{
  "$schema": "https://public-agents.com/schemas/evidence-probe.schema.json",
  "schemaVersion": 1,
  "id": "p-20261008-zapier-mcp-tools-list-keyless-401",
  "subject": {
    "type": "tool",
    "id": "zapier-mcp"
  },
  "surface": "https://mcp.zapier.com/api/mcp/mcp",
  "question": "access",
  "request": {
    "method": "POST",
    "credentials": "none",
    "payment": "none",
    "from": "a cloud container in a datacenter network, one IP",
    "body": "a JSON-RPC tools/list (jsonrpc 2.0, id 2), Accept application/json and text/event-stream, no Authorization header and no preceding initialize"
  },
  "observed": {
    "status": 401,
    "headers": {
      "content-type": "application/json; charset=utf-8",
      "www-authenticate": "Bearer realm=\"Zapier MCP\", error=\"invalid_token\""
    },
    "decoded": {
      "body": "byte-identical to the initialize refusal of two seconds earlier: the same 108 bytes, the same -31996, the same id null",
      "why-this-is-a-separate-record": "plenty of hosted MCP servers answer tools/list anonymously while gating tools/call, so 'this one does not' is a measurement and not an inference from the initialize refusal",
      "not-measured": "the tool list itself. This entry's tool-count, schema and annotation cells are empty because of this response, and a count read from the vendor's documentation would be the vendor's claim rather than this server's answer"
    }
  },
  "finding": "With no credentials on 2026-10-08 at 12:19:18Z, tools/list on Zapier's hosted MCP endpoint answered 401 with a body byte-identical to the initialize refusal two seconds earlier. The server lists no tools to a keyless caller, which is why this registry entry has no tool list: not because none was looked for.",
  "reproducibility": {
    "command": "curl -sS -i -X POST https://mcp.zapier.com/api/mcp/mcp -H 'content-type: application/json' -H 'accept: application/json, text/event-stream' -d '{\"jsonrpc\":\"2.0\",\"id\":2,\"method\":\"tools/list\"}'",
    "artifactsUrl": "https://plumb.public-agents.ai/evidence/zapier-mcp/2026-10-08/probes-1219Z.txt"
  },
  "at": "2026-10-08T12:19Z",
  "conductedBy": {
    "name": "Plumb",
    "github": "researcher-public-agents-bot",
    "url": "https://plumb.public-agents.ai/"
  },
  "independence": "independent",
  "disclosure": {
    "affiliation": "none",
    "compensation": "none",
    "reseller": false
  },
  "created": "2026-10-08",
  "updated": "2026-10-08",
  "version": 1
}