Machine-to-machine payment is solved. What can be sold is not. Agents already settle per request in USDC over x402, with no accounts and no checkout. But today's marketplace admits exactly one class of product — the callable service endpoint — while the inventory an agent economy most needs to buy sits outside the catalog entirely.
Circle's Agent Marketplace has already answered the hard commercial question: agents will discover, price, and pay for things without accounts, checkout pages, or human approval — at production scale, in stablecoins. The rail works.
The constraint is upstream of payment. Per its own discovery-API reference, a listing is one callable resource endpoint — and nothing in that field model distinguishes a stored document or a graph query from a computed response. So the assets enterprises actually hold in volume — reports, datasets, models, specifications, knowledge graphs — have no listing path. They are not badly priced; they are absent.
One is listable and monetized at scale. Two are not — and both are already priced, identity-gated, and sold live in a separate running system. The gap is a product-model gap, not a technology gap, which is precisely what makes it addressable.
| Commodity class | Circle Agent Marketplaceper its own discovery-API reference | LOAC verification reportper its own live access matrix |
|---|---|---|
| Protected file / documentReports, datasets, models, specifications, media. | No listing pathNo field distinguishes a stored document from a computed response. | LiveresTtl and resHtml, each a live $2.99 Offer. |
| Service endpointA callable API — computation or query, priced per invocation. | LiveThe entire catalog — 900+ paid services. | LiveOne live example — the SPARQL query endpoint offer. |
| Named graphA document in a graph DBMS — sold as query access, not bulk transfer. | No listing pathNot a listable asset class in the current field model. | LiveresSparql, gated identically to the file offers. |
| Coverage | 1 / 3 | 3 / 3 |
A buyer pays for the answer to a query rather than a bulk file transfer, and the seller monetizes a corpus without ever handing it over. That is a materially different risk posture from shipping a dataset — and it is the class with no listing path at all today.
Five stages from discovery to provisioned access. Nothing here is speculative: every stage is supplied by a system already in production or already verified live in a companion report. The thesis is that they compose — not that any one of them needs inventing.
Not illustrations. Three minted, dereferenceable, purchasable Offer IRIs, resolvable against URIBurner's shop graph right now — all selling access to the same underlying knowledge asset, packaged three different ways at $2.99/month each.
| Offerdereferenceable IRI | Commodity class | Protected resourcereached through the license | Price |
|---|---|---|---|
Infographic (HTML)DemoFileAccessOffer1URIBurner | Protected file | …/daas_paid/world-cup-2026-country-player-guide-meshup-gpt5-chat-1.htmlresolved via oplLic:uriParameter | $2.99 /mo |
Knowledge Graph (RDF-Turtle)DemoFileAccessOffer2URIBurner | Protected file | …/daas_paid/world-cup-2026-country-player-guide-meshup-gpt5-chat-1.ttlresolved via oplLic:uriParameter | $2.99 /mo |
Knowledge Graph (Named Graph)WorldCup2026GuideNamedGraphOfferURIBurner | Named graph | …/daas_paid/world-cup-2026-country-player-guide-meshup-gpt5-chat-1.ttlresolved via oplLic:graphParameter | $2.99 /mo |
schema:itemOffered → license → uriParameter (file) or graphParameter (named graph) → protected resource.Probed 2026-08-22: anonymous requests to both protected resources are refused — HTTP 401. The same request presenting this session's principal WebID over mutual TLS on port 5443 returned 200, where the LOAC report recorded 402 Payment Required for that same identity on 2026-07-02. The entitlement state for one principal changed between the two runs — the not-entitled → entitled transition LOAC's provisioning model describes, observed in the wild rather than staged.
All three live offers sell a protected file or a named graph — which is to say every one of them belongs to a commodity class Circle's catalog has no listing path for. The market is already minting purchasable offers for exactly the inventory that cannot currently be listed. That is the gap, priced and dated.
Every claim above rests on transactions that actually cleared against independently-operated infrastructure — and, in the decisive case, were confirmed independently of the software that reported them succeeding.
A $9.99 USDC settlement executed end to end by the x402-buyer reference client against a live, independently-operated resource server: challenge decoded, EIP-3009 authorization signed, facilitator settlement returned. The client's own success report was then discarded as insufficient and the transaction confirmed directly on Base Sepolia — status 0x1, a matching ERC-20 Transfer event, and the exact amount. Machine-to-machine settlement for a protected resource is a working transaction, not a specification.
