When your MCP server fails with “Connection closed” or tools silently fail to execute in Claude Desktop, use this systematic diagnostic guide to fix the underlying issue. The top 4 reasons MCP servers fail in Claude Desktop Stdio Pollution (Console Logging): In stdio transport, stdout is reserve...
Source: [Dev.to](https://dev.to/woda_toki/debugging-mcp-connection-timeouts-and-tool-calling-failures-in-claude-cursor-and-sadasend-432p)