What are the limitations of the STDIO transport?

The primary limitation is that both client and server must run on the same machine because they communicate through process pipes. You cannot use STDIO to connect to a remote MCP server hosted in the cloud or on another computer. This makes STDIO unsuitable for production deployments where the server needs to be publicly accessible or shared across multiple clients on different machines. For those scenarios, you need the StreamableHTTP transport, which introduces its own set of trade-offs around server-to-client communication capabilities. ---