connect_material_property · Unreal MCP: Risk & Policy

WHAT IT DOES

What connect_material_property does on Unreal

AI agents use connect_material_property to create or update resources in Unreal — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Unreal environment.

WHY IT NEEDS A POLICY

Why connect_material_property needs a policy

This tool creates or modifies material properties within Unreal Engine, which is a reversible operation (connections can be disconnected or replaced). It does not execute arbitrary code, delete assets, or cause financial transactions. It fits the Write category as it creates/modifies data (material property connections).

From the tool's definition Tool 'connect_material_property' connects an expression to a material output property, which modifies material definitions in the Unreal Engine project.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

connect_material_property Rate-limited

connect_material_property 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.

View as policy code

policy.json

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

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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 connect_material_property

What does the connect_material_property tool do? +

Connect an expression to a material output property (BaseColor, Normal, Metallic, Roughness, etc.). It is categorised as a Write tool in the Unreal MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on connect_material_property? +

Register the Unreal MCP server in PolicyLayer and add a rule for connect_material_property: 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 connect_material_property? +

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

Can I rate-limit connect_material_property? +

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

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

connect_material_property 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.