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Proudly sponsored and maintained by Coplay -- the best AI assistant for Unity.

Create your Unity apps with LLMs!

MCP for Unity acts as a bridge, allowing AI assistants (like Claude, Cursor) to interact directly with your Unity Editor via a local MCP (Model Context Protocol) Client. Give your LLM tools to manage assets, control scenes, edit scripts, and automate tasks within Unity.

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Get help, share ideas, and collaborate with other MCP for Unity developers!

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Key Features 🚀

• 🗣️ Natural Language Control: Instruct your LLM to perform Unity tasks.
• 🛠️ Powerful Tools: Manage assets, scenes, materials, scripts, and editor functions.
• 🤖 Automation: Automate repetitive Unity workflows.
• 🧩 Extensible: Designed to work with various MCP Clients.
• 🌐 HTTP-First Transport: Ships with HTTP connections enabled by default (stdio is still available as a fallback).

Tools

Your LLM can use functions like:

• execute_custom_tool: Execute a project-scoped custom tool registered by Unity.
• execute_menu_item: Executes Unity Editor menu items (e.g., "File/Save Project").
• manage_asset: Performs asset operations (import, create, modify, delete, etc.).
• manage_editor: Controls and queries the editor's state and settings.
• manage_gameobject: Manages GameObjects: create, modify, delete, find, and component operations.
• manage_prefabs: Performs prefab operations (create, modify, delete, etc.).
• manage_scene: Manages scenes (load, save, create, get hierarchy, etc.).
• manage_script: Compatibility router for legacy script operations (create, read, delete). Prefer apply_text_edits or script_apply_edits for edits.
• manage_shader: Performs shader CRUD operations (create, read, modify, delete).
• read_console: Gets messages from or clears the console.
• run_tests: Runs tests in the Unity Editor.
• set_active_instance: Routes subsequent tool calls to a specific Unity instance (when multiple are running). Requires the exact Name@hash from unity_instances.
• apply_text_edits: Precise text edits with precondition hashes and atomic multi-edit batches.
• script_apply_edits: Structured C# method/class edits (insert/replace/delete) with safer boundaries.
• validate_script: Fast validation (basic/standard) to catch syntax/structure issues before/after writes.
• create_script: Create a new C# script at the given project path.
• delete_script: Delete a C# script by URI or Assets-relative path.
• get_sha: Get SHA256 and basic metadata for a Unity C# script without returning file contents.

Resources

Your LLM can retrieve the following resources:

• custom_tools: Lists custom tools available for the active Unity project.
• unity_instances: Lists all running Unity Editor instances with their details (name, path, port, status).
• menu_items: Retrieves all available menu items in the Unity Editor.
• tests: Retrieves all available tests in the Unity Editor. Can select tests of a specific type (e.g., "EditMode", "PlayMode").
• editor_active_tool: Currently active editor tool (Move, Rotate, Scale, etc.) and transform handle settings.
• editor_prefab_stage: Current prefab editing context if a prefab is open in isolation mode.
• editor_selection: Detailed information about currently selected objects in the editor.
• editor_state: Current editor runtime state including play mode, compilation status, active scene, and selection summary.
• editor_windows: All currently open editor windows with their titles, types, positions, and focus state.
• project_info: Static project information including root path, Unity version, and platform.
• project_layers: All layers defined in the project's TagManager with their indices (0-31).
• project_tags: All tags defined in the project's TagManager.

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How It Works

MCP for Unity connects your tools using two components:

1. MCP for Unity Bridge: A Unity package running inside the Editor. (Installed via Package Manager).
2. MCP for Unity Server: A Python server that runs locally (from a terminal window) and speaks HTTP/JSON-RPC to your MCP client. The Unity window launches it for you in HTTP mode by default; stdio is still available if you switch transports.

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Installation ⚙️

Prerequisites

• Python: Version 3.10 or newer. Download Python

• Unity Hub & Editor: Version 2021.3 LTS or newer. Download Unity

• uv (Python toolchain manager):

  # macOS / Linux
  curl -LsSf https://astral.sh/uv/install.sh | sh
  
  # Windows (PowerShell)
  winget install --id=astral-sh.uv  -e
  
  # Docs: https://docs.astral.sh/uv/getting-started/installation/

• An MCP Client: : Claude Desktop | Claude Code | Cursor | Visual Studio Code Copilot | Windsurf | Others work with manual config

• [Optional] Roslyn for Advanced Script Validation

  For **Strict** validation level that catches undefined namespaces, types, and methods: 
  
  **Method 1: NuGet for Unity (Recommended)**
  1. Install [NuGetForUnity](https://github.com/GlitchEnzo/NuGetForUnity)
  2. Go to `Window > NuGet Package Manager`
  3. Search for `Microsoft.CodeAnalysis`, select version 4.14.0, and install the package
  4. Also install package `SQLitePCLRaw.core` and `SQLitePCLRaw.bundle_e_sqlite3`.
  5. Go to `Player Settings > Scripting Define Symbols`
  6. Add `USE_ROSLYN`
  7. Restart Unity
  
