delete_material_expression

Delete a single expression node by index. Recompiles and saves automatically.

SERVERUnreal-MCP SOURCEaadeshrao123/unreal-mcp

Critical RISK CLASS

Category Destructive

Parameters 00 required

Recommended Hiddensee the rule below

Registry record Grade F, identity unverified Pull the record →

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

WHAT IT DOES

What delete_material_expression does on Unreal-MCP

AI agents call delete_material_expression to permanently remove resources in Unreal-MCP, typically in cleanup and lifecycle workflows. It does its job in a single call, and there is no undo.

RISK

Why delete_material_expression is rated Critical

The tool irreversibly deletes material expression nodes in the Unreal Engine editor. The deletion is automatic, persistent (saves immediately), and cannot be undone programmatically by the tool itself. This fits the Destructive category as it removes data that would require manual recreation.

From the tool's definition delete_material_expression deletes a single expression node by index. Recompiles and saves automatically.

Attacks that exploit this kind of access

RECOMMENDED RULE

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

delete_material_expression Hidden

delete_material_expression is removed from the agent's tool list entirely, so the agent never calls it. The rest of the server keeps working.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "hide": [
    "delete_material_expression"
  ]
}

RESTRICT THIS TOOL → Instant setup, no code required.

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

FAQ

Questions about delete_material_expression

What does the delete_material_expression tool do? +

Delete a single expression node by index. Recompiles and saves automatically. It is categorised as a Destructive tool in the Unreal-MCP MCP Server, which means it can permanently delete or destroy data. Block by default and require explicit approval.

How do I enforce a policy on delete_material_expression? +

Register the Unreal MCP server in PolicyLayer and add a rule for delete_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 delete_material_expression? +

delete_material_expression is a Destructive tool with critical risk. Critical-risk tools should be blocked by default and only enabled with explicit human approval.

Can I rate-limit delete_material_expression? +

Yes. Add a rate_limit block to the delete_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 delete_material_expression completely? +

Set action: deny in the PolicyLayer policy for delete_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 delete_material_expression? +

delete_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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