimeFormat('en-GB', {
+    timeZone: 'Europe/Monaco', dateStyle: 'long', timeStyle: 'short',
+  })
+  const subject = 'Choose your lunch dish — Monaco Ocean Protection Challenge'
+  const venuePhrase = opts.venue
+    ? `lunch at ${escapeHtml(opts.venue)}`
+    : 'the Monaco Ocean Protection Challenge lunch'
+  const eventLine = opts.eventAt
+    ? `<strong>When:</strong> ${escapeHtml(fmt.format(opts.eventAt))} (Europe/Monaco)`
+    : ''
+  const notesLine = opts.notes ? escapeHtml(opts.notes) : ''
+  const content = `
+    ${sectionTitle('Choose your lunch dish')}
+    ${paragraph(`Hi ${escapeHtml(opts.name)},`)}
+    ${paragraph(
+      `You are joining us for ${venuePhrase}. Please pick your dish and let us know ` +
+        'about any allergies so the kitchen can cater for you.',
+    )}
+    ${eventLine ? paragraph(eventLine) : ''}
+    ${notesLine ? paragraph(notesLine) : ''}
+    ${
+      opts.changeDeadline
+        ? infoBox(
+            `<strong>Please choose by ${escapeHtml(fmt.format(opts.changeDeadline))}.</strong>`,
+            'warning',
+          )
+        : ''
+    }
+    ${ctaButton(opts.pickUrl, 'Choose my dish')}
+    ${paragraph(
+      `<span style="color:#64748b;font-size:13px;">If you have any questions, reply to this email and we'll help.</span>`,
+    )}
+  `
+  const html = getEmailWrapper(content)
+  const text = [
+    `Choose your lunch dish — Monaco Ocean Protection Challenge`,
+    ``,
+    `Hi ${opts.name},`,
+    ``,
+    `Please pick your dish for ${
+      opts.venue ? `lunch at ${opts.venue}` : 'the Monaco Ocean Protection Challenge lunch'
+    }.`,
+    opts.eventAt ? `When: ${fmt.format(opts.eventAt)} (Europe/Monaco)` : '',
+    opts.notes ? opts.notes : '',
+    opts.changeDeadline ? `Please choose by: ${fmt.format(opts.changeDeadline)}` : '',
+    ``,
+    `Choose your dish: ${opts.pickUrl}`,
+  ]
+    .filter((l) => l !== '')
+    .join('\n')
+  await sendEmail({ to: opts.to, subject, text, html })
+}
+
 /**
  * Send the lunch recap manifest to admins + extra recipients.
  * Caller passes the assembled recap payload from `buildRecapPayload`.

src/lib/external-lunch-token.ts

@@ -0,0 +1,45 @@
+import { createHmac, timingSafeEqual } from 'crypto'
+
+export type ExternalLunchTokenPayload = {
+  externalId: string
+  /** Unix seconds. Token is rejected after this. */
+  exp: number
+}
+
+function getSecret(): string {
+  const s = process.env.NEXTAUTH_SECRET
+  if (!s) throw new Error('NEXTAUTH_SECRET is not set; cannot sign external lunch tokens')
+  return s
+}
+
+function hmac(payloadB64: string): string {
+  return createHmac('sha256', getSecret()).update(payloadB64).digest('hex')
+}
+
+export function signExternalLunchToken(payload: ExternalLunchTokenPayload): string {
+  const payloadB64 = Buffer.from(JSON.stringify(payload)).toString('base64url')
+  const sig = hmac(payloadB64)
+  return `${payloadB64}.${sig}`
+}
+
+export function verifyExternalLunchToken(token: string): ExternalLunchTokenPayload {
+  const parts = token.split('.')
+  if (parts.length !== 2) throw new Error('Invalid external lunch token: malformed')
+  const [payloadB64, sig] = parts
+  const expected = hmac(payloadB64)
+  const a = Buffer.from(sig, 'hex')
+  const b = Buffer.from(expected, 'hex')
+  if (a.length !== b.length || !timingSafeEqual(a, b)) {
+    throw new Error('Invalid external lunch token: signature mismatch')
+  }
+  let payload: ExternalLunchTokenPayload
+  try {
+    payload = JSON.parse(Buffer.from(payloadB64, 'base64url').toString('utf-8'))
+  } catch {
+    throw new Error('Invalid external lunch token: payload not parseable')
+  }
+  if (typeof payload.exp !== 'number' || payload.exp < Math.floor(Date.now() / 1000)) {
+    throw new Error('Invalid external lunch token: expired')
+  }
+  return payload
+}

