Unity MCP Plugin — AI-Powered Unity Editor Bridge (UPM Package)

The Unity Editor side of the most comprehensive MCP (Model Context Protocol) integration for Unity game development. Install via Unity Package Manager to let Claude, Cursor, Windsurf, or any MCP-compatible AI assistant control your Unity Editor with 288 tools across 30+ categories. Built and maintained by AnkleBreaker Studio.

What It Does

This package runs a lightweight HTTP bridge inside the Unity Editor on localhost:7890. The companion Unity MCP Server connects to it, exposing 288 tools to AI assistants across 30+ feature categories — scenes, GameObjects, components, builds, profiling, Shader Graph, Amplify Shader Editor, terrain, physics, NavMesh, animation, multiplayer, and much more.

Neon Brick Breaker — Built from scratch by AI in under 5 minutes

Claude creates the entire game: scene setup, neon materials with bloom post-processing, brick grid layout, game scripts, VFX, and UI — all through Unity MCP commands.

3D Medieval Village — AI-generated terrain, houses, and environment

From an empty scene to a fully decorated village: terrain sculpting, material creation, procedural house building via C# editor scripts, trees, fences, and pathways.

3D Castle — Complete level with FPS walkthrough

AI builds a multi-room castle with courtyard, throne room, armory, and guard room. Adjusts lighting, spawns the player, and runs an FPS walkthrough to verify the result.

How It Works — AI → MCP Server → Unity Plugin → Unity Editor

The Model Context Protocol connects your AI assistant to Unity through a lightweight bridge. Commands flow from your AI chat directly into the editor in real-time.

Core Capabilities:

• Scene Management — Open, save, create scenes; browse full hierarchy tree
• GameObjects — Create (primitives or empty), delete, inspect, set transforms (world/local)
• Components — Add/remove components, get/set any serialized property
• Assets — List, import, delete assets; create prefabs and materials; assign materials
• Scripts — Create, read, update C# scripts
• Builds — Trigger multi-platform builds (Windows, macOS, Linux, Android, iOS, WebGL)
• Console & Compilation — Read errors/warnings/logs, clear console; get C# compilation errors via CompilationPipeline (independent of console buffer)
• Testing — Run EditMode/PlayMode tests, poll results, list available tests via Unity Test Runner API
• Play Mode — Play, pause, stop
• Editor — Execute menu items, run arbitrary C# code, check editor state, get project info

Extended Capabilities:

• Animation — List clips, get clip info, list Animator controllers and parameters, set Animator properties, play animations
• Prefab (Advanced) — Open/close prefab editing mode, check prefab status, get overrides, apply/revert changes
• Physics — Raycasts, sphere/box casts, overlap tests, get/set physics settings (gravity, layers, collision matrix)
• Lighting — Manage lights, configure environment lighting/skybox, bake lightmaps, list/manage reflection probes
• Audio — Manage AudioSources, AudioListeners, AudioMixers, play/stop clips, adjust mixer parameters
• Terrain — Create/modify terrains, paint heightmaps/textures, manage terrain layers, trees, and detail objects
• Navigation — NavMesh baking, agents, obstacles, off-mesh links
• Particles — Particle system creation, inspection, module editing
• UI — Canvas, UI elements, layout groups, event system
• Tags & Layers — List tags and layers, add/remove tags, assign tags/layers to GameObjects
• Selection — Get/set editor selection, find objects by name/tag/component/layer
• Graphics — Scene and game view capture as inline images for visual inspection
• Input Actions — List action maps and actions, inspect bindings (Input System package)
• Assembly Definitions — List, inspect, create, update .asmdef files
• ScriptableObjects — Create, inspect, modify ScriptableObject assets
• Constraints — Position, rotation, scale, aim, parent constraints
• LOD — LOD group management and configuration

Profiling & Debugging:

• Profiler — Start/stop profiler, get stats, take deep profiles, save profiler data
• Frame Debugger — Enable/disable frame debugger, get draw call list and details, get render target info
• Memory Profiler — Memory breakdown by asset type, top memory consumers, take memory snapshots (with com.unity.memoryprofiler package)

Shader & Visual Tools (conditional on packages):

• Shader Graph — List, inspect, create, open Shader Graphs; inspect shader properties; list Sub Graphs and VFX Graphs (requires com.unity.shadergraph / com.unity.visualeffectgraph)
• Amplify Shader Editor — Full graph manipulation: list, inspect, create, add/remove/connect/disconnect/duplicate nodes, set properties, templates, save/close (requires Amplify Shader Editor asset)

Multiplayer (conditional on MPPM package):

• MPPM Scenarios — List, activate, start, stop multiplayer playmode scenarios; get status and player info (requires com.unity.multiplayer.playmode)

Infrastructure:

