Unity Project Bootstrap

You are running Phase 4 of the FirstPlayable workflow: preparing a Unity project. Safety over convenience — this skill must be idempotent and must never destroy existing work.

Before doing real work, read references/unity-setup.md in this plugin — it has the detailed editor-settings checks, asmdef dependency rules, package guidance, scene-creation fallbacks, and the idempotency checklist. Ready-made asmdef JSON files, a Unity .gitignore, and the PROJECT_STATUS.md template are in templates/unity/.

Hard rules

• Show the full plan of changes (dry-run) and get user approval before creating or modifying anything.
• Never overwrite an existing file without explicit consent.
• Modify Scenes and Prefabs only through Unity MCP or Editor API — never edit Unity YAML directly.
• Never touch Assets/ThirdParty originals, never delete or regenerate .meta files, never remove packages.
• Re-running bootstrap on an already-bootstrapped project must be a no-op plus a report of what already exists.

Preflight checks

Report each as pass/fail/unknown before proposing changes:

• Is this a Unity project? Which Unity version? (target: Unity 6)
• Render pipeline (Built-in / URP / HDRP)
• Input System package present?
• Test Framework package present?
• Cinemachine in use?
• Git repository and a Unity-appropriate .gitignore?
• Editor settings: Visible Meta Files, Asset Serialization = Force Text
• Unity MCP connection available?
• Unity CLI available (unity --version)? If so: signed in (unity auth status --json → loggedIn)? com.unity.pipeline present for live control? Not signed in means headless tests fail on licensing and unity open stalls silently at Hub sign-in — see references/unity-cli.md §1. Sign-in is the user's to do (browser OAuth).
• Existing scenes and asmdefs that could conflict

Starting from nothing (no Unity project yet)? That is out of scope here — hand off to Unity's own new-unity-project skill, then run bootstrap on the result. Game already in development (real code, its own folder layout)? Use /first-playable:adopt instead. It runs only the preflight and blocking checks below and never imposes this skill's folder structure.

Blocking checks (fix these, don't just warn)

PlayerSettings.runInBackground must be true. When the Editor is not focused — which is always the case while an agent drives it over MCP — play mode does not advance frames. Every runtime observation then silently reports stale values, and verification reports come out confidently wrong. Set it, confirm by reading it back, and record it in Docs/PROJECT_STATUS.md.

Install the play-mode marker. Copy templates/unity/PlayModeMarker.cs to Assets/_Game/Scripts/Editor/PlayModeMarker.cs. It writes Temp/firstplayable_playmode during play mode so the unity-guard hook can block script edits that would otherwise deadlock the MCP bridge (deferred recompile ⇄ isCompiling guard — only a human pressing Stop breaks it).

Project modes

Ask which mode fits (default Standard):

What gets created (Standard)

Assets/
├─ _Game/
│  ├─ Art/  Audio/  Configs/  Prefabs/
│  ├─ Scenes/
│  │  ├─ Bootstrap/      # init & shared services
│  │  ├─ Gameplay/       # FirstPlayable scene lives here
│  │  └─ Test/           # Sandbox + automated/manual verification
│  ├─ Scripts/
│  │  ├─ Core/  Gameplay/  Presentation/  Infrastructure/  Editor/
│  └─ Tests/
│     ├─ EditMode/
│     └─ PlayMode/
└─ ThirdParty/

Plus, at the project root:

• CLAUDE.md — project rules (source-of-truth order, Unity rules, verification checklist). Use this plugin's templates/CLAUDE.project.md as the base. If a CLAUDE.md already exists, propose a merged diff instead of replacing it.
• Docs/PROJECT_STATUS.md — current phase, what is playable, what is next.
• Assets/_Game/Scripts/Editor/PlayModeMarker.cs — from templates/unity/PlayModeMarker.cs (see Blocking checks above).

Completion

Done when the structure exists, preflight issues are either fixed or explicitly accepted by the user, and CLAUDE.md is in place. Then suggest /first-playable:feature <first-feature> following Docs/Design/DEVELOPMENT_ORDER.md.