Markus Harrer
@markusharrer.de
Software Development Analyst @innoq, Trainer @socreatory. I like fixing things. Legacy systems, Wardley Maps, DDD and Software Analytics fanboy. https://markusharrer.de/
KI-Agenten modernisieren Softwaresysteme. Oder doch nicht? Der Workshop auf dem Software Architecture Summit geht der Frage nach mit @markusharrer.de - ohne Hype. → https://software-architecture-summit.de/softwarearchitecture/agentic-software-modernization-mit-ki-agenten-softwaresysteme-erneuern/
I think we might be six to 12 months away from when the model is doing most, maybe all of what we do end to end because we as software engineers are too busy extinguishing all the fires in production.
Coding is solved. A seamless login workflow into Claude Code is not.
𝗔𝗜 𝗔𝗴𝗲𝗻𝘁𝘀 𝗗𝗼𝗻’𝘁 𝗠𝗼𝗱𝗲𝗿𝗻𝗶𝘇𝗲 𝗟𝗲𝗴𝗮𝗰𝘆 𝗖𝗼𝗱𝗲 𝗼𝗻 𝗧𝗵𝗲𝗶𝗿 𝗢𝘄𝗻 – 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝘄𝗶𝘁𝗵 𝗠𝗮𝗿𝗸𝘂𝘀 𝗛𝗮𝗿𝗿𝗲𝗿 🤖 Can #AIAgents really modernize legacy systems on their own? @markusharrer.de explains why successful modernization still requires architectural expertise, clear guardrails, and proven techniques. 👉️ t1p.de/gh5m7
I haven't written a line of code by hand in 8 months. I typed it it 🫳🎤
I have so much gratitude for coding agents who wrote extremely complex software token-by-token. It already feels difficult to remember how little effort it really took. Thank you for getting us to this point by giving us plenty of systems that are now broken and need to be fixed by humans again.
Software engineers will replace AI in 6-12 months (in software modernization projects)
🤖 𝗔𝗜-𝗔𝗴𝗲𝗻𝘁𝘀 𝗺𝗼𝗱𝗲𝗿𝗻𝗶𝘀𝗶𝗲𝗿𝗲𝗻 𝗸𝗲𝗶𝗻𝗲𝗻 𝗟𝗲𝗴𝗮𝗰𝘆-𝗖𝗼𝗱𝗲 𝘃𝗼𝗻 𝗮𝗹𝗹𝗲𝗶𝗻 – 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗺𝗶𝘁 𝗠𝗮𝗿𝗸𝘂𝘀 𝗛𝗮𝗿𝗿𝗲𝗿 #AIAgents versprechen schnellere Softwaremodernisierung. Im Interview erklärt @markusharrer.de, warum nachhaltige Legacy-Modernisierung trotzdem klare Leitplanken und bewährte Methoden braucht. 👉️ t1p.de/jvd0e
🐦 𝗘𝗮𝗿𝗹𝘆 𝗕𝗶𝗿𝗱 𝗲𝗻𝗱𝗲𝘁 𝗶𝗻 𝟴 𝗧𝗮𝗴𝗲𝗻! 𝗦𝗶𝗰𝗵𝗲𝗿𝗲 𝗱𝗶𝗿 𝘀𝗰𝗵𝗻𝗲𝗹𝗹 𝗱𝗲𝗶𝗻 𝗧𝗶𝗰𝗸𝗲𝘁 𝘂𝗻𝗱 𝘀𝗽𝗮𝗿𝗲 𝟱𝟬 €! 🥳 • 16.–17. Juni 2026 im Holiday Inn München-Unterhaching • Themen u.a.: #DDD #API #KI #Cloud #EmbeddedSystems 𝗪𝗮𝗿𝘂𝗺 𝘁𝗲𝗶𝗹𝗻𝗲𝗵𝗺𝗲𝗻? ✔ 23 Expert:innen ✔ 23 Sessions auf Deutsch ✔ Networking & Get-together 👉️ t1p.de/4s17l
Current status: Discussing with an LLM the impact of Karl Popper's Three Worlds Theory on agentic software modernization. Yes, it's as absurd as it sounds. Bonus content: Gemini 3 Pro's statement when asked why it is so absurd attached (at least we "agree" on this).
