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Alexandru Nedelcu

@alexn.org
1.2K followers 187 following 828 posts

Software developer, FP, Scala, Kotlin, Java / JVM, Haskell, Rust; contributor to alexn.org, monix.io, typelevel.org. 🌍 Bucharest, Romania alexn.org/about

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Alexandru Nedelcu @alexn.org · 23h
I like conventional commits. At $work we don't use them for semver automation, but rather for other kinds of red tape related to version & deployment management. And it does helps the humans Good commit messages take a discipline & craftsmanship that many have never learned, myself included.
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Alexandru Nedelcu @alexn.org · 23h
If you are a vibe-coder, you depend on the latest and greatest SOTA models to unblock work and cleanup the mess made by the previous model. The solution is to learn programming and stop listening to influencers suffering from AI psychosis. #ai #vibecoding #llm
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Alexandru Nedelcu @alexn.org · 23h
New LLMs announced and I ... couldn't care less. If you're not a vibe-coder, truth is that you can have a productive workflow that depends more on your harness configuration, with newer models only competing for token efficiency, in a race to the bottom, where they belong.
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Alexandru Nedelcu @alexn.org · 23h
Agentic programming started being viable at Opus 4 / GPT 5. We've had a year of experience with it, not a lot, but things are moving fast. Where are the great apps built with it? Great games? Do you have anything to show for it, other than personal utilities? Why not?
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Alexandru Nedelcu @alexn.org · 29/09/2026
Actually yes, unless we're using Java libraries, and unfortunately we do. Case in point: Logback.
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Alexandru Nedelcu @alexn.org · 29/09/2026
Having runtime surprises that don't manifest when running on the JVM is a serious UX issue. IMO this is its biggest roadblock to wider adoption. Other issues don't matter as much (e.g., slow compilation is irrelevant given people are developing on the JVM, AOT being last step).
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Alexandru Nedelcu @alexn.org · 29/09/2026
#GraalVM Native Image is great in principle. Problem is it doesn't mix with runtime reflection well, as #Java and #Kotlin libraries are a minefield of runtime reflection; even with all facilities (reachability metadata repo, tracing agent, good tests) I still bump into issues.
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Alexandru Nedelcu @alexn.org · 29/09/2026
I'm a cat person now
A black cat named Zuzi and a gray tabby Scottish Fold cat named Thomas rest side-by-side on a gray corduroy ottoman. Zuzi is on the left, and Thomas is on the right with one paw hanging down. Both cats look directly at the camera.
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Alexandru Nedelcu @alexn.org · 28/09/2026
I'm always waiting for the x.x.1 release
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Alexandru Nedelcu @alexn.org · 28/09/2026
The Web is the ultimate platform because: ‣ Browser is always available, users have no installation requirement; ‣ Browser is the best sandbox; ‣ It can be quite fast. People don't target native apps, as they suck for a myriad reasons, only one of which being the extra effort.
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Alexandru Nedelcu @alexn.org · 27/09/2026
English isn't optimal for AI, being too abstract (every word is an abstraction), a bottleneck in the way of achieving real gains. Soon you'll communicate with grunts, barks, chirps, or body language, like showing teeth, chest pounding, touching or grooming yourself. #ai #llm
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Reposted by Alexandru Nedelcu
Arman Bilge @armanbil.ge · 26/09/2026
Before I head to @scaladays.org in Berlin I am stopping in Prague and giving a talk at the Functional JVM meetup! www.meetup.com/functional-j...
meetup.com
Arman Bilge from Typelevel: Towards Scala Native and optimizing Cats Effect, Thu, Oct 8, 2026, 6:30 PM | Meetup
Arman Bilge from Typelevel is coming to town! He'll talk to us about the TypeLevel road to Scala Native and how they have optimized Cats Effect along the way. Mark the date
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Alexandru Nedelcu @alexn.org · 27/09/2026
Age of AI is bringing with it some of the dumbest takes imaginable. Newer samples: - Generated code can be assembly; - You no longer need unit tests, or DRY, or abstractions. This is the result of “cargo cult programming”, and of doing stuff based on vibes, which precedes AI.
