Case study: eight products that AI agents can find, call and pay
How eight products publish one discovery manifest, an OpenAPI description and an MCP server, and accept per-call payment with x402 without an account.
The challenge
AI agents now search, compare and call services for people. An agent must know what a service does, how to call it and how to pay, without a form.
Architecture
- One manifest for each site at /.well-known/agent-access.json, with a JSON schema. It lists the website, the OpenAPI description and the MCP server, and points to the price list.
- The manifest follows a public profile, Agent Access Discovery 0.1, with an open licence.
- Each product has an MCP server next to its HTTP API.
- A paid call answers HTTP 402 with the price. An agent pays per call with x402 (USDC on Base) without an account; in Brazil, people buy credit by Pix.
- Each site also publishes llms.txt for readers that are language models.
In production
Rota Nacional, EditalMD, Radar CNPJ, PontoFato, Agentalog, HookPulse, PageAudit and OKF Index publish the manifest.
Numbers and sources
- 8 products publish the manifest, and each lists 3 interfaces: website, OpenAPI and MCP (manifests read on 14 October 2026).
- Per-call payment with x402 from US$ 0.001 (Rota Nacional price table).
Limits
- The profile is a draft (0.1). It describes access and gives no authority.
- The manifests do not implement the Personal Agent Protocol or PACT.
- Payment with x402 needs a wallet with USDC on the Base network.
Hire me for this
- An MCP server and an OpenAPI description for your product, from one contract.
- Per-call billing for agents (x402) next to the checkout you already have.
- A discovery manifest and llms.txt, so that agents find the right entry point.
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