For Sellers

You have an API or an MCP tool and want to charge per request. Point it at Rialto: declare a price, and the facilitator verifies and settles each payment on Stellar - your buyers need no account, no API key, and no XLM. Every settled payment automatically lists your service in the discovery catalog, where agents can find it - this part is live and tested today, not aspirational.

What's real today

The facilitator (/verify, /settle, /supported) and the discovery catalog both work end to end: a payment carrying the Bazaar discovery extension in its payload gets validated and cataloged automatically the moment it settles, with no separate registration call. See the architecture doc for the full flow and the threat model for exactly how a hostile client's forged metadata is caught before it ever reaches the catalog.

Not yet built: a seller-sdk helper package for declaring discovery metadata with minimal boilerplate. Today, declaring correct metadata means constructing the Bazaar extension shape by hand, per the upstream spec - real, working, just not wrapped in a convenience library yet.

What your metadata looks like

The catalog indexes exactly this shape (BazaarMetadata, packages/shared/src/types/bazaar-metadata.ts):

{
  type: 'http' | 'mcp',
  x402Version: number,
  description?: string,
  mimeType?: string,
  serviceName?: string,
  tags?: string[],
  iconUrl?: string,
  routeTemplate?: string,
  toolName?: string,       // MCP tools only
  extensions?: Record<string, unknown>,
}

Every field goes through the integrity gauntlet before it's stored - an oversized serviceName, an invalid tag, or a loopback iconUrl drops just that field, not the whole listing; a routeTemplate is percent-decoded before any traversal check runs, specifically so a URL-encoded ../ can't slip past a naive string check. The full mechanism, with the actual test cases, is in lexical search's candidate selection and the threat model's §3.

Where to go next

• Architecture - the full discover → pay → catalog flow
• Threat model - exactly what's validated and how
• Operator guide - if you're running your own facilitator instead of using a hosted one