Install ClaudusBridge 2.0

ClaudusBridge 2.0 targets Unreal Engine 5.8. Install the plugin into your matching engine or project, then choose the CLI, an external MCP client, or the embedded agent.

Requirements

Requirement	When needed
Unreal Engine 5.8 and a compatible plugin build	Engine-backed tool calls, with or without an editor window.
Windows x64, macOS, or Linux x64	The CLI builds for each platform; the macOS build covers Intel and Apple Silicon. Plugin modules must also match your engine and platform.
A C++ toolchain	Building the CLI, and any project whose modules need compilation. On Windows that is Visual Studio 2022 Build Tools with the Desktop development with C++ (x64) workload, which every Unreal C++ project already requires; on macOS and Linux, clang or gcc.
Node.js on PATH	The embedded ClaudusCode agent and ACP interface. The native CLI does not require Node.js.
Your provider account	AI conversations in the embedded agent or your external assistant; ordinary CLI calls do not require a model account.

Install the plugin

For a Fab installation, select the supported engine version in your library. For a manual project installation, put the folder containing ClaudusBridge.uplugin at:

<YourProject>/Plugins/ClaudusBridge/

Before replacing plugin files, close that project's editor, pause MCP clients that could launch it again, and stand the hidden backend down with claudus quiesce --project-path <your .uproject>. A closed editor window alone does not mean its DLLs are free: quiesce returns only once they are actually writable. See Rebuilding the plugin. Build source modules with your engine's normal project or plugin build workflow.

Enable ClaudusBridge under Edit → Plugins and restart when requested. Its engine dependencies include ToolsetRegistry, AllToolsets, MultiUserClient and PythonScriptPlugin. Keep the plugin's complete Resources directory when copying or packaging it.

Build the CLI

ClaudusBridge is distributed as source, so the CLI is compiled on your machine the first time you need it. Marketplace policy does not allow a plugin to distribute executables, and building locally also means the CLI matches the platform and toolchain you actually use.

In the editor, choose Tools → Generate Claudus CLI, or run this in the console:

ClaudusBridge.BuildCli

Either one compiles the CLI and the asset converter from Source/Programs/, off the game thread, and then rewrites the MCP configuration of every agent client. A cold build takes roughly ten to fifteen seconds. If the CLI is missing when the editor starts, a notification offers to build it.

You can also run the build scripts directly, which is what CI and air-gapped machines use:

.\Plugins\ClaudusBridge\Source\Programs\ClaudusMcpProxy\build.bat

On macOS and Linux the equivalent is build.sh in the same directory.

If the build fails, the message names the cause rather than a generic error: no C++ toolchain, a plugin directory this account cannot write to, or a missing engine .NET SDK. The last one only affects the asset converter, which is built with the .NET SDK that ships inside Unreal.

Installed under Program Files

An Epic Launcher installation puts the plugin under a directory a standard account cannot write. The build needs to write into the plugin's own Resources, so install ClaudusBridge into your project's Plugins folder, or run the build once from an elevated shell.

Find the executable

The build lands where the editor and every generated client configuration look for it:

Platform	Path inside the plugin
Windows	Resources/Proxy/Win64/claudus.exe
macOS	Resources/Proxy/Mac/claudus
Linux	Resources/Proxy/Linux/claudus

claudus-mcp-proxy.exe / claudus-mcp-proxy in the same directory is a byte-identical alias used by generated MCP configurations. Use an absolute path, or add that platform directory to PATH.

On macOS/Linux, retain the executable permissions of both files. CI downloads contain a .tar archive; extract it to preserve those permissions. A build for one platform cannot be used on another.

Verify the installation

These PowerShell examples assume claudus.exe is on PATH:

claudus.exe --version
claudus.exe doctor --project-path "C:\Projects\MyProject\MyProject.uproject" --json
claudus.exe status --project-path "C:\Projects\MyProject\MyProject.uproject" --json

doctor checks prerequisites without launching Unreal. status reads the instance registry; no running backend is a normal result when the project is closed.

To start a backend and wait for its tool catalog:

claudus.exe ready --wait --timeout 300 --project-path "C:\Projects\MyProject\MyProject.uproject" --launch-headless
claudus.exe toolsets --json --project-path "C:\Projects\MyProject\MyProject.uproject"

The second command can reconnect or launch another hidden backend if the first one has already reached its idle shutdown. A persistent MCP connection keeps the backend available while that client remains connected.

If engine discovery fails, inspect doctor and pass --unreal-editor-cmd with the absolute path to the matching engine executable. Never point a project at a different engine version merely to bypass discovery.

Use the embedded agent

Open Tools → ClaudusCode in the editor. Check node --version first if the agent does not launch. Follow Your First Conversation for provider login and the terminal workflow.

For terminal automation, continue to Claudus CLI. For an external assistant, follow Connecting.