mutate · RPG Ledger MCP Server MCP: Risk & Policy

WHAT IT DOES

What mutate does on RPG Ledger MCP Server

AI agents invoke mutate to trigger actions in RPG Ledger MCP Server. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why mutate needs a policy

The server description explicitly references 'campaign mutations' and 'managing campaign state', and the tool is named 'mutate', strongly implying it modifies state. However, the exact scope (write, destructive, or execute) is unclear due to the empty description. 'Mutate' could encompass creation, modification, or deletion.

From the tool's definition Tool name 'mutate' and server description mentions 'campaign mutations' — but the tool description is empty and uninformative.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

mutate Rate-limited

mutate 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.

View as policy code

policy.json

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

RATE-LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches RPG Ledger MCP Server, so you can run agents against it safely.

FAQ

Questions about mutate

What does the mutate tool do? +

mutate. It is categorised as a Execute tool in the RPG Ledger MCP Server MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on mutate? +

Register the RPG Ledger MCP Server MCP server in PolicyLayer and add a rule for mutate: 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 Ledger MCP Server. Nothing to install.

What risk level is mutate? +

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

Can I rate-limit mutate? +

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

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

mutate is provided by the RPG Ledger MCP Server MCP server (sepa79/rpg-ledger-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.