resize_room · Loenn MCP: Risk & Policy

WHAT IT DOES

What resize_room does on Loenn

AI agents use resize_room to create or update resources in Loenn — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Loenn environment.

WHY IT NEEDS A POLICY

Why resize_room needs a policy

This tool modifies map file structure by changing room dimensions—a write operation. It is not destructive because data is preserved and the operation is reversible (a room can be resized again). It is not execute/financial/other. Severity is medium because misconfiguration could corrupt map layouts or make rooms unusable, but the effect is confined to a single map file and can be undone.

From the tool's definition Tool description states it resizes a room and 'preserves tile data', indicating modification of room dimensions in the .bin map file. The name 'resize_room' and verb 'Resize' confirm a mutative operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

resize_room Rate-limited

resize_room stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "resize_room": {
      "limits": [
        {
          "counter": "resize_room_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

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

FAQ

Questions about resize_room

What does the resize_room tool do? +

Resize a room (snaps to 8-pixel grid, preserves tile data). It is categorised as a Write tool in the Loenn MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on resize_room? +

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

What risk level is resize_room? +

resize_room is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit resize_room? +

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

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

resize_room is provided by the Loenn MCP server (magedeline/loenn-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.