list_material_expression_types

List available material expression node types.

SERVERUnreal-MCP SOURCEaadeshrao123/unreal-mcp

Low RISK CLASS

Category Read

Parameters 00 required

Recommended Allowedsee the rule below

Registry record Grade F, identity unverified Pull the record →

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

WHAT IT DOES

What list_material_expression_types does on Unreal-MCP

AI agents call list_material_expression_types to retrieve information from Unreal-MCP without modifying anything. It is typically the context-gathering step in research, monitoring, and reporting workflows, before the agent takes action elsewhere.

RISK

Why list_material_expression_types is rated Low

This tool retrieves and enumerates data about available node types in the Unreal Engine material editor. It performs no modifications, deletions, or external operations. It is a straightforward informational query, placing it firmly in the Read category with low severity.

From the tool's definition Tool name is 'list_material_expression_types' and description states it 'List[s] available material expression node types' — a pure query operation with no side effects.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs list_material_expression_types 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 list_material_expression_types, this is the rule to start with:

list_material_expression_types Allowed

list_material_expression_types is read-only, so it stays allowed. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "list_material_expression_types": {}
  }
}

ALLOW ONLY THIS TOOL → Instant setup, no code required.

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

FAQ

Questions about list_material_expression_types

What does the list_material_expression_types tool do? +

List available material expression node types. It is categorised as a Read tool in the Unreal-MCP MCP Server, which means it retrieves data without modifying state.

How do I enforce a policy on list_material_expression_types? +

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

list_material_expression_types is a Read tool with low risk. Read-only tools are generally safe to allow by default.

Can I rate-limit list_material_expression_types? +

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

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

list_material_expression_types 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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