What Changed Across 16 Versions Of My AI-Built Retirement Countdown

🔍 Read the full analysis: What Changed Across 16 Versions Of My AI-Built Retirement Countdown on ThorstenMeyerAI.com

Age 18–24?Offer from Amazon

Prime made for students and young adults

• Fast, free delivery for dorm and study essentials
• Prime Video and Amazon Music included
• Member-only deals

Try Prime for Young Adults →Free trial for eligible 18–24 year olds

As an affiliate, we earn on qualifying purchases.Hide

Thorsten Meyer says a request for a one-minute animated film grew into Altersteilzeit, a free web app for counting down working days before retirement, built with an AI coding agent over five days. In an October 13 account, Meyer describes 16 versions of the project and says the agent handled substantial development and production work, while he directed the concept, made decisions and approved the releases.

Meyer began the project on Monday, September 28, 2026, with a film about the two stages of German Altersteilzeit in the block model: a period of regular work followed by an equally long period away from work. By Friday, October 2, the public site included a daily countdown, a narrated film, games, language options and other planning tools. The source describes the finished game as having 19 ways to play; its day-by-day development account also refers to 15 modes, and does not explain the difference.

Users enter the start date of either phase and select a model from 1:1 to 5:5. The app calculates the other date and counts weekdays, excluding public holidays for the selected German federal state and leave entered by the user. The daily view includes milestones, a progress ring and a saying of the day. Other listed features include calendar exports, a printable calendar, a bridge-day finder, badges and a team countdown.

The project’s games use calendar time as their structure: months and weeks become maze sections, working days become emails, and leave can affect gameplay. Meyer says the agent produced code, tests, translations and audio assets. He reports 24 commits co-authored by Claude Opus 5.5, and says the project included about 18,000 lines of JavaScript and Python, 15 test scripts, and 1,224 voice clips. These figures are from Meyer’s account, not an independent technical audit.

From Film Request to Planning Tool

The account offers a concrete example of how an AI coding agent can be used across a small software project, from a narrow creative brief to a public-facing site with multiple features. It describes not just code generation but a workflow involving planning, testing and deployment, as well as translation and audio production. That scope helps readers understand what Meyer means by an AI-built project.

It also draws a line between the agent’s contribution and the creator’s role. Meyer says he set the idea and tone, chose features and voices, and approved releases. Those decisions shaped how the countdown would feel and what the public site presented. The account therefore describes human direction alongside automated production, rather than an app produced without human judgment.

The privacy design may matter to people entering personal dates. Meyer says the app has no accounts, cookies or tracking, and calculates information in the browser. Shared dates are placed after the “#” in a web address, which his account says is not sent to the server in a standard browser request. The source does not provide an external privacy review, so the description should be understood as the creator’s account of the implementation.

Five Days of Iterations

The build began with an animation about Altersteilzeit, a German partial-retirement arrangement. In the block model, a person works their normal schedule during an active phase and then has a passive phase away from work. Meyer says he wanted to make the waiting period more engaging for people counting down to that change.

His timeline starts with the film and date calculations on day one, followed by personal date entry and early game prototypes. Later days added a daily dashboard, seven-language support, more games, badges, a bridge-day tool and narration. Meyer says the fifth day included his approval and five German dialects with voice support. He also reports an iPhone scrolling problem that was fixed during development, illustrating that the rapid pace included troubleshooting, not only new features.

Meyer describes a recurring process: he gave a short instruction, the agent drafted a plan, built and tested the feature, recorded its work and deployed it. For larger tasks, he says it split work among parallel agents, including translators. He says the completed app supports seven languages and five German dialects, while another part of the account says production generated voice clips in 12 languages. The source does not reconcile those counts or specify which languages appear in each part of the app.

“The interesting part is not how much an AI agent can build, but what was still left for me to do.”

— Thorsten Meyer, describing the project’s focus

Limits of the Project Account

The account does not provide an independent review of the app, its code, its privacy safeguards or the reported development metrics. It also does not say how many people have used the site, whether users have reported problems, or whether Meyer plans to maintain it. The relationship between the 19 listed game modes and the 15 modes mentioned in the timeline is not explained. Nor does the source clarify why it describes seven languages in the app but 12 languages in its voice-production figures.

The report establishes that Meyer says the site was built and published during the five-day period; it does not establish that the app has been independently tested across devices or checked for accuracy in every jurisdiction’s holiday calendars. No user feedback or formal evaluation is included. Claims about privacy and technical output should therefore be treated as the creator’s descriptions, not independently verified findings.

Maintenance and User Feedback

Meyer’s account does not announce a future release date or a specific next feature. The immediate next step for readers interested in the app is to check the public site and its legal and privacy information, then verify dates and holiday calculations for their own circumstances. Because the countdown depends on a selected German state, the entered dates and leave, those settings affect the result.

Whether Altersteilzeit will receive further updates, how it performs with users, and whether the reported language and game-count differences will be clarified remain open. Meyer’s article presents the five-day build as a completed release, but gives no maintenance schedule or independent assessment of the software.

Key Questions

What is Altersteilzeit?

Altersteilzeit is a form of partial retirement in Germany. In the block model described by Meyer, a person works during an active phase and then has a passive phase away from work.

What does the Altersteilzeit app do?

Users enter the start of one phase and choose a model. The app calculates the other date and counts working days, with adjustments for the selected German state’s public holidays and user-entered leave. It also offers milestones, a film, games and calendar tools, according to Meyer.

How long did the project take?

Meyer says development ran from September 28 to October 2, 2026, with the public app online by the end of the five-day period.

What did the AI agent do, and what did Meyer do?

Meyer says the agent wrote and tested code, produced translations and audio, and helped deploy the project. He says he set the concept and tone, made product and voice choices, reviewed the work and approved releases.

Has the app’s privacy or accuracy been independently verified?

The source reports Meyer’s description of the app’s browser-based calculations and lack of accounts, cookies and tracking, but provides no independent privacy or accuracy review.

Source: ThorstenMeyerAI.com