Open-source UMG MCP project for Unreal Engine creators
Let AI build Unreal UIs while you stay the director.
UMG MCP connects AI assistants to Unreal Engine through MCP and FabServer, so they can edit UMG widgets, Blueprint logic, Sequencer animation, and HLSL UI materials under your approval.
Designed for local-first production: fewer wasted tokens, fewer blind edits, and more useful output per human decision.
Edition boundary / 版本边界
Open source gives the protocol. FabServer gives the finished editor product layer.
This documentation site is public because the UMG MCP protocol and tool surface are public. The Fab package is paid because it adds the private in-editor product layer: ChatWithUnreal, FabServer approval flow, provider setup, local LiteRT-LM, task agents, and production context handling.
| Capability | Open-source UMG MCP | Fab / FabServer package |
|---|---|---|
| Core Widget, Blueprint, Sequencer, Material, and HLSL MCP tools | Included | Included |
| Python MCP server for external AI clients | Included, manual setup | Shares the same protocol; main product path is editor-first |
| Manual clone and source-level debugging | Included | Not the primary workflow |
| Unreal Launcher / Fab installation | Not included | Included |
| ChatWithUnreal in-editor chat panel | Not included | Included |
| FabServer approval cards and direct in-memory execution | Not included | Included |
| Agent modes: chat, develop, learning, task | Not included | Included |
| Provider settings UI: Google OAuth, API key providers, ZhipuAI, OpenAI-compatible endpoints | Not included | Included |
| Local LiteRT-LM runtime | Not included | Included |
| Best buyer/user fit | Developers and teams building custom MCP pipelines | Artists, technical artists, and production teams who want the complete editor experience |
Product index
Find the part of UMG MCP that matches your job.
The plugin is easier to evaluate when it is separated into surfaces, agents, model providers, and editions. Use this index as the map.
Who it is for
A practical AI workflow for teams that ship UI.
UMG MCP is not a chatbot pasted beside Unreal. It is a production control layer for people who need repeatable assets, readable changes, and fast iteration inside the editor.
Core capability
One plugin, four creative surfaces.
The same AI conversation can move from widget structure to Blueprint behavior, then into animation timing and shader polish without leaving the Unreal project.
Agent system
A specialist agent stack, not one giant prompt.
FabServer breaks UI production into agents with narrower jobs. That keeps tool choices smaller, context cleaner, and human review easier.
How a complex UI request is divided
A Master Agent extracts the concept, a Layout Agent expands it into concrete UI regions, and specialized Widget, Material, Animation, and Blueprint agents finish the parts that need their tools. FileManage Agent can quietly resolve target assets when a task is missing a path.
MCP explained
MCP turns AI intent into structured editor actions.
The Model Context Protocol gives an AI client a typed list of tools. Instead of guessing how Unreal works, the model asks for exact actions such as reading the widget tree, creating a Button, setting an anchor, compiling Blueprint, or applying HLSL.
UMG MCP maps those tool calls into native C++ and Python routes for Unreal. The result is more reliable than screen scraping and more reviewable than asking AI to describe manual clicks.
Open MCP command indexFabServer advantage
The Fab version adds the production layer around MCP.
FabServer is the editor-side experience that makes MCP usable by real creators: agents, approvals, provider routing, local model support, task orchestration, context compression, and focused tool modes.
UMG ToolMode
Material ToolMode
Animation ToolMode
Agent StackA day in Unreal
From prompt to asset without losing authorship.
The plugin is built around a reviewable loop: inspect, propose, approve, execute, save, and keep the context focused for the next step.
Product philosophy
We optimize AI for human energy efficiency.
The highest-efficiency engine in production is still the human.
UMG MCP is designed to amplify judgment, not bury it under endless automated output.Local-first AI
Small and local models become useful when the tools are precise.
A local model does not need to remember the whole editor. UMG MCP gives it focused tool schemas, active targets, cached prompts, and structured editor feedback.
Free and Pro
Open-source by belief, Pro by convenience and local safety.
Think of it like a Free / Go / Pro product ladder: the open-source edition remains the free protocol foundation, while the Fab edition is the Pro workflow for buyers who want less setup and safer local usage.
Open source and Fab
Choose the path that matches your project.
The open-source repository is the protocol testbed. The Fab edition packages the polished setup and production-oriented FabServer workflow for buyers who want less configuration and more delivery time.
Questions buyers ask
What to know before purchase.
Bring AI into Unreal where your assets actually live.
Use the open-source repository as the canonical project; choose the Fab package for marketplace installation, then connect your preferred AI provider: local LiteRT-LM, Google login, API keys, OpenAI-compatible gateways, ZhipuAI, or Codex CLI.