• Multi-Instance Support — Multiple Unity Editor instances discovered automatically (including ParrelSync clones)
• Port Affinity — Each editor remembers its last-used port via EditorPrefs and reclaims it on restart, minimizing port swaps across sessions
• Registry Heartbeat — The plugin sends a heartbeat every 30 seconds to the shared instance registry (lastSeen timestamp), enabling the MCP server to distinguish between compiling editors (fresh entry) and crashed editors (stale entry >5 minutes)
• Multi-Agent Support — Multiple AI agents can connect simultaneously with session tracking, action logging, and queued execution
• Play Mode Resilience — MCP bridge survives domain reloads during Play Mode via SessionState persistence
• Dashboard — Built-in Editor window (Window > MCP Dashboard) showing server status, category toggles, agent sessions, and update checker
• Project Context — Auto-inject project-specific documentation and guidelines for AI agents (via Assets/MCP/Context/)
• Settings — Configurable port, auto-start, and per-category enable/disable via EditorPrefs
• Update Checker — Automatic GitHub release checking with in-dashboard notification

Installation via Unity Package Manager

1. Open Unity > Window > Package Manager
2. Click the + button > Add package from git URL...
3. Enter:
   hljs language-bash

   Copy

   https://github.com/AnkleBreaker-Studio/unity-mcp-plugin.git
   

4. Click Add

Unity will download and install the package. You should see in the Console:

[MCP Bridge] Server started on port 7890

Verify

Open a browser and visit: http://127.0.0.1:7890/api/ping

You should see JSON with your Unity version and project name.

Companion: MCP Server

This plugin is one half of the system. You also need the Node.js MCP Server that connects Claude to this bridge:

👉 unity-mcp-server

Dashboard

Open Window > MCP Dashboard to access:

• Server status with live indicator (green = running, red = stopped)
• Start / Stop / Restart controls
• Per-category feature toggles (enable/disable any of the 30+ categories)
• Port and auto-start settings
• Active agent session monitoring
• Version display with update checker

Requirements

• Unity 2021.3 LTS or newer (tested on 2022.3 LTS and Unity 6)
• .NET Standard 2.1 or .NET Framework

Optional Packages

Some features activate automatically when their corresponding packages are detected:

Configuration

Configuration is managed through the MCP Dashboard (Window > MCP Dashboard > Settings):

• Port — HTTP server port (default: 7890)
• Auto-Start — Automatically start the bridge when Unity opens (default: true)
• Category Toggles — Enable/disable any of the 30+ feature categories

Settings are stored in EditorPrefs and persist across sessions.

Security

• The server only binds to 127.0.0.1 (localhost) — it is not accessible from the network
• No authentication is required since it's local-only
• All operations support Unity's Undo system
• Multi-agent requests are queued to prevent conflicts

288 Tools Across 30+ Categories

Scene management, GameObjects, components, physics, terrain, Shader Graph, Amplify Shader Editor, profiling, animation, NavMesh, builds, multiplayer, and more.

Why AnkleBreaker Unity MCP?

AnkleBreaker Unity MCP is the most comprehensive MCP integration for Unity, purpose-built to leverage the full power of Claude Cowork and other AI assistants. Here's how it compares to alternatives:

Feature Comparison

Cost Comparison

AnkleBreaker Unity MCP is completely free and open source. The prices below reflect only the cost of the AI assistant (Claude) itself — the MCP plugin and server are $0.

Key Advantages

vs. Bezi: Bezi runs as a proprietary Unity plugin with its own credit-based billing — $20–$200/mo on top of your AI subscription. It has historically suffered from freezing the Unity Editor during AI tasks, blocking your workflow. AnkleBreaker MCP is completely free and open source, runs entirely in the background with zero editor impact, and offers 8x more tools — the only cost is your existing Claude subscription.

vs. Coplay MCP: Coplay MCP provides 34 tools across ~5 categories. AnkleBreaker MCP delivers 288 tools across 30+ categories including advanced features like physics raycasts, terrain editing, shader graph management, profiling, NavMesh, particle systems, and MPPM multiplayer — none of which exist in Coplay. Our two-tier lazy loading system is specifically optimized for Claude Cowork's tool limits.

vs. Unity AI: Unity AI (successor to Muse) is built into Unity 6.2+ but limited to Unity's own AI models and a credit-based "Unity Points" system. It cannot be used with Claude or any external AI assistant, has no MCP support, and offers a fraction of the automation capabilities. AnkleBreaker MCP works with any MCP-compatible AI while giving you full control over which AI models you use.

Support the Project

If Unity MCP helps your workflow, consider supporting its development! Your support helps fund new features, bug fixes, documentation, and more open-source game dev tools.

Sponsor tiers include priority feature requests — your ideas get bumped up the roadmap! Check out the tiers on GitHub Sponsors or Patreon.

What's New in v2.32.0

• Editor-window screenshots (screenshot/editor-window) — capture any EditorWindow (Inspector, Project, Console, custom windows) to a PNG via the Win32 PrintWindow API. Occlusion-proof (the window renders itself offscreen — no raising or focus-stealing), with automatic docked-vs-floating handling. Defaults to Assets/Screenshots/, accepts any .png path. Windows editor only (#if UNITY_EDITOR_WIN) — on macOS/Linux it returns a clear "unsupported platform" error (PrintWindow has no equivalent there); use scene/game capture, which are camera-based and cross-platform. Companion to unity-mcp-server v2.30.0.
• Welcome window reworked — the single-file welcome window is replaced by a modular, themed system (UnityMCP.Editor.Welcome assembly): USS theme, Welcome + Studio tabs, auto-open on first load with per-project detection, a config-driven content seam, and a devlog feed.

