Philipp Leitner
philippleitner.net
Philipp Leitner
@philippleitner.net
Associate Professor @ Chalmers University of Technology

http://icet-lab.eu
I heard the term "spec-based programming" from a colleague for the paradigm where you really only provide and refine requirements, and do not care at all about the code. I don't think the tools I am using are there yet.
November 6, 2025 at 11:38 AM
IDK. My definition of vibe coding is "coding based almost exclusively on prompts, without or with minimal manual editing afterwards". Not sure if that is a standard definition, but it feels right.
November 6, 2025 at 11:27 AM
(8) An interesting mind shift happens when you vibe code a lot. Code turns into a kind of transient artifact that you just aren't very attached to. Is the code messy? Who cares (as long as it works), you aren't looking very much at it anyway.

This has strong implications for security, safety, etc.
November 6, 2025 at 7:50 AM
(7) Overall, the final system turns kind of messy, but realistically so did all other research prototypes I implemented by hand. But now, nobody, not even me, really understands the messy system.
November 6, 2025 at 7:47 AM
(6) Planning mode is great. Claude is surprisingly good at creating, updating, and evaluating a plan of what to do. Complex changes became much more feasible once I started working more with planning mode upfront.
November 6, 2025 at 7:44 AM
(5) For non-trivial code, you'll still need decent understanding of the solution space. I feel like some of the more hairy implementation issues I could only solve because I implemented similar systems in the past, and could prompt the AI with *very* fine-grained designs.
November 6, 2025 at 7:41 AM
(4) Somewhat relatedly, AI loves to generate tests alongside changes (good) but they are often not very useful. They often stub out all business logic, turning them into classic "Python isn't broken" kind of tests. Getting it to write (and keep!) useful end-to-end tests seems surprisingly hard.
November 6, 2025 at 7:37 AM
(3) Do.Not. Trust. the AI when it declares success. Whether something actually *works* you need to check yourself. I'll leave this example here - the AI broken 25 tests, and decided after fixing one of the failures that the rest probably isn't their fault.
November 6, 2025 at 7:33 AM
(2) Validation is king, but also very hard. Again, these tools produce a lot of code. I quickly realized that reviewing it line-by-line is unrealistic. It may be more realistic when doing small changes in an established system, but in greenfield dev you have to go with the flow.
November 6, 2025 at 7:30 AM
Lesson Learned (1): you feel more productive than you truly are. These tools produce *a lot* of code in short time, but if you take a step back after a few weeks you notice than a fair bit of it wasn't actually that useful. It still takes time to build something that actually works, and not just 75%
November 6, 2025 at 7:27 AM
I initially used Gemini (in the console), but eventually moved on to Claude Console. They seem similar, but results from Claude where subjectively better, the tooling seems more mature, and the rates allowed me to work without much interruption. I am using the Pro subscription for USD 25 / month.
November 6, 2025 at 7:25 AM
27:0 ist aber auch im American Football eine richtige Klatsche.
October 29, 2025 at 6:02 PM
Note that this work does not judge correctness of papers, but only innovation. A crackpot theory is certainly very innovative.
October 13, 2025 at 2:06 PM
I do agree that formal peer review as we know it is a dead idea walking, but mostly because we have long swooped past a breaking point where the effort justified the systemic gains.

(if there ever were systemic gains to start with, which isn't super clear to me)
October 7, 2025 at 11:36 AM
Everything is cyclical. Some 25 years ago European institutions pushed for quantitative assessment because previous qualitative, subjective assessments meant that departments were riddled with nepotism.
October 7, 2025 at 11:33 AM
What even was that? youtu.be/D5_xwX_jxB0?...
Kansas City Chiefs vs Jacksonville Jaguars Game Highlights | 2025 NFL Season Week 5
YouTube video by NFL
youtu.be
October 7, 2025 at 10:05 AM
As a sidenote, I don't truly think that teaching students how to use AI effectively is all that important. These tools aren't hard to use, and the "tricks of the trade" are ephemeral. Teaching students how to prompt feels a lot like teaching SEO or googling.
October 1, 2025 at 7:32 AM