spawn_niagara_attached · Unreal MCP: Risk & Policy

WHAT IT DOES

What spawn_niagara_attached does on Unreal

AI agents invoke spawn_niagara_attached to trigger actions in Unreal. What it does depends on the arguments the agent supplies, and its effects often reach beyond the immediate call — builds kicked off, notifications sent, workflows started.

WHY IT NEEDS A POLICY

Why spawn_niagara_attached needs a policy

This tool spawns (instantiates and runs) a Niagara particle system attached to an existing actor in the Unreal Engine scene. It triggers an external operation within the engine that creates a runtime object and initiates simulation. It's not purely a write (data creation) but an execution of a live system component.

From the tool's definition Spawn a Niagara system attached to an actor

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

spawn_niagara_attached Rate-limited

spawn_niagara_attached stays usable, but rate-capped — a runaway agent can't fire it dozens of times a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "spawn_niagara_attached": {
      "limits": [
        {
          "counter": "spawn_niagara_attached_rate",
          "window": "minute",
          "max": 10,
          "scope": "grant"
        }
      ]
    }
  }
}

RATE-LIMIT THIS TOOL →

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 spawn_niagara_attached

What does the spawn_niagara_attached tool do? +

Spawn a Niagara system attached to an actor. It is categorised as a Execute tool in the Unreal MCP Server, which means it can trigger actions or run processes. Use rate limits and argument validation.

How do I enforce a policy on spawn_niagara_attached? +

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

spawn_niagara_attached is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.

Can I rate-limit spawn_niagara_attached? +

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

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

spawn_niagara_attached 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.