move_material_expression

Move a material expression node to a new graph position.

SERVERUnreal-MCP SOURCEaadeshrao123/unreal-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/aadeshrao123-unreal-mcp/move-material-expression.md

WHAT IT DOES

What move_material_expression does on Unreal-MCP

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

RISK

Why move_material_expression is rated Medium

Moving a material expression node is a reversible modification to the visual layout of a material graph—it changes the node's position but does not delete data, execute arbitrary code, or cause destructive effects. This is a Write operation because it updates the state of an editor resource (material graph layout).

From the tool's definition Tool name is "move_material_expression" and description states it "Move[s] a material expression node to a new graph position." This modifies the layout/positioning of an existing material graph element.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs move_material_expression safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Unreal-MCP, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For move_material_expression, this is the rule to start with:

move_material_expression Rate-limited

move_material_expression 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": {
    "move_material_expression": {
      "limits": [
        {
          "counter": "move_material_expression_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Unreal-MCP, apply this rule, and every move_material_expression call is checked against it from then on.

FAQ

Questions about move_material_expression

What does the move_material_expression tool do? +

Move a material expression node to a new graph position. It is categorised as a Write tool in the Unreal-MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on move_material_expression? +

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

What risk level is move_material_expression? +

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

Can I rate-limit move_material_expression? +

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

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

move_material_expression is provided by the Unreal MCP server (aadeshrao123/unreal-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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