Unity-MCP copilot-instructions.md

A set of coding rules for an AI assistant working on a Unity project, where Unity is a tool for building games and interactive applications. It includes restrictions on accessing private C# code and instructions for code review.

In plain words
What is it for?
Use it when writing or reviewing Unity C# code, especially code that might access internal or private members.
Why use it?
It prevents changes that bypass the project's access rules and makes reviews follow the repository's documented standards.

Instructions file for GitHub Copilot

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add instructions/ivanmurzak/unity-mcp/copilot-instructions
Clone the repo
git clone --depth 1 https://github.com/IvanMurzak/Unity-MCP

Made for: GitHub Copilot.

Per session 895 This file is loaded in full into every session.
When invoked 895 The same file — it is already loaded in full.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

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.

ModelPer sessionOnce invoked
Fable 5 $0.00895 $0.00895
Opus 5 $0.00447 $0.00447
Sonnet 5 $0.00179 $0.00179
Haiku 4.5 $0.00089 $0.00089

Measured 3d ago against content hash 711e3a538ec1, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

Unity-MCP copilot-instructions.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 3d 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.

.github/copilot-instructions.md · 63 lines

How it starts

The opening of the file, as written. The whole thing — 63 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Project Guidelines

Critical Rules

No C# Reflection for Private Access

PROHIBITED: Using System.Reflection to access private, internal, or otherwise non-public fields, properties, methods, or classes in project code. This includes Type.GetType, BindingFlags.NonPublic, GetMethod, GetField, GetProperty, and similar reflection APIs when used to bypass access modifiers.

Example of prohibited code:

// WRONG: Accessing internal Unity API via reflection
var logEntriesType = Type.GetType("UnityEditor.LogEntries, UnityEditor.CoreModule")
                  ?? Type.GetType("UnityEditorInternal.LogEntries, UnityEditor.CoreModule")
                  ?? Type.GetType("UnityEditor.LogEntries, UnityEditor")
                  ?? Type.GetType("UnityEditorInternal.LogEntries, UnityEditor");
logEntriesType?.GetMethod("Clear", BindingFlags.Static | BindingFlags.Public)
              ?.Invoke(null, null);

Note: This rule does NOT apply to ReflectorNet library usage, which is an external dependency specifically designed for reflection-based access patterns.

Code Review

Before performing any code review, you MUST read the project constitution: .specify/memory/constitution.md. All code review feedback must verify adherence to the principles defined in the constitution. Constitution principles supersede ad-hoc practices when conflicts arise.

Code Style

  • C#: Use 4 spaces indentation. PascalCase for classes/methods/properties, _camelCase for private readonly fields.
  • PowerShell: Use K&R brace style.

Architecture

  • Unity-MCP-Plugin: Main Unity package.
  • MCP Server: lives in the shared GameDev-MCP-Server repo (binary gamedev-mcp-server); the plugin downloads the release pinned by McpServerManager.ServerVersion.
  • Installer: Installer/ wraps the package installation.
  • Unity-Tests: Unity-Tests/ contains projects for different Unity versions (2022, 2023, 6000) linking locally to the Plugin.

Read the full file on GitHub · 63 lines

Changes

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.

  1. 3d ago First seen · 63 lines · 895 tokens per session scan A 711e3a538ec1

Subscribe to this mod's changes

Unity-MCP copilot-instructions.md is an instructions file published in the GitHub repository IvanMurzak/Unity-MCP (4,047 stars, last pushed 9d ago), licensed Apache-2.0. It adds 895 tokens to every session, about $0.0045 per session on Opus 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.