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Install on Windows

This page sets up everything once. Take it one step at a time: type (or paste) the command, press Enter, and compare what you see with "You should see". It takes about 20-30 minutes, mostly waiting for downloads.

You need Windows 10 or 11 and permission to install programs on this PC.

1. Open the terminal

The terminal is a window where you type commands instead of clicking. It looks old-fashioned, but you only need a handful of commands.

  1. Press the Windows key.
  2. Type terminal.
  3. Click Terminal (on Windows 10 it may be called Windows PowerShell).

You should see a dark window with a line like:

PS C:\Users\YourName>

That line is the prompt. It means "ready, type a command". The PS tells you it is PowerShell, which is what this guide uses.

Pasting

Copy a command from this page with the copy button in the corner of each box. In the terminal, paste with right-click or Ctrl+V, then press Enter.

2. Check winget

winget is Windows' own app installer. It is built into Windows 10 and 11. Type:

winget --version

You should see a version number, for example v1.9.25200.

If it fails with "winget is not recognized": open the Microsoft Store, search for App Installer, click Update (or Get), then close and reopen the terminal and try again.

The first time you use winget it may ask you to accept the store terms. Type Y and press Enter.

3. Install Git

Git downloads the modkit and keeps it up to date. Claude Code also uses it on Windows.

winget install --id Git.Git -e

Windows may ask "Do you want to allow this app to make changes to your device?". Click Yes.

You should see a download bar and then Successfully installed.

Close and reopen the terminal now

Windows only learns about new programs in a fresh terminal window. Close the terminal and open it again (step 1). Do this after every install on this page.

Check it:

git --version

You should see something like git version 2.47.1.windows.1.

If it fails with "git is not recognized": you probably did not reopen the terminal. Close it, open it again, try once more.

4. Install the GitHub CLI

The GitHub CLI (gh) connects your terminal to GitHub, the website where the modkit lives.

winget install --id GitHub.cli -e

Close and reopen the terminal, then check:

gh --version

You should see something like gh version 2.63.0.

5. Install Claude Code

Claude Code is the AI agent that writes and checks your mods. Remember: it needs a paid Claude subscription (Pro or higher). No subscription? Skip to step 7 and use Without an AI agent later.

Prefer open source? OpenCode instead of Claude Code

OpenCode is an open-source agent that uses the same rules. The program is free; the AI model behind it is paid per use or one of a few free, weaker models offered for a limited time. Install it with winget install --id SST.opencode -e instead of this step, then read the OpenCode page.

winget install Anthropic.ClaudeCode

Close and reopen the terminal, then check:

claude --version

You should see a version number followed by (Claude Code).

If it fails: reopen the terminal once more. If it still fails, run claude doctor and paste its output into the Discord modding channel.

Python lets the agent run the mod checker (the validator) directly. Without it the agent downloads a ready-made version of the checker instead, so this step is optional, but recommended.

winget install --id Python.Python.3.12 -e

Close and reopen the terminal, then check:

python --version

You should see Python 3.12.x.

\"Python was not found\" or the Microsoft Store opens

Windows ships a fake python that only points to the Microsoft Store, and it can hide the real one. You see "Python was not found; run without arguments to install from the Microsoft Store..." (German Windows: "Python wurde nicht gefunden..."), even though winget says Python is already installed. Fix it like this:

  1. Try the Python launcher, which comes with the same install:

    py --version

    If this shows Python 3.12.x, Python works. You can type py wherever this site says python. The AI agent knows this too.

  2. To make python work as well, open Settings → Apps → Advanced app settings → App execution aliases and switch off App Installer python.exe and python3.exe. Close the terminal and open a new one.

  3. Still not working? Type where.exe python. If it only lists a path containing WindowsApps, that is still the fake one. Reinstall with winget install --id Python.Python.3.12 -e --force and open a new terminal.

7. Create a GitHub account and log in

  1. Go to github.com/signup and create a free account. Confirm your email.
  2. In the terminal, type:
gh auth login

It asks a few questions. Use the arrow keys and Enter:

Question Choose
Where do you use GitHub? GitHub.com
What is your preferred protocol for Git operations? HTTPS
Authenticate Git with your GitHub credentials? Yes
How would you like to authenticate GitHub CLI? Login with a web browser

Then comes the part in the browser. Take it slowly - the terminal waits for you:

  1. The terminal shows a one-time code, for example ABCD-1234, and says "Press Enter to open github.com in your browser". Write the code down (or leave the terminal visible), then press Enter.
  2. Your browser opens a GitHub page titled Device Activation. If GitHub asks you to sign in first, do that.
  3. Type the code from the terminal into the boxes and click Continue.
  4. GitHub now shows Authorize GitHub CLI. This lets the gh tool on your computer act for your GitHub account, so it can download the modkit. Click Authorize github (GitHub may ask for your password once more).
  5. The browser says "Congratulations, you're all set!". Now go back to the terminal and wait until it shows ✓ Logged in as YourName. Only then go on - if you close the terminal or type something else before that, the login is not finished.

Check it at any time:

gh auth status

You should see ✓ Logged in to github.com account YourName. If it says "You are not logged into any GitHub hosts", run gh auth login again.

Accept your invitation. During the developer preview the modkit is private, so you also need the invitation from Blindflug Studios (see Get access first). GitHub sends it by email; you can also open github.com/blindflugstudios/goa-modkit/invitations while logged in and click Accept invitation. Do this once, before the next step.

Two-factor authentication is required

Blindflug Studios requires two-factor authentication (2FA) on GitHub for everyone with access. When you open the invitation, GitHub asks you to set it up first - that is expected and takes about five minutes. The easiest way is an authenticator app on your phone (GitHub Mobile, Microsoft Authenticator or Google Authenticator): scan the QR code GitHub shows, type the 6-digit code from the app, and save the recovery codes somewhere safe. Then accept the invitation. GitHub's own guide: Configuring two-factor authentication.

8. Get the modkit

Invitation needed

During the developer preview the modkit is private. This step only works once you have accepted the GitHub invitation - see Get access first.

This downloads the modkit into a folder called goa-modkit inside your user folder. You do this once.

cd ~
gh repo clone blindflugstudios/goa-modkit
cd goa-modkit

You should see a few lines ending in done, and your prompt now ends in goa-modkit>.

Later, to get updates (new docs, examples, checker fixes), open the terminal and type:

cd ~\goa-modkit
git pull

Your own mods live in goa-modkit\mods\. Updates never touch that folder.

9. Start Claude Code and log in

Still inside the goa-modkit folder, type:

claude

The first time:

  1. Pick a color theme with the arrow keys and Enter.
  2. Choose to log in with your Claude account (your subscription). Your browser opens. Log in and click Authorize.
  3. Claude Code asks whether you trust the files in this folder. Choose Yes.

You should see a box with a cursor where you can type. That is where you talk to the agent. Type /exit (or press Ctrl+C twice) to leave.

Done

You are ready for Your first AI mod in 10 minutes.

Keeping tools up to date

winget does not update these tools on its own. Every few weeks, run:

winget upgrade Anthropic.ClaudeCode
winget upgrade --id Git.Git -e
winget upgrade --id GitHub.cli -e

Close Claude Code before upgrading it.