stop_proxy · Mitm MCP: Risk & Policy

WHAT IT DOES

What stop_proxy does on Mitm

AI agents invoke stop_proxy to trigger actions in Mitm. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why stop_proxy needs a policy

Stopping the proxy is an Execute action because it triggers termination of an active external operation (mitmproxy session) whose effects are immediate and state-changing—it halts traffic interception and writes finalized logs. While not destructive (logs are preserved), it is an active manipulation of a running system process.

From the tool's definition Tool name 'stop_proxy' and description 'Stop a running mitmproxy session and finalize logs' indicates termination of an active network interception process.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stop_proxy Rate-limited

stop_proxy stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "stop_proxy": {
      "limits": [
        {
          "counter": "stop_proxy_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Mitm, so you can run agents against it safely.

FAQ

Questions about stop_proxy

What does the stop_proxy tool do? +

Stop a running mitmproxy session and finalize logs. It is categorised as a Execute tool in the Mitm MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on stop_proxy? +

Register the Mitm MCP server in PolicyLayer and add a rule for stop_proxy: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Mitm. Nothing to install.

What risk level is stop_proxy? +

stop_proxy is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit stop_proxy? +

Yes. Add a rate_limit block to the stop_proxy rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block stop_proxy completely? +

Set action: deny in the PolicyLayer policy for stop_proxy. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides stop_proxy? +

stop_proxy is provided by the Mitm MCP server (mplogas/mitmproxy-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.