Thinking about the second work, I got stuck on sign-in.
POTENTIA connected to Google directly inside the game. But what if Mukkit List and the second episode did the same?
Testers would have to connect Google again for every work, and I would have to build sign-in again and look after it again for every work.
So I made a separate thing that only handles sign-in. It’s called the STUDIO GOAT account.
How it works
- A work only asks “who is this?”
- The account service checks with Google and gives the work back just one number tag
- Sign in once, and the next work lets you straight through without a Google screen
All a work knows is that number tag. Google account details never reach the work.
What I kept
- Starting right away as a guest stays. Connecting an account only if you want to
- Cookies are separate for each service. So if one is broken into, it doesn’t spread to sign-ins elsewhere
- Took the Google script out of the game. With sign-in moved out, the game actually got lighter and tighter
Moving day
I worried about testers who had already connected with Google.
I kept the same Google settings, so anyone who had connected wouldn’t have to do anything.
When I actually counted, the only person connected with Google was me.
Almost all the testers came in through KakaoTalk’s in-app browser, and Google sign-in was blocked there.
I set it up so one switch could go back and forth between the new way and the old way, and turned it on.
Nothing went wrong, so a few hours later I took the old code out. Done in a day.
How I did it with AI
- The planning Claude wrote the design document and split the work into three cards — account service · game connection · homepage
- With three repos, Claude Code worked separately in each repo
- The game-side card was read once more by the Claude that plans the game, which added to it. Things like the home-screen app and the KakaoTalk browser came from there
With planning in one place, three repos didn’t get confusing.
What I learned
The earlier you split out sign-in, the cheaper it is.
Moving people over is cheapest while there are few to move.
The order sign-in goes in
- In a work, press “Connect with STUDIO GOAT account”
- You move to the account page. If you’re already signed in, it goes straight to step 3
- Google sign-in → the account service checks it
- The account service sends you back to the work holding a short code that can be used only once
- The work’s server shows that code to the account service and gets the number tag. The code is done after a minute or after one use