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Markus Harrer

@markusharrer.de
329 followers 264 following 154 posts

Software Development Analyst @innoq, Trainer @socreatory. I like fixing things. Legacy systems, Wardley Maps, DDD and Software Analytics fanboy. markusharrer.de

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Markus Harrer @markusharrer.de · 12h
"Coding is solved", marketing is not www.anthropic.com/research/glm...
anthropic.com
GLM-5.3 and the spread of advanced cyber capabilities
GLM-5.3 can autonomously build end-to-end cyber exploits, but unlike other frontier models, it was released without meaningful safeguards to limit misuse.
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Markus Harrer @markusharrer.de · 23/09/2026
"Opus, count from 3.0 to 5.5. Make no mistakes!" Opus: - 3 Opus - Opus 4 - Opus 4.1 - Opus 4.5 - Opus 4.6 - Opus 4.7 - Opus 4.8 - Opus 5 - Opus 5.5
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Markus Harrer @markusharrer.de · 22/09/2026
Claude Opus 5.5 completed a 680,000-line code migration in under a day. It converted the files from ASCII to UTF-8 using the iconv command on Bash.
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Markus Harrer @markusharrer.de · 15/09/2026
Will AI wipe out humankind? However unlikely it may be, I'm prepared for the Terminator scenario. I always keep a piece of old legacy code with me.
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Software Architecture Summit @softwarearchsummit.bsky.social · 10/09/2026
Neue Apps? Kein Problem für KI-Agenten. 40 Jahre alter COBOL-Code? Eine andere Geschichte. @markusharrer.de zeigt, wo Agenten bei Legacy-Code helfen. 🔗 software-architecture-summit.de/sof…
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Markus Harrer @markusharrer.de · 11/08/2026
For which engineering practice is the Claude Code team most famous? a) Harness Engineering b) Loop Engineering c) Graph Engineering d) Term Engineering
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Markus Harrer @markusharrer.de · 10/08/2026
Harnesses. Loops. Graphs. I cannot stand it anymore. Wake me up when you discover something called "code" if you want to implement agentic systems.
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Markus Harrer @markusharrer.de · 19/07/2026
Only one more step ...
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Markus Harrer @markusharrer.de · 16/07/2026
Claude Code is special.
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Markus Harrer @markusharrer.de · 16/07/2026
Tja. www.youtube.com/watch?v=m9uC...
youtube.com
Rekordzahl beim Auswandern: Warum so viele junge Leute gehen I akkurat
YouTube video by tagesschau
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Software Architecture Summit @softwarearchsummit.bsky.social · 29/06/2026
KI-Agenten modernisieren Softwaresysteme. Oder doch nicht? Der Workshop auf dem Software Architecture Summit geht der Frage nach mit @markusharrer.de - ohne Hype. → software-architecture-summit.de/sof…
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Markus Harrer @markusharrer.de · 25/06/2026
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Markus Harrer @markusharrer.de · 23/06/2026
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.
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Markus Harrer @markusharrer.de · 15/06/2026
Coding is solved. A seamless login workflow into Claude Code is not.
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iSAQB® - International Software Architecture Qualification Board @isaqb.bsky.social · 11/06/2026
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
𝗔𝗜 𝗔𝗴𝗲𝗻𝘁𝘀 𝗗𝗼𝗻’𝘁 𝗠𝗼𝗱𝗲𝗿𝗻𝗶𝘇𝗲 𝗟𝗲𝗴𝗮𝗰𝘆 𝗖𝗼𝗱𝗲 𝗼𝗻 𝗧𝗵𝗲𝗶𝗿 𝗢𝘄𝗻 – 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝘄𝗶𝘁𝗵 𝗠𝗮𝗿𝗸𝘂𝘀 𝗛𝗮𝗿𝗿𝗲𝗿
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Markus Harrer @markusharrer.de · 12/06/2026
I haven't written a line of code by hand in 8 months. I typed it it 🫳🎤
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Markus Harrer @markusharrer.de · 09/06/2026
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.
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Markus Harrer @markusharrer.de · 29/05/2026
Software engineers will replace AI in 6-12 months (in software modernization projects)
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iSAQB® - International Software Architecture Qualification Board @isaqb.bsky.social · 18/05/2026
🤖 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
𝗔𝗜-𝗔𝗴𝗲𝗻𝘁𝘀 𝗺𝗼𝗱𝗲𝗿𝗻𝗶𝘀𝗶𝗲𝗿𝗲𝗻 𝗸𝗲𝗶𝗻𝗲𝗻 𝗟𝗲𝗴𝗮𝗰𝘆-𝗖𝗼𝗱𝗲 𝘃𝗼𝗻 𝗮𝗹𝗹𝗲𝗶𝗻 – 𝗜𝗻𝘁𝗲𝗿𝘃𝗶𝗲𝘄 𝗺𝗶𝘁 𝗠𝗮𝗿𝗸𝘂𝘀 𝗛𝗮𝗿𝗿𝗲𝗿
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iSAQB® - International Software Architecture Qualification Board @isaqb.bsky.social · 04/05/2026
🐦 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
Software Architecture Forum 2026Software Architecture Forum 2026
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Markus Harrer @markusharrer.de · 26/04/2026
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).
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Markus Harrer @markusharrer.de · 01/04/2026
The one and only AI benchmark I really care about: Did AI do my dishes? feststelltaste.github.io/DishEval/
feststelltaste.github.io
DishEval Benchmark
The only eval that actually matters.
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Markus Harrer @markusharrer.de · 27/03/2026
I still don't get for what I should use OpenClaw.
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Markus Harrer @markusharrer.de · 23/03/2026
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
youtu.be
Is RAG Still Needed? Choosing the Best Approach for LLMs
YouTube video by IBM Technology
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Markus Harrer @markusharrer.de · 15/03/2026
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
feststelltaste.github.io
Software Modernization Strategies
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Markus Harrer @markusharrer.de · 04/03/2026
🤬
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Markus Harrer @markusharrer.de · 01/03/2026
"Make people dependent enough and then? Make it shitty!" A Day in the Life of an Ensh*ttificator youtu.be/T4Upf_B9RLQ
youtu.be
A Day in the Life of an Ensh*ttificator
