UnrealEngineLink

📌 Note: This is a fork of rmoubayed/engine-link with added VS Code and Claude Code support. The original author has not yet merged the pull request, so this version is published independently under the same MIT license with full attribution.

🌐 Original project: enginelink.dev

Unreal Engine build bridge for AI-powered editors — build, launch, and live-code UE projects with MCP tooling in Cursor and Claude Code.

EngineLink connects your AI editor to Unreal Engine so you can compile, iterate, and debug C++ projects without leaving the editor. It auto-detects your .uproject, discovers engine installations from the Windows registry, and exposes every build action to the AI agent via a built-in MCP server.

🧪 Status: Early preview. Windows-only for now.

👋 TL;DR: I've been building software for 10 years but game dev is new to me. As I learn Unreal Engine, I found Rider and Visual Studio to be old-fashioned compared to modern AI-first editors — so I decided to give AI editors full UE capabilities. I'm testing this extension as I go, learning and breaking things along the way. Contributions and feedback are very welcome :)

Supported Editors

EngineLink auto-detects which editor you're using. You can override this with the enginelink.aiAssistant setting ("auto", "cursor", or "claude").

Setup Guide

Getting EngineLink running is a three-step process: install the system prerequisites, install EngineLink, then install the C/C++ extension for IntelliSense.

Step 1 — System Prerequisites

You need Windows, Unreal Engine, and Visual Studio with the right components.

Unreal Engine 5.4+

Install via the Epic Games Launcher. EngineLink has been tested on UE 5.4 – 5.8.

Visual Studio with C++ and Clang

Open Visual Studio Installer, click Modify on your install (Community / Build Tools / etc.), and make sure these components are enabled:

Workload:

• Desktop development with C++ (this gives you MSVC, Windows SDK, and the core build tools UE needs)

Individual Components (search in the installer):

• C++ Clang Compiler for Windows — needed by UBT to generate compile_commands.json for IntelliSense
• MSBuild support for LLVM (clang-cl) toolset (optional but recommended)

If you skip Clang, EngineLink will still build your project fine (UE uses MSVC), but compile_commands.json generation will fail and you won't get full IntelliSense. You can always add Clang later.

Editor

Cursor: Install Cursor (version 1.85.0 or later).

VS Code + Claude Code: Install VS Code (version 1.85.0 or later), then install the Claude Code extension.

Step 2 — Install EngineLink

From Marketplace — coming soon.

From VSIX — download or build the .vsix, then in your editor: Extensions → ... → Install from VSIX...

From Source:

git clone https://github.com/rmoubayed/engine-link.git
cd engine-link
npm install
npm run build

Press F5 to launch the Extension Development Host, or package it with npm run package.

Step 3 — C/C++ IntelliSense

EngineLink handles building your project, but you need a language server for IntelliSense (code completion, go-to-definition, diagnostics on the fly).

Install a clangd-based C/C++ extension:

• Cursor: Install C/C++ for Cursor — Cursor's official C/C++ extension with clangd under the hood.
• VS Code: Install clangd by LLVM, or C/C++ by Microsoft.

Where compile_commands.json lives

UnrealBuildTool often writes the database next to the engine (e.g. UE_5.8\compile_commands.json). EngineLink always copies it to your .uproject folder as compile_commands.json at the project root after a successful run, so clangd can find it when you open files under Source/ (it walks up to the workspace root).

If IntelliSense still cannot find the compilation database (e.g. generation failed or you use a non-standard layout), you can point clangd at the engine folder manually in .vscode/settings.json:

{
  "clangd.arguments": [
    "--compile-commands-dir=C:/Program Files/Epic Games/UE_5.8"
  ]
}

Use the directory that contains compile_commands.json, forward slashes, then reload the window.

MSVC intrinsic false positives (builtin_definition)

When clangd parses UE code with MSVC-style headers, you may see "definition of builtin function" errors on system headers. This is a known clangd/MSVC quirk, not an error in your code — the real UE build is unaffected.

EngineLink handles this automatically. On activation it upserts a managed block in your project's .clangd file:

# <<< enginelink-managed >>>
Diagnostics:
  Suppress: builtin_definition
# <<< end-enginelink-managed >>>

This only suppresses that one diagnostic class. EngineLink replaces only its own managed region and won't touch the rest of your .clangd. To disable: set enginelink.upsertClangdConfig to false.

Quick Start

Once everything is installed:

1. Open a folder containing a .uproject file in your editor
2. EngineLink activates automatically and:
   • Finds your .uproject and parses EngineAssociation
   • Discovers the matching UE installation from the registry
   • Locates VS Build Tools
   • Generates AI rules (.cursor/rules/*.mdc for Cursor, CLAUDE.md for Claude Code)
   • Generates compile_commands.json (if Clang is installed)
   • Creates/updates .clangd for MSVC suppression
   • Registers the MCP server in .cursor/mcp.json or .mcp.json
3. The status bar shows your project name, engine version, and build actions
4. Press Ctrl+Shift+B to build

If auto-detection fails, override paths in Configuration.