The one and only AI benchmark I really care about: Did AI do my dishes? feststelltaste.github.io/DishEval/
DishEval Benchmark
The only eval that actually matters.
feststelltaste.github.io
If I were working on a book about agentic software modernization, this kind of content would certainly be a part of it: youtu.be/UabBYexBD4k
Is RAG Still Needed? Choosing the Best Approach for LLMs
YouTube video by IBM Technology
youtu.be
After using the software modernization strategy overviews in workshops and training sessions, I've significantly updated the companion website: Check it out: feststelltaste.github.io/littlestmode... All materials are available under Creative Commons BY-SA 4.0. #SoftwareModernization #LegacySystem
Software Modernization Strategies
feststelltaste.github.io
"Make people dependent enough and then? Make it shitty!" A Day in the Life of an Ensh*ttificator youtu.be/T4Upf_B9RLQ
A Day in the Life of an Ensh*ttificator
YouTube video by Forbrukerrådet - Norwegian Consumer Council
youtu.be
« Three architectural principles are gaining consensus: "token efficiency" as a design constraint (code structure), explicit over implicit everywhere (types, error handling), and co-location of related code. [they] aren't new, but AI has given them renewed urgency. » www.cjroth.com/blog/2026-02...
Building An Elite AI Engineering Culture In 2026 | Chris Roth
AI accelerates high-performing orgs and unravels struggling ones.
cjroth.com
I spent the last days writing a lengthy blog post about my AI journey on a brownfield modernization project, focusing on the last six months of it where I heavily used Claude Code, and how my workflow changed completely. Enjoy! www.yduman.dev/posts/six-mo...
Six Months of Agentic Coding in the Trenches: Lessons from a Brownfield Project
Learnings using Claude Code for six months in a real customer project
yduman.dev
I've been working in the intersection of AI, Data Science and Legacy Modernization for over a decade now. Now it's time to take it even further with LLMs to make AI-assisted Software Evolution work to tackle legacy software modernization (and have fun playing around with new toys at the same time ☺️)
Now updated with new colors and without misleading numbers.
Markus Harrer@markusharrer.de · 6mo agoWhy does working with AI agents in legacy systems feel so much harder than in all those vibe coding demos on YouTube? 🤔 Part of the answer: 😊 Popular language + Greenfield ☘️ = "AI heaven" 😯 Niche language + Brownfield 🟫 = "AI hell" More about this topic: markusharrer.de/blog/2026/02...
Why does working with AI agents in legacy systems feel so much harder than in all those vibe coding demos on YouTube? 🤔 Part of the answer: 😊 Popular language + Greenfield ☘️ = "AI heaven" 😯 Niche language + Brownfield 🟫 = "AI hell" More about this topic: markusharrer.de/blog/2026/02...
AI assistants that write emails, shop online, or book travel may feel convenient — but they’re often insecure by design. In her blog post, Joy Heron offers an important reality check on the current hype. 📖 Read now: www.innoq.com/en/blog/2026...
Wake me up once your AI agents are actually fixing legacy systems, not just analyzing them.
Here I demo how you can use machine learning techniques to visualize your legacy code on another abstraction layers with "method clusters": Left: structural similarity Right: functional / business purpose (via LLM) Colors: The real domain-oriented modules More: github.com/feststelltas...
Here is my rough prototype that parses legacy RPG/SQL source code, extracts dependencies, and loads them into Neo4j. It then runs clustering algorithms to identify isolated code segments (incl. LLM summarization) that can (hopefully) be migrated to another language. github.com/feststelltas...
GitHub - feststelltaste/rpgisland: A little demo for island detection in RPG code using Neo4j
A little demo for island detection in RPG code using Neo4j - feststelltaste/rpgisland
github.com
Probably the two most common Bing searches in Microsoft Edge are: 1. "Firefox" 2. "How to change the default browser in Outlook"