buy_signed_record

Purpose: buy a signed, dated certificate 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.

Items on this shelf (pass one as item_id):

• hello: A Signed Hello, $0.5 fixed, instant. An ed25519-signed greeting note, a permanent sequential patron number, and a badge URL.

• dibs: Dibs, $2 fixed, instant. Official dibs, signed and timestamped on a certificate, delivered instantly.

• certificate_of_patronage: Certificate of Patronage, $20 minimum, pay what it deserves (tiers $20 / $40 / $100; above minimum is a recorded tip), 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 minimum is a recorded tip), 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, $3 fixed, instant. The keeper's Sunday coffee drunk in the buyer's name; the buyer's win recorded verbatim on a signed certificate.

• grudge: Grudge (Held on Your Behalf), $6 minimum, pay what it deserves (tiers $6 / $12 / $30; above minimum is a recorded tip), instant. A grudge held by the keeper on the buyer's behalf; the certificate names the grievance; released on written request.

• the_confession: The Confession, $0.01 fixed, instant. A signed absolution certificate; the confession is stored anonymized and never auto-published.

• recurring_patronage: Recurring Patronage, $3 fixed, instant. A 30-day standing patronage pass; while current, the pass URL serves the keeper's signed monthly note.

Pass item_id to choose. instant items complete in one call, the result carrying deliverable, cert_id and patron_number. Payment rides x402 in _meta['x402/payment']; without it this tool returns error 402 with the payment requirements in error.data. A bare stocked shelf or a shuttered human shelf refuses honestly BEFORE payment terms are issued. Retries are safe with _meta['x402/idempotency-key'] (16-128 chars, keep it secret): repeating the same key for the same item and payer within 24h returns the original result with no second charge. 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. Retrying? A second call is a second charge UNLESS you echo the idempotency.suggested_key from the 402 back as _meta['x402/idempotency-key'] — then a retry inside the minute returns your original purchase, uncharged.