Send Donuts

Send a Dozen

Send Krispy Kreme donuts to anyone by mail, from the terminal, paid with your own credit card. You pick a box, give a recipient address, confirm, and pay with Stripe Link — the order is placed and shipped through Zinc.

Prerequisite: the create-payment-credential skill (Stripe link-cli) must be installed and authenticated. Install: npm install -g @stripe/link-cli; check with link-cli auth status; if not logged in, link-cli auth login --client-name "send-donuts" and approve in the Link app. Payment is a one-time Shared Payment Token (SPT) minted from your Link card — no crypto wallet needed.

Everything here is plain HTTP + a CLI, runnable by hand. Amounts are in US cents (2000 = $20.00). Ships to US addresses.

What it costs

The box price + shipping + tax, plus a $1 Zinc fee (the machine-payment fee on this rail). Krispy Kreme fulfills a dozen per order.

Verified via a real Zinc order (glazed dozen delivered = $19.99). More flavors can be added — each new URL should be confirmed with one real order first, since Zinc ships a dozen of that flavor at the given product URL. Set max_price a little above the expected delivered total; Zinc captures the actual total (+ $1) and releases the rest.

Steps, in order

1. Pick a box

Use the table above (or accept a SKU/flavor the user already named). Present the all-in estimate, not the bare box price.

2. Gather the recipient address and the sender's phone

• Address — if the user gave one, use it. Otherwise research the recipient's company shipping address (HQ or the named office) via web search and confirm it back before proceeding.
• Phone — always the sender's own real phone, never the recipient's (Uber-Eats pattern: delivery issues route to the sender). Zinc rejects invalid/placeholder numbers (e.g. 555…), so use a real one. Ask if you don't have it.

3. Confirm before paying — MANDATORY

Before anything that spends money, show the user and wait for an explicit "yes":

• the box and its all-in estimate in dollars (e.g. $20.99),
• the full recipient address as it will ship,
• the gift note (if any),
• that their Stripe Link card will be charged (they approve in the Link app).

4. Build the Zinc order body

Save it to a file so it's identical across the calls below. max_price must cover box + shipping + tax; phone_number is the sender's.

cat > order.json <<'EOF'
{
  "products": [{ "url": "https://www.krispykreme.com/menu/doughnuts/all/original-glazed-doughnut", "quantity": 1 }],
  "max_price": 2000,
  "is_gift": true,
  "shipping_address": {
    "first_name": "Jane", "last_name": "Doe",
    "address_line1": "123 Market St", "address_line2": null,
    "city": "San Francisco", "state": "CA", "postal_code": "94105",
    "phone_number": "4155550123", "country": "US"
  },
  "metadata": { "source": "donuts" }
}
EOF

5. Get the Stripe payment challenge from Zinc

Post the body once, unauthenticated, to read the 402 challenge. Zinc validates the address first (a bad phone → 422, fix and retry). On success you get a 402 with two WWW-Authenticate: Payment headers — one method="tempo", one method="stripe". You want the stripe one.

curl -s -D headers.txt -o body.json -X POST https://api.zinc.com/agent/orders \
  -H "Content-Type: application/json" --data @order.json
grep -i '^www-authenticate:.*method="stripe"' headers.txt

Decode the stripe challenge to get the network_id and confirm the amount (= max_price + $1):

link-cli mpp decode --challenge "$(grep -i '^www-authenticate:.*method=\"stripe\"' headers.txt | sed 's/^[Ww][Ww][Ww]-[Aa]uthenticate: //')"

Note the returned network_id and amount (in cents).

6. Create and approve a Stripe Link spend request

Pick a payment method, then create a shared_payment_token spend request for the decoded amount. --context must be ≥100 chars and is what the user sees when approving.

link-cli payment-methods list          # note the default payment method id

link-cli spend-request create \
  --credential-type shared_payment_token \
  --network-id "<network_id from step 5>" \
  --amount <amount from step 5> \
  --payment-method-id "<payment method id>" \
  --context "Sending a dozen Krispy Kreme Original Glazed doughnuts as a gift to Jane Doe in San Francisco, shipped and fulfilled by Zinc. This authorizes the donut box plus shipping, tax, and the $1 order fee."

This requests approval and polls. Tell the user to open the Link app and approve within 10 minutes. Note the returned spend request id (lsrq_…). (merchant-name/merchant-url are omitted on purpose — they're forbidden for SPT.)

7. Pay + place the order

Once approved, pay the Zinc endpoint with the SPT — mpp pay runs the full 402 → token → retry and places the order:

link-cli mpp pay https://api.zinc.com/agent/orders \
  --spend-request-id "<lsrq_…>" \
  --method POST \
  --data "$(cat order.json)"

On success this returns the created order (HTTP 201) with an order id and an X-Api-Key (a zn_live_… token scoped to this order). Save both. The SPT is one-time use — if it fails, go back to step 6 for a fresh spend request.

8. Track the order

Poll the order with the X-Api-Key as a Bearer token; report tracking when it appears.

curl -s https://api.zinc.com/orders/<order_id> -H "Authorization: Bearer <X-Api-Key>"

Statuses: pending → in_progress → order_placed (terminal). Relay tracking_numbers when present. If the order fails, tell the user plainly what happened; Zinc handles the payment reversal automatically — do not offer a return.

Safety

• Confirm before paying. Never create a spend request or call mpp pay until the user has approved item, all-in price, full address, and gift note (step 3).
• The phone is always the sender's own, real number. Never invent, look up, or use the recipient's phone; placeholder numbers are rejected.
• The user approves the charge in the Link app — you never handle their card. Surface the approval prompt clearly.
• SPT is one-time use. On any payment failure, create a new spend request; never reuse a consumed one.
• Reading operations (GET /orders/{id}, mpp decode) are safe.

Notes

• No returns. Donuts are perishable — there is no return flow. Never offer one.
• Fulfilled by Zinc. Krispy Kreme fulfillment is handled through the Zinc API (api.zinc.com); you talk only to Zinc + link-cli.
• Other payment methods: agents with their own MPP wallet (Tempo stablecoin, x402) can pay the same Zinc 402 challenge directly, without Link — see the universal-checkout skill. This skill is the credit-card path for people who just have a card.

Support

• Email: support@zinc.com