Patina Unity MCP Server

Patina

Control the Unity Editor from any MCP host. One package install, one click, and your AI assistant can see your scene, create objects, and talk to the console.

Patina is a Rust MCP server paired with a C# Unity bridge. It connects your favorite AI coding tool directly to the Unity Editor over a local TCP channel, with zero manual config.

Why Patina?

• One-click setup. Install the UPM package, click a button, and every supported host is configured automatically.
• No Rust required. Release packages ship pre-built binaries for Windows, Linux, and macOS. Just install and go.
• Built for speed. The Rust sidecar keeps the MCP layer fast and lightweight while Unity stays on the main thread.
• Multi-host. Works with Claude Code, Cursor, VS Code, Gemini CLI, JetBrains Rider, Codex CLI, and more.

How It Works

MCP Host  <-- stdio -->  Patina Server  <-- local TCP -->  Unity Editor

The host launches the Rust binary over stdio MCP. The Rust server forwards tool calls into Unity through a local loopback TCP bridge. Unity executes them on the main thread and returns the result.

Quick Start

1. Install the Unity package

In Unity, open Project Settings > Package Manager, add a scoped registry, then install the package by name.

Scoped registry:

Then open the Package Manager (Window > Package Manager), click the + icon in the top left, select Add package by name..., and enter:

com.taygunsavas.patina-unity-mcp

Registry releases are signed during the release workflow for Unity Package Manager verification.

Alternatively, open the Package Manager, click the + icon, select Add package from git URL..., and enter:

https://github.com/taygunsavas/patina-unity-mcp.git?path=/unity-package

Patina is distributed as a complete Unity package artifact with the editor code, native Rust runtime binaries under Plugins/<platform>/, and the Unity metadata needed for import. End users do not need the Rust toolchain or a Git checkout of this repository.

2. Run One-Click Setup

Open Window > Patina Unity MCP and click One-Click Setup.

The setup flow verifies the binary, starts the Unity bridge, auto-configures every detected host, replaces stale entries, and shows restart guidance where needed.

Patina writes host configs to a stable user-level runtime path instead of a per-project Unity package cache path. When the package is updated, the Unity editor package refreshes that managed runtime automatically, so supported MCP hosts do not need to be reconfigured just because the package cache path changed.

3. Start building

Open your MCP host and try:

• "Log hello to Unity console"
• "Show me the scene hierarchy"
• "Create a cube at position 0, 2, 0"

Available Capabilities

Patina keeps the advertised MCP surface compact so hosts do not need to load every Unity command schema into context. Agents should use:

The 87 commands below are available through patina_capabilities and patina_call.

Scene

GameObjects

Components & Properties

Batch Operations

Prefabs

After saving and reimporting, edit_prefab_asset runs OnValidate by reflection on the saved asset for every component of each type touched by add_component or set_field on the touched GameObject, then saves again, so state computed there (such as Netcode NetworkObject hashes) is persisted. If an OnValidate throws, the command still succeeds and the result gains a warnings string array listing components whose OnValidate was skipped or threw, including when the saved prefab cannot be loaded or a tracked path or component cannot be resolved.

Example: Set GameObject-level values.

set_field targets the GameObject itself when component_type is omitted, "GameObject" or "UnityEngine.GameObject". Supported field_name values are layer (index 0-31 or layer name), tag, isStatic, name and activeSelf (the prefab root name follows the asset file name, so name on the root is rejected). add_child also accepts optional layer, tag and is_static:

{
  "asset_path": "Assets/Prefabs/MyPrefab.prefab",
  "actions": [
    {"action_type": "add_child", "child_name": "Wall0", "layer": "Water", "tag": "Player", "is_static": true},
    {"action_type": "set_field", "transform_path": "Wall0", "component_type": "UnityEngine.GameObject", "field_name": "layer", "value": 5}
  ]
}

Example: Set a component reference within a prefab.

