What is MCP Game Deck?

MCP Game Deck is a Unity Editor package that exposes your entire project to Claude Code through the Model Context Protocol (MCP). It is not an AI itself — it is the bridge that lets Claude Code see, create, modify, and inspect everything in your Unity Editor: scenes, GameObjects, prefabs, materials, scripts, builds, and more.

How it works: The package runs a custom MCP server inside the Unity Editor. Claude Code connects to it and gains access to 268 tools that control the editor. You talk to Claude Code, Claude Code talks to your Unity project.

What's included:

MCP Server — A custom C# HTTP server with 268 tools, 7 resources, and 5 prompts. Runs inside the Editor process. No external MCP libraries.
Intelligence Layer — 10 specialized agents, 18 slash commands, and a 16-document knowledge base that give Claude Code deep Unity domain expertise.
Chat UI — An optional EditorWindow (powered by Claude Agent SDK + Node.js) for chatting with Claude directly inside Unity.

Features

268 MCP Tools

Full programmatic control over the Unity Editor, organized into 37 categories:

Category	Count	Description
ProBuilder	35	Mesh creation, extrusion, face/edge/vertex operations, UV editing, smoothing, merge, weld
Graphics	26	Lightmap baking, reflection probes, light probes, URP volumes, post-processing, render stats
Physics	25	Raycast, linecast, overlap, shape cast, rigidbody, joints, physics materials, collision matrix
Camera	20	Camera creation, Cinemachine configuration (body, aim, noise, blend, lens, target, priority)
Profiler	16	Start/stop profiling, memory snapshots, frame debugger, frame timing, performance counters
Editor	13	Play/pause/stop, execute menu items, manage tags/layers, get editor state, preferences, undo
Package	13	List, add, remove, embed, search packages; manage scoped registries; resolve, status
Asset	11	Create, copy, move, rename, delete assets; inspect/set import settings; refresh AssetDatabase
GameObject	10	Create, find, get, update, delete, duplicate, select, set parent, look-at, move relative
Scene	10	Create, load, save, unload, delete scenes; get info/hierarchy; list scenes; frame objects
UIToolkit	9	Create UXML/USS, attach documents, panel settings, get visual tree, inspect, read/update files
Prefab	8	Create, instantiate, open, modify, save, close prefabs; get prefab info
Script	8	Create, read, update, delete C# scripts; apply targeted edits; validate compilation
Build	6	Build, batch build, get/set build settings, switch platform, manage build scenes
Texture	6	Create, inspect, configure textures; apply gradients and procedural patterns
Component	5	Add, get, update, remove, list components on GameObjects
Reflect	5	Get type info, search types, call methods, get members, find methods via reflection
ScriptableObject	5	Create, inspect, list, modify ScriptableObjects
Screenshot	4	Capture Game view, Scene view, camera-specific, and multi-view screenshots
Animation	4	Create clips, add keyframes, configure Animator controllers, get animation info
Material	4	Create, update, assign materials; get shader properties
Light	4	Create, configure, list lights
Transform	4	Move, rotate, scale, get transform info
UnityDocs	4	Get API docs, get manual pages, open documentation
Console	3	Get logs, log messages, clear console
Meta	3	List all tools, enable/disable tools
NavMesh	3	Get NavMesh info, bake NavMesh
Object	3	Get object data, modify objects by instance ID
PlayerSettings	3	Get and set player settings (company, product, scripting backend)
Selection	3	Get and set editor selection
Shader	3	Inspect and list shaders
Terrain	3	Create terrains, get terrain data
Tests	3	Run EditMode/PlayMode tests, get test results
Audio	2	Create and configure audio sources
Ping	2	Server connectivity check
Type	2	Get type schema for serialized types
VFX	2	List and inspect particle systems

7 MCP Resources

Read-only access to live project state:

Resource	Description
Assets	List project assets filtered by type (Prefab, Material, ScriptableObject, etc.)
Console Logs	Recent console entries with timestamps and stack traces
GameObject	Full detail on any GameObject — transform, components, properties, children
Menu Items	Available Editor menu items
Packages	All installed Unity packages with metadata
Scenes Hierarchy	Complete hierarchy of all loaded scenes
Tests	Available test assemblies and scripts

