stop_capture · Mitm MCP: Risk & Policy

WHAT IT DOES

What stop_capture does on Mitm

AI agents invoke stop_capture 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_capture needs a policy

stop_capture halts an ongoing packet capture session, which is an operational action that changes the state of a running system component (tshark). While not destructive (the captured data is retained) or write-level (it doesn't create/modify persistent data), it executes a control command that terminates a process/service.

From the tool's definition Tool description states 'Stop tshark packet capture for a session' — this terminates an active network monitoring operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

stop_capture Rate-limited

stop_capture 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_capture": {
      "limits": [
        {
          "counter": "stop_capture_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_capture

What does the stop_capture tool do? +

Stop tshark packet capture for a session. 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_capture? +

Register the Mitm MCP server in PolicyLayer and add a rule for stop_capture: 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_capture? +

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

Can I rate-limit stop_capture? +

Yes. Add a rate_limit block to the stop_capture 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_capture completely? +

Set action: deny in the PolicyLayer policy for stop_capture. 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_capture? +

stop_capture 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.