pcg_markov_fill · Loenn MCP: Risk & Policy

WHAT IT DOES

What pcg_markov_fill does on Loenn

AI agents use pcg_markov_fill 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 pcg_markov_fill needs a policy

This tool creates or modifies map data reversibly within a .bin file (procedural generation context), which is a Write operation. It does not delete or overwrite existing data irreversibly (not Destructive), does not execute arbitrary code (not Execute), and has no financial impact.

From the tool's definition Tool name 'pcg_markov_fill' suggests procedural content generation (PCG) using Markov chains to fill map data. Server description states the MCP enables agents to 'procedurally generate...Celeste .bin map files'.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

pcg_markov_fill Rate-limited

pcg_markov_fill 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": {
    "pcg_markov_fill": {
      "limits": [
        {
          "counter": "pcg_markov_fill_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 pcg_markov_fill

What does the pcg_markov_fill tool do? +

pcg_markov_fill. 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 pcg_markov_fill? +

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

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

Can I rate-limit pcg_markov_fill? +

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

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

pcg_markov_fill 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.