antelier
Get Antelier

Setup

From download to your first world.

You set this up once. After that, Antelier opens straight to your projects.

The short way
  1. Sign in with Google at preview.antelier.co/signin. The Windows download is on the page you land on. A starter or idea you chose on the homepage is waiting there too.
  2. Sign in to Claude Code on your PC, once. Antelier builds with your own Claude Code (how).
  3. Extract the zip and open Antelier.exe. Windows asks you to confirm the first time (what it says).
  4. Start a project. Pick a template and press Create project: it opens with no Claude request, and your first change is a message in the chat. Or choose Blank, paste your idea, and press Create project: that starts the first change.
  5. Try it, change it, share it. Ask for something different, press Play, send friends a link.

Antelier is free during early access. It runs on Windows, on your own PC, for adults 18 and over in the United States. Prefer email to Google? Ask for an access link; it arrives by email, so Google is the quicker way in.

Windows setup

Claude Code first, then Antelier.

Building requires Claude Code access through a Claude subscription or an API or cloud billing account. Antelier uses Claude Code on your PC, signed in however you already use it: a Claude plan, an Anthropic API key, or a cloud account (Amazon Bedrock, Google Vertex AI or Microsoft Foundry). Do this before you open Antelier the first time. Usage counts against that account; what a turn costs.

  1. Install Claude Code and sign in.

    Follow Anthropic’s quickstart and choose its native Windows PowerShell installer; that is the installation Antelier detects. Claude Code needs Windows 10 version 1809 or later, 4 GB of RAM or more and an internet connection (Anthropic’s system requirements). Git for Windows is optional: Claude Code uses PowerShell without it, and Antelier’s version history is built in, so you don’t need to install Git. Then open a new PowerShell window and run:

    claude

    Follow the browser sign-in with your Claude plan, or configure Claude Code with your own API key or cloud account. Signing in on the Claude website alone does not sign in Claude Code. Antelier never asks for, stores or exports your credentials; it uses whichever sign-in Claude Code already has. If that sign-in isn’t a Claude plan (an API key or cloud account, which bill by usage), Antelier asks you to confirm it once before the first turn.

  2. Download and open Antelier.

    Download Antelier for Windows once you are signed in (the sign-in page takes you to it). Right-click the zip, choose Extract All, then open Antelier.exe in the extracted folder. Keep the other files beside it.

    Your browser opens Antelier at a local address such as 127.0.0.1:4397. It runs on your PC, and your projects stay on your PC.

    The early-access package is not code-signed yet, so the first time you open Antelier.exe Windows shows Windows protected your PC: “Microsoft Defender SmartScreen prevented an unrecognized app from starting”, with only a Don’t run button. That window is expected for this package. Continue only if you downloaded the zip from this page after signing in and its SHA-256 is 6252ae22769b5ed6a7eb7f4219f4ce2ff69aed8281f04a9622380362c3cabfc4 (PowerShell: Get-FileHash Antelier-Windows.zip). Then click More info: the window shows “App: Antelier.exe” and “Publisher: Unknown publisher”. Click Run anyway. Stop Antelier.exe and Connect Unreal.exe can show the same window the first time, naming themselves. If the hash differs, the app name is different, or Windows shows any other warning, choose Don’t run, keep Windows protections on, and email hello@antelier.co. To update, finish or stop any running turn, run Stop Antelier.exe from the old folder, then open the new one. Closing the browser does not stop Antelier.

Your first world

Start from a place, or from your own words.

A template is a working world you can walk around at once, so your first request is a change, not a blank page. Blank is an empty scene and your idea.

  1. Start a project.

    On Projects, choose New project. Template (River boat, Racing, Voxel sandbox and more): pick one and press Create project. The world opens on the right and the chat on the left, and nothing has gone to Claude yet; your first change is the first message you send. Blank: describe what you want and press Create project, and that description becomes the first change, using your Claude Code account.

  2. Ask for what you want to see.

    Say what someone should see and be able to do. Best (Opus) is for bigger builds; Quick (Sonnet) is for small fixes. You watch it work, with previews and the running usage, and you can stop a turn at any time.

  3. Play it.

    Press Play and try the world yourself. The Checks tab lists the checks the agent wrote for what you asked, and after a completed change they run again for the behaviors they cover. A passing check is not a guarantee about everything else, so your own play-through is the real test.

  4. Keep going, or go back.

    Every turn is saved as a version in the project folder. Undo turn steps back; Versions restores any earlier one without losing the others. Start a New chat for an unrelated change.

  5. Send it to friends.

    Share publishes a link that opens in a desktop browser with a keyboard and mouse, no account needed. Phone controls are not built yet.

Unreal Engine plugin

The same chat, inside your editor.

Tested with Unreal Engine 5.8 on Windows. Install Unreal separately. The Unreal creator guide has connection help and a longer walkthrough of the dock.

  1. Connect a project.

    With Antelier running, open Connect Unreal.exe from the same folder. Make a new world, or pick an existing .uproject (close it in Unreal first). Check the summary and click OK; Unreal opens the project.

  2. Open the panel and sign in.

    Choose Tools → Open Antelier. The first time, choose Sign in to Antelier: your browser opens antelier.co, you sign in with Google and get an 8-character code to type into the panel.

  3. Chat in the dock.

    Describe a change. The agent changes the level live as it works, plays and checks what it built, and saves each turn as a version. Undo turn restores the project exactly as it was before that turn.

If you get stuck

A way forward.

Google or email: which should I use?

Google is the quick way: sign in at preview.antelier.co/signin and the download is on the next page. Email is a separate route: you ask for an access link on the homepage and it arrives by email, so it takes longer. Both lead to the same Windows app.

I chose a starter or wrote an idea on the homepage. Where is it?

It waits on your account page after Google sign-in, saved in that browser for 7 days with a Copy button (if the browser blocks storage, the page says so and you copy it at once). Antelier on your PC cannot read it yet, so you bring it across yourself. Starter and idea: create that template (no Claude request), then paste the idea in the project chat and send it. Idea only: choose Blank, paste it into the description and press Create project. Starter only: create the template and ask for your first change in the chat.

Antelier says Claude is not connected.

Check that you used Claude Code’s native Windows installer, then ran claude and signed in. If you installed it after starting Antelier, stop any running turn, run Stop Antelier.exe, then open Antelier.exe again. Closing the browser alone does not restart it.

How much Claude usage does a turn take?

It depends on the request. In our eight measured first builds in Best mode, a build cost $9.48 to $18.17 at API-equivalent prices (median $13.13); a recorded color change in Quick mode cost $0.09. Your request may cost more or less. Each turn has a runaway backstop: $25 in Best mode and $2 in Quick mode; because spending is checked between model calls, a turn can run up to a quarter over that before it stops. Usage counts against your Claude plan, API key or cloud account, whichever Claude Code is signed in with; stopping a turn may still use some. If you're on an API key or cloud account, Antelier shows this and asks you to confirm once before your first turn.

Where are my projects?

On your PC. Each web project is an ordinary folder with its own git history, listed on the Projects page with the most recently edited first. Open Antelier.exe again to come back to them. Unreal projects stay ordinary Unreal projects; back them up as you normally would.

I have a recovery file from the earlier trial.

A recovery file belongs to the server where it was made. To move to Google sign-in, open the sign-in page, choose the option for an earlier workspace and use your recovery key once.

How do I send feedback?

Email hello@antelier.co with what you asked for, what happened and which version you used. Don’t send recovery keys or Claude credentials.