Template for AI MCP Tools for AI Game Developer (Unity-MCP). Use this template to create your custom MCP tools for Unity Engine in 30 minutes. Read more about custom MCP tools here.

This template repository is designed to be easily updated into a real Unity package. Please follow the instruction bellow, it will help you to go through the entire process of package creation, distribution and installing.

Steps to make your package

1️⃣ Click the button - create repository

2️⃣ Clone your new repository

3️⃣ Initialize Project

Use the initialization script to rename the package and replace all placeholders.

./commands/init.ps1 -PackageId "com.company.package" -PackageName "My Package"

This script will:

• Rename directories and files.
• Replace YOUR_PACKAGE_ID, YOUR_PACKAGE_NAME, etc. in all files and folder names.

4️⃣ Update package.json

Open Unity-Package/Assets/root/package.json and update:

• description
• author
• keywords
• unity (minimum supported Unity version)

1. Generate Meta Files To ensure all Unity meta files are correctly generated:
   • Open Unity Hub.
   • Add the Installer folder as a project.
   • Add the Unity-Package folder as a project.
   • Open both projects in Unity Editor. This will generate the necessary .meta files.

5️⃣ Generate Meta Files

Using script

Open Unity project to generate .meta files. On Mac and Linux:

./commands/open-all-projects-unix.sh

On Windows:

./commands/open-all-projects-windows.ps1

OR Manually

You may open the projects manually to achieve the same result.

• Open Unity Hub.
• Add the Installer folder as a project.
• Add the Unity-Package folder as a project.
• Open both projects in Unity Editor. This will generate the necessary .meta files.

6️⃣ Add MCP Tools

Decide what type of MCP tool you need:

• MCP tool for Unity Editor
  • ✔️ Works in Unity Editor (Edit Mode)
  • ✔️ Works in Unity Editor (Play Mode)
  • ✔️ Has access to Editor API
  • ❌ Available in a game build
• MCP tool for Unity Runtime
  • ✔️ Works in Unity Editor (Edit Mode)
  • ✔️ Works in Unity Editor (Play Mode)
  • ❌ Has access to Editor API
  • ✔️ Available in a game build

Based on your choice create script at the location

• Editor: Unity-Package/Assets/root/Editor
• Runtime: Unity-Package/Assets/root/Runtime

Read detailed instructions about custom tool development here.

[McpPluginToolType]
public static class MyCustomTool
{
    [McpPluginTool("my-custom-feature", Title = "Do my custom feature")]
    [Description("Put here the tool description for LLM.")]
    public static Task<bool> DoTurn(
        [Description("Add description to the input property, help LLM better understand it.)]
        int figureId,
        [Description("Add description to the input property, help LLM better understand it.)]
        Vector2Int position)
    {
        // do any logic in background thread here
        return MainThread.Instance.RunAsync(() =>
        {
            // do any logic in main thread here

            return true;
        });
    }
}

Optional steps

1. Version Management

To update the package version across all files (package.json, Installer.cs, etc.), use the bump version script:

.\commands\bump-version.ps1 -NewVersion "1.0.1"

2. Setup CI/CD

To enable automatic testing and deployment:

1. Configure GitHub Secrets Go to Settings > Secrets and variables > Actions > New repository secret and add:

   • UNITY_EMAIL: Your Unity account email.
   • UNITY_PASSWORD: Your Unity account password.
   • UNITY_LICENSE: Content of your Unity_lic.ulf file.
     • Windows: C:/ProgramData/Unity/Unity_lic.ulf
     • Mac: /Library/Application Support/Unity/Unity_lic.ulf
     • Linux: ~/.local/share/unity3d/Unity/Unity_lic.ulf

2. Enable Workflows Rename the sample workflow files to enable them:

   • .github/workflows/release.yml-sample ➡️ .github/workflows/release.yml
   • .github/workflows/test_pull_request.yml-sample ➡️ .github/workflows/test_pull_request.yml

3. Update Unity Version Open both .yml files and update the UNITY_VERSION (or similar variable) to match your project's Unity Editor version.

4. Automatic Deployment The release workflow triggers automatically when you push to the main branch with an incremented version in package.json.

3. Add files into Unity-Package/Assets/root folder

Unity guidelines about organizing files into the package root directory

  <root>
  ├── package.json
  ├── README.md
  ├── CHANGELOG.md
  ├── LICENSE.md
  ├── Third Party Notices.md
  ├── Editor
  │   ├── [company-name].[package-name].Editor.asmdef
  │   └── EditorExample.cs
  ├── Runtime
  │   ├── [company-name].[package-name].asmdef
  │   └── RuntimeExample.cs
  ├── Tests
  │   ├── Editor
  │   │   ├── [company-name].[package-name].Editor.Tests.asmdef
  │   │   └── EditorExampleTest.cs
  │   └── Runtime
  │        ├── [company-name].[package-name].Tests.asmdef
  │        └── RuntimeExampleTest.cs
  ├── Samples~
  │        ├── SampleFolder1
  │        ├── SampleFolder2
  │        └── ...
  └── Documentation~
       └── [package-name].md

Final polishing

• Update the README.md file (this file) with information about your package.
• Copy the updated README.md to Assets/root as well.

⚠️ Everything outside of the root folder won't be added to your package. But still could be used for testing or showcasing your package at your repository.

1. Deploy to any registry you like

• Deploy to OpenUPM (recommended)
• Deploy using GitHub
• Deploy to npmjs.com

2. Install your package into Unity Project

When your package is distributed, you can install it into any Unity project.

Don't install into the same Unity project, please use another one.

• Install OpenUPM-CLI

• Open a command line at the root of Unity project (the folder which contains Assets)

• Execute the command (for OpenUPM hosted package)

  openupm add YOUR_PACKAGE_NAME
  

Final view in Unity Package Manager