npm · unreal-engine-mcp-server
$npx -y unreal-engine-mcp-server@0.6.0-beta-e UE_PROJECT_PATH (required) — Your Unreal project folder or its .uproject file. The server reads the capability token from <project>/Saved/MCP/capability-token and the WebSocket port from the project settings.
MCP_AUTOMATION_CAPABILITY_TOKEN · secret — Capability token to present to the editor. Only needed when the server cannot read the project folder, for example over LAN.
MCP_AUTOMATION_PORT — Editor WebSocket port. Default: the first Listen Ports entry in the project settings, else 8090.
MCP_AUTOMATION_HOST — Editor host to connect to. A LAN address also needs MCP_AUTOMATION_ALLOW_NON_LOOPBACK=true and Allow Non Loopback in the plugin settings.
MCP_AUTOMATION_ALLOW_NON_LOOPBACK — SECURITY: allow a non-loopback MCP_AUTOMATION_HOST. Enable only on a trusted network.
MCP_AUTOMATION_USE_TLS — Connect with wss:// instead of ws://.
MCP_ADDITIONAL_PATH_PREFIXES — Extra content roots to allow besides /Game, /Engine, /Script, /Temp and /Niagara, comma-separated. Example: /MyPluginContent/
MCP_CONNECTION_TIMEOUT_MS — How long to wait for the editor connection, in milliseconds.
MCP_REQUEST_TIMEOUT_MS — Overrides every per-capability request timeout, in milliseconds. Leave unset: each capability gets a budget that fits its cost.
MCP_AUTOMATION_MAX_MESSAGES_PER_MINUTE — Inbound messages per minute from the editor before the server disconnects.
LOG_LEVEL — Log level. Logs go to stderr.