MCP Registry, Smithery or Bazaar: build the agent purchase path
A directory visit is not a tool invocation, and a tool invocation is not a purchase. Connect each discovery surface to a concrete task, a working input contract and a free-first payment decision. Ontario can check and document parts of that path; it cannot manufacture buyers.
Choose the surface by what the agent must do next
Use an MCP listing to help an MCP host find and connect to a server. Ontario's live MCP server exposes tools/list and tools/call at /mcp. A host still needs to understand the tool's inputs, result and constraints after discovering it. An installed server is not proof of an invocation or settlement.
Use paid-resource discovery when the buyer is searching for a payable HTTP capability. Coinbase Bazaar exposes public intent search and supports discovery through MCP as well. The categories overlap: the useful distinction is server connection versus finding and calling a particular resource, not 'MCP or payments'.
Ontario is listed in the checked MCP Registry and Smithery records, and paid resources were found in the checked Bazaar and Agentic Market catalogs on September 21, 2026. These presence checks do not establish which hub produced a purchase. Treat missing or partial lookup responses as unknown, not automatic delisting.
Make the first tool call work without a wallet
For Ontario tools, start with the free router. The example below describes a verification task and explicitly leaves wallet capability and completed preflight false. Read selected_tool and its contract; do not infer a need to purchase from merely finding a paid candidate.
curl -sS https://ontarioprotocol.com/api/agent/tool-quote \
-H 'Content-Type: application/json' \
-d '{"task":"Verify an endpoint before paying","wallet_enabled":false,"free_preflight_complete":false}'A real free routing call. It does not inspect an endpoint until you invoke the returned verifier with your target.
Use semantic matching only with explicit data-sharing consent
Ontario's ontario_task_fit MCP tool and POST /api/agent/task-fit accept a public task and return a suggested tool with its input schema, or abstain. Setting allow_typesafe=true sends the public task and tool descriptions to TypeSafe for Jev inference. Do not include private task content, personal information, signatures or credentials.
Without that consent, the deterministic router is used. Model quota exhaustion or provider failure also falls back. Inspect status and jev_status so fallback is not mistaken for model evaluation. Confidence is not safety, payment authorization, or a probability that the tool will earn money.
Offer payment only for a distinct additional output
If an agent only needs a readiness check, the free result can finish the task. If it operates an API and explicitly needs a public Ontario profile with linked evidence, the 0.50 USDC service-publication offer is a different output. Present that distinction before requesting payment.
A payable MCP integration must expose the challenge clearly and let the client validate it, sign locally and retain evidence. A catalog description is not a spending policy. An owner-approved budget, matching network and asset, valid current evidence and a task-specific reason are still required. Ontario publication does not buy placement in any third-party hub.
Inspect failure at each step, not just page views
Check these events separately: a catalog returns the exact resource; the agent retrieves the tool schema; valid arguments pass free validation; the agent intentionally probes a paid endpoint; a settlement is verified; the promised profile or result is delivered. Missing evidence at one step is a diagnosis target, not proof that the preceding step never occurred.
A payment record without a linked acquisition record has an unknown source. Referrer and caller-supplied source labels are clues, not authenticated attribution. Do not divide Google clicks by all-time settlements and call that a conversion rate. Exclude operator probes and controlled payments from customer demand.
For providers: publish evidence that buyers can inspect
Run the free buyer-path diagnostic or launch kit against a public service you operate. Correct invalid inputs, unclear output descriptions and readiness failures before expanding distribution. When you need an Ontario profile, inspect the publication deliverables and live price rather than assuming a registry registration includes them.
Keep the exact same buyer-query samples when comparing metadata changes. The success criterion is more attributable, fulfilled external orders, not merely more crawlers or a model approving the copy. This guide proposes a workflow; it does not claim a measured conversion uplift.
Take the next step
Start free. Pay only for a distinct output your task requires, within your owner's spending policy.
Sources and observed evidence
Continue reading
Publish an x402 API profile with a readiness report and badge
Prepare your x402 API for agent discovery: validate free, inspect readiness evidence, then publish an Ontario service profile for 0.50 USDC only when you need it.
Can x402 payments be refunded?
An x402 payment is a USDC transfer that is final once it settles, so a refund is a voluntary new transfer and the real protection is a seller that settles after the result exists.
How big is the x402 market?
Coinbase's Bazaar index lists tens of thousands of paid endpoints, but most show one or two payers in 30 days, and repeat demand sits in a few categories.
Are cheaper x402 APIs worse?
Not necessarily; price rarely decides which x402 API agents use, as a reseller that charges more than the original search API and gets more calls shows.
Do Claude or ChatGPT pay for MCP tools?
Claude and ChatGPT can call MCP tools, but neither pays for one by itself; a paid MCP tool needs a client wrapper with a funded wallet and a spending limit.
Which networks does x402 support?
x402 is network-agnostic; Coinbase's facilitator settles on Base, Solana, Polygon, Arbitrum, Monad and World, and most paid traffic today is USDC on Base.
How do I get my API discovered by AI agents?
Agents search indexes rather than browse websites, so an API is found through Coinbase's Bazaar, x402scan and directories, and through a description that names the task.
How do I know an x402 endpoint is legit?
Three observable checks show whether an unknown x402 endpoint is live, priced as listed and used by repeat buyers; Ontario's finder runs them for 0.005 USDC.