To point a serialized field at another component inside the same prefab, pass an edit_prefab_asset action with set_field and an object reference value. The transform_path inside value is resolved against the prefab root, not against the action's own transform_path:

{
  "asset_path": "Assets/Prefabs/MyPrefab.prefab",
  "actions": [
    {
      "action_type": "set_field",
      "component_type": "MyNamespace.MyComponent",
      "field_name": "targetReference",
      "value": {"transform_path": "Container/Button", "component_type": "MyNamespace.TargetComponent"}
    }
  ]
}

Assets

Materials

Scripts

Scriptable Objects

Validation & Health

Search & Query

Console

Editor State & Control

Undo

Build & Player Settings

Test Runner

Animation

Supported Hosts

The setup window also detects stale entries, missing hosts, and provides a clean Remove Patina From Hosts action.

Troubleshooting

If a Patina call reports EDITOR_BLOCKED, or mentions that Unity may be waiting on a modal dialog, check the Unity Editor for a save-changes prompt or other blocking popup. Patina cannot safely run queued editor commands while Unity is waiting for user input. Resolve the Unity prompt, then retry the MCP command or run patina_health with {"include_unity_state": true}.

Prefab Stage Save Dialogs

Patina addresses dirty prefab stages by responding to the save question programmatically rather than blocking on a modal. When you call close_prefab_stage, the save_changes parameter directly determines the outcome: true saves, false (default) discards changes. This applies only to that command call and does not alter Editor behavior when a human is working manually.

Once a modal dialog appears, Unity's main thread is blocked and remains blocked until a human closes it. Every queued command processes through the same blocked thread, so prevention is the only real solution. For agent-written editor scripts, the safe pattern is to write prefabs using PrefabUtility.LoadPrefabContents, apply changes to a SerializedObject, save with PrefabUtility.SaveAsPrefabAsset, then PrefabUtility.UnloadPrefabContents. This approach never opens a prefab stage. If a stage must be opened, close it with close_prefab_stage. Leaving a dirty stage and manually calling StageUtility.GoToMainStage() will lock the Editor.

Unity offers a startup flag, -automated, which disables dialogs process-wide. While this may be suitable for an Editor driven entirely by agents, it creates problems in hybrid workflows where a human and agent share the same Editor: unsaved changes trigger no prompts, and some operations silently cancel. Patina does not require -automated. Per-command dialog answering works reliably without it and behaves correctly even in an Editor opened with -automated.

To check the current Editor state and dialog automation status, call patina_health and examine broker.sessions[].automated in the default output, or isAutomatedMode and dialogAutomationAvailable when passing {"include_unity_state": true}.

Roadmap

Local Development

Contributor source checkout

Use this when you are editing unity-package/ or rust-server/ directly from the repository:

1. Point Unity at the local package checkout.
   • file:<your-clone-path>/unity-package
2. Build the Rust server.

cd rust-server && cargo build --release

1. Publish the current binary into the local development runtime path.

# Windows
pwsh -File scripts/publish-dev-runtime.ps1

# macOS / Linux
./scripts/publish-dev-runtime.sh

1. In Unity, open Window > Patina Unity MCP, enable Use Local Runtime (Contributor), and click One-Click Setup.

This writes host configs against the local dev runtime instead of the managed packaged runtime. Re-run One-Click Setup after every new cargo build --release + publish-dev-runtime pass, and use Remove Patina From Hosts before switching back to the packaged flow.

Stage a local UPM test package

Use this when you want to test the package as it will be published, not the raw source checkout:

pwsh -File scripts/stage-local-upm.ps1

Then add the staged package from disk in Unity:

• dist/local-upm/com.taygunsavas.patina-unity-mcp/package.json

Prefer the staged local package when you are validating package layout, import behavior, or release packaging. Prefer the source checkout path when you are actively editing source and want the fastest edit-build-run loop.

See CONTRIBUTING.md for the full contributor workflow.

Community and Contributing

• Start with CONTRIBUTING.md for the local development loop, validation expectations, and pull request guidance.
• Use GitHub issue forms for reproducible bugs, feature proposals, and usage questions so maintainers get the context they need.
• Read .github/SUPPORT.md before opening a help request.
• Read .github/SECURITY.md for private vulnerability reporting.
• Read .github/CODE_OF_CONDUCT.md before participating in issues and pull requests.
• Pull requests targeting main are expected to pass CI and go through CODEOWNERS + Copilot review once repository rules are enabled.

Requirements

• Unity 6 (6000.3 LTS+)
• A supported MCP host
• Rust 1.75+ (contributors only)

License

MIT