unreal-official-mcp ยท diff
git:20260719.d0e4225 to git:20261101.d739dfc
33 added, 1 removed. Audit A to A.
---
name: unreal-official-mcp
description: >-
Enable, discover, and call Unreal Engine 5.8+ built-in Unreal MCP tools
through the DCC MCP gateway. Use when the user asks to set up, include,
compare, inspect, or use Epic's official MCP or Toolset Registry
capabilities. Not a replacement for DCC MCP on Unreal 4.18-5.7.
license: MIT
compatibility: DCC MCP Unreal 0.2+, optional Unreal Engine 5.8+ Unreal MCP plugin
allowed-tools: Read Bash
metadata:
dcc-mcp:
dcc: unreal
version: "0.2.0"
layer: integration
stage: runtime
search-hint: "enable setup bootstrap official epic unreal mcp model context protocol toolset registry bridge"
tags: [unreal, mcp, epic, toolset-registry, compatibility]
tools: tools.yaml
---
# Unreal Official MCP Bridge
Enable and bridge Epic's optional Unreal MCP into DCC MCP without
redistributing the Epic plugin. The engine plugin must be installed with the
engine; this skill can enable it for the current project and configure its
loopback HTTP endpoint.
## Workflow
1. Call `official_mcp_bridge` with `operation=status`.
2. If status is unavailable on Unreal Engine 5.8+, obtain explicit permission
to change project configuration, then call `prepare_official_mcp`. Enable
- `NiagaraToolsets` only when the task needs Niagara authoring.
+ `NiagaraToolsets` only when the task needs Niagara authoring. Set
+ `include_pcg_toolset=true` only for a PCG task; it defaults to false.
3. When `restart_required` is true, restart the editor and verify the DCC MCP
instance before retrying `operation=status`. Do not claim success from the
configuration write alone.
4. Use `list_toolsets`, then `describe_toolset`, before calling an unfamiliar
tool. Preserve Epic's tool names and schemas.
5. Use `call_tool` with the selected toolset and arguments. Do not issue
overlapping mutating calls; Epic serializes tool invocations on the game
thread.
6. Fall back to the normal DCC MCP Unreal skills when the official endpoint is
unavailable or the running engine is older than 5.8.
The bridge accepts loopback HTTP endpoints only. Run it with `affinity:any`;
never block Unreal's game thread while making an HTTP request back into the
same editor process.
+
+ ## PCG opt-in and safe setup
+
+ `prepare_official_mcp` checks actual installed descriptors, not an engine-version
+ guess. Epic's experimental `PCGToolset` descriptor is at
+ `Engine/Plugins/Experimental/Toolsets/PCGToolset/PCGToolset.uplugin` and declares
+ `PCG` as a required dependency. Setup parses that declaration and the installed
+ PCG descriptor at `Engine/Plugins/PCG/PCG.uplugin` (or the legacy
+ `Engine/Plugins/Experimental/PCG/PCG.uplugin` location). Missing, malformed,
+ ambiguous, unsupported, or explicitly project-disabled direct dependencies block
+ setup before any writes. It does not silently override a disabled dependency or
+ change unrelated project plugins. Newly encountered direct dependencies outside
+ the supported descriptor paths require manual review rather than an engine scan.
+
+ Both the project JSON and existing editor INI are validated before writing.
+ Setup preserves all existing INI bytes, including comments, repeated sections,
+ duplicate entries and array commands, appending only a final MCP settings block
+ when the four scalar settings need updating. Repeating setup makes no further
+ changes. Writes use atomic replacement; on a write failure, setup attempts to
+ restore the exact original file bytes or original absence. An incomplete
+ rollback is reported explicitly with the affected file paths. This is not a
+ crash-safe transaction across both files; keep normal project backups.
+
+ Successful setup means configuration was prepared, not that any plugin loaded
+ or PCG tool is available. `runtime_verified` remains false. Restart when requested,
+ then verify the live endpoint and discover its actual toolsets before authoring;
+ setup never starts a service, loads Unreal, or mutates a PCG graph.
+
+ References: [PCGToolset](https://dev.epicgames.com/documentation/unreal-engine/API/PluginIndex/PCGToolset),
+ [PCG](https://dev.epicgames.com/documentation/unreal-engine/API/PluginIndex/PCG), and
+ [Unreal plugins](https://dev.epicgames.com/documentation/en-us/unreal-engine/plugins-in-unreal-engine).
## Scripts
- `prepare_official_mcp`
- `official_mcp_bridge`