Unity MCP connects AI coding assistants to the Unity Editor through the Model Context Protocol, letting them manage game assets, scenes, scripts, tests, and builds. It is for developers who want to control Unity workflows with natural-language requests, and the catalogue entries provide add-ons for using the project.
Borrowing it
Nothing to install: this file belongs to CoplayDev/unity-mcp. Take a copy, put it at the same path in your own repository, and replace the rules that are about this project with yours.
curl -O https://raw.githubusercontent.com/CoplayDev/unity-mcp/beta/CLAUDE.mdgit clone --depth 1 https://github.com/CoplayDev/unity-mcpWrote this? Show the measurements
A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.
[](https://agentmods.dev/instructions/coplaydev/unity-mcp/claude-md)<a href="https://agentmods.dev/instructions/coplaydev/unity-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/coplaydev/unity-mcp/claude-md/github.svg" alt="Measured on agentmods" height="20"></a>Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.
<a href="https://agentmods.dev/instructions/coplaydev/unity-mcp/claude-md"><img src="https://agentmods.dev/badge/instructions/coplaydev/unity-mcp/claude-md.svg" alt="Reviewed on agentmods" width="80" height="20"></a>What it costs to keep this loaded
Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.
| Model | Per session | Once invoked |
|---|---|---|
| Fable 5.1 | $0.02379 | $0.02379 |
| Opus 5.5 | $0.00952 | $0.00952 |
| Sonnet 5.5 | $0.00476 | $0.00476 |
| Haiku 4.5 | $0.00238 | $0.00238 |
Grade A, and why
unity-mcp CLAUDE.md scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 13d ago.
A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.
Nothing flagged
None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.
How it starts
The opening of the file, as written. The whole thing — 207 lines — stays where its author put it; the contents beside it link to each section on GitHub.
CLAUDE.md
This file provides guidance to Claude Code (claude.ai/code) when working with code in this repository.
What This Project Is
MCP for Unity is a bridge that lets AI assistants (Claude, Cursor, Windsurf, etc.) control the Unity Editor through the Model Context Protocol (MCP). It enables AI-driven game development workflows - creating GameObjects, editing scripts, managing assets, running tests, and more.
Architecture
AI Assistant (Claude/Cursor)
↓ MCP Protocol (stdio/HTTP)
Python Server (Server/src/)
↓ WebSocket + HTTP
Unity Editor Plugin (MCPForUnity/)
↓ Unity Editor API
Scene, Assets, Scripts
Two codebases, one system:
Server/- Python MCP server using FastMCPMCPForUnity/- Unity C# Editor package
Three Layers on the Python Side
The Python server has three distinct layers. These are not auto-generated from each other:
| Layer | Location | Framework | Purpose |
|---|---|---|---|
| MCP Tools | Server/src/services/tools/ |
FastMCP (@mcp_for_unity_tool) |
Exposed to AI assistants via MCP protocol |
| CLI Commands | Server/src/cli/commands/ |
Click (@click.command) |
Terminal interface for developers |
| Resources | Server/src/services/resources/ |
FastMCP (@mcp_for_unity_resource) |
Read-only state exposed to AI assistants |
MCP tools call Unity via WebSocket (send_with_unity_instance). CLI commands call Unity via HTTP (run_command). Both route to the same C# HandleCommand methods.
Transport Modes
- Stdio: Single-agent only. Separate Python process per client. Legacy TCP bridge to Unity. New connections stomp old ones.
- HTTP: Multi-agent ready. Single shared Python server. WebSocket hub at
/hub/plugin. Session isolation viaclient_id.
Code Philosophy
1. Domain Symmetry
Python MCP tools mirror C# Editor tools. Each domain exists in both:
Server/src/services/tools/manage_material.py↔MCPForUnity/Editor/Tools/ManageMaterial.cs- CLI commands (
Server/src/cli/commands/) also mirror these but are a separate implementation.
What this file has done since we first saw it
Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.
- 13d ago Changed · +3 tokens per session 7ca14efe2a68
- 27d ago Changed · +6 lines · +115 tokens per session 6527690b825b
- 1mo ago First seen · 201 lines · 2,261 tokens per session scan A ddf38c904a14
unity-mcp CLAUDE.md is an instructions file published in the GitHub repository CoplayDev/unity-mcp (15,028 stars, last pushed 8d ago), licensed MIT. It adds 2,379 tokens to every session, about $0.0095 per session on Opus 5.5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.
Other instructions, from other repositories
vscode buildNext.instructions.md
Working notes and architecture documentation for the new esbuild-based build system in build/next. Use when making changes to the new build pipeline (transpile/bundle commands, NLS plugin, source-map handling, resource copying, or self-hosting watch tasks).
next.js AGENTS.md
AGENTS.md instructions for vercel/next.js, covering next.js development guide, codebase structure, monorepo overview, core package: packages/next and other important packages.
vscode oss-third-party-notices.instructions.md
Instructions for microsoft/vscode, covering vs code oss third-party-notices pipeline, architecture, pipeline flow in ci, cache eligibility and rollout and applying the notice (cutover).
langchain AGENTS.md
AGENTS.md instructions for langchain-ai/langchain, covering global development guidelines for the langchain monorepo, corridor security analysis, project architecture and context, monorepo structure and development tools & commands.
deepseek-harness AGENTS.md
AGENTS.md instructions for deepseek-ai/deepseek-harness, covering agents.md, pre-stable apis and released session data, repository layout, commands and host sandbox failures.
vscode copilot-instructions.md
Copilot instructions for microsoft/vscode, covering vs code copilot instructions, project overview, root folders, core architecture (src/ folder) and built-in extensions (extensions/ folder).