My Apps and Games

Signet

Particularly proud of this one. An ultra-clean and minimalistic (yet well-featured) app to write stories together with an AI. Complete focus on a beautiful rendered text while you type. And only a small diamond shape, there for you to request the next sentence from your trusty LLM. Nothing distracts. An optional sidepanel for fast chapter navigation, summarizing the story for the LLM for good results etc.
THe app has not even a login screen. Always immediately see your story. Invite-only.

Implementation Details

Designed together with ChatGPT 5.2 as sparring partner. Then built from a prompt ChatGPT has created, by Cursor + ChatGPT 5.2.

If you want to use it, drop me a mail and I'll send you an invite link.

Glyph Grid

A retro "thinking person's Tetris". Place increasingly complex Tetris-like shapes in a playing area. Get coins for placing and clearing, spend coins to continue in tough situations. The difference to similar games is the randomly generated shapes that get more and more difficult, requiring you to spend hard-earned coins to blast them away. Now includes a unique "mirror mode". Don't rotate, mirror. For computers and mobile devices.

Implementation Details

Javascript + Phaser, built mostly with Google Gemini 2.5 pro, later with Cursor and Claude 4 sonnet, images by ChatGPT, sounds by Elevenlabs.

Can be installed on the home screen of your phone or tablet.
Please note that to in some browsers you might need to reduce the scaling.

Start

or read the online help

Update (October 2025): now rotating and dropping shapes are animated.

Second Roll - Backgammon Training Quiz

A quiz for Dailygammon users. It will import recent matches, analyze them with the superhuman AI Gnu Backgammon, and store your blunders. Then it will show you your blunders, one at a time, in a multiple choice quiz.

Implementation Details

Javascript + a python script to control Gnu Backgammon. Built with Cursor and GPT-5, Sonnet 4.5, Sonnet 4.6, Opus 4.6, GPT5.2, GPT5.3codex.

Start

genpassword - SecureSafe style password generator

A simple web app that generates passwords that are easy to enter yet secure. Since I moved from SecureSafe to Apple's password app, I miss the easy-to-enter passwords that SecureSafe generates. The passwords the Apple app generates are abominations of usability. So here's an app that creates the ones SecureSafe creates, but with more control over the length.

Comparison: a random Securesafe-style password: "Pibide24sudi-". A random Apple password: "bYbhyk-tupmin-3potgi"

Implementation Details

Javascript + Cursor

Start

Admin Klaus – administer your unix system in natural language

A SSH CLI that connects to a remote Unix system and uses an LLM (Claude Sonnet 4.5) to understand your intent and turn it into one or more Unix commands. Each command is shown to you for explicit confirmation before execution. Supports sudo and streaming commands.

The name “Klaus” is a reference to the legendary 90s YouTube video “Gabelstaplerfahrer Klaus”, which starts as a sober technical instruction film and ends in blood and gore.

But trust me: this is not pure vibe-coding. I took great care to ensure that Klaus’ LLM never sees passwords, and that the command you confirm is executed exactly as shown, unchanged. I actually use it regularly myself, because I no longer remember all the finer details of Unix commands I learned long ago.

Implementation Details

Built with Cursor and Claude Opus 4.5.

View on GitHub

Kalaha

The African strategy board game Hus / Kalaha. Two versions with slightly different rule sets.

Implementation Details

built with Google Gemini 2.5 pro, Cursor / Claude 3.7 sonnet for finer work. Images by ChatGPT.

Start

Wortwelt (German)

Re-interpretation of crosswords in the age of AI. You get all empty words, and no description of what to enter. Instead you get an overall goal like "Find words for plants", and have to creatively find the most exotic words that fulfill the goal. An LLM will judge your effort and award points.

Implementation Details

Originally built with Replit and ChatGPT 4. Later ported to a SPA UI with ChatGPT o1. Calls ChatGPT as "Oracle" that evaluates your play. Wonderful piano background music by Stability.ai's Stable Audio

Start - currently not working, as I'm moving all my apps to HTTPS...

Please note: this app calls ChatGPT, and every call costs me a tiny bit of money. Therefore I had to add a simple login mechanism, and a user and transaction limit. Drop me a mail if you need a user or more queries.

Storytellers

Take turns with an AI to write a story. Write as many sentences as you want. At any time ask ChatGPT o1 or Deepseek R1 to continue your story with the next sentence. You can also create chapters and give every chapter a summary of what to tell in this chapter.

Originally built with Replit and ChatGPT 4. Used Llama3, Mistral and ChatGPT4 as LLMs. Later reduced to ChatGPT 4o and Deepseek R1, and reworked the UI with help of ChatGPT o1.

Start

Please note: this app calls ChatGPT and Deepseek, and every call costs me a tiny bit of money. Therefore I had to add a simple login mechanism, and a user and transaction limit. Drop me a mail if you need a user or more queries.

Speccer

A collaborative tool to write a specification for an app that you then can give an LLM agent to implement. The flow is: you write the core idea, and then GPT-5 will create the specification markdown document and ask followup questions to all participants until it is convinced that the spec is finished. Result is a markdown document. Only runs locally.

Implementation Details

Built with GitHub Copilot and Claude 4. This is a very simple app but I find it useful.

View on GitHub

Wortkunst

A German variant of Scrabble where 1-4 players play scrabble, but the scoring system does not base on letter values and special square multipliers. Instead, an LLM judge assigns a score to the word(s) based on creativity, rarity, beauty. This makes the game less about tactics and more about appreciating language. Very early version where the core game works.

Implementation Details

Built with Cursor and GPT-5 from a specification. Uses Mistral Large, Claude Haiku 4.5, or deepseek chat as LLM judges.

View on GitHub

RPGMaker AICharacter

A plugin for the app "RPGMaker MZ". It can turn an Event that represents an NPC in an autonomous, LLM-controlled NPC you can chat or trade with, who can move around, achieve goals, change game switches. NB : the screenshot is in German, but the plugin supports any language the LLM supports.

Implementation Details

Built with Cursor and GPT-5.

View on GitHub