Eight weeks ago, I stopped reading about AI and started building with it.
Not because I had a grand plan. Because I had a very ordinary problem.
Property income and expenses across multiple units. WEG statements. Bills, receipts, and documents across dozens of categories — all needing to be tracked, sorted and filed. Eight years of self-filing complete German tax returns on top of that.
All of it important. All of it repetitive. All of it eating my weekends.
I asked one simple question: what if AI could take these back?
Here is what actually happened in eight weeks.
I tested every major AI tool — Claude, ChatGPT, Gemini. Not as a user. As someone trying to understand where each genuinely thinks differently and where each fails.
Then I went deeper into agentic AI — systems that do not just answer questions but execute multi-step workflows autonomously. I configured agents. Watched them fail. Rebuilt them. Learned more from the failures than the wins.
The decision that changed everything: a hybrid architecture. Local AI models running privately on-device for document processing — zero cost, fully GDPR compliant. Cloud API reserved only for tasks needing genuine reasoning — German tax law interpretation, financial analysis, legal documents.
Result: 60–70% of tasks handled locally and free. Total monthly AI cost targeting under €30.
What I did not expect: my early career as a Java developer mattered more than my last decade as a Senior PM.
The ability to think in systems, read APIs, make architecture trade-offs — that is what separated using AI tools from building with them.
The fear did not disappear. It transformed into something more useful.
AI is not replacing experienced practitioners. It is creating a gap between those who build with it and those who watch from a safe distance.
I know which side I want to be on.
First post in a series. Documenting exactly what I build, what breaks, and what I learn. No theory. No predictions. A Senior PM and recovering developer building AI systems in Germany — sharing what actually happens.
Next post: the infrastructure I designed to run seven specialist AI agents for under €30 a month.
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