generate_room_from_pattern · Loenn MCP: Risk & Policy

WHAT IT DOES

What generate_room_from_pattern does on Loenn

AI agents use generate_room_from_pattern 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 generate_room_from_pattern needs a policy

This tool procedurally generates room content, which creates new data structures within the map file. While the description is empty (lowering confidence slightly), the name combined with the server's stated procedurally generate capability and parallel write-class tools (add_room, add_entity) indicate it creates/adds map rooms. This is reversible (can be undone via editing), making it Write rather than Destructive.

From the tool's definition Tool name 'generate_room_from_pattern' and server description indicating ability to 'procedurally generate' Celeste map files. Sibling tools like 'add_room', 'add_entity', and 'add_trigger' are write operations that create map content.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_room_from_pattern Rate-limited

generate_room_from_pattern 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": {
    "generate_room_from_pattern": {
      "limits": [
        {
          "counter": "generate_room_from_pattern_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 generate_room_from_pattern

What does the generate_room_from_pattern tool do? +

generate_room_from_pattern. 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 generate_room_from_pattern? +

Register the Loenn MCP server in PolicyLayer and add a rule for generate_room_from_pattern: 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 generate_room_from_pattern? +

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

Can I rate-limit generate_room_from_pattern? +

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

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

generate_room_from_pattern 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.