Software developer of 2027
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Alexandru Nedelcu @alexn.org · 23/09/2026
I like #OpenCode because you can just instruct the AI to build you plugins for adding functionality and the experience is pretty good (also, #EffectTS FTW). Here's another simple plugin that adds the Brave Search API as a `websearch` (tool) provider: github.com/alexandru/...
github.com
GitHub - alexandru/opencode-brave-search: OpenCode v2 plugin adding the Brave Search API as a `websearch` (tool) provider
OpenCode v2 plugin adding the Brave Search API as a `websearch` (tool) provider - alexandru/opencode-brave-search
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Alexandru Nedelcu @alexn.org · 23/09/2026
I published my #Jev-based #OpenCode plugin, a plugin that blocks unsafe shell commands… github.com/alexandru/...
github.com
GitHub - alexandru/opencode-shell-safety: OpenCode v2 plugin that blocks unsafe shell commands (via Jev)
OpenCode v2 plugin that blocks unsafe shell commands (via Jev) - alexandru/opencode-shell-safety
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Alexandru Nedelcu @alexn.org · 22/09/2026
My article reached HN 😎 alexn.org/blog/2026/0...
Screenshot of a Hacker News page. Top story: “AI Has No Wisdom and Neither Will You” from alexn.org. It has 178 points, posted by dimonomid 1 hour ago, with 223 comments. Above is the orange Hacker News navigation bar with new, past, comments, ask, show, jobs, and submit links.
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Alexandru Nedelcu @alexn.org · 22/09/2026
Ha, I'm yelling and cursing at AI so much that I fear that one of these days I'll blurt out something similar to one of my colleagues
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Alexandru Nedelcu @alexn.org · 22/09/2026
New blog post: #AI Has No Wisdom and Neither Will You alexn.org/blog/2026/0...
alexn.org
AI Has No Wisdom and Neither Will You
Certainly the industry is transforming, however, the people and organizations falling into the trap of no longer reading and writing code only do so at their peril.
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Alexandru Nedelcu @alexn.org · 21/09/2026
My #OpenCode configuration now has a custom plugin that evaluates shell commands for safety via #Jev. It evaluates if shell expressions are within the agent's permissions, according to its configuration & system prompt. github.com/alexandru/...
Code editor showing a JSON configuration file. The snippet defines a "shell-safety" plugin with options like endpoint and model, and configures "Explorer" and "Librarian" agents.
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Alexandru Nedelcu @alexn.org · 18/09/2026
“I haven't edited code by hand since…” That's like saying you stopped reading & writing, and that the agent is doing all the writing (and thinking) for you. It's all very novel, but I'm pretty sure that all people going down this path will regret it.
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Alexandru Nedelcu @alexn.org · 17/09/2026
New blog post. #CSharp #Clojure #FSharp #Haskell #Java #Kotlin #Python #Ruby #Rust #Scala #TypeScript #Snippet #Programming #Languages alexn.org/blog/2026/0...
alexn.org
Executable Scripts with Dependencies
On programming and personal projects
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Alexandru Nedelcu @alexn.org · 15/09/2026
On every single HN thread talking Java there's at least one top comment lamenting type erasure. .NET generics reification is only needed b/c of runtime reflection. This doesn't come up in languages with type classes at all. Nobody asks for reification în Rust or Scala.
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Alexandru Nedelcu @alexn.org · 15/09/2026
"If you don't pay, you are the product" has stopped making sense for software long ago. Even if you pay, your data is still getting sold. If you don't want to be the product, you need to read the fine print and also prefer Open Source from volunteers (which you should sponsor).
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Alexandru Nedelcu @alexn.org · 15/09/2026
github.com/nguyenyou/...
github.com
GitHub - nguyenyou/scalex: Scala code intelligence for coding agents. Zero Build Server. Zero Compilation. Just answers.
