unreal-engine-skills-for-claude-code

Unreal Engine Skills for Claude Code

Control Unreal Editor directly from Claude Code via MCP. Hundreds of tools exposed via Unreal's ToolsetRegistry across 30+ toolsets: actors, blueprints, materials, Niagara, Control Rigs, Sequencer, State Trees, widgets, Gameplay Ability System, automation testing, and more.

Contents

Skills

• unreal-mcp (skills/unreal-mcp) - instructions and workflows for driving the Unreal Editor via MCP.

Hooks

• SessionStart (hooks/unreal-context.sh) - injects a short note identifying the repo as an Unreal Engine project so Claude defaults to UE conventions (C++/UObject, Slate, UHT) and prefers the unreal-mcp skill. Runs on startup, resume, and clear.

Prerequisites

1. Unreal Editor with the ModelContextProtocol and AllToolsets plugins enabled (AllToolsets provides the tools; the server exposes none without it)
2. Editor running with the MCP server started - run ModelContextProtocol.StartServer in the console, or enable bAutoStartServer per skills/unreal-mcp/references/setup.md
3. A bash shell on PATH - required for the SessionStart hook (see Platform Support)

Platform Support

Supported: macOS, Linux, and Windows via Git Bash or WSL.

The SessionStart hook is a bash script (hooks/unreal-context.sh) invoked by hooks/hooks.json as bash ${CLAUDE_PLUGIN_ROOT}/hooks/unreal-context.sh. It requires a working bash on PATH:

• macOS / Linux: works out of the box.
• Windows: install Git for Windows (provides Git Bash) or run Claude Code under WSL. Native PowerShell without one of those does not have bash on PATH, and the hook will not run. The plugin's MCP tools still work; you just lose the short project-context note the hook injects at session start. There is no separate PowerShell companion script today.

Installation

This plugin is published in Anthropic's official Claude Code plugin marketplace, claude-plugins-official, which is available automatically when you start Claude Code. Browse it at claude.com/plugins or in the Discover tab of the /plugin panel.

Install for a single developer

In Claude Code:

/plugin install unreal-engine-skills-for-claude-code@claude-plugins-official

If the official marketplace is not present, add it first, then run the install command above:

/plugin marketplace add anthropics/claude-plugins-official

Install for a team

Commit this to .claude/settings.json in the project that should use the plugin. Anyone who trusts the project folder is prompted to install it automatically:

{
  "enabledPlugins": {
    "unreal-engine-skills-for-claude-code@claude-plugins-official": true
  }
}

Verification

1. Launch Unreal Editor, then run ModelContextProtocol.StartServer in the console to start the MCP server.
2. Check the Output Log for MCP server startup messages.
3. In Claude Code, run /plugin. The Installed tab should list unreal-engine-skills-for-claude-code as enabled. This confirms the plugin itself (skills, hooks) is loaded.
4. Run /mcp. You should see unreal-mcp listed as a connected server. This confirms the plugin's MCP server is reachable.
5. Try: "List all actors in the current level".

Configuration

The default port is 8000 with URL path /mcp. If the port is in use, run ModelContextProtocol.StartServer <port> in the console with a different port number.

Note: This plugin does not ship a static .mcp.json file. Run ModelContextProtocol.GenerateClientConfig ClaudeCode in the editor console to generate it from the current server port and URL; re-run after changing either.

Tool search is enabled by default: the MCP server exposes three meta-tools (list_toolsets, describe_toolset, call_tool) instead of the full tool catalog, so Claude discovers toolsets on demand, the prompt cache stays warm, and discovered tools are callable on the same turn through call_tool. Toggle with the bEnableToolSearch setting in [/Script/ModelContextProtocolEngine.ModelContextProtocolSettings]; when disabled, every tool is registered upfront (path used by the hash-mapping commandlet). The model-facing usage contract lives in skills/unreal-mcp/SKILL.md.

Security

Installing this plugin gives Claude broad, live access to the running Unreal Editor. Treat that access the same way you would treat running arbitrary code from an assistant, because in practice it is.

Localhost is not a trust boundary. The MCP server binds to localhost:8000 with origin validation. Origin validation protects against a browser tab talking to the server, but any process running as the same user on the same machine can connect. Do not run the MCP server on shared or untrusted machines, and do not expose the port outside the loopback interface.