An MCP server is a program that reads JSON-RPC from standard input and writes JSON-RPC to standard output. The SDK hides that, which is convenient until something does not work — at which point the frames below are the only thing that tells you where the failure is. The whole server Using the o...
Source: [Dev.to](https://dev.to/multigrid/building-an-mcp-server-a-complete-walkthrough-2e62)