create_material · MCP For Unity MCP: Risk & Policy

WHAT IT DOES

What create_material does on MCP For Unity

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

WHY IT NEEDS A POLICY

Why create_material needs a policy

This tool creates new material assets in the Unity project, which is a reversible write operation. While it modifies the project state by adding assets, the action can be undone (deleted). The blast radius is moderate because incorrect material creation could clutter the project or interfere with asset organization, but the impact is containable.

From the tool's definition Tool description states it "Creates a new Material in Assets/Materials/Generated with a specific color." The verb "Creates" indicates asset generation and modification without irreversible deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_material Rate-limited

create_material 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": {
    "create_material": {
      "limits": [
        {
          "counter": "create_material_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches MCP For Unity, so you can run agents against it safely.

FAQ

Questions about create_material

What does the create_material tool do? +

Creates a new Material in Assets/Materials/Generated with a specific color. It is categorised as a Write tool in the MCP For Unity MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_material? +

Register the MCP For Unity MCP server in PolicyLayer and add a rule for create_material: 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 MCP For Unity. Nothing to install.

What risk level is create_material? +

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

Can I rate-limit create_material? +

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

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

create_material is provided by the MCP For Unity MCP server (yunuscan/mcpforunity). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.