Unreal Spatial Twin
Read persistent Unreal world data, prepare spatial changes offline, validate them in Shadow, and apply through Unreal's official MCP. Unreal remains the authority for execution, compilation, saving and rendering.
Qualified target: Unreal Engine 5.8.2 / Windows x64, Python 3.11+ (tested 3.12), Codex with Agent Plugins support. Blender authoring was tested with 5.2.1 LTS. Other engine builds and platforms need separate qualification.
Install
- Copy the accompanying
UnrealSpatialTwinfolder into your project'sPluginsdirectory and build with your licensed Unreal toolchain. - Enable Unreal's official ModelContextProtocol toolsets. Follow Installation for the AllToolsets prerequisite.
- Create a Python environment and install
runtime/tools/UnrealSpatialTwinMCP/requirements.txt. - Install this folder as a local Codex plugin using a repository marketplace.
Set
SPATIAL_TWIN_PROJECTto your.uprojectandSPATIAL_TWIN_PYTHONto your Python executable when workspace discovery is ambiguous. - Launch Unreal with
SPATIAL_TWIN_HOMEpointing to this folder'sruntimefor native patch dispatch. Perform the initial explicit scan once. Inspectworld_readstatus before subsequent work; reuse the cached snapshot.
The source archive contains a marketplace example. Its source.path is
relative to the extracted archive root. Use Codex's documented local plugin
installation flow; no manual rewrite of an existing configuration is needed.
Use
Ask Codex to use the unreal-spatial skill. The focused MCP advertises
world_read, shadow_plan and tool_describe; the complete query/operation
schemas remain available through these entrypoints. Known deterministic
queries and validation work without a model API. Jev is optional.
Unsupported or stale geometry, missing navigation, ambiguous identities and uncertain write outcomes remain explicit. Never edit Canonical, force a PASS, replay an uncertain mutation or infer a complete game playthrough from a test.
Verification and measurements
Read Coverage and Package qualification. The four-activity, 16-trial portfolio measured 68.3121% fewer native whole-agent tokens and 54.1777% less verified-delivery time. These are measured portfolio results, with variable baseline and uncontrolled caches, not universal gains. Earlier failures and costs are retained in the benchmark reports.
Publication channel
This plugin uses a local stdio MCP and a locally installed Unreal editor. It is prepared for downloadable source/repository distribution. OpenAI's public directory uses a remotely reachable, verified MCP service; the local package does not claim that integration or directory approval.
Public reference: OpenAI packaging. For a reproducible bug report, see Support.