mcp-log-proxy
mcp-log-proxy is a small web-based logging proxy that sits between an MCP client and server over stdio, so a developer can watch every message passed between them in a browser while debugging an MCP integration.
The proxy is started with the full command line needed to launch the target MCP server, and every message exchanged between the client and that server is visible on a local web page, currently only for the stdio transport. Multiple running proxy instances register themselves in a shared file in the user's home directory, and the web page can switch between them.
Host, port, page title and log file location are all configurable through command-line flags, and the tool automatically picks a different port if its default one is already taken, so several proxies can run side by side without manual coordination.
It installs through Homebrew or go install, is written in Go, and is released under the MIT license.