Scala code intelligence for coding agents. Zero Build Server. Zero Compilation. Just answers. - nguyenyou/scalex
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Alexandru Nedelcu @alexn.org · 13/09/2026
Lazy Sunday
A black cat named Zuzy rests behind a gray cat named Thomas on a textured pink blanket. Zuzy looks toward the camera from above, while Thomas lies in front, gazing forward with a relaxed expression.
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Alexandru Nedelcu @alexn.org · 13/09/2026
This is like how one of the best things you can do for getting better at math is penmanship. A division line for people is the ability to write prose (i.e. to have coherent thoughts, to explain, to convince). And this is caused by how much people read & write. Volume matters.
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Alexandru Nedelcu @alexn.org · 13/09/2026
It's 2026, we have AI reading and writing for people, we have powerful voice-to-text engines that work better than ever before, such that we can speak instead of type, and yet, one of the best things you can do for your career is (still) 🥁 ... touch-typing.
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Alexandru Nedelcu @alexn.org · 12/09/2026
VS Code is better than Zed in every possible way that matters. I wish it wasn't so. Even the often exaggerated problem of VS Code, being built on top of a browser, is a pro, as its design is better & has more rendering abilities. And Zed sucks at startup too.
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Alexandru Nedelcu @alexn.org · 09/09/2026
This is how a setup with delegation to cheaper models looks like, pics show a single session. It was harder to balance back in the days of Haiku 4.5. A dumb model can do damage that the smarter model won't fix, but nowadays, Luna, or DeepSeek are quite capable. #LLM #AI
A table titled "Agents" listing four agents sorted by cost. Orchestrator is the most expensive at $100.04, followed by Explorer at $18.53, Junior at $10.77, and Librarian at $4.06. The table includes token usage and message counts.A table titled "Models" listing usage stats for two OpenAI models. Row 1: gpt-5.6-sol with 3.3M input, 243K output, 188.6M total, 187ms/1K, and cost $98.88. Row 2: gpt-5.6-luna-fast with 55.7M input, 2.3M output, 885.3M total, 99ms/1K, and cost $33.37.
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Alexandru Nedelcu @alexn.org · 08/09/2026
Much of the shit we have to deal w/ has nothing to do w/ the love of the craft that made us fall in love with programming. When I was a teen & dreaming of programming computers, I was not dreaming of notarizing an app for distribution or fixing flaky tests in CI.
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Alexandru Nedelcu @alexn.org · 08/09/2026
I've had my own skepticism or dread regarding LLMs, however, I can now say that w/ LLMs ... programming is more fun. That's because we've been dealing with a lot of shit that's now automate-able. E.g., ever tried publishing a library to Maven Central? If so, does it still work?
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Alexandru Nedelcu @alexn.org · 07/09/2026
I'm migrating a big #Scala project to sbt 2.x, and in my setup (VirtioFS, aggressive antivirus) it suffers from a 2x to 10x performance regression. Sol (xhigh) fixed it, Astra (high) did not, while lying that it fixed it twice, ignoring its input (compile in this directory, don't copy to /tmp).
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Alexandru Nedelcu @alexn.org · 06/09/2026
Commenting on the latest LLM models, as that's what boring people do... I dislike GPT-6 Astra. Compared with GPT 5.6 Sol, improvements are only marginal, if any, while being significantly more expensive (in my actual use, not benchmarks). AI may have peaked.
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Alexandru Nedelcu @alexn.org · 04/09/2026
Many "best practices" that are absolute BS in software development, and I have to suffer from AI slop now following them. Ex: don't use magic strings and numbers. The string is more clear than the name replacing it, it never changes, but if it does, it's just search&replace ffs
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Alexandru Nedelcu @alexn.org · 03/09/2026
Tech news is dominated by LLMs these days, but it's same old, same old, and I'm actually more excited about the new #Scala 3.9 LTS 😍 www.scala-lang.org/ne...
scala-lang.org
Scala 3.9 LTS released!
