This record as markdown: /tools/jjpxdev-unreal-mcp/compile-blueprint.md
What compile_blueprint does on Unreal
AI agents invoke compile_blueprint 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 |
|---|---|---|---|
blueprint_path | string | Yes | Blueprint asset path |
Parameters from the server's own tool schema.
Why compile_blueprint is rated High
Compilation is an Execute action because it runs an external operation (the Unreal Engine compiler) whose effects depend on the state of the Blueprint being compiled. A misused compile could corrupt assets, trigger cascading failures in dependent Blueprints, or consume significant resources.
From the tool's definition Compile a Blueprint — this triggers a compilation process in Unreal Engine, which executes code generation and shader compilation.
Attacks that exploit this kind of access
The rule that runs compile_blueprint 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 compile_blueprint, this is the rule to start with:
compile_blueprint 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 compile_blueprint call is checked against it from then on.
Questions about compile_blueprint
Compile a Blueprint. 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.
compile_blueprint accepts 1 parameter: blueprint_path. Required: blueprint_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 compile_blueprint: 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.
compile_blueprint 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 compile_blueprint 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 compile_blueprint. 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.
compile_blueprint 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.
More on Unreal, and thousands of servers like it.
Across the catalogue