Agent Bridge for Unity

Let AI actually operate the Unity Editor — build scenes, run Play Mode, capture screenshots, and iterate from visual feedback.

Works with Claude Code, Cursor, Windsurf, VS Code, or any MCP-compatible client.

Not just code edits — the agent can create objects, adjust lighting, wait for compilation, enter Play Mode, take screenshots, compare against references, and keep refining until the scene is right.

What Can It Do?

Runtime Scripting — Create C# scripts, wait for compilation, attach behaviors, enter Play Mode, and validate results.

Visual QA — Adjust lighting and materials, capture screenshots, compare against references, refine iteratively.

Scene Reconstruction — Reconstruct 3D structures from reference images using iterative visual validation.

Try prompts like:

Create a stylized forest with 30 trees, scattered rocks, and warm lighting.

Block out a 2D platformer level with floating platforms, a player spawn, and a goal area.

Set up horror lighting: dim blue ambient, flickering point light, red emergency light, volumetric fog.

Build an obstacle course with moving platforms, a rotating blade, and a jump pad.
Then add a player controller and a win condition.

Create a solar system with orbiting planets, add the scripts, enter Play Mode, and verify it works.

Quick Start

Prerequisites

• Unity 6 (6000.0+) with URP
• .NET 10 SDK
• An MCP-compatible client

1. Install the Package

Git URL (recommended) — In Unity: Window > Package Manager > + > Add package from git URL:

https://github.com/sebastiankurvers-dev/agent-bridge-for-unity.git

cd YourUnityProject/Packages
git clone https://github.com/sebastiankurvers-dev/agent-bridge-for-unity.git com.sebastiankurvers.agent-bridge

{
  "dependencies": {
    "com.sebastiankurvers.agent-bridge": "file:/path/to/agent-bridge-for-unity"
  }
}

2. Verify the Bridge

The bridge starts automatically on port 5847 when Unity compiles. Check Window > Agent Bridge in Unity, or:

curl http://127.0.0.1:5847/health

3. Configure Your MCP Client

Create .mcp.json in your Unity project root:

{
  "mcpServers": {
    "unity": {
      "type": "stdio",
      "command": "dotnet",
      "args": ["run", "--project", "Packages/com.sebastiankurvers.agent-bridge/UnityMCP~/UnityMCP.csproj"],
      "env": {}
    }
  }
}

If using a local path install, replace with the absolute path to your UnityMCP.csproj.

4. Start Using It

Open your MCP client from the Unity project directory. Tools are available immediately.

How It Works

┌─────────────────┐       ┌──────────────────────────────┐
│   MCP Client    │       │  UnityMCP (.NET 10 Server)   │
│  (Claude Code,  │─stdio─│  Receives tool calls,        │
│  Cursor, etc.)  │       │  forwards to Unity over HTTP │
└─────────────────┘       └──────────────┬───────────────┘
                                         │
                                    HTTP :5847
                                         │
                          ┌──────────────┴───────────────┐
                          │  UnityAgentBridge (Editor)    │
                          │  Dispatches to Unity main     │
                          │  thread, executes commands    │
                          └──────────────┬───────────────┘
                                         │
                                  Unity Editor API

The ~ suffix on UnityMCP~/ tells Unity to ignore the folder — it won't compile .NET 10 code as Unity scripts.

Tool Coverage

248 tools across scene building, terrain, particles, visual QA, automation, editor control, assets, and scripting. You don't need to learn them — your AI agent discovers and calls them as needed.

Compatibility

Security

The bridge listens on 127.0.0.1 only — not accessible from other machines.

No authentication required by default. For shared machines, set BRIDGE_AUTH_TOKEN:

export BRIDGE_AUTH_TOKEN="your-secret-token"

Troubleshooting

Support

If this project saves you time, consider buying me a coffee.

Community

Contributing | Security Policy | Code of Conduct

License

Apache 2.0