FAQ

Short answers. Each links to the page with the detail.

Does Hayba run on macOS or Linux?

No. Hayba is Windows only. The plugin uses Windows APIs, for example to encrypt chat keys.

Which Unreal Engine versions are supported?

Unreal Engine 5.7+. The plugin does not pin an engine version, but it has to be compiled for the version that opens your project. See Plugin does not load.

Is there an installer or a Fab listing?

Not yet. You build Hayba from source, as described in Getting started.

Which AI clients work with it?

Any client that runs MCP servers over stdio. Getting started has configs for Claude Code, Claude Desktop, Cursor and VS Code. You can also use the in-editor chat without an external client.

What does it cost?

Hayba is open source under the MIT license. You pay your model provider for any hosted model you use, through your client or your own API key. Local models through Ollama or LM Studio cost nothing to run beyond your hardware.

Does my project leave my machine?

The server and plugin run locally and listen only on 127.0.0.1. What the agent reads from the editor is sent to whichever model you use, as part of the conversation. With a local model, it stays on your machine. Tools that search or download from Poly Haven, ambientCG or Sketchfab contact those sites when the agent calls them.

Why does my client show only 7 Hayba tools?

That is by design. The agent searches for the other 450 or so tools and calls them through hayba_invoke, which keeps its context free for your task. See Code Mode and tool search.

Why are my agent's edits refused?

Most often Plan Mode. With Review each external edit on, the default, only edits to an existing actor can be approved, and everything else that writes is refused with exact_approval_unavailable. Turn it off in a scratch project for creation work. See Plan Mode, approvals and undo and the refusal codes.

Can I undo what the agent did?

Mostly. Each editing command is one entry in Unreal's undo history. Saves, asset deletes, work done during Play and most Python changes cannot be undone. See Undo. Keep your project under source control.

Is it safe to point at my main project?

Start with a scratch project. When you move to a real one, use source control, keep Plan Mode on for anything you do not want changed without review, and read the safety model for what is and is not checked.

Can several agents work in one editor?

Yes. Each agent runs its own server and connects to the same editor. Leases stop them from writing over each other. This is part of the 0.4.0 release candidate in the current source. See Leases.

Can the agent run any Python it likes?

It can run editor Python with python_run, which is useful for anything no typed tool covers. Scripts that touch host files, processes or the network are refused, and each script has a short deadline. Python changes are hard to undo. See Python.

Can the agent write C++ for my project?

Your client's own file tools can, if it has them. Hayba can trigger a Live Coding compile with editor_live_compile, but Live Coding cannot safely apply class layout changes. See Live Coding and class layout.

Where do I report a bug?

Open an issue on GitHub with your engine version, the tool call, its reply, and the logs. Report security problems privately, as described in the repository's security policy.