run · Python MCP: Risk & Policy

WHAT IT DOES

What run does on Python

AI agents invoke run to trigger actions in Python. 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 run needs a policy

This tool executes scripts or files, which allows running arbitrary code with side effects that depend on the content executed. This falls under the Execute category as it triggers external operations whose effects are argument-dependent. Severity is high because a compromised AI could execute malicious scripts, install packages, or cause system damage.

From the tool's definition Tool name 'run' with description 'Runs a script or file with' indicates execution of arbitrary code or scripts. Despite incomplete description, the verb 'Runs' and context of a Python-focused tool clearly indicates code execution capability.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

run Rate-limited

run 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": {
    "run": {
      "limits": [
        {
          "counter": "run_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 Python, so you can run agents against it safely.

FAQ

Questions about run

What does the run tool do? +

Runs a script or file with. It is categorised as a Execute tool in the Python MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on run? +

Register the Python MCP server in PolicyLayer and add a rule for run: 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 Python. Nothing to install.

What risk level is run? +

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

Can I rate-limit run? +

Yes. Add a rate_limit block to the run 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 run completely? +

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

run is provided by the Python MCP server (Dave-London/Pare). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.