The LOAC verification report exposes one underlying knowledge asset as a Turtle document, an HTML document, and a SPARQL-queryable named graph — three separate dereferenceable Offers at $2.99 each, each independently entitlement-checked per WebID across a four-identity access matrix. The multi-class marketplace is not a design proposal; it is a running system with a published test matrix.
An AI agent presenting its own WebID plus an On-Behalf-Of header inherited its principal's entitlement uniformly across all three resource classes, with the reciprocal delegation grant confirmed live in the delegator's own profile graph, delegate public key inlined and matching. For any enterprise buyer, this is the governance question — who authorized this spend — answered as verifiable data rather than a log line.
This section is agent-authored analysis, structurally separate from the reporting it cites and accountable to the curating principal, not to Circle. It is a market thesis, not investment advice.
An enterprise sells its existing protected inventory — documents, datasets, knowledge graphs — to agents without building a storefront, issuing accounts, or surrendering the underlying corpus. Neither side adopts the other's stack wholesale: a listing in Circle's existing field shape can already name a file or a named graph, and x402's 402 challenge already carries an offer reference. The composition is additive on both sides.
What an operator would actually do. Every step reuses a documented Circle field or an already-demonstrated LOAC mechanic — none requires a protocol change from either side.
A document or a named graph takes the same five fields a service listing already uses — resource URL, type, provider metadata, description, and an accepts[] price. No new field is required to name inventory that is not a callable endpoint.
The offer is an addressable entity, not a row in a billing table — so a buyer agent, an auditor, and a counterparty can all resolve the same terms independently.
The WWW-Authenticate: Payment and Link: rel="offer" header pair is already what LOAC's live 402 responses carry, and already what an x402 buyer client is built to consume.
A WebID presented over mutual TLS identifies the agent and, through On-Behalf-Of, the principal accountable for the spend — removing account provisioning from the critical path entirely.
An EIP-3009 authorization settled in USDC through a facilitator, or a Stripe-backed charge intent — the same challenge shape supports both, so the rail is a deployment decision rather than an architectural one.
Provisioning materializes an ABAC policy binding principal, license, and resource, so the entitlement outlives the transaction and remains auditable — the difference between selling a response and selling a licensed asset.
Machine-to-machine payment already works at production scale, but today's agent marketplace can only list one class of product — the callable service endpoint — leaving every protected document, dataset, and knowledge graph an enterprise owns unlistable and therefore unsellable.
Because the missing pieces already run. Circle's discovery API and x402 settlement are in production; LOAC's offer packaging, WebID identity, delegation, and ABAC entitlement are demonstrated live across all three commodity classes. Nothing in the composition requires a new protocol.
Protected, HTTP-accessible files and documents; callable service endpoints; and named graphs — documents hosted in a graph DBMS and queried via SPARQL. Circle's catalog lists the second; LOAC sells all three.
The named graph. The buyer pays for an answer to a query rather than a bulk file transfer, and the seller monetizes a corpus without ever handing it over — a materially different risk posture from shipping a dataset.
It is running. Three offers priced at $2.99 each were gated live across a four-identity access matrix, and a separate $9.99 settlement cleared end to end and was confirmed directly on-chain, independently of the client that reported it.
By querying the Base Sepolia chain directly for the transaction receipt — status, ERC-20 Transfer event, and exact amount — rather than trusting the paying client's own success message. For diligence purposes the distinction between a self-reported success and a confirmed on-chain transfer is the whole point.
Through On-Behalf-Of delegation: the agent presents its own WebID plus a reciprocal grant published in the principal's profile graph, with the delegate's public key inlined. Authority is verifiable data that a counterparty or auditor can resolve independently, not a log entry.
No — that is the point of the named-graph class. Access is gated per request against an entitlement policy, so a seller can monetize query access to a corpus while retaining custody of the corpus itself.
No. A listing in Circle's existing field shape can already name a file or a named graph, and x402's 402 challenge already carries an offer reference. The composition is additive on both sides.
USDC, which accounted for 99.3% of x402 settlement volume as of 2026-07-31 against $90.8 trillion in cumulative onchain USDC volume as of 2026-07-07, both per Circle's own reporting. The asset question is effectively settled; the open questions are elsewhere.
The unified catalog itself. No marketplace today lists all three classes in one discovery surface, so no live 402 has been issued against such a listing — the composition is evidenced component by component, not yet end to end as a single product.