src/server/routers/lunch.ts

@@ -1,10 +1,12 @@
 import { z } from 'zod'
 import { TRPCError } from '@trpc/server'
-import { router, adminProcedure, protectedProcedure } from '../trpc'
+import { router, adminProcedure, protectedProcedure, publicProcedure } from '../trpc'
 import { logAudit } from '../utils/audit'
 import { buildManifest, buildRecapPayload } from '../services/lunch-recap'
-import { selectUnpickedAttendees } from '../services/lunch-reminders'
+import { selectUnpickedAttendees, selectUnpickedExternals } from '../services/lunch-reminders'
+import { sendExternalDishInvite } from '../services/lunch-external-invite'
 import { sendLunchRecapEmail, sendLunchReminderEmail } from '@/lib/email'
+import { verifyExternalLunchToken } from '@/lib/external-lunch-token'
 import { csvCell } from '@/lib/csv'
 
 // ─── Shared zod schemas ──────────────────────────────────────────────────────
@@ -179,6 +181,19 @@ export const lunchRouter = router({
         entityId: ext.id,
         detailsJson: { name: ext.name, projectId: ext.projectId },
       })
+      // Auto-send the dish-selection invite when an email is on file. Never throws
+      // — a failed send leaves inviteSentAt null so the admin can resend.
+      if (ext.email) {
+        try {
+          const event = await ctx.prisma.lunchEvent.findUnique({
+            where: { id: input.lunchEventId },
+            select: { eventAt: true, venue: true, notes: true, changeCutoffHours: true },
+          })
+          if (event) await sendExternalDishInvite(ctx.prisma, ext, event)
+        } catch (e) {
+          console.error('[lunch.createExternal] dish invite send failed', e)
+        }
+      }
       return ext
     }),
 
@@ -229,6 +244,159 @@ export const lunchRouter = router({
       return { ok: true as const }
     }),
 
