AI Agents & MCP
Let an AI agent build UModeler X shapes in your open scene through MCP — or paste a script from any AI chat, with no setup at all.
UModeler X hands its modeling over to AI. An agent creates and edits shapes directly in the scene you have open, and you watch it happen in Unity — the objects it makes are ordinary Parametric Shapes you can keep adjusting by hand afterwards.
There are two ways in. They run exactly the same code, so pick whichever suits you.
| What you need | Best for | |
|---|---|---|
| Script Window | Nothing — it ships with UModeler X | Trying this out in the next five minutes, using an AI chat you already have |
| MCP client | An MCP package in your Unity project | Handing an agent a task and letting it build, check and correct on its own |
The five-minute path — no setup
You do not need MCP, an API key or an account to try this. Any AI chat will do.
- Open Window > UModeler X > AI Shape Script (Window).
- Press Copy Prompt. The whole syntax guide goes to your clipboard.
- Paste it into ChatGPT, Claude or any other chat, and say what you want — "a two-seat park bench" is enough.
- Copy the reply, press Paste in the window, then press Run.
The shapes appear in the open scene. One Ctrl+Z undoes the entire script.
If something comes back wrong, press Validate instead of Run — it reports the errors without touching the scene. Errors arrive with a line number and the list of valid values, and handing that list straight back to the AI is usually the fastest fix.
Connecting an MCP client
Install any one of these packages into your Unity project.
| MCP package | Package name |
|---|---|
| Unity Assistant / Unity MCP | com.unity.ai.assistant |
| MCP for Unity (Coplay) | com.coplaydev.unity-mcp |
| Unity-MCP (Ivan Murzak) | com.ivanmurzak.unity.mcp |
There is nothing to configure on the UModeler X side. It detects whichever package is present and registers its tools automatically. Each package has its own instructions for pointing an MCP client — Claude Desktop, Claude Code, Cursor and the like — at your Unity Editor; follow those, and UModeler X comes along for free.
Once compilation finishes, two tools appear in your client's tool list:
| Tool | What it does | Syntax |
|---|---|---|
umx_parametric_shape | Builds and edits shapes in the scene | Scene Script Syntax |
umx_hotspot | Builds and edits hotspot layout assets | Hotspot Script Syntax |
Then just ask in plain language — "Build a park bench with a slatted seat, then twist the backrest 15 degrees." The agent writes the script; UModeler X builds it.
Both tools take a whole script in one call, so an entire assembly costs a single tool call rather than one per object. That keeps agent runs fast and cheap.
Checking the connection
If the umx_ tools are missing from the tool list:
- Wait for Unity to finish compiling, then have the client reload its tools.
- Make sure the Editor is not in Play mode, and not mid-import.
- Confirm the MCP package itself is installed in this project — the tools ride on it.
Unity Assistant Agent mode
With com.unity.ai.assistant installed, UModeler X also registers tools for Agent mode inside Unity Assistant, separately from the MCP tools above. These act one object at a time rather than through a script.
| Tool | What it does |
|---|---|
UModelerX.CreateObject | Creates an empty UModeler X editable mesh object |
UModelerX.CreatePrimitive | Creates a primitive shape |
UModelerX.CreateParametricShape | Creates a shape whose parameters stay live and editable |
UModelerX.UpdateParametricShape | Changes an existing shape's parameters and rebuilds its mesh |
UModelerX.AddModifier | Adds a modifier to an existing shape |
They find their target by GameObject name, or fall back to whatever is selected in the scene.
What an agent can build
Everything the agent produces is a real parametric shape, so nothing here is a dead end — you can open the Inspector and keep working.
- Shapes — Box, Sphere, Cylinder, Capsule, Cone, Torus, Pipe, Icosphere, Stair, Spiral Stair, Room, Wedge, Arch, Dome, Regular Polyhedron, Superellipsoid, NURBS Surface, Gear, Quad Strip and N-gon, plus groups and layout boxes for structure. See Shape Types and Parameters.
- Modifiers — Twist, Bend, Push, Mirror, Screw, Subdivide, Shell, Decimate, Linear Array, Radial Array and the FFD lattices. See Modifiers.
- Materials, hotspot UVs, colliders and prefabs, and edits to shapes that already exist in the scene.
Where to go next
DSL Language
How scripts are parsed, validated and undone — shared by both paths.
Script Window
Every button in the window, the result panel, and the common errors.
Parametric Shape
What the agent is actually building, and how to keep editing it by hand.