MCP Server Logger
About
MCP Server Logger provides a way to use console.log and other console methods in an MCP server using stdio transport without breaking protocol communication. It patches console.log, warn, error, and debug to redirect their output to a separate terminal. This project is for…
Details
- Author
- mlshv
- GitHub stars
- 23
- Downloads
- 172
- Categories
- Other
Jump to
- Patches console.log, warn, error, and debug
- Redirects logs to a separate terminal
- Prevents JSON parse errors in MCP Inspector
- Simple one-line import to activate
- Supports conditional use in development mode
Setting up with Highlight
This MCP is not yet compatible with Highlight’s one-click setup. However, you can still use it with Highlight by following these steps:
- Download and install Highlight from highlightai.com/download
- Navigate to the plugins tab and select "Add Custom Plugin"
-
Configure the plugin with the settings below
Plugin Name
MCP Server LoggerCommand (node, npx, python, etc.)Please refer to the README for specific instructions on how to obtain API keys or other required environment variables.
- Enable "Start Automatically" if you want the plugin to start when Highlight launches
From the repository
First run npx mcps-logger in a terminal where you want to see logs. Then install the package (npm install mcps-logger) and add import "mcps-logger/console" to your MCP server’s entry file. For development‑only usage, wrap the import in a NODE_ENV !== "production" condition.
Claude Desktop / Cursor
Paste into your MCP client config file to install this server.
{
"mcpServers": {
"mcp server logger": {
"mcps-logger": {
"command": "npx",
"args": [
"mcps-logger"
]
}
}
}
}McpServers
{
"mcps-logger": {
"command": "npx",
"args": [
"mcps-logger"
]
}
}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");
}
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