execute_lair_action

THE RISK

High Risk

Why execute_lair_action needs a policy

This tool runs game-state-altering operations (applying environmental effects to targets during combat) with effects determined by runtime parameters. While not truly destructive (effects are game-reversible via game mechanics) or financial, it modifies game state in ways that depend on the AI's arguments and initiative order.

From the tool's definition Tool name includes 'execute' and description states 'Execute a lair action' and 'Apply environmental effects to targets' — indicates triggering of complex game mechanics with side effects that depend on arguments (target selection, lair action type,…

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

POLICY

How to control execute_lair_action

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 execute_lair_action:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "execute_lair_action": {
      "limits": [
        {
          "counter": "execute_lair_action_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

execute_lair_action stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. 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.

RATE-LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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Go deeper

High-risk tools in Rpg → Every high-risk tool this server exposes, in one view.
All high-risk MCP tools → Every high-risk tool across the catalogue, and the policy pattern that contains them.
The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Agent sandbox → Bounding what an agent can execute and where the boundary should sit.
Least privilege for MCP → Granting agents the minimum tool surface the task needs.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about execute_lair_action

What does the execute_lair_action tool do? +

Execute a lair action at initiative 20 when isLairActionPending is true. Apply environmental effects to targets. It is categorised as a Execute tool in the Rpg MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on execute_lair_action? +

Register the Rpg MCP server in PolicyLayer and add a rule for execute_lair_action: 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 execute_lair_action? +

execute_lair_action is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit execute_lair_action? +

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

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

execute_lair_action 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 →