Server startup and connection failures

Stdio process exits during initialization

Run the configured command directly from the configured working directory. Check that its stdout contains only MCP protocol traffic; write diagnostics to stderr. Confirm every argument is a separate StdioServer.args value.

HTTP connection fails

Start the endpoint separately and verify the exact Streamable HTTP URL. A URL to the service root may not be the MCP route. Add endpoint credentials through HTTPServer.headers.

Nonlocal HTTP trust error

Classify a public or trusted private endpoint explicitly. Omitting trust is accepted only for addresses that resolve exclusively to loopback.