5 Workflow Prompts

Structured templates for common multi-step workflows:

build-pipeline — Configure and execute single or multi-platform builds
gameobject-handling-strategy — Best practices for creating and organizing GameObjects
prefab-workflow — Prefab creation, editing, and management
scene-setup — Scene organization with proper lighting, camera, and structure
ui-toolkit-workflow — UI Toolkit patterns with UXML, USS, and C# backing

10 Specialized AI Agents

Domain experts with deep knowledge and access to all MCP tools:

Agent	Expertise
unity-specialist	Architecture decisions, Unity APIs, MonoBehaviour vs DOTS, platform builds
unity-ui-specialist	UI Toolkit (UXML/USS), data binding, runtime UI performance, input handling
unity-shader-specialist	Shader Graph, custom HLSL, VFX Graph, URP customization, post-processing
unity-dots-specialist	ECS architecture, Jobs system, Burst compiler, hybrid renderer
unity-addressables-specialist	Asset groups, async loading, memory management, content catalogs
gameplay-programmer	Game mechanics, player systems, combat, input, state machines
systems-designer	Combat formulas, progression curves, crafting recipes, balance math
technical-artist	Shaders, VFX, rendering optimization, art pipeline
performance-analyst	Profiling, memory analysis, frame time budgets, bottlenecks
qa-lead	Test strategy, bug triage, release quality gates, regression planning

18 Slash Commands

Quick-access structured workflows:

Command	Description
`/architecture-decision`	Create an Architecture Decision Record (ADR)
`/asset-audit`	Audit assets for naming, file sizes, and orphaned references
`/balance-check`	Analyze game balance data for outliers and degenerate strategies
`/brainstorm`	Guided game concept ideation with structured techniques
`/bug-report`	Structured bug reports with reproduction steps and severity
`/changelog`	Auto-generate changelog from git history
`/code-review`	Architectural and quality code review for Unity C#
`/design-review`	Review game design docs for completeness and balance
`/estimate`	Task effort estimation with complexity analysis
`/hotfix`	Emergency fix workflow with audit trail
`/map-systems`	Decompose a game concept into systems with dependency mapping
`/perf-profile`	Structured performance profiling with budgets
`/playtest-report`	Generate or analyze structured playtest reports
`/prototype`	Rapid prototyping — validate a mechanic with throwaway code
`/reverse-document`	Generate design/architecture docs from existing code
`/scope-check`	Analyze a feature for scope creep
`/sprint-plan`	Generate or update a sprint plan from the project backlog
`/tech-debt`	Scan codebase for technical debt (TODO, FIXME, HACK)

16-Document Knowledge Base

Comprehensive Unity reference documentation covering:

Project Architecture — Assembly definitions, 4-layer pattern, bootstrapper
ScriptableObjects — Event channels, runtime sets, data-driven design
Design Patterns — Observer, Command, State Machine, Object Pool, Singleton, Factory
DOTS/ECS — Entity Component System, Burst, Jobs, decision frameworks
Architecture by Genre — RPG, 2D platformer, multiplayer, roguelike patterns
Mobile Optimization — Profiling, pooling, NonAlloc APIs, compression
Core Gameplay Systems — Combat, progression, economy, meta-progression
UI/UX — UI Stack, MVP/MVVM, Canvas splitting, virtualized lists
Dependency Injection & Testing — VContainer vs Zenject, NUnit, testing pyramid
AI-Assisted Workflow — MCP patterns, known limitations, best practices
Asset Pipeline & Addressables — Sprite Atlas, texture/audio compression
Procedural Content & Balancing — Generation algorithms, mathematical balancing
Audio & VFX — Audio design, Wwise, VFX Graph best practices
Save System & Meta-Progression — Serialization, progression tracking
Publishing & Live Ops — Store requirements, analytics, monetization
Case Studies — 12 real games analyzed, 10 recurring architectural patterns