Features

Build Integration

• Build / Rebuild / Clean — invoke UnrealBuildTool directly with full output streaming
• Live Coding (Ctrl+Alt+F11) — hot-reload in a running Unreal Editor session
• Editor-aware builds — detects when Unreal Editor is running and suggests Live Coding over a full build to avoid DLL lock errors
• compile_commands.json — auto-generates via UBT's GenerateClangDatabase mode
• .clangd management — suppresses MSVC/Clang builtin_definition false positives

Auto-Detection

• Project — scans workspace for .uproject files, parses EngineAssociation
• Engine — reads Windows registry (launcher + source builds) and common paths
• Build tools — locates Visual Studio via vswhere

AI Integration

• MCP server — exposes build, clean, rebuild, launch, live-coding, diagnostics, and project info as MCP tools for both Cursor's AI agent and Claude Code
• Editor auto-detection — automatically generates the right config format for your editor (.cursor/mcp.json or .mcp.json)
• AI rules — generates .cursor/rules/*.mdc for Cursor or CLAUDE.md for Claude Code so the AI writes idiomatic Unreal C++

Editor UX

• Status bar — project name, engine version, build config, and action buttons
• Problems panel — MSVC and UBT errors surfaced as native diagnostics
• Progress notifications — build progress via spinner and toast
• Task provider — enginelink tasks for the Tasks panel and tasks.json

Commands

Build, Launch, and Live Coding also appear as icon buttons in the editor title bar.

Configuration

All settings live under enginelink.* in your workspace or user settings.json.

MCP Server (AI Agent Tools)

EngineLink ships a built-in MCP server that AI agents can call directly. It's spawned on activation and registered in the appropriate config file for your editor.

AI Rules

On project detection, EngineLink generates guidance files so the AI follows UE conventions. The format depends on your editor:

Cursor (.cursor/rules/*.mdc)

Claude Code (CLAUDE.md)

A single CLAUDE.md at the project root combines all the guidance above into one file. Claude Code reads this automatically for project context.

Existing files are never overwritten — EngineLink only creates rules if they don't exist yet, so your customizations are safe.

This is where we need the most help. If you're an experienced UE developer, your feedback on these rules would be incredibly valuable — please open an issue or PR!

Task Provider

EngineLink registers an enginelink task type for .vscode/tasks.json:

{
  "version": "2.0.0",
  "tasks": [
    {
      "type": "enginelink",
      "action": "build",
      "configuration": "Development",
      "targetType": "Editor",
      "label": "EngineLink: Build Editor (Development)"
    }
  ]
}

Problem matchers $enginelink-msvc and $enginelink-ubt are included for parsing build output.

Contributing

This project is early and there's a lot to improve. Jump in!

1. Fork the repo
2. Create a feature branch (git checkout -b feature/my-feature)
3. Make your changes
4. Run npm run typecheck
5. Open a pull request

Areas where help is needed:

• Testing — Vitest is set up but no tests exist yet
• AI rules — UE experts: are the rules correct? What's missing?
• macOS / Linux — engine discovery and Live Coding are Windows-only right now

Project Structure

src/
├── extension.ts                  # Entry point — activation, command registration
├── constants.ts                  # IDs, command names, config keys
├── types.ts                      # Shared TypeScript interfaces
├── build/
│   ├── ubt.ts                    # UBT command-line construction
│   └── taskProvider.ts           # VS Code task provider
├── commands/
│   ├── buildCommands.ts          # Build, rebuild, clean execution
│   ├── launchCommands.ts         # Launch Unreal Editor
│   ├── liveCodingCommand.ts      # Live Coding keystroke simulation
│   └── generateCommands.ts       # compile_commands.json generation
├── config/
│   └── settings.ts               # Typed settings accessor
├── ai/
│   ├── mcpServer.ts              # MCP server lifecycle and IPC
│   ├── mcpRegistration.ts        # MCP config registration (Cursor / Claude)
│   ├── editorDetect.ts           # AI assistant auto-detection
│   ├── cursorRulesGenerator.ts   # .cursor/rules/*.mdc generation
│   ├── claudeRulesGenerator.ts   # CLAUDE.md generation
│   └── clangdConfig.ts           # .clangd managed block upsert
├── detection/
│   ├── projectDetector.ts        # .uproject scanning and selection
│   ├── engineDiscovery.ts        # Engine discovery (registry + filesystem)
│   └── buildToolsDetector.ts     # VS Build Tools detection via vswhere
├── mcp/
│   ├── server.ts                 # Standalone MCP server process
│   ├── tools.ts                  # MCP tool definitions
│   └── protocol.ts               # IPC message types
├── parsers/
│   ├── buildOutputParser.ts      # MSVC / UBT / linker output parsing
│   └── uprojectParser.ts         # .uproject JSON parsing
├── platform/
│   ├── process.ts                # spawnAsync, isUnrealEditorRunning
│   ├── paths.ts                  # File/directory helpers
│   └── registry.ts               # Windows registry read utilities
└── ui/
    ├── statusBar.ts              # Status bar items
    ├── outputChannel.ts          # Output channel factory
    └── quickPicks.ts             # Quick-pick menus

Development

npm install
npm run build        # one-shot build
npm run watch        # rebuild on change
npm run format       # Prettier
npm run typecheck    # TypeScript type checking
npm run test         # Vitest
npm run package      # produces .vsix via vsce

Built with esbuild — produces dist/extension.js and dist/mcp-server.js.

To run locally: open this repo in Cursor or VS Code, press F5, then open a UE project folder in the new window.

License

MIT © 2026 EngineLink