What changed in 5.8
Since Unreal Engine 5.8, the editor has an MCP server built in. Epic calls it Unreal MCP ↗. With it switched on, an AI assistant can use editor tools directly: place and edit actors, work on Blueprints and materials, and build Sequencer content.
- YouDescribe the job
- AI assistantPlans it and picks the tools
- Unreal MCPRuns inside the editor
- Your levelActors, sequences and renders change
MCP is the standard way an assistant talks to another app. GPT-6 Astra for Blender and Houdini explains it in two paragraphs.
OpenAI’s launch post for GPT-6 Astra ↗ shows the model taking a house it built in Blender and making it walkable in Unreal Engine 5. This guide is about doing that kind of work on your own project. The same steps work with the other assistants Epic lists.
Epic marks Unreal MCP as Experimental. That means it can change between versions and it can break things. Use it on a copy of your project, never on the only one.
What you need
- Unreal Engine 5.8. The latest fix release when this was checked is 5.8.4. A 5.9 preview exists, but Epic says to treat it as unstable, so keep client work on 5.8.
- An assistant Epic’s page names: Codex, Claude Code, Cursor, Gemini CLI, or VS Code with GitHub Copilot. GPT-6 Astra runs in Codex on the Plus plan and above. You need your own account with whichever one you use.
- A copy of the project, or source control you know how to roll back.
Switch it on
- Open Edit → Plugins. Enable Unreal MCP and All Toolsets, then restart the editor. Without All Toolsets the assistant gets no tools for editing the level.
- Start the MCP server. In 5.8 it does not start by itself. Epic’s page shows the setting that starts it with the editor.
- In the editor’s console, run
ModelContextProtocol.GenerateClientConfigfollowed by the name of your assistant. It writes the small settings file the assistant needs. - Open your assistant in the project folder and send the first message below.
The server runs at http://127.0.0.1:8000/mcp, which means “this computer only”.
For jobs that touch many things at once, also enable Python Editor Script Plugin and Editor Scripting Utilities under Plugins → Scripting. Then the assistant can write one script and run it, which is faster than a hundred single actions.
What it can do for cinematics
- BlockoutShapes, a sky and a key light
- ShotA Level Sequence with a camera cut
- RenderJobs queued with Movie Render Graph
Block out the set before you light it.
Give sizes in centimetres, because Unreal’s unit is 1 cm. The assistant places basic shapes, a sky and a key light, and names every actor so you can find it again.
TryBlock out a landing pad 20 metres wide with three crates and a tower. Name everything PVZ_.
Frame from Mission to Minerva, krt.creatives.
Set up the shot, then animate it yourself.
It can create a Level Sequence, set the frame rate and length, add a camera with a camera cut and add your actors. 5.8 added Sequencer tools for assistants. The moves and the timing stay with you.
TryCreate SEQ_020 at 24 frames per second, 6 seconds long, with a 50mm camera low to the ground. Cut to it.
Frame from Mission to Minerva, krt.creatives.
Queue the renders in one go.
Movie Render Graph is production-ready in 5.8. One script can add every sequence to the queue, pick the graph and set the resolution for each job.
TryQueue SEQ_010 to SEQ_050 at 3840 x 2160 with my graph. Show me the script first.
Frame from Mission to Minerva, krt.creatives.
Make it check its own work.
After each change, ask for a screenshot. The assistant reads the picture and can catch a missing light or an actor in the wrong place.
TryTake a screenshot from the shot camera and tell me what looks wrong.
Frame from Mission to Minerva, krt.creatives.
Epic also lists materials, PCG, Niagara and Blueprints. Those work less reliably. See the limits below.
More things to try
Use it as a reader before a writer.
Reading a Blueprint is safe and useful. Editing one is where the assistant is least reliable, so start by asking what a graph does.
TryWalk me through BP_LandingLight: what starts it, what it changes, and what could go wrong.
Compare three lighting set-ups.
Lights are actors with numbers, which suits an assistant. Ask for versions and a screenshot of each, then choose with your own eye.
TryMake three versions of the key light: dawn, noon and night. Screenshot each from the shot camera.
Change many material instances at once.
One request can adjust the same setting across a whole set of props and list what it touched.
TryFind every material instance on the crates, lower roughness by 0.1, and list what you changed.
Ask what a graph really does.
Procedural graphs are hard to read. Have the assistant explain each node and each setting before you trust the result.
TryExplain this PCG graph node by node, and what each exposed setting changes.
Find out why a level is slow.
Epic lists profiling among the things an assistant can do. Ask for the biggest costs first.
TryProfile the open level and tell me the three most expensive things in it.
Bring in a folder of assets.
Importing files one by one is pure repetition. A script does the folder and reports what failed.
TryImport every glTF file in [folder] into /Game/Props and tell me which ones failed.
What to ask for
List the toolsets you can use in this project and what each one is for. Then describe the open level: actors, lights and cameras. Do not change anything yet.
YouList the toolsets you can use, then describe the open level. Change nothing.
