Hayba documentation
Hayba lets an AI agent work inside a running Unreal Engine editor. It has two parts: an MCP server written in TypeScript and a C++ editor plugin. Your agent places actors, builds Blueprints, materials, UMG widgets and PCG graphs, runs Play-In-Editor tests, and reads the editor back to check its own work.
Hayba is in development and open for testing; it is not a finished product. Expect rough edges and breaking changes, and use a copy of your project or source control.
Hayba runs on Windows only and supports Unreal Engine 5.7+. There is no installer yet: you
build it from source. These pages describe the current source on the main
branch. The latest completed release is v0.3.0. Where a page describes the 0.4.0 release
candidate that is already in the source, it says so.
- Getting startedRequirements, install from source, client setup and a first run.
- How Hayba worksThe server, the plugin and the local connection between them.
- Plan Mode and undoWhat an agent can change, what you approve and what Ctrl+Z covers.
- GuidesSix short walkthroughs with prompts you can paste.
- Tool referenceEvery callable tool with its parameters, generated from source.
- TroubleshootingPorts, builds, Node.js, timeouts and where the logs are.
Quick start
The short version. Getting started has every step in full.
- Install Node.js 22.5 or newer, Git, and Visual Studio with the C++ toolchain your engine version needs.
- Clone the repo and build the MCP server.
- Link
unreal/HaybaMCPToolkitinto your project'sPluginsfolder and build the project. - Register the server with your MCP client, open the project, and ask the agent to check the connection.
git clone https://github.com/zajalist/hayba.git
cd hayba
npm install
npm --prefix mcp-tools/hayba-mcp run buildStart in a scratch project. Hayba can change and save editor state, and some changes cannot be undone.
What is in these docs
- Concepts explain how the parts fit, how an agent finds tools, approvals and undo, the in-editor chat and the safety model.
- Guides walk through one task each: Blueprints, UMG widgets, materials, actors and the viewport, PIE tests and PCG.
- Reference covers the tool list, troubleshooting and the FAQ.
Found a mistake? Open an issue on GitHub.