set_window_size · Moom MCP Server MCP: Risk & Policy

WHAT IT DOES

What set_window_size does on Moom MCP Server

AI agents invoke set_window_size to trigger actions in Moom 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 set_window_size needs a policy

This tool executes an external operation that changes the size of an application window. While not destructive or financial, it triggers a side-effecting action in the OS environment (window resizing), making it Execute. Misuse could disrupt user workflows by resizing windows unexpectedly, but the blast radius is limited to UI state changes.

From the tool's definition "Resize a window to specific dimensions" — triggers an external operation (window management action on macOS via Moom) that modifies the state of the windowing environment

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_window_size Rate-limited

set_window_size 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": {
    "set_window_size": {
      "limits": [
        {
          "counter": "set_window_size_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 Moom MCP Server, so you can run agents against it safely.

FAQ

Questions about set_window_size

What does the set_window_size tool do? +

Resize a window to specific dimensions. It is categorised as a Execute tool in the Moom 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 set_window_size? +

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

What risk level is set_window_size? +

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

Can I rate-limit set_window_size? +

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

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

set_window_size is provided by the Moom MCP Server MCP server (itrimble/moom-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.