AssistantI have tools for actors, materials, Sequencer and screenshots. The level has 32 actors, one directional light and no camera.
YouCreate SEQ_010 at 24 frames per second, 5 seconds long, with a 35mm cine camera at eye height. Cut to it.
AssistantSEQ_010 now has one camera and a camera cut track. Nothing is animated yet. Here is the camera view.
In a new level called PREVIZ_[name], block out [the scene in one or two lines] with basic shapes at real-world scale, in centimetres. Add a sky and one key light coming from [camera left, low]. Name every actor PVZ_[what it is]_[number]. Take a screenshot from eye height and show me.
Create a Level Sequence called SEQ_[shot number], [24] frames per second, [5] seconds long. Add a cine camera with a [35mm] lens at [where], looking at [what], and cut to it. Add [actor name] to the sequence. Do not animate anything yet. Tell me which tracks now exist.
Write one Python script that adds [SEQ_010 to SEQ_050] to the render queue with the graph [graph name], at [3840 x 2160], saving to [folder]. Show me the script and explain it before you run it.
There is a problem in the level: [what you see]. Check the level and the Output Log, and give me the three most likely causes, most likely first. Change nothing until I choose.
- One script for many edits, single actions for looking. That is Epic’s own advice for working with assistants.
- Keep jobs short. Actions run one at a time, and some assistants give up after about two minutes. Split big jobs.
- Ask for the plan first, and for the script before it runs.
- Name things. PVZ_wall_01 can be found again. Cube7 cannot.
If you are on an older version
Before 5.8 there is no built-in server, so people use community plugins. Two that were being kept up to date when this was checked:
| Project | Unreal versions | How it connects | Notes |
|---|---|---|---|
| EngineWire ↗ | 5.0 to 5.8 | A plugin inside the editor | Covers actors, lighting, materials, PCG, Level Sequences and Movie Render Queue |
| runreal/unreal-mcp ↗ | 5.4 and newer | No plugin. It uses Unreal’s own Python remote execution | Small. Runs Python, moves the camera, takes screenshots |
The most starred project, chongdashu/unreal-mcp, has not been updated since April 2025 and calls itself experimental. Skip it.
Real examples
| Who | What happened | Where |
|---|---|---|
| OpenAI | In the demo that introduced GPT-6 Astra, the model took a house it had built in Blender and made it walkable in Unreal Engine 5 | Launch post ↗ |
| Puget Systems | An independent test of the 5.8 server in July 2026. Simple grey-box rooms and a light switch worked. Player controls broke. Replies took five to fifteen minutes | Their write-up ↗ |
| Epic Games | The 5.9 preview adds an Unreal Assistant panel that runs Codex or Claude Code inside the editor | Epic’s page ↗ |
In the Puget test a “procedural city” turned out to be meshes placed one by one. The lesson: open what it made and look.
Is it worth switching?
| By hand | With an assistant | |
|---|---|---|
| Setting up twenty shots | The same clicks twenty times | One script, then you check the result |
| Finding why something broke | Searching logs and forums | It reads the log and the level and suggests causes |
| Learning a new part of the editor | Tutorials on someone else’s project | Questions answered on your own project |
| Speed | Steady | Fast on chores, slow on long jobs |
| Risk | You know what you changed | It can change things you did not ask for |
| Look, timing and taste | Yours | Still yours |
Switch for the set-up and the chores. Keep the camera, the light and the cut in your own hands.
Limits to know first
- It works in the editor only. Python does not run in a packaged game or while the game is playing. This is for building, not for gameplay code.
- Blueprints are the weak spot. The 5.8.1 and 5.8.4 fixes both repaired crashes from assistant-made Blueprint edits. Stay on the latest fix release.
- Undo is not guaranteed. Some actions, such as imports, cannot be undone. Save before each job.
- It can be slow, and wrong with confidence. The Puget Systems test above shows both. Always open the result and check it.
Good to know
- Imports. A script can bring in glTF, FBX and USD files. FBX through the new importer is still experimental.
- PCG. Epic’s scripting page says a PCG graph cannot be regenerated from Python. Press Generate yourself.
- Astra’s allowance. Long Unreal jobs use up Plus-plan messages quickly. Put the whole request in one clear message instead of five short ones.
- What 5.9 changes. In the 5.9 preview the server starts by itself, and a new Unreal Assistant panel can run Codex or Claude Code inside the editor. It is a preview, so wait for the full release before you rely on it.
Keep your project safe
- There is no password. Epic says any program on your computer can call the tools while the server runs, and that it is not built for use from another machine. Switch it off when you are done.
- Save before you start. One of the tools can close the editor and drop unsaved changes.
- Keep approvals on in your assistant, so it asks before it acts.
- Mind client work. Screenshots and project details go to the company that runs your assistant. Check your agreement before using this on a job under NDA.
The pictures in this guide are frames from Mission to Minerva, built in Unreal Engine 5. Read the breakdown.
Tools, prices and platform rules change often. Everything here was checked in November 2026; confirm on the tool’s own page before you rely on it.