build_plugin · Unreal MCP: Risk & Policy

WHAT IT DOES

What build_plugin does on Unreal

AI agents invoke build_plugin 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 build_plugin needs a policy

This tool triggers compilation and build processes, which are external code execution operations. While not destructive by itself, building plugins can invoke arbitrary build scripts, dependencies, and external tools. The blast radius is substantial if an attacker controls what gets built or can inject malicious code into the build pipeline.

From the tool's definition Tool name is 'build_plugin' with description 'Build a plugin standalone.' The verb 'build' indicates compilation/execution of code.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

build_plugin Rate-limited

build_plugin 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": {
    "build_plugin": {
      "limits": [
        {
          "counter": "build_plugin_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 build_plugin

What does the build_plugin tool do? +

Build a plugin standalone. 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 build_plugin? +

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

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

Can I rate-limit build_plugin? +

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

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

build_plugin 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.