reset_niagara_system · Unreal MCP: Risk & Policy

WHAT IT DOES

What reset_niagara_system does on Unreal

AI agents invoke reset_niagara_system 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 reset_niagara_system needs a policy

Resetting a Niagara particle system triggers an external operation within Unreal Engine (restarting the particle simulation on an actor). It is not a simple read, nor does it irreversibly delete data. It executes a runtime action whose effects depend on which actor/system is targeted, placing it in the Execute category.

From the tool's definition Reset a Niagara system on an actor

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

reset_niagara_system Rate-limited

reset_niagara_system 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": {
    "reset_niagara_system": {
      "limits": [
        {
          "counter": "reset_niagara_system_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 reset_niagara_system

What does the reset_niagara_system tool do? +

Reset a Niagara system on 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 reset_niagara_system? +

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

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

Can I rate-limit reset_niagara_system? +

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

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

reset_niagara_system 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.