MCP Server Logger
by mlshv
MCP Server Logger redirects console logs to a separate terminal when developing an MCP server with stdio transport. This prevents console.log from interfering with the protocol communication.
Last updated: N/A
MCP Server Logger
console.log for your stdio MCP server
Why?
When developing an MCP (Model Context Protocol) server with stdio transport, console.log interferes with the protocol communication.
For example, this is what you normally get in MCP inspector npx @modelcontextprotocol/inspector when calling console.log in your MCP server code:
Error from MCP server: SyntaxError: Unexpected token S in JSON at position 0
Solution
This package patches the console methods (log, warn, error, debug) and redirects logs to a separate terminal.
https://github.com/user-attachments/assets/33ff367e-74b4-48e8-9f04-0bcafbad5e00
Usage
Start the logger in a terminal where you want to see the logs:
npx mcps-logger
Install the logger in your MCP server:
npm install mcps-logger
Add it to your MCP server entry file:
import "mcps-logger/console";
Or if you want to use in development mode only:
if (process.env.NODE_ENV !== "production") {
import("mcps-logger/console");
}