My Retirement Countdown, Reworked 16 Times With An AI Agent

🔍 Read the full analysis: My Retirement Countdown, Reworked 16 Times With An AI Agent on ThorstenMeyerAI.com

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Thorsten Meyer says he built and released Altersteilzeit, a free web app for people counting down to partial retirement in Germany, with help from the AI coding agent Claude Opus 5.5. The project grew from a request for a one-minute animated film into a public website over five days and 16 versions, while Meyer directed the work, made product decisions and approved releases.

Meyer’s account, published October 13 on ThorstenMeyerAI.com, says development began on Monday, September 28, 2026, with a request for a short film about the working days remaining in an Altersteilzeit arrangement. In Germany’s block model, a person works during an active phase and then has an equally long passive phase away from work; Meyer gives a four-years-working, four-years-off arrangement as an example.

By Friday, October 2, Meyer says, the project had become an app with a daily countdown, animated film and 3D games. Users enter a date and choose a model from 1:1 to 5:5. The app calculates the other phase date and remaining working days, accounting for weekdays, public holidays in the user’s German federal state and entered leave. Other features include milestones, calendar exports, a bridge-day finder, badges and a team countdown.

Meyer describes the app as available in seven languages and five German dialects, with narration and sound. The source account says 19 game modes were included, with each year of the active phase represented as a level. It also reports 24 commits co-authored by Claude Opus 5.5, around 18,000 lines of JavaScript and Python, and 15 test scripts. Those figures are Meyer’s description of the project; no independent technical audit is cited.

A Countdown Built Around Personal Dates

The project offers a specific example of how an AI coding agent can contribute to a small software release: generating code and tests, supporting localization and producing audio assets, while a person sets the purpose and makes decisions about the finished product. Meyer’s account does not establish how the app compares with other development methods, but it documents a complete workflow from an initial request to a public-facing site.

For prospective users, the practical question is whether the countdown reflects their own work pattern accurately. The app’s calculations depend on the dates, leave and regional public holidays entered by the user. Meyer says calculations happen in the browser and that the site has no accounts, cookies or tracking. He also says shared dates are stored after the “#” in a link, which browsers do not send to servers. These are relevant privacy and usability details for a tool built around employment and retirement dates.

The account also illustrates where human oversight remained part of this particular project. Meyer says he selected the tone and imagery, chose voices and dialects, reviewed the experience and approved releases. The development speed is his report, not evidence that every project can be built in five days or that an agent can make those product judgments without direction.

From Film to Public Web App

Altersteilzeit is a German partial-retirement arrangement. In the block model described by Meyer, the active phase comes first, followed by a passive phase of the same length. The app is intended to make that interval easier to track and, in its film and games, more engaging than a static number of days.

Meyer’s timeline starts with the film request on September 28. He says the first day also brought date entry, working-day calculations and early game prototypes; later days added the daily view, languages, more games, a bridge-day finder, narration and sound. He reports that an iPhone scrolling problem required a hotfix. The account was published October 13, after the stated October 2 release approval.

According to Meyer, Claude Opus 5.5 followed a repeated process: it proposed a plan, built and tested a feature, recorded what it had done, and deployed it. He supplied directions and reviewed the results. The article therefore describes a collaboration led by a human, rather than a product created and released autonomously by an AI system.

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

— Thorsten Meyer, writing on ThorstenMeyerAI.com

Independent Checks and User Data

The source is Meyer’s own account of the project. It does not provide independent verification of the five-day timeline, code volume, test coverage or feature count, nor does it include an external review of the app’s calculations, accessibility or security. The article also does not report usage figures, user feedback or whether the app has been tested across all supported languages and regional holiday calendars.

Meyer says the app has no tracking and calculates dates in the browser, but the source does not include a separate technical assessment of those privacy claims. It also does not explain how the app handles every possible employment arrangement or exceptions to standard working-day calculations. Users’ individual workplace rules may differ from the assumptions described.

How the App Performs in Use

Meyer’s published account presents the app as released after his approval on October 2; it does not announce a specific next release or development milestone. The next evidence readers can look for is how the tool performs in public use, including whether users report calculation errors, compatibility problems or gaps in language support.

Anyone using the countdown will need to enter dates and leave accurately and check that the selected federal state matches their circumstances. The article does not say whether Meyer plans further updates, publishes the code for independent review or will provide a formal method for reporting errors. Those points remain open.

Key Questions

What is Altersteilzeit?

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

What does the app calculate?

Users enter the date of one phase and select a model from 1:1 to 5:5. According to Meyer, the app calculates the other date and remaining working days, taking weekdays, public holidays in a selected German federal state and entered leave into account.

What did the AI agent contribute?

Meyer says Claude Opus 5.5 helped with coding, testing, localization, voice clips, sound effects and deployment. He says he provided direction, made choices and approved releases; the source does not independently verify the work totals.

Does the app collect users’ dates?

Meyer says date calculations take place in the browser and that the app has no accounts, cookies or tracking. He says dates in shared links are placed after the “#” character. The source does not include an independent privacy audit.

Source: ThorstenMeyerAI.com