+  /**
+   * Send (or resend) the dish-selection invite to one external attendee.
+   * Stamps `inviteSentAt` and audit-logs. Fails if the attendee has no email.
+   */
+  sendExternalInvite: adminProcedure
+    .input(z.object({ externalId: z.string() }))
+    .mutation(async ({ ctx, input }) => {
+      const external = await ctx.prisma.externalAttendee.findUnique({
+        where: { id: input.externalId },
+        include: {
+          lunchEvent: {
+            select: { eventAt: true, venue: true, notes: true, changeCutoffHours: true },
+          },
+        },
+      })
+      if (!external) throw new TRPCError({ code: 'NOT_FOUND' })
+      if (!external.email) {
+        throw new TRPCError({
+          code: 'PRECONDITION_FAILED',
+          message: 'This attendee has no email address. Add one first.',
+        })
+      }
+      try {
+        await sendExternalDishInvite(ctx.prisma, external, external.lunchEvent)
+      } catch (e) {
+        throw new TRPCError({
+          code: 'INTERNAL_SERVER_ERROR',
+          message: `Failed to send invite: ${e instanceof Error ? e.message : String(e)}`,
+          cause: e,
+        })
+      }
+      await logAudit({
+        prisma: ctx.prisma,
+        userId: ctx.user.id,
+        action: 'LUNCH_EXTERNAL_INVITE_SENT',
+        entityType: 'ExternalAttendee',
+        entityId: external.id,
+        detailsJson: { email: external.email },
+      })
+      return { ok: true as const }
+    }),
+
+  // ─── Public tokenized external dish picker ───────────────────────────────
+
+  /**
+   * Read an external attendee + their event + dishes by a signed, no-login token.
+   * Token verification throws on bad signature / expiry; the page maps those to
+   * friendly states.
+   */
+  getExternalByToken: publicProcedure
+    .input(z.object({ token: z.string() }))
+    .query(async ({ ctx, input }) => {
+      const payload = verifyExternalLunchToken(input.token) // throws on bad sig / expired
+      const external = await ctx.prisma.externalAttendee.findUnique({
+        where: { id: payload.externalId },
+        include: {
+          lunchEvent: {
+            select: {
+              id: true,
+              eventAt: true,
+              endAt: true,
+              venue: true,
+              notes: true,
+              changeCutoffHours: true,
+            },
+          },
+        },
+      })
+      if (!external) throw new TRPCError({ code: 'NOT_FOUND' })
+      const dishes = await ctx.prisma.dish.findMany({
+        where: { lunchEventId: external.lunchEventId },
+        orderBy: [{ sortOrder: 'asc' }, { createdAt: 'asc' }],
+      })
+      const eventAt = external.lunchEvent.eventAt
+      const changeDeadline = eventAt
+        ? new Date(eventAt.getTime() - external.lunchEvent.changeCutoffHours * 3_600_000)
+        : null
+      return {
+        external: {
+          id: external.id,
+          name: external.name,
+          dishId: external.dishId,
+          allergens: external.allergens,
+          allergenOther: external.allergenOther,
+        },
+        event: {
+          eventAt,
+          endAt: external.lunchEvent.endAt,
+          venue: external.lunchEvent.venue,
+          notes: external.lunchEvent.notes,
+        },
+        dishes,
+        changeDeadline,
+      }
+    }),
+
+  /**
+   * Save an external attendee's dish pick via their signed token. Enforces the
+   * lunch change cutoff (eventAt − changeCutoffHours); past it, the attendee must
+   * contact an admin.
+   */
+  setExternalPick: publicProcedure
+    .input(
+      z.object({
+        token: z.string(),
+        dishId: z.string().nullable(),
+        allergens,
+        allergenOther: z.string().max(500).nullable(),
+      }),
+    )
+    .mutation(async ({ ctx, input }) => {
+      const payload = verifyExternalLunchToken(input.token)
+      const external = await ctx.prisma.externalAttendee.findUnique({
+        where: { id: payload.externalId },
+        include: {
+          lunchEvent: { select: { eventAt: true, changeCutoffHours: true } },
+        },
+      })
+      if (!external) throw new TRPCError({ code: 'NOT_FOUND' })
+
+      const eventAt = external.lunchEvent.eventAt
+      if (eventAt) {
+        const deadline = new Date(
+          eventAt.getTime() - external.lunchEvent.changeCutoffHours * 3_600_000,
+        )
+        if (new Date() > deadline) {
+          throw new TRPCError({
+            code: 'PRECONDITION_FAILED',
+            message: 'Past the lunch change deadline. Please contact an admin.',
+          })
+        }
+      }
+
+      // Dish must belong to this attendee's event (defends against cross-event ids).
+      if (input.dishId) {
+        const dish = await ctx.prisma.dish.findFirst({
+          where: { id: input.dishId, lunchEventId: external.lunchEventId },
+          select: { id: true },
+        })
+        if (!dish) throw new TRPCError({ code: 'BAD_REQUEST', message: 'Unknown dish' })
+      }
+
+      const updated = await ctx.prisma.externalAttendee.update({
+        where: { id: external.id },
+        data: {
+          dishId: input.dishId,
+          allergens: input.allergens,
+          allergenOther: input.allergenOther,
+        },
+      })
+      return { ok: true as const, dishId: updated.dishId }
+    }),
+
   // ─── Single-row pick read (used by per-row picker UI) ────────────────────
 