YouTube video by Forbrukerrådet - Norwegian Consumer Council
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Adrien Joly @adrienjoly.com · 28/02/2026
« 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...
cjroth.com
Building An Elite AI Engineering Culture In 2026 | Chris Roth
AI accelerates high-performing orgs and unravels struggling ones.
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Yadullah Duman @y-duman.bsky.social · 12/12/2025
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...
yduman.dev
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
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Markus Harrer @markusharrer.de · 21/02/2026
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 ☺️)
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Markus Harrer @markusharrer.de · 19/02/2026
Now updated with new colors and without misleading numbers.
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Markus Harrer @markusharrer.de · 18/02/2026
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...
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INNOQ @innoq.bsky.social · 13/02/2026
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...
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Markus Harrer @markusharrer.de · 12/02/2026
Wake me up once your AI agents are actually fixing legacy systems, not just analyzing them.
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Markus Harrer @markusharrer.de · 11/02/2026
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...
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Markus Harrer @markusharrer.de · 09/02/2026
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.com
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
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Markus Harrer @markusharrer.de · 30/01/2026
Probably the two most common Bing searches in Microsoft Edge are: 1. "Firefox" 2. "How to change the default browser in Outlook"
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Markus Harrer @markusharrer.de · 29/01/2026
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Nick Tune @nick-tune.me · 28/01/2026
Dependency cruiser is nice. An elegant way to express and enforce architectural constraints. github.com/sverweij/dep...
github.com
GitHub - sverweij/dependency-cruiser: Validate and visualize dependencies. Your rules. JavaScript, TypeScript, CoffeeScript. ES6, CommonJS, AMD.
Validate and visualize dependencies. Your rules. JavaScript, TypeScript, CoffeeScript. ES6, CommonJS, AMD. - sverweij/dependency-cruiser
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Markus Harrer @markusharrer.de · 27/01/2026
It's not just "Human 🧒 vs. AI 🤖" these days when you're thinking about transforming legacy code on a larger scale. That is why I visualized a part of the refactoring tools landscape using my favorite thinking tool: PowerPoint 🧡
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Nicolas Fränkel 🇪🇺🇺🇦🇬🇪 @frankel.ch · 24/01/2026
Why We've Tried to Replace #Developers Every Decade Since 1969 www.caimito.net...
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Quarkus @quarkus.io · 09/01/2026
How to turn architecture guidelines into executable rules using Quarkus, JQAssistant, and graph-based analysis www.the-main-thread.com/p/quarkus-jq...
Stop Hoping Your Architecture Holds: Enforcing Quarkus Design Rules with JQAssistant
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Peter W🤓 @wang.social · 24/01/2026
Only if you maintain it! Otherwise, it’s just a data transform. Data, of course, is the real liability.
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Nicolas Carlo @nicoespeon.com · 15/12/2025
Hey, my talk "6 Safe Refactorings for Untested Legacy Code" that I gave at @confooca.bsky.social 2025 is available online! How cool is that? 😄 So here it is: I'm presenting you with 6 moves you can use in VS Code to refactor untested code ✊ www.youtube.com/watch?v=5YEm...
youtube.com
6 Safe Refactorings for Untested Legacy Code — Nicolas Carlo
YouTube video by ConFoo Developer Conference
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MenderCon @mendercon.bsky.social · 02/12/2025
We have started preparing our 2026 edition 🤫 In the meantime, you can find all the talks from previous editions on our YouTube channel: www.youtube.com/@mendercon/v... Stay tuned to learn more about what's coming 😉 #MenderCon #LegacyCode
youtube.com
MenderCon
MenderCon is a virtual conference celebrating the menders of legacy code. Menders love fixing bugs, refactoring, and testing to make software applications more stable, scalable and secure. MenderCon ...
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Dylan Beattie @dylanbeatt.ie · 28/11/2025
And it's up! All together now... 🎶 Somebody told me the user provider should use an adaptor to proxy the query factory builder... 🎶 www.youtube.com/watch?v=p03o...
youtube.com
Somebody Told Me (The User Provider Should Use An Adaptor To Proxy The Query Factory Builder)
YouTube video by Dylan Beattie
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Markus Harrer @markusharrer.de · 27/11/2025
Certainly I am not the only one to notice, but "ai" is right there in "naive."
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Markus Harrer @markusharrer.de · 26/11/2025
"Starting now, you’ll be able to make a career out of un-LLM-ifying applications." Psst 🤫, don't tell everyone! www.oreilly.com/radar/job-fo...
oreilly.com
Job for 2027: Senior Director of Million-Dollar Regexes
The following article originally appeared on Medium and is being republished here with the author’s permission.Don’t get me wrong, I’m up all night
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Nicolas Fränkel 🇪🇺🇺🇦🇬🇪 @frankel.ch · 20/11/2025
jMolecules 2.0 – Stereotypical odrotbohm.de/202...
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Nick Tune @nick-tune.me · 15/11/2025
The modernization progress illusion is an almost universal pattern I've observed over the past decade. You can make quick progress early by building new things outside the legacy or extracting pieces on the edges that have few dependencies. Quick wins, low risk. 1/4
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