mcp-log-proxy

mcp-log-proxy

`mcp-log-proxy` can be used to see the messages to and from a MCP client and a MCP server using a Web interface.

Currently, it only supports the STDIO interface.

Multiple proxies

All running mcp-log-proxy processes will register themselves in `.mcp-log-proxy-instances.json` located in your home directory. On the web page, you can use the selector to switch to another proxy instance.

install

brew tap "emicklei/tap"

and then

brew install emicklei/tap/mcp-log-proxy

or via Go

go install github.com/emicklei/mcp-log-proxy@latest

usage

`mcp-log-proxy` requires one argument `-command` that contains the full command line for starting the MCP server.

For example, to proxy traffic to the `melrose-mcp` server, the full command is:

mcp-log-proxy -command melrose-mcp

This example assumes that both tools are available on your execution PATH.

Once the proxy is started, messages can be viewed on `http://localhost:5656`.

optional flags

You can override the HTTP host address (default `localhost`) using the `host` flag, for example to listen on all interfaces or a specific interface address:

mcp-log-proxy -command melrose-mcp -host 0.0.0.0

mcp-log-proxy -command melrose-mcp -host 1.2.3.4

You can override the Web page title using the `title` flag:

mcp-log-proxy -command melrose-mcp -title "Melrōse (proxy)"

You can override the HTTP port(default 5656) using the `port` flag:

mcp-log-proxy -command melrose-mcp -port 9999

When running multiple proxies, the `mcp-log-proxy` will detect whether a HTTP port is taken and choose a different port instead. Using the Web UI you can select any of the other running proxies.

You can override the log file location of the proxy that captures errors in the proxy itself using the `log` flag:

mcp-log-proxy -command melrose-mcp -log /your/logs/mcp-log-proxy.log

Claude examples

This example proxies the use of the `melrose-mcp` server.

Locate the binaries to get the correct paths.

"melrōse": {

"command": "/Users/SOME-USER/go/bin/mcp-log-proxy",

"args": [

"-command",

"/Users/SOME-USER/go/bin/melrose-mcp -log /Users/SOME-USER/Library/Logs/claude-melrose.log",

"-log",

"/Users/SOME-USER/Library/Logs/claude-melrose-proxy.log",

"-port",

"7788",

"-title",

"Claude Melrose MCP"

]

},

Proxying the `browsermcp` server.

"browsermcp": {

"command": "/Users/SOME-USER/go/bin/mcp-log-proxy",

"args": [

"-command",

"npx @browsermcp/mcp@latest",

"-log",

"/Users/SOME-USER/Library/Logs/claude-browsermcp-proxy.log",

"-port",

"7799",

"-title",

"Claude Browser MCP"

]

}

Goose Example

This example proxies the use of the `melrose-mcp` server.

Locate the binaries to get the correct paths.

/Users/SOME-USER/go/bin/mcp-log-proxy -command /Users/SOME-USER/go/bin/melrose-mcp -log /Users/SOME-USER/Library/Logs/goose-melrose.log -port 8888 -title Melrose-MCP

Error information

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