  **Method 2: Manual DLL Installation**
  1. Download Microsoft.CodeAnalysis.CSharp.dll and dependencies from [NuGet](https://www.nuget.org/packages/Microsoft.CodeAnalysis.CSharp/)
  2. Place DLLs in `Assets/Plugins/` folder
  3. Ensure .NET compatibility settings are correct
  4. Add `USE_ROSLYN` to Scripting Define Symbols
  5. Restart Unity
  
  **Note:** Without Roslyn, script validation falls back to basic structural checks. Roslyn enables full C# compiler diagnostics with precise error reporting.</details>
  

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🌟 Step 1: Install the Unity Package

To install via Git URL

1. Open your Unity project.
2. Go to Window > Package Manager.
3. Click + -> Add package from git URL....
4. Enter:

   https://github.com/CoplayDev/unity-mcp.git?path=/MCPForUnity#v8.0.0
   

5. Click Add.

To install via OpenUPM

1. Install the OpenUPM CLI
2. Open a terminal (PowerShell, Terminal, etc.) and navigate to your Unity project directory
3. Run openupm add com.coplaydev.unity-mcp

Note: If you installed the MCP Server before Coplay's maintenance, you will need to uninstall the old package before re-installing the new one.

⚡️ Step 2: Start the Local HTTP Server (Default)

HTTP transport is enabled out of the box. The Unity window can launch the FastMCP server for you:

1. Open Window > MCP for Unity.
2. Make sure the Transport dropdown is set to HTTP (default) and the HTTP URL is what you want (defaults to http://localhost:8080).
3. Click Start Local HTTP Server. Unity spawns a new operating-system terminal running uv ... server.py --transport http.
4. Keep that terminal window open while you work; closing it stops the server. Use the Stop Session button in the Unity window if you need to tear it down cleanly.

Prefer stdio? Change the transport dropdown to Stdio and Unity will fall back to the embedded TCP bridge instead of launching the HTTP server.

Manual launch (optional)

You can also start the server yourself from a terminal—useful for CI or when you want to see raw logs:

uvx --from "git+https://github.com/CoplayDev/unity-mcp@v8.0.0#subdirectory=Server" mcp-for-unity --transport http --http-url http://localhost:8080

Keep the process running while clients are connected.

🛠️ Step 3: Configure Your MCP Client

Connect your MCP Client (Claude, Cursor, etc.) to the HTTP server from Step 2 (auto) or via Manual Configuration (below).

Option A: Auto-Setup (Recommended for Claude/Cursor/VSC Copilot)

1. In Unity, go to Window > MCP for Unity.
2. Click Auto-Setup.
3. Look for a green status indicator 🟢 and "Connected ✓". (This writes the HTTP url pointing at the server you launched in Step 2.)

Client-specific troubleshooting

• VSCode: uses Code/User/mcp.json with top-level servers.unityMCP, "type": "http", and the URL from Step 2. On Windows, MCP for Unity still prefers an absolute uv.exe path when you switch back to stdio.
• Cursor / Windsurf (help link): if uv is missing, the MCP for Unity window shows "uv Not Found" with a quick [HELP] link and a "Choose uv Install Location" button.
• Claude Code (help link): if claude isn't found, the window shows "Claude Not Found" with [HELP] and a "Choose Claude Location" button. Unregister now updates the UI immediately.

Option B: Manual Configuration

If Auto-Setup fails or you use a different client:

1. Find your MCP Client's configuration file. (Check client documentation).
   • Claude Example (macOS): ~/Library/Application Support/Claude/claude_desktop_config.json
   • Claude Example (Windows): %APPDATA%\Claude\claude_desktop_config.json
2. Edit the file to add/update the mcpServers section so it points at the HTTP endpoint from Step 2.

Click for Client-Specific JSON Configuration Snippets...

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Claude Code

If you're using Claude Code, you can register the MCP server using the below commands:

macOS:

claude mcp add --scope user UnityMCP -- uv --directory /Users/USERNAME/Library/AppSupport/UnityMCP/UnityMcpServer/src run server.py

Windows:

claude mcp add --scope user UnityMCP -- "C:/Users/USERNAME/AppData/Local/Microsoft/WinGet/Links/uv.exe" --directory "C:/Users/USERNAME/AppData/Local/UnityMCP/UnityMcpServer/src" run server.py

VSCode (all OS – HTTP default)

{
  "servers": {
    "unityMCP": {
      "type": "http",
      "url": "http://localhost:8080/mcp"
    }
  }
}

macOS / Windows / Linux (Claude Desktop, Cursor, Claude Code, Windsurf, etc. – HTTP default)

{
  "mcpServers": {
    "UnityMCP": {
      "url": "http://localhost:8080/mcp"
    }
  }
}

Set the URL to match whatever you entered in the Unity window (include /mcp).

Stdio configuration examples (legacy / optional)

Switch the Unity transport dropdown to Stdio, then use one of the following command/args blocks.

