Unreal-MCP

Option B —unreal-mcp-cli(current / advanced)

The CLI is the recommended pathtoday, until the Fab listing is live. Install it from npm —no repo clone, no build step. By defaultinstall-plugin/updateuse a localUnrealMCP/checkout when one is present; otherwise they download the dedicatedunreal-mcp-plugin-source-<version>.zipsource asset from the public GitHub Release that matches the CLI version. That source asset keeps the distributed descriptor semantics (noEngineVersionpin) and carries the signed bridge payload underSource/ThirdParty/UnrealMcpBridge/<rid>/; the installer materializes it intoBinaries/ThirdParty/...for first-open convenience.--plugin-source <dir>remains the offline / CI / dev override. The CLI copies (or, for dev, junctions) the plugin into your project and, onupdate, automatically clears the stale UE build cache so you always get a clean recompile of the new code (seeUpdating the plugin). Ondesktop platforms(Win64/Mac/Linux),unreal-mcp-cli openalso runs a pre-launch build when the project/plugin state still needs native editor binaries, then auto-dismisses the known Unreal blocker dialogs (Missing ... Modules,UnrealMCP is Incompatible) if they still appear during startup. Linux dialog automation isX11-only; Wayland is detected and warned as unsupported.

# 1. Install unreal-mcp-cli (or use npx unreal-mcp-cli@latest <command> for a one-off, no install) npm install -g unreal-mcp-cli # 2. Install the UnrealMCP plugin into your project unreal-mcp-cli install-plugin ./YourProject # 3. Authorize against the cloud server (ai-game.dev) unreal-mcp-cli login ./YourProject # 4. Open the Unreal Editor for the project (wires the MCP connection env vars) unreal-mcp-cli open ./YourProject

Seecli/README.mdfor the full 16-command reference.
- CopyUnrealMCP/into<YourProject>/Plugins/UnrealMCP/(or create a directory junction / symlink to it for live development).
- Open the project; UE compiles theUnrealMcpEditormodule on first launch.
- On editor boot the Output Log prints[Unreal-MCP] plugin loaded— that confirms the plugin and its game-thread dispatcher started.

The sidecar binary (unreal-mcp-bridge) isbundled inside the pluginin a packaged release: a prebuilt, self-contained binary for your platform ships underUnrealMCP/Binaries/ThirdParty/UnrealMcpBridge/<rid>/and the editorauto-spawns it on startup with zero user action— no .NET install, no env var, no manual launch (ARCHITECTURE §6). The first Cloud OAuth device-code browser approval is the only remaining human step; after that, reconnect on later launches is zero-click (the cloud token is cached inSaved/Config/UnrealMcp/).

When you copy the reposource checkout directly(Option C/manual or a live dev junction), the bundled binary is not present — the plugin then resolves the sidecar from theUNREAL_MCP_BRIDGE_PATHenvironment variable instead: point that at a locally built sidecar, or rununreal-mcp-cli bootstrap-localto build the bridge from source into<YourProject>/Intermediate/UnrealMCP/and set the var to the result. With neither a bundled binary nor the env var resolved, the plugin's TCP listener still starts but logs[Unreal-MCP] no sidecar binary resolved for rid <rid> …and spawns nothing.

Updating in place must always leave you running thenewcode. The risk is UE's incremental compiler: if the plugin source changes (new.cppfiles, a new module) but the oldUnrealMCP/Intermediate/build cache survives, UE can do a partial recompile against a stale module file-list and silently leave you on old/partial code. Each channel handles this differently:

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Fab / Epic Marketplace → automatic.The Epic Games Launcher replaces the precompiled binaries in place; nothing to compile, no cache to clear. This is why Fab is the recommended channel.

unreal-mcp-cli update→ automatic clean rebuild.updatere-copies the plugin source and, bydefault, deletes the installed plugin's staleIntermediate/and the C++Binaries/so UE performs a clean compile on the next editor launch — no manual steps. The bundled sidecar bridge underBinaries/ThirdParty/UnrealMcpBridge/<rid>/is kept intact: release-source installs refresh it fromSource/ThirdParty/..., while repo/dev installs preserve the previously bundled copy when needed. Devjunctioninstalls are never cleaned (that would wipe your live source tree's outputs). Pass--no-cleanto opt out of the cache wipe.

node bin/unreal-mcp-cli.js update <YourProject> # default: clean rebuild on version change node bin/unreal-mcp-cli.js update <YourProject> --force # re-copy even when versions match node bin/unreal-mcp-cli.js update <YourProject> --no-clean # keep the existing build cache

Manual copy → clear the cache yourself.If you overwrite<YourProject>/Plugins/UnrealMCP/by hand,close the editor first, delete<YourProject>/Plugins/UnrealMCP/Intermediate/and the C++Binaries/(keepBinaries/ThirdParty/if a bundled bridge is present), then relaunch so UE recompiles cleanly.
- Open theAI Game Developermain window from the editor'sToolsmenu (the tab is registered under the Tools menu category).
- Choose a connection mode:

- Cloud(default) — connects toai-game.dev. ClickAuthorizeto start the OAuthdevice-code flow: the window shows a verification URL and a short user code; open the URL, enter the code, approve, and the editor finishes authorizing. UseRevoketo clear the stored cloud token.
- Custom— connects to a localgamedev-mcp-serveryou run (or any compatible server). Enter the server URL and point your AI client at it. (The plugin does not start the local server for you — rununreal-mcp-clior your own process; seeTroubleshooting.)

Unreal-MCP ships61 built-in ("core") toolsacross7 familiesthat your AI can call, plus3 system toolsit cannot (see below). Tool ids are kebab-case (actor-create,blueprint-compile), matching the Unity/Godot naming convention. Extensions can add more (seeCustomize Tools, Prompts & Resources).

A cross-platform Node CLI (unreal-mcp-cli) that scaffolds projects, installs the plugin, configures connection settings, drives the local server, and invokes tools over HTTP. It is a port ofunity-mcp-cli/godot-cli. Full reference:[cli/README.md.

Published on npm — install withnpm install -g unreal-mcp-cli, or run a one-off withnpx unreal-mcp-cli@latest <command>.