unity_play_mode

THE RISK

High Risk

This tool triggers execution of the Unity Editor's play mode, causing the engine to run/simulate game logic. It is an active operation that triggers external execution within the Unity environment. It does not permanently delete data but can cause side effects depending on what scripts and logic run during play mode.

From the tool's definition Control Unity Editor play mode: enter play, pause, or stop.

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

HOW TO CONTROL UNITY_PLAY_MODE

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_play_mode:

policy.json

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

unity_play_mode 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

More Unity MCP Server tools

Destructive unity_amplify_remove_node Remove a node from the currently open Amplify Shader Editor graph by its unique ID. Cannot Destructive unity_animation_remove_curve Remove an entire animation curve binding from a clip. Useful for cleaning up or restructur Destructive unity_animation_remove_event Remove an animation event by its index. Use get_animation_events first to find the index. Destructive unity_animation_remove_keyframe Remove a keyframe from an animation curve by its index. Use get_curve_keyframes first to f Destructive unity_animation_remove_layer Remove a layer from an Animator Controller by index. Cannot remove the base layer (index 0 Destructive unity_animation_remove_parameter Remove a parameter from an Animator Controller by name. Destructive unity_animation_remove_state Remove a state from an Animator Controller layer. Destructive unity_animation_remove_transition Remove a transition from an Animator Controller state. Can target by source/destination na

All 324 Unity MCP Server tools →

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Go deeper

High-risk tools in Unity MCP Server → 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.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

What does the unity_play_mode tool do? +

Control Unity Editor play mode: enter play, pause, or stop. 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_play_mode? +

Register the Unity MCP Server MCP server in PolicyLayer and add a rule for unity_play_mode: 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_play_mode? +

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

Can I rate-limit unity_play_mode? +

Yes. Add a rate_limit block to the unity_play_mode 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_play_mode completely? +

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

unity_play_mode 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.

GOVERN UNITY →

Free to start. No card required.

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

// WHAT UNITY_PLAY_MODE ON UNITY MCP SERVER DOES

// THE RISK

// HOW TO CONTROL UNITY_PLAY_MODE

// EXPLORE