generate_lightmap_uvs · Unreal MCP: Risk & Policy

WHAT IT DOES

What generate_lightmap_uvs does on Unreal

AI agents use generate_lightmap_uvs 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.

WHY IT NEEDS A POLICY

Why generate_lightmap_uvs needs a policy

Generating lightmap UVs modifies the static mesh asset by adding or updating UV channel data used for baking lighting information. This is a reversible change that falls under Write operations (creates/modifies data). Severity is medium because incorrect lightmap UV generation could degrade rendering quality or cause baking artifacts, but the change is non-destructive and can be regenerated or undone.

From the tool's definition Tool name 'generate_lightmap_uvs' and description 'Generate lightmap UVs for a static mesh' indicate modification of mesh data (UV generation). This creates or alters asset properties without deletion.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

generate_lightmap_uvs Rate-limited

generate_lightmap_uvs 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": {
    "generate_lightmap_uvs": {
      "limits": [
        {
          "counter": "generate_lightmap_uvs_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

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Instant setup, no code required.

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

FAQ

Questions about generate_lightmap_uvs

What does the generate_lightmap_uvs tool do? +

Generate lightmap UVs for a static mesh. 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.

How do I enforce a policy on generate_lightmap_uvs? +

Register the Unreal MCP server in PolicyLayer and add a rule for generate_lightmap_uvs: 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.

What risk level is generate_lightmap_uvs? +

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

Can I rate-limit generate_lightmap_uvs? +

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

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

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