unity_mppm_start

THE RISK

High Risk

This tool executes a scenario in the Unity editor's Play mode, which runs arbitrary game code/logic. While not destructive by itself, it triggers execution of potentially complex game logic whose side effects are unpredictable and depend on the scenario's contents.

From the tool's definition Tool name 'unity_mppm_start' combined with description stating it 'Start[s] the currently active scenario' and 'enters Play mode on the main editor'.

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

HOW TO CONTROL UNITY_MPPM_START

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

policy.json

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

unity_mppm_start 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 Unity MCP Server — 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

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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.
Rate Limiting MCP Tool Calls: A Practical Guide →
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FAQ

What does the unity_mppm_start tool do? +

Start the currently active scenario. By default also enters Play mode on the main editor. It is categorised as a Execute tool in the Unity 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 unity_mppm_start? +

Register the Unity MCP Server MCP server in PolicyLayer and add a rule for unity_mppm_start: 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 Unity MCP Server. Nothing to install.

What risk level is unity_mppm_start? +

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

Can I rate-limit unity_mppm_start? +

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

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

unity_mppm_start is provided by the Unity MCP Server MCP server (anklebreaker-studio/unity-mcp-server). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Unity MCP Server tool call.

Deterministic rules across all 324 Unity MCP Server tools. Per-identity grants. Full audit log. Live in minutes. Nothing to install.

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324 Unity MCP Server tools catalogued and risk-classified — across an index of 42,500+ MCP servers.

// WHAT UNITY_MPPM_START ON UNITY MCP SERVER DOES

// THE RISK

// HOW TO CONTROL UNITY_MPPM_START

// EXPLORE