create_material_function
Create a reusable material function.
This record as markdown: /tools/jjpxdev-unreal-mcp/create-material-function.md
What create_material_function does on Unreal
AI agents use create_material_function 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.
| Parameter | Type | Required | Description |
|---|---|---|---|
name | string | Yes | Material function name |
path | string | — | Content directory |
Parameters from the server's own tool schema.
Why create_material_function is rated Medium
This tool creates new material functions, which are reversible asset modifications in Unreal Engine. It does not execute arbitrary code, delete assets, move money, or trigger external operations with unpredictable effects.
From the tool's definition Tool name is 'create_material_function' and description states 'Create a reusable material function.' The verb 'create' indicates data creation/modification within Unreal Engine's material system.
Risk signalsAccepts file system path (path)
Attacks that exploit this kind of access
The rule that runs create_material_function safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Unreal, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For create_material_function, this is the rule to start with:
create_material_function 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.
The button opens the PolicyLayer dashboard: create your workspace, connect Unreal, apply this rule, and every create_material_function call is checked against it from then on.
Questions about create_material_function
Create a reusable material function. 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.
create_material_function accepts 2 parameters: name, path. Required: name. The full parameter table on this page comes from the server's own tool schema.
Register the Unreal MCP server in PolicyLayer and add a rule for create_material_function: 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.
create_material_function is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.
Yes. Add a rate_limit block to the create_material_function 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.
Set action: deny in the PolicyLayer policy for create_material_function. 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.
create_material_function is provided by the Unreal MCP server (@jjpxdev/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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