MCP stdio Protocol's 3 Hidden Traps: When All Unit Tests Pass but the MCP Server Won't Respond

This article records a real MCP Server debugging session: every automated test of story-cli passed, yet in a real environment the MCP Server couldn't respond to any request at all. The root cause turned out to be 3 bugs, each touching low-level details of the Node.js process model and the stdio protocol. TL;DR If you're building an MCP Server (or...