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Alexandru Nedelcu @alexn.org · 03/09/2026
Funfix Database — v0.5.2 release. Provides components built on top of RDBMSs. Currently, it provides a very useful "delayed queue". #Java, #Kotlin and #Scala library. Plays well with virtual threads & Scala version is powered by Cats-Effect. github.com/funfix/dat...
github.com
Release v0.5.2 · funfix/database
This patch release improves Scala interoperability, expands Scala documentation, and updates the build and release tooling. Changes OfferOutcome.fromJava now throws IllegalArgumentException when i...
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Alexandru Nedelcu @alexn.org · 01/09/2026
No paradigm does modules and components better than OOP. Pick your favorite non-OOP language; admit that its abilities for expressing components, even modules, suck, and any defense you can have rely on hacked-in virtual dispatch tables (poor man's OOP).
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Alexandru Nedelcu @alexn.org · 30/08/2026
Funfix Tasks v0.5.0 #Java #Kotlin #Scala This is a library exposing `Task` and `Fiber`, JVM datatypes meant primarily for JVM interop. NOTE: Trying to have scheduled releases for all projects I care about, so polishing up the maintenance infra. github.com/funfix/tas...
github.com
Release v0.5.0 · funfix/tasks
This release changes the asynchronous task API and improves cancellation handling. Breaking changes AsyncFun<T> now receives a single public Continuation<? super T> and returns void. Task.fromAsync...
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Alexandru Nedelcu @alexn.org · 28/08/2026
Continuations4s version 0.2.0: just a maintenance release. #Scala #Scala3 This is a micro-library providing continuations, for Scala 3, supported across JVM, WASM and Native, extracted from the Gears library. github.com/funfix/con...
github.com
Release v0.2.0 · funfix/continuations4s
Continuations4s provides low-level delimited continuations for Scala 3 on JVM, Scala.js with WebAssembly JSPI, and Scala Native. Version v0.2.0 is just maintenance release. There are no library sou...
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Alexandru Nedelcu @alexn.org · 27/08/2026
Migrated the project at work to #Scala 3. ~600,000 lines of code. Used an AI-driven loop; took a week with continuous interventions from me; superficial changes, few problems discovered. The project already had a codebase preparing for it (no problematic deps, -Xsource:3-cross).
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Alexandru Nedelcu @alexn.org · 25/08/2026
Monix Newtypes: v1.0.0 release. #Scala Regular maintenance, no breaking changes planned, so might as well declare it semver-stable. github.com/monix/newtyp...
github.com
Release v1.0.0 · monix/newtypes
Monix Newtypes 1.0.0 Features Added Cats 2 integration with derived Eq, Hash, Order, and Show instances through the new newtypes-cats-v2 module. #244 Build changes Adopted the semver-spec versio...
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Alexandru Nedelcu @alexn.org · 23/08/2026
Monix v3.5.0: maintenance release; more are coming. #Scala github.com/monix/moni...
github.com
Release v3.5.0 · monix/monix
This version updates the supported runtime and Scala versions, dependencies, and includes several concurrency and scheduler bug fixes. NoteIt does not upgrade Cats-Effect to 3.x, because that's sti...
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Alexandru Nedelcu @alexn.org · 23/08/2026
Failure to balance delimiters is a common occurrence for me, spoiling project-wide refactorings. Luna is not a dumb model. For modifying a syntax tree, I was expecting delimiters to help instead of causing issues, but I guess that's only true for deterministic tools, not AI.
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Alexandru Nedelcu @alexn.org · 23/08/2026
I may change my tune on significant indentation in #Scala 3. I've witnessed GPT 5.6 Luna (high) refactoring code, then struggling to balance the parens & braces, making a complete mess. Understanding & modifying the structure of your program have different challenges...
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Alexandru Nedelcu @alexn.org · 21/08/2026
To add in AGENTS.md if you're using GPT models: "- Banned words: seam"
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Alexandru Nedelcu