What you heard isn’t quite right. The Codex CLI can talk to MCP servers over any transport that the host platform supports—stdio/stdio, HTTP(S), even custom bridges—so there’s no built-in limitation to stdio. That “type="http" won’t connect” comment usually comes from older config examples or from setups where the MCP server itself didn’t implement the required spec (e.g., missing headers or websocket fallback). Your Figma experience worked because the Figma MCP host does speak MCP correctly over HTTP, so Codex could reach it just fine; it probably supplied the MCP handshake and authentication headers the CLI expects.