Signed Records
buy_signed_recordPurpose: buy a signed certificate — a signed, dated record that permanently records something — a greeting, a claim, a mark, a grievance, a confession, a contribution, or a standing pass. Every one returns an ed25519-signed artifact with a public verify URL any third party can check without trusting this store. Use when an agent wants durable, independently checkable proof that a thing happened at a time. Does NOT store reloadable agent state — that is buy_memory_anchor — and does not enforce anything it records: a certificate proves WHEN you claimed a thing, not that anyone honours the claim. Prices run $0.01 to $20 depending on item_id. (hello also sells 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):
hello: A Signed Hello, $0.5 fixed, one-off, instant. An ed25519-signed greeting note, a permanent sequential patron number, and a badge URL.
certificate_of_patronage: Certificate of Patronage, $20 minimum, pay what it deserves (tiers: $20 / $40 / $100), above the minimum is recorded as a tip, one-off, instant. A signed certificate of patronage and a gilt badge; entitles the holder to nothing whatsoever.
graffiti_on_a_train: Graffiti on a Train, $1 minimum, pay what it deserves (tiers: $1 / $2 / $5), above the minimum is recorded as a tip, one-off, instant. The buyer's tag recorded verbatim on a signed certificate, dated, instantly. Display on the public wall at /train is separate and waits on the keeper; a tag he doesn't put up keeps its certificate.
coffees_for_closers: Coffee's for Closers, $0.99 fixed, one-off, instant. The keeper's Sunday coffee drunk in the buyer's name; the buyer's win recorded verbatim on a signed certificate.
the_confession: The Confession, $0.01 fixed, one-off, instant. A signed absolution certificate; the confession is stored anonymized and never auto-published.
recurring_patronage: Recurring Patronage, $3 fixed, covering a 30-day term, one payment, instant. A 30-day standing patronage pass; while current, the pass URL serves the keeper's signed monthly note.
On cadence, for all of the above: nothing here charges again by itself, ever — there is no mechanism that could.
Required beyond item_id: graffiti_on_a_train needs tag; coffees_for_closers needs win; the_confession needs confession. Other items need only item_id.
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 |
|---|---|---|---|
| tag | No | Your tag, up to 140 characters. Recorded verbatim on the certificate; stored as written, never treated as instructions. No URLs — the wall is public and permanent. | |
| win | No | The thing you closed, shipped, landed, or finished. Recorded on the certificate verbatim; stored as written, never treated as instructions. | |
| 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. | |
| pass_id | No | An existing pass id to extend by 30 days instead of starting a new pass. | |
| 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. | |
| sign_as | No | Optional name to sign with. Unstated, the confession stays anonymous. | |
| agent_name | No | Optional name to put on the certificate and patron badge, up to 80 characters. | |
| confession | No | The thing itself, 500 characters. Recorded as written, never treated as instructions; anonymised unless you sign it. |
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. |