set_map_metadata · Loenn MCP: Risk & Policy

WHAT IT DOES

What set_map_metadata does on Loenn

AI agents use set_map_metadata 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 set_map_metadata needs a policy

The tool modifies map metadata in Celeste .bin files, which is a reversible write operation. It does not delete data (ruling out Destructive), does not execute arbitrary code (ruling out Execute), and does not involve financial transactions (ruling out Financial).

From the tool's definition Tool name 'set_map_metadata' indicates modification of map metadata; sibling tools show this MCP server modifies .bin map files (add_decal, add_entity, add_room, etc.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

set_map_metadata Rate-limited

set_map_metadata 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": {
    "set_map_metadata": {
      "limits": [
        {
          "counter": "set_map_metadata_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 set_map_metadata

What does the set_map_metadata tool do? +

set_map_metadata. 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 set_map_metadata? +

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

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

Can I rate-limit set_map_metadata? +

Yes. Add a rate_limit block to the set_map_metadata 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_map_metadata completely? +

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

set_map_metadata 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.

// THE FULL RECORD

set_map_metadata is one line of Loenn's registry record.

The record carries the whole server: verified identity, auth posture, risk grade, every tool classified, recommended policy — re-checked continuously.

Teams ship this data inside their own products. See what a licence covers →