This record as markdown: /tools/jjpxdev-unreal-mcp/build-plugin.md
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.
| Parameter | Type | Required | Description |
|---|---|---|---|
platform | object | — | Target platform |
output_path | object | Yes | Output directory for the built plugin |
plugin_path | string | Yes | Path to the .uplugin file |
Parameters from the server's own tool schema.
Why build_plugin is rated High
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
The rule that runs build_plugin safely
PolicyLayer is an MCP gateway: it sits between your AI agents and Unreal, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For build_plugin, this is the rule to start with:
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.
The button opens the PolicyLayer dashboard: create your workspace, connect Unreal, apply this rule, and every build_plugin call is checked against it from then on.
Questions about build_plugin
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.
build_plugin accepts 3 parameters: platform, output_path, plugin_path. Required: output_path, plugin_path. The full parameter table on this page comes from the server's own tool schema.
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.
build_plugin is a Execute tool with high risk. Execute tools should be rate-limited and have argument validation enabled.
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.
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.
build_plugin is provided by the Unreal MCP server (@jjpxdev/unreal-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.
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