set_actor_properties

THE RISK

Medium Risk

Why set_actor_properties needs a policy

This tool creates or modifies actor properties within the Unreal editor, which is a reversible Write operation. While the description is empty (lowering confidence slightly), the name combined with sibling context clearly indicates property modification rather than deletion, execution of arbitrary code, or financial operations.

From the tool's definition Tool name 'set_actor_properties' indicates modification of actor properties in Unreal Editor. The server context (UEFN - Unreal Editor for Fortnite) and sibling tools like 'actor_move_to_folder', 'actor_set_label', 'actor_show', 'actor_unlock' confirm this is…

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

POLICY

How to control set_actor_properties

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

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "set_actor_properties": {
      "limits": [
        {
          "counter": "set_actor_properties_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

set_actor_properties stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

Create a free account and register Uefn — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

Related tools and policies

More Uefn tools

Destructive delete_actors Delete actors by their labels. Destructive delete_asset Delete an asset. Destructive tag_remove tag_remove Destructive shutdown Stop the MCP listener. Destructive snapshot_restore Restore the level to a previously saved snapshot state. Destructive undo Undo the last editor action via the transaction system. Execute batch_exec Execute multiple bridge commands in a single editor tick — faster than sending one-by-one. Execute blueprint_compile Compile a Blueprint asset and return compilation status.

All 143 Uefn tools →

Write tools on other servers

M-Team MCP Server download_torrent YouTube MCP Server generate_video_title Android Forensics ADB MCP Server combine_reports 0xarchive web3_signup

Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about set_actor_properties

What does the set_actor_properties tool do? +

set_actor_properties. It is categorised as a Write tool in the Uefn MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on set_actor_properties? +

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

What risk level is set_actor_properties? +

set_actor_properties is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit set_actor_properties? +

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

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

set_actor_properties is provided by the Uefn MCP server (quangdang46/uefn-verse-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Uefn tool call.

Start from Uefn, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →