run_script · PowerShell MCP Server MCP: Risk & Policy

WHAT IT DOES

What run_script does on PowerShell MCP Server

AI agents invoke run_script to trigger actions in PowerShell MCP Server. 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_script needs a policy

The tool runs scripts on Windows systems, which is an Execute-category action. Effects depend entirely on script content, making it high-severity due to potential for system compromise, data exfiltration, or malicious operations. Confidence is high despite empty tool description because the server's stated purpose and tool name clearly indicate code execution capability.

From the tool's definition Tool name 'run_script' combined with server description stating it 'enables AI assistants to execute PowerShell commands' and 'run scripts on Windows systems' indicates execution of arbitrary code.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

run_script Rate-limited

run_script 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_script": {
      "limits": [
        {
          "counter": "run_script_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 PowerShell MCP Server, so you can run agents against it safely.

FAQ

Questions about run_script

What does the run_script tool do? +

run_script. It is categorised as a Execute tool in the PowerShell MCP Server 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_script? +

Register the PowerShell MCP Server MCP server in PolicyLayer and add a rule for run_script: 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 PowerShell MCP Server. Nothing to install.

What risk level is run_script? +

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

Can I rate-limit run_script? +

Yes. Add a rate_limit block to the run_script 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_script completely? +

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

run_script is provided by the PowerShell MCP Server MCP server (posidron/mcp-powershell). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.