Mount on UE 5.8's official MCP server

Unreal Engine 5.8 ships its own MCP server (Epic’s ModelContextProtocol plugin). Instead of running ClaudeUnreal’s standalone server, you can mount ClaudeUnreal’s tools onto Epic’s server through the Toolset Registry. Your agent then talks to a single MCP server (unreal-mcp) that hosts both Epic’s tools and ClaudeUnreal’s.

Note

This mode is UE 5.8 only. On UE 5.7, keep the default Standalone mode — see Architecture & tools.

Enable it

1. Enable the plugins. In Edit → Plugins, enable Epic’s Model Context Protocol (it pulls in Toolset Registry) and Claude Unreal. Unreal will offer to restart — hold off and do step 2 first to save a restart.

2. Switch ClaudeUnreal to official mode. Open Project Settings → Plugins → Claude Unreal → MCP Mode and pick Mount on official UE MCP server (5.8+) (the default is Standalone).

3. Restart the editor. On restart, ClaudeUnreal registers its tools onto the Toolset Registry and removes its own claude-unreal entry from .mcp.json, so you don’t end up with duplicate tools.

4. Start Epic’s server and write the config. Press ~ to open the console and run:

   ModelContextProtocol.StartServer
   ModelContextProtocol.GenerateClientConfig ClaudeCode

   StartServer binds http://127.0.0.1:8000/mcp (pass a port to override, e.g. ModelContextProtocol.StartServer 9000). GenerateClientConfig ClaudeCode writes .mcp.json to the project root with a single unreal-mcp entry pointing at the running server.

   Tip

   Enable Edit → Editor Preferences → General → Model Context Protocol → Auto Start Server to skip StartServer on future launches.

5. Verify from your agent. Reconnect your MCP client so it picks up the new .mcp.json, then ask the agent to run list_toolsets (it should list ClaudeUnreal.ClaudeUnrealOfficialToolset) and call_tool with that toolset and GetActorsInLevel. For a one-shot check, run /cu/verify-official-mcp. If the toolset doesn’t show up, run ModelContextProtocol.RefreshTools in the console and reconnect.

What’s mounted

Mounting registers a toolset — ClaudeUnreal.ClaudeUnrealOfficialToolset — onto Epic’s Toolset Registry. UE 5.8’s server exposes it through the registry gateway rather than as standalone tools: the server’s own tools are list_toolsets, describe_toolset, and call_tool. An agent discovers the toolset with list_toolsets, inspects it with describe_toolset, and invokes a tool with call_tool (the three tools are SpawnActor, GetActorsInLevel, TakeScreenshot). For the complete ClaudeUnreal surface with direct, snake-cased tools, use the default Standalone mode plus the cu CLI — see Architecture & tools. The cu CLI keeps working in either mode; it talks to the editor’s TCP bridge directly, not through .mcp.json.