   /**
@@ -611,6 +779,19 @@ export const lunchRouter = router({
           console.error('[lunch.sendReminders] send failed for', am.user.email, e)
         }
       }
+
+      // External attendees: chase the ones with an email and no dish yet, via
+      // their own tokenized pick page.
+      const externals = await selectUnpickedExternals(ctx.prisma, { id: event.id })
+      for (const ext of externals) {
+        if (!ext.email) continue
+        try {
+          await sendExternalDishInvite(ctx.prisma, ext, event)
+          sent++
+        } catch (e) {
+          console.error('[lunch.sendReminders] external send failed for', ext.email, e)
+        }
+      }
       return { sent }
     }),
 

src/server/services/lunch-external-invite.ts

@@ -0,0 +1,61 @@
+import type { Prisma, PrismaClient } from '@prisma/client'
+import { signExternalLunchToken } from '@/lib/external-lunch-token'
+import { getBaseUrl, sendExternalDishInviteEmail } from '@/lib/email'
+
+type PrismaLike = PrismaClient | Prisma.TransactionClient
+
+export type InvitableExternal = {
+  id: string
+  name: string
+  email: string | null
+}
+
+export type InviteLunchEvent = {
+  eventAt: Date | null
+  venue: string | null
+  notes: string | null
+  changeCutoffHours: number
+}
+
+/**
+ * Build the public, tokenized dish-pick URL for an external attendee.
+ * The token is a stateless HMAC signature (see external-lunch-token) carrying the
+ * externalId; `exp` is generous (event day + 1, or 30 days when no event date)
+ * so the link outlives the change deadline, which is enforced separately at write.
+ */
+export function buildExternalPickUrl(externalId: string, eventAt: Date | null): string {
+  const exp = eventAt
+    ? Math.floor(eventAt.getTime() / 1000) + 86_400
+    : Math.floor(Date.now() / 1000) + 30 * 86_400
+  const token = signExternalLunchToken({ externalId, exp })
+  return `${getBaseUrl()}/lunch/pick/${token}`
+}
+
+/**
+ * Send (or resend) the dish-selection invite to one external attendee and stamp
+ * `inviteSentAt`. Throws if the external has no email or the email send fails;
+ * callers that must not fail (e.g. createExternal) wrap this in try/catch.
+ */
+export async function sendExternalDishInvite(
+  prisma: PrismaLike,
+  external: InvitableExternal,
+  event: InviteLunchEvent,
+): Promise<void> {
+  if (!external.email) throw new Error('External attendee has no email address')
+  const changeDeadline = event.eventAt
+    ? new Date(event.eventAt.getTime() - event.changeCutoffHours * 3_600_000)
+    : null
+  await sendExternalDishInviteEmail({
+    to: external.email,
+    name: external.name,
+    eventAt: event.eventAt,
+    venue: event.venue,
+    notes: event.notes,
+    changeDeadline,
+    pickUrl: buildExternalPickUrl(external.id, event.eventAt),
+  })
+  await prisma.externalAttendee.update({
+    where: { id: external.id },
+    data: { inviteSentAt: new Date() },
+  })
+}

src/server/services/lunch-reminders.ts

@@ -30,3 +30,21 @@ export async function selectUnpickedAttendees(
     include: { user: { select: { name: true, email: true } } },
   })
 }
+
+/**
+ * Return external attendees for a LunchEvent that can still be chased for a dish
+ * pick: they have an email on file and have not yet been assigned a dish.
+ * Externals with no email (un-emailable) or an existing dish are excluded.
+ */
+export async function selectUnpickedExternals(
+  prisma: PrismaClient,
+  event: { id: string },
+) {
+  return prisma.externalAttendee.findMany({
+    where: {
+      lunchEventId: event.id,
+      dishId: null,
+      AND: [{ email: { not: null } }, { email: { not: '' } }],
+    },
+  })
+}