How An AI Coding Agent Helped Me Build, Revise, And Play

🔍 Read the full analysis: How An AI Coding Agent Helped Me Build, Revise, And Play on ThorstenMeyerAI.com

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Developer Thorsten Meyer says an AI coding agent helped him build Altersteilzeit, a free web app for counting down the working days in a German partial-retirement plan, and publish it after five days of development. The app combines a personalised countdown with a short animated film and a collection of calendar-based games; Meyer says he set the direction, made key choices and approved releases while the agent handled much of the implementation.

Meyer’s account, published October 13 on ThorstenMeyerAI.com, traces the project from a small request on September 28, 2026: make a short animated film about the two phases of Altersteilzeit in Germany’s block model. Users in that model work as usual during an active phase and then take an equal-length passive phase away from work. Meyer wanted a playful way to count down the remaining workdays.

By October 2, the project had expanded into a public web app. Users enter a date and choose a work-to-leave model from 1:1 to 5:5. The app calculates weekdays, subtracts public holidays for the selected German state and accounts for leave entered by the user. Its daily screen shows the remaining working days, milestones and a saying; other features include a film, calendar exports, a bridge-day finder and games themed around work and time off.

Meyer reports that the game collection eventually included 19 3D games, with each year of the active phase serving as a level. He says the app offered seven languages and five German dialects, and that the agent helped generate narration and sound effects. His account describes 24 commits co-authored by Claude Opus 5.5. These are figures and descriptions reported by Meyer; the article does not provide an independent audit of the code, counts or app performance.

What the Agent Built

The account offers a concrete example of how a coding agent can contribute to a small software project beyond producing snippets of code. Meyer says the agent worked across engineering, testing, translation, audio production and deployment, while he focused on product direction and decisions about tone and presentation. That range matters to developers evaluating whether agents can support an entire production workflow rather than a single programming task.

It is also a case study, not a controlled test of AI productivity. Meyer describes one project and his own working process; he does not compare the schedule with a human-only team or provide an independently verified measure of time saved. The reported five-day timeline therefore shows what he says happened in this instance, not a general benchmark for how quickly coding agents can build comparable apps.

From Film to Countdown App

The project began with a film about the user’s own work and leave phases, then grew as Meyer and the agent added features over five successive days. Meyer says the first day included date calculations, game prototypes and publishing; subsequent days added languages, the daily countdown, more games, badges, a bridge-day tool and voice work. A mobile scrolling problem prompted a hotfix during development.

A design principle Meyer highlights is that calendar time drives the games: months, weeks, workdays and holidays become game mechanics. He also says privacy shaped the app from the outset. According to his description, there are no accounts, cookies or tracking, calculations happen in the browser, and shared dates are placed after the “#” in a URL. Those technical and privacy details are reported by the author and have not been independently assessed here.

“I gave directions, made decisions and approved releases.”

— Thorsten Meyer, describing his role in the project

What the Account Does Not Verify

The published account does not include an independent technical review, source-code repository, usage data or external confirmation of the app’s feature and production counts. It is not clear how much time Meyer spent reviewing, debugging or integrating the agent’s work, or how the five-day schedule would compare with development by people using other tools.

Meyer says the app has no tracking and performs its calculations in the browser, but no privacy audit or security assessment is provided. The source also describes 19 games in one passage and says the game was playable in 15 modes elsewhere; it does not explain the relationship between those figures. Readers should treat the project details as the author’s account unless independently checked.

Testing the App in Public

Meyer’s article presents Altersteilzeit as a public website, but it does not set out a future release schedule or announce a planned evaluation. The next useful evidence will be how the app performs for users across different German states, leave schedules, devices and language options, and whether the calculations and privacy claims withstand independent review.

For the broader question of AI-assisted development, further examples with documented review time, defects, maintenance needs and comparisons against other workflows would help establish what coding agents contribute in practice. Meyer’s report records one completed project; its longer-term reliability and user response remain unknown.

Key Questions

What is Altersteilzeit?

Altersteilzeit is a German form of partial retirement. In the block model described by Meyer, a person works during an active phase and then has a passive phase away from work; a 4:4 plan, for example, has four years in each phase.

What does the app calculate?

Users enter a date and select a work-to-leave model. Meyer says the app calculates the remaining working days by counting weekdays, subtracting public holidays for the selected German state and taking entered leave into account.

What did the AI coding agent do?

Meyer says Claude Opus 5.5 assisted with coding, tests, translation, voice clips, sound effects and deployment. He says he provided the concept and direction, made product and creative choices, and approved releases.

Has the app’s performance been independently verified?

The source is Meyer’s account of his own project. It does not provide an independent audit, comparative productivity study, user data or external verification of the app’s reported features and production figures.

Source: ThorstenMeyerAI.com