Getting Started

Prerequisites

Claude Code — This package is designed to work with Claude Code. Install Claude Code
Unity 6 (6000.0 or later)
Node.js 18+ (required for the Agent SDK Server and Chat UI)
Claude API key (for Claude Code and the integrated Chat UI)

Installation

Clone or download this repository
In Unity, go to Window > Package Manager
Click + > Add package from disk...
Select the package.json at the root of this repository
Build the Agent SDK Server:
```
cd Server~
npm install
npm run build
```
On first import, the package automatically copies .claude/, knowledge-base/, and CLAUDE.md to your project root

First Launch

The MCP server starts automatically when the Unity Editor loads. To use the integrated chat:

Open Window > MCP Game Deck Chat
The Agent SDK server starts automatically (or run npm start in Server~/)
Start chatting — Claude now has full access to your Unity project

To use with Claude Code CLI instead:

Navigate to your Unity project root
Run claude — the CLAUDE.md instructs Claude on available tools
Claude will connect to the MCP server on port 8090

How It Works

Unity Editor
 |
 |-- MCP Server (C# HTTP, port 8090)
 |    |-- 268 Tools ......... create, modify, inspect editor state
 |    |-- 7 Resources ....... read-only project data
 |    '-- 5 Prompts ......... structured workflow templates
 |
 |-- Chat UI (EditorWindow, UI Toolkit)
 |    '-- WebSocket client -> Agent SDK Server
 |
 '-- Agent SDK Server (Node.js, port 9100)
      |-- Claude API integration
      |-- MCP proxy -> forwards tool calls to C# server
      '-- Session management & cost tracking

The MCP server runs inside the Unity Editor process with zero external dependencies. All tool calls that touch Unity APIs execute on the main thread via an internal dispatcher. The server automatically stops during assembly reload and play mode transitions.

Configuration

Settings are stored in ProjectSettings/GameDeckSettings.json and editable via Project Settings > MCP Game Deck.

Setting	Default	Description
MCP Port	`8090`	Port for the C# MCP HTTP server
Agent Port	`9100`	Port for the Agent SDK WebSocket server
Host	`localhost`	Hostname the MCP server binds to
Request Timeout	`30s`	Timeout for tool execution
Auto Start	`true`	Auto-start servers when the Chat window opens
Default Model	`claude-sonnet-4-6`	Claude model used by the Agent SDK

Project Structure

mcp-game-deck/
|-- package.json              Unity package manifest
|-- CLAUDE.md                 AI context file (copied to user project)
|-- README.md                 This file
|
|-- Editor/                   C# editor-only code
|    |-- MCP/                 Custom MCP framework
|    |    |-- Attributes/     [McpTool], [McpToolType], [McpResource], [McpPrompt]
|    |    |-- Models/         ToolResponse, ResourceResponse, McpToolInfo
|    |    |-- Discovery/      Reflection-based tool/resource/prompt discovery
|    |    |-- Registry/       In-memory registries for tools, resources, prompts
|    |    |-- Server/         TCP/HTTP server, JSON-RPC 2.0 handler
|    |    '-- Utils/          MainThreadDispatcher, JsonHelper, McpLogger
|    |-- Tools/               268 MCP tools (37 categories)
|    |-- Resources/           7 MCP resources
|    |-- Prompts/             5 MCP prompts
|    |-- ChatUI/              Integrated chat EditorWindow
|    |-- Settings/            Project settings UI and persistence
|    '-- Utils/               PackageSetup, helpers
|
|-- Server~/                  Agent SDK Server (TypeScript, ~ = ignored by Unity)
|    |-- src/                 Source files
|    |-- dist/                Compiled output
|    '-- package.json         Node.js dependencies
|
|-- .claude/                  AI intelligence layer
|    |-- agents/              10 specialized agent definitions
|    '-- skills/              18 slash command definitions
|
'-- knowledge-base/           16 Unity reference documents

Requirements

Requirement	Version
Claude Code	Latest
Unity	6000.0+ (Unity 6)
Node.js	18+
npm	9+
Platform	Windows, macOS, Linux

License

This project is licensed under the MIT License.

Author

Ramon Bedin — GitHub

MCP Game Deck