preview_map_patch

THE RISK

Low Risk

Why preview_map_patch needs a policy

This is a dry-run/preview operation that explicitly does not apply any changes to the world. It only reads and simulates what the patch would do, producing output without side effects.

From the tool's definition 'Previews what a DSL patch script would do without applying it to the world'

Documented attack patterns abuse exactly the kind of access preview_map_patch gives an agent:

POLICY

How to control preview_map_patch

PolicyLayer is an MCP gateway — it sits between your AI agents and Rpg, and nothing reaches the server without passing your rules. This is the rule we recommend for preview_map_patch:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "preview_map_patch": {}
  }
}

preview_map_patch is read-only, so it stays allowed — but everything else on the server is denied unless you say otherwise.

Create a free account and register Rpg — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

CAP THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Rpg tools

Execute improvisation_manage Manage improvised actions, custom effects, and arcane synthesis. Actions: stunt, apply_eff Execute execute_lair_action Execute a lair action at initiative 20 when isLairActionPending is true. Apply environment Execute concentration_manage Manage spell concentration (D&D 5e rules). 🎯 WHEN TO USE: - After damage: check_save (CO Execute roll_death_save Roll a d20 death saving throw for a character at 0 HP. 10+ success, nat 20 regains 1 HP, n Execute turn_manage Turn-based strategy game lifecycle (multi-agent coordination). 🎮 STRATEGY TURN CYCLE: 1. Write world_map World map operations - viewing, rendering, and modification. Actions: overview, region, ti Write advance_turn Advance to the next combatant\ Write agent_manage Manage LLM-driven NPCs (

All 47 Rpg tools →

Read tools on other servers

M-Team MCP Server get_torrent_detail YouTube MCP Server search_channel Android Forensics ADB MCP Server parse_browser_history 0xarchive web3_challenge

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Data exfiltration → How read access becomes an exfiltration channel when chained with untrusted content.
MCP token cost → What connecting this server costs in context-window tokens on every request.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about preview_map_patch

What does the preview_map_patch tool do? +

Previews what a DSL patch script would do without applying it to the world. It is categorised as a Read tool in the Rpg MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on preview_map_patch? +

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

What risk level is preview_map_patch? +

preview_map_patch is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit preview_map_patch? +

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

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

preview_map_patch is provided by the Rpg MCP server (mnehmos/mnehmos.rpg.mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Rpg tool call.

Start from Rpg, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →