select_actors · Unreal MCP: Risk & Policy

WHAT IT DOES

What select_actors does on Unreal

AI agents invoke select_actors to trigger actions in Unreal. 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 select_actors needs a policy

Selecting actors in the Unreal Editor changes the editor's selection state, which is an editor operation/action rather than a pure read. It triggers external state changes in the Unreal Engine editor environment. The description is cut off and uninformative, which lowers confidence.

From the tool's definition Tool name 'select_actors' and partial description 'Set the editor' — description is truncated/uninformative

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

select_actors Rate-limited

select_actors 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": {
    "select_actors": {
      "limits": [
        {
          "counter": "select_actors_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 Unreal, so you can run agents against it safely.

FAQ

Questions about select_actors

What does the select_actors tool do? +

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

How do I enforce a policy on select_actors? +

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

What risk level is select_actors? +

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

Can I rate-limit select_actors? +

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

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

select_actors is provided by the Unreal MCP server (sam-david/unreal-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.