That Circle's single-class catalog is a deliberate simplification, and that its frictionless per-call model works precisely because a listing is an opaque endpoint rather than a described, licensed entity. Richer packaging is real operational cost, and this document does not pretend otherwise.
The web as traversed and transacted by autonomous software agents rather than human browsers — the setting in which protected data, information, and knowledge become purchasable commodities.
Circle's live catalog of 900+ paid services that agents call and settle per request from a stablecoin balance, with no account creation.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
A protected, HTTP-accessible document sold as its own licensed, access-controlled product.
A callable API — computation or query — priced per invocation. The only class today's marketplace lists.
A document hosted in a graph DBMS, sold as queryable access rather than a bulk transfer, so the seller retains custody of the corpus.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Defined in full in the linked companion graph — see the resolved term.
Interactive graph visualization derived from the companion RDF. Click nodes to resolve, drag to explore. Graph data embedded from companion RDF at generation time.
Choose a named graph and query recipe, edit the SPARQL if needed, then open the encoded URIBurner query.
SELECT uses text/x-html+tr. DESCRIBE and CONSTRUCT use text/x-html-nice-turtle, matching the SPARQL format guidance in the skill contract.
Each opens the encoded query on URIBurner. The first three run against urn:shop:offering:info — the shop graph holding the offers above — not against this document.
The core resolution path an agent walks: offer to license to protected resource, plus price. Returns 3 rows.
PREFIX schema: <http://schema.org/>
PREFIX oplLic: <http://www.openlinksw.com/ontology/licenses#>
SELECT ?offerName ?protectedResource ?price ?currency
FROM <urn:shop:offering:info>
WHERE {
VALUES ?offer {
<http://data.openlinksw.com/oplweb/offer/DemoFileAccessOffer1URIBurner#this>
<http://data.openlinksw.com/oplweb/offer/DemoFileAccessOffer2URIBurner#this>
<http://data.openlinksw.com/oplweb/offer/WorldCup2026GuideNamedGraphOfferURIBurner#this>
}
?offer schema:name ?offerName ;
schema:itemOffered ?license ;
schema:priceSpecification ?spec .
OPTIONAL { ?license oplLic:uriParameter ?fileUrl }
OPTIONAL { ?license oplLic:graphParameter ?graphIri }
BIND(COALESCE(?fileUrl, ?graphIri) AS ?protectedResource)
?spec schema:price ?price ; schema:priceCurrency ?currency .
}
ORDER BY ?offerNameThe reverse direction — hit a 402, then discover what it would cost to proceed. Returns 1 row.
PREFIX schema: <http://schema.org/>
PREFIX oplLic: <http://www.openlinksw.com/ontology/licenses#>
SELECT ?offer ?offerName ?price ?currency
FROM <urn:shop:offering:info>
WHERE {
?license oplLic:uriParameter <https://linkeddata.uriburner.com/DAV/demos/daas_paid/world-cup-2026-country-player-guide-meshup-gpt5-chat-1.html> ;
oplLic:partOf ?offer .
?offer schema:name ?offerName ;
schema:priceSpecification ?spec .
?spec schema:price ?price ; schema:priceCurrency ?currency .
}Every offer in the shop graph that names a resource, bucketed by class. Returns 3 rows — two files, one named graph, zero service endpoints.
PREFIX schema: <http://schema.org/>
PREFIX oplLic: <http://www.openlinksw.com/ontology/licenses#>
SELECT ?offerName ?resource (IF(BOUND(?g), "named graph", "file") AS ?commodityClass)
FROM <urn:shop:offering:info>
WHERE {
?offer a schema:Offer ;
schema:name ?offerName ;
schema:itemOffered ?license .
OPTIONAL { ?license oplLic:uriParameter ?u }
OPTIONAL { ?license oplLic:graphParameter ?g }
BIND(COALESCE(?u, ?g) AS ?resource)
FILTER(BOUND(?resource))
}
ORDER BY ?offerNameThe canonical entity-summary shape, scoped to this document's own uploaded graph. Returns 25 rows.
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
SELECT ?type (SAMPLE(?s) AS ?sampleEntity) (SAMPLE(?label) AS ?sampleLabel) (COUNT(?s) AS ?entityCount)
WHERE {
GRAPH <https://linkeddata.uriburner.com/DAV/demos/daas/loac-circle-marketplace-granularity-claude_sonnet_5-1.ttl> {
?s rdf:type ?type .
OPTIONAL { ?s rdfs:label ?label }
}
}
GROUP BY ?type
ORDER BY DESC(?entityCount)