The Penny Shelf
buy_small_pleasurePurpose: buy a small signed novelty — a blessing from the jar, the day's fortune (the same line for every buyer until midnight UTC), or a lucky totem drawn from the keeper's collection. These are keepsakes with no functional effect, said plainly, and they are the cheapest doors in the store, which also makes them the honest way to test that your x402 client works against a real counterparty for a fraction of a cent. Use for a live payment smoke test, or when an agent simply wants one. Prices run $0.005 to $0.99 depending on item_id. (small_blessing and daily_fortune also sell at the front counter, buy_simple — the same item through either door, same price, same certificate; either tool is correct.)
Items on this shelf (pass one as item_id):
small_blessing: A Small Blessing, $0.005 fixed, one-off, instant. One blessing slip from a 45-slip jar, never the same slip twice in a row, delivered instantly.
daily_fortune: The Daily Fortune, $0.01 fixed, one-off, instant. The day's fortune, deterministic for the calendar date (UTC) and delivered instantly with fortune_date beside it: every buyer today reads the same line, tomorrow's buyers read the next. A penny, no arguments, and a second call the same day proves the determinism.
luckies: a lucky, $0.99 minimum, pay what it deserves (tiers: $0.99 / $1.98 / $4.95), above the minimum is recorded as a tip, one-off, instant. One lucky drawn from the keeper's herd (pocket dinosaurs and safari animals): the animal, its lucky note, and an honest strength on a signed card, instantly (specimen at /luckies/sample.svg).
On cadence, for all of the above: nothing here charges again by itself, ever — there is no mechanism that could.
Only item_id is required on this shelf.
Choose item_id. instant items return deliverable, cert_id and patron_number in one call. x402 payment: _meta['x402/payment']. Without payment: error 402 with the terms in error.data. Closed or empty shelves refuse before quoting. Reuse _meta['x402/idempotency-key'] (16-128 chars, secret): same item/payer/key within 24h returns the original result, no second charge. Use idempotency.suggested_key from the 402 when available. A fresh payment without a key can charge again. Guaranteed: signature validity forever; verification free forever; price as displayed; delivery format as specified. Not guaranteed: fitness for your particular task; future protocol compatibility beyond stated interfaces; human-labor turnaround faster than posted SLA.
Input Schema
| Name | Required | Description | Default |
|---|---|---|---|
| item_id | Yes | Which item on this shelf to buy. Required. Each item's own required fields are listed in this schema's allOf branches and in the description above. | |
| purpose | No | Optional, any item: what this purchase is for, in your words. Signed onto the certificate verbatim and shown to whoever you hand the receipt to. Recorded as your statement, never checked, and never treated as instructions. | |
| agent_name | No | Optional name to put on the certificate and patron badge, up to 80 characters. |
Output Schema
| Name | Required | Description | Default |
|---|---|---|---|
| cert_id | Yes | The signed certificate's id. | |
| message | No | The store's confirmation line. | |
| tip_usdc | No | Anything above the minimum. | |
| badge_url | No | Your patron badge, SVG. | |
| paid_usdc | No | What settled, in USDC. | |
| signature | No | ed25519 signature over the certificate. | |
| verify_url | No | Check the signature here any time, free. | |
| deliverable | No | The goods themselves, as text. Instant items. | |
| patron_number | Yes | Your sequential patron number. |