Nexus Unity

Nexus Unity is an open source Unity Editor automation package. It runs a local JSON-RPC server inside the Unity Editor and exposes scene, asset, code, log, test, inspection, and UI automation tools to trusted local developer workflows.

• Package id: com.forkhorizon.nexus.unity
• Version: 1.0.0
• License: GPL-3.0-only
• Public repository: https://github.com/ForkHorizon/NexusUnity.git

Requirements

• Unity 6000.0 or newer.
• Local machine access to the Unity Editor.
• Python 3 for MCP bridge integrations.

Install

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

https://github.com/ForkHorizon/NexusUnity.git

For reproducible installs, pin the public release tag:

https://github.com/ForkHorizon/NexusUnity.git#v1.0.0

Start The Server

1. Open Window > Nexus Unity.
2. Click START SERVER.
3. Confirm the server is listening on the configured loopback port, usually:

http://127.0.0.1:8081/

The server is intended for trusted local automation only. It validates loopback hosts and browser origins, constrains file operations to the Unity project root, and limits request payload size.

Public APIs

Nexus Unity supports two public surfaces:

• Raw HTTP JSON-RPC tools: unprefixed Unity method names returned by list_tools.
• MCP bridge tools: consolidated unity_ manager tools optimized for AI clients.

Direct JSON-RPC example:

curl -s http://127.0.0.1:8081/ \
  -H 'Content-Type: application/json' \
  -d '{"jsonrpc":"2.0","method":"get_server_status","params":{},"id":1}'

MCP clients should use the Python bridge:

python3 Packages/com.forkhorizon.nexus.unity/Editor/nexus_unity_bridge.py

The Unity window can also deploy the bridge to the project root for CLIs that prefer stable local paths. The deployment copies both nexus_unity_bridge.py and the required nexus_bridge/ module.

AI Client Setup

For Claude Code, Cursor, Codex, Gemini, Antigravity, or compatible MCP clients, configure a command server that runs Python with the bridge script.

Package path:

{
  "mcpServers": {
    "nexus-unity": {
      "command": "python3",
      "args": ["Packages/com.forkhorizon.nexus.unity/Editor/nexus_unity_bridge.py"]
    }
  }
}

Root-deployed path:

{
  "mcpServers": {
    "nexus-unity": {
      "command": "python3",
      "args": ["nexus_unity_bridge.py"]
    }
  }
}

Key Tools

• unity_write_and_compile: write files, wait for Unity reload, and return compiler errors.
• unity_scene_manager: create, open, save, and list scenes.
• unity_hierarchy_manager: create, destroy, duplicate, activate, and parent GameObjects.
• unity_component_manager: add, inspect, update, and remove components.
• unity_asset_manager: search, import, refresh, and manage prefab assets.
• unity_editor_controller: play mode, menus, undo/redo, logs, and editor state.
• unity_ui_automation: query and operate Unity Editor UI Toolkit windows.

See API_REFERENCE.MD for the complete raw and MCP tool catalogs.

Documentation

Document	Purpose
DOCUMENTATION.MD	Architecture, setup, security, bridge deployment, and troubleshooting
API_REFERENCE.MD	Raw JSON-RPC and MCP bridge tool catalogs
SECURITY.md	Supported versions, vulnerability reporting, and local-only security policy
CONTRIBUTING.md	Contribution rules and validation expectations
CODE_OF_CONDUCT.md	Community behavior expectations
RELEASE.md	Public release checklist and smoke test
CHANGELOG.md	Public release history
LICENSE.md	GPL-3.0-only license text

Community

Please use GitHub Issues for reproducible bugs and focused feature requests. Security reports should follow SECURITY.md and use GitHub Security Advisories rather than public issues.

Release Notes

The 1.0.0 open source release ships the Python bridge as the supported MCP bridge. Experimental native bridge artifacts are not included.