Unity CLI Loop

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(Logo inspired by Daft Punk's <i>Human After All</i> album art)  

Let an AI agent compile, test, and operate your Unity project from popular LLM tools via CLI.

Designed to keep AI-driven development loops running autonomously inside your existing Unity projects.

[!IMPORTANT]

• What's New in V3 — no more Node.js setup or port management, the new hot-reload / pause-point tools, automatic CLI updates with per-project version selection, and improved connection stability
• Migrating Custom Tools and Skills to V3 — for anyone who has written C# custom tools, or skills and scripts that call the uloop command. Everyone else migrates just by updating the package and the CLI

Concept

Unity CLI Loop is a Unity integration tool designed so that AI can drive your Unity project forward with minimal human intervention. Tasks that humans typically handle manually — compiling, running the Test Runner, checking logs, editing scenes, capturing windows to verify UI layouts, and even operating a freshly implemented feature to confirm it actually works — can all be carried out from LLM tools.

Unity CLI Loop is built around four core ideas:

1. A self-hosted development loop where AI autonomously compiles, tests, inspects logs, and fixes issues — it can even pause execution at any source line without editing code and read the variables at that moment to pin down a cause. Method-body fixes can be applied instantly to the running game without waiting for a recompile. Uses compile, run-tests, get-logs, clear-console, pause-point, hot-reload.
2. AI-driven Unity Editor operation — scene building, object manipulation, menu execution, and UI refinement from screenshots. Uses execute-dynamic-code, screenshot.
3. PlayMode automated testing — AI clicks buttons, drags elements, presses keys, replays recorded input, and verifies game behavior. Uses simulate-mouse-ui, simulate-mouse-input, simulate-keyboard, replay-input, execute-dynamic-code, screenshot.
4. Achieving the above with a minimal set of tools. See Design Philosophy.

https://github.com/user-attachments/assets/569a2110-7351-4cf3-8281-3a83fe181817

Quickstart

This guide installs three things — the CLI, the Unity package, and the skills — so that your LLM tool can drive Unity. You can install everything from the terminal or from the Unity UI; either path is complete on its own.

Before you begin

Make sure you have:

• A Unity project on Unity 2022.3 or later
• An LLM tool that can load skills, such as Claude Code or Codex

[!NOTE] Upgrading from V2: if the project has custom tools written against the V2 API, compile errors appear right after the V3 package is installed. This is expected. Do not fix them by hand: choose Ignore in Unity's Safe Mode prompt on startup, then press Migrate in the migration window that opens automatically (Window > Unity CLI Loop > Custom Tool Migration). See Migrating Custom Tools and Skills to V3 for the full procedure.

Install from the terminal

Step 1: Install the CLI

macOS, Linux (x86_64), Windows Git Bash:

On Linux, focus-window is not supported.