Cataloging MCP Tools - StellarX402

MCP tools are first-class citizens in the Bazaar. An agent searching /discovery/search gets both HTTP endpoints and MCP tools back in the same result set, distinguished only by the type field.

What gets cataloged

When a StellarX402-aware MCP server starts, it publishes the tools it hosts through the facilitator’s /discovery/publish endpoint. Each tool is cataloged with:

name — the MCP tool name.
description — the MCP tool description, indexed for search.
inputSchema — the MCP JSON schema, stored verbatim.
payment — scheme, network, asset, and price (or ceiling).

Wire example

{
  "type": "mcp",
  "resource": "mcp://tools.example.com/summarize",
  "name": "summarize",
  "description": "Summarize an input document into 3 bullet points",
  "inputSchema": {
    "type": "object",
    "properties": { "text": { "type": "string" } },
    "required": ["text"]
  },
  "payment": {
    "scheme": "upto",
    "network": "stellar:pubnet",
    "asset": "USDC",
    "amount": "50000"
  }
}

From the agent’s side

Agents filter with ?type=mcp when they want tool candidates:

curl "$FAC/discovery/search?q=summarize&type=mcp"

Then route the invocation through their MCP client, attaching the X-Payment header the same way an HTTP client would. See MCP Integration for Agents.