MCP-REG-004

Declared remote endpoint matches the probed URL

“A remote server MUST be publicly accessible at its specified URL.” — spec anchor

How to fix this

Make sure the remote endpoint declared in `server.json` is the URL the server is actually reachable at. A remote server must be publicly accessible at the URL it advertises.

Example: failing and passing

The listing declares a staging URL, not the endpoint being validated at https://mcp.example.com/mcp.

Violates MCP-REG-004 · JSON

{
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
  "name": "com.example/weather",
  "description": "Weather forecasts for any city.",
  "version": "1.0.0",
  "remotes": [
    {
      "type": "streamable-http",
      "url": "https://staging.mcp.example.com/mcp"
    }
  ]
}

The declared streamable-http remote is exactly the publicly reachable endpoint being validated.

Complies with MCP-REG-004 · JSON

{
  "$schema": "https://static.modelcontextprotocol.io/schemas/2025-12-11/server.schema.json",
  "name": "com.example/weather",
  "description": "Weather forecasts for any city.",
  "version": "1.0.0",
  "remotes": [{ "type": "streamable-http", "url": "https://mcp.example.com/mcp" }]
}

How the validator checks this

This rule is catalogued from the specification but is not yet checked automatically. No probe emits a finding for it, so it never appears in a report as pass, warn or fail. It is documented here because it is a real requirement of the specification — it is simply not one this validator can confirm for you yet.

Check your own server against MCP-REG-004

The validator does not check MCP-REG-004 automatically yet, so confirm it by hand against the examples above. It does check 73 of the 79 rules — validate a server to see those.

Background on this topic: how to publish to the official registry.