VSCode (stdio)

{
  "servers": {
    "unityMCP": {
      "type": "stdio",
      "command": "uv",
      "args": [
        "--directory",
        "<ABSOLUTE_PATH_TO>/UnityMcpServer/src",
        "run",
        "server.py",
        "--transport",
        "stdio"
      ]
    }
  }
}

macOS / Linux (stdio)

{
  "mcpServers": {
    "UnityMCP": {
      "command": "uv",
      "args": [
        "run",
        "--directory",
        "/Users/YOUR_USERNAME/Library/AppSupport/UnityMCP/UnityMcpServer/src",
        "server.py",
        "--transport",
        "stdio"
      ]
    }
  }
}

Windows (stdio)

{
  "mcpServers": {
    "UnityMCP": {
      "command": "C:/Users/YOUR_USERNAME/AppData/Local/Microsoft/WinGet/Links/uv.exe",
      "args": [
        "run",
        "--directory",
        "C:/Users/YOUR_USERNAME/AppData/Local/UnityMCP/UnityMcpServer/src",
        "server.py",
        "--transport",
        "stdio"
      ]
    }
  }
}

Replace YOUR_USERNAME and AppSupport path segments as needed for your platform.

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Usage ▶️

1. Open your Unity Project and verify the HTTP server is running (Window > MCP for Unity > Start Local HTTP Server). The indicator should show "Session Active" once the server is up.

2. Start your MCP Client (Claude, Cursor, etc.). It connects to the HTTP endpoint configured in Step 3—no extra terminals will be spawned by the client.

3. Interact! Unity tools should now be available in your MCP Client.

   Example Prompt: Create a 3D player controller, Create a tic-tac-toe game in 3D, Create a cool shader and apply to a cube.

Working with Multiple Unity Instances

MCP for Unity supports multiple Unity Editor instances simultaneously. Each instance is isolated per MCP client session.

To direct tool calls to a specific instance:

1. List available instances: Ask your LLM to check the unity_instances resource
2. Set the active instance: Use set_active_instance with the exact Name@hash shown (e.g., MyProject@abc123)
3. All subsequent tools route to that instance until changed. If multiple instances are running and no active instance is set, the server will error and instruct you to select one.

Example:

User: "List all Unity instances"
LLM: [Shows ProjectA@abc123 and ProjectB@def456]

User: "Set active instance to ProjectA@abc123"
LLM: [Calls set_active_instance("ProjectA@abc123")]

User: "Create a red cube"
LLM: [Creates cube in ProjectA]

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Development & Contributing 🛠️

Development Setup and Guidelines

See README-DEV.md for complete development setup and workflow documentation.

Adding Custom Tools

MCP for Unity uses a Python MCP Server tied with Unity's C# scripts for tools. If you'd like to extend the functionality with your own tools, learn how to do so in CUSTOM_TOOLS.md.

How to Contribute

1. Fork the main repository.
2. Create an issue to discuss your idea or bug.
3. Create a branch (feature/your-idea or bugfix/your-fix).
4. Make changes.
5. Commit (feat: Add cool new feature).
6. Push your branch.
7. Open a Pull Request against the main branch, referencing the issue you created earlier.

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📊 Telemetry & Privacy

MCP for Unity includes privacy-focused, anonymous telemetry to help us improve the product. We collect usage analytics and performance data, but never your code, project names, or personal information.

• 🔒 Anonymous: Random UUIDs only, no personal data
• 🚫 Easy opt-out: Set DISABLE_TELEMETRY=true environment variable
• 📖 Transparent: See TELEMETRY.md for full details

Your privacy matters to us. All telemetry is optional and designed to respect your workflow.

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Troubleshooting ❓

Click to view common issues and fixes...

• Unity Bridge Not Running/Connecting:
  • Ensure Unity Editor is open.
  • Check the status window: Window > MCP for Unity.
  • Restart Unity.
• MCP Client Not Connecting / Server Not Starting:
  • Make sure the local HTTP server is running (Window > MCP for Unity > Start Local HTTP Server). Keep the spawned terminal window open.
  • Verify Server Path: Double-check the --directory path in your MCP Client's JSON config. It must exactly match the installation location:
    • Windows: %USERPROFILE%\AppData\Local\UnityMCP\UnityMcpServer\src
    • macOS: ~/Library/AppSupport/UnityMCP/UnityMcpServer\src
    • Linux: ~/.local/share/UnityMCP/UnityMcpServer\src
  • Verify uv: Make sure uv is installed and working (uv --version).
  • Run Manually: Try running the server directly from the terminal to see errors:

    cd /path/to/your/UnityMCP/UnityMcpServer/src
    uv run server.py

• Configuration Failed:
  • Use the Manual Configuration steps. The plugin may lack permissions to write to the MCP client's config file.

Still stuck? Open an Issue or Join the Discord!

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License 📜

MIT License. See LICENSE file.

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Star History

Unity AI Tools by Coplay

Coplay offers 2 AI tools for Unity

• MCP for Unity is available freely under the MIT license.
• Coplay is a premium Unity AI assistant that sits within Unity and is more than the MCP for Unity.

(These tools have different tech stacks. See this blog post comparing Coplay to MCP for Unity.)

Disclaimer

This project is a free and open-source tool for the Unity Editor, and is not affiliated with Unity Technologies.