What's New in v2.27.0

• Path-based lookup works on inactive GameObjects — Every tool that accepts a path (prefab_info, set_active, info, delete, set_transform, reparent, etc.) now correctly finds and operates on inactive targets, where previously it silently failed with "GameObject not found". Fix contributed by @BadranRaza.
• Prefab-instance detection fixed on scene instances — prefab_info no longer falsely reports valid scene prefab instances as "not a prefab instance". Switched to PrefabUtility.IsPartOfPrefabInstance, the authoritative API. Fix contributed by @BadranRaza.
• Bridge no longer runs in batch-mode subprocesses — The plugin previously started its HTTP bridge inside every AssetImportWorker Unity spawned for parallel asset import, claiming ports on top of the main Editor and exhausting the 7890-7899 range. It now detects batch mode and stays out of the way.
• Port-discovery infinite loop fixed — When no port was available, the plugin would spam Failed to start on port 7890 forever. It now gives up cleanly and logs a single actionable error.

What's New in v2.26.0

• SpriteAtlas management — 7 new HTTP endpoints for creating, inspecting, adding/removing sprites, configuring settings, deleting, and listing SpriteAtlases. Contributed by @zaferdace.
• Self-test system overhaul — Probes for all 43 command modules, robust test runner with domain reload resume and timeout handling.
• Unity 2023+ / Unity 6 compatibility — Resolved 43 CS0618 deprecation warnings across the codebase.

What's New in v2.24.0

• Compilation error tracking — New dedicated compilation error buffer powered by CompilationPipeline.assemblyCompilationFinished. Captures errors and warnings per assembly with file, line, column, message, and severity. Independent of the console log buffer — not affected by Clear() or Play Mode log flooding. Auto-clears on each new compilation cycle via compilationStarted. Exposed via the compilation/errors HTTP route for the MCP server's unity_get_compilation_errors tool.

What's New in v2.21.1

• Port affinity — The plugin now remembers its last-used port via EditorPrefs and attempts to reclaim it on restart. This prevents port swaps when multiple Unity projects are open — each editor consistently uses the same port across restarts.
• Enriched ping response — The /api/ping endpoint now returns projectPath alongside the existing projectName, enabling the MCP server to validate instance identity by both name and path.
• Registry heartbeat — A new heartbeat mechanism updates the lastSeen timestamp in the shared instance registry every 30 seconds. This lets the MCP server distinguish between a compiling editor (fresh entry, temporarily unresponsive) and a crashed editor (stale entry, no heartbeat for >5 minutes).
• Crash resilience — Combined with the server-side staleness check, the heartbeat ensures that if Unity crashes mid-compile and OnDisable never fires, the stale registry entry is detected and cleared within 5 minutes, allowing proper re-discovery.

Frequently Asked Questions

What is Unity MCP Plugin? The Unity MCP Plugin is a Unity Package Manager (UPM) package that runs an HTTP bridge inside the Unity Editor, enabling AI assistants like Claude, Cursor, and Windsurf to control Unity through the Model Context Protocol (MCP). It's the editor-side component of the AnkleBreaker Unity MCP system.

How do I install the Unity MCP Plugin? Open Unity > Window > Package Manager > click + > Add package from git URL > paste https://github.com/AnkleBreaker-Studio/unity-mcp-plugin.git > click Add. The bridge starts automatically.

Does it work with Claude Desktop and Claude Cowork? Yes. AnkleBreaker Unity MCP is purpose-built for Claude Desktop and Claude Cowork, with a two-tier lazy loading architecture optimized for MCP client tool limits.

Does it work with Cursor or Windsurf? Yes. Any MCP-compatible AI client can use this plugin through the companion Unity MCP Server.

What Unity versions are supported? Unity 2021.3 LTS and newer, including Unity 2022.3 LTS and Unity 6.

Is the Amplify Shader Editor required? No. Amplify Shader Editor support is fully optional — 23 extra tools activate automatically when ASE is detected. Projects without Amplify work perfectly; the tools gracefully indicate that ASE is not installed.

Is it free? Yes. The plugin and server are completely free and open source. The only cost is your AI assistant subscription.

Related Projects

• unity-mcp-server — The Node.js MCP server that connects AI assistants to this plugin
• Model Context Protocol — The open standard powering this integration
• Claude Desktop — Anthropic's AI assistant with built-in MCP support
• AnkleBreaker Studio — The game studio behind this project

License

AnkleBreaker Open License v1.0 — see LICENSE

This license requires: (1) including the copyright notice, (2) displaying "Made with AnkleBreaker MCP" (or "Powered by AnkleBreaker MCP") attribution in any product built with it (personal/educational use is exempt), and (3) reselling the tool is forbidden — you may not sell, sublicense, or commercially distribute this software or derivatives of it. See the full LICENSE for details.