> ## Documentation Index
> Fetch the complete documentation index at: https://docs.provenlog.com/llms.txt
> Use this file to discover all available pages before exploring further.

# MCP Proxy

> Intercept and audit all MCP tool calls

The MCP proxy sits between any MCP client and server, transparently forwarding all JSON-RPC messages while logging every `tools/call` request and response to the audit trail.

## Setup

```bash theme={null}
plog proxy --command "npx @modelcontextprotocol/server-filesystem /path/to/dir"
plog proxy --command "npx @modelcontextprotocol/server-filesystem /tmp" --agent-id my-agent
```

The proxy:

1. Spawns the given command as a child process
2. Intercepts all JSON-RPC messages on stdin/stdout
3. Logs `tools/call` requests and responses to ProvenLog
4. Forwards everything transparently — the client and server are unaware of the proxy

## What gets captured

| Event              | Action Type   | Details                    |
| ------------------ | ------------- | -------------------------- |
| Tool call request  | `TOOL_CALL`   | Tool name, input arguments |
| Tool call response | `TOOL_RESULT` | Tool output, duration      |

## Use cases

* Audit MCP tool usage in Claude Desktop, Cursor, or any MCP client
* Monitor which tools agents are calling and what data they access
* Create a verifiable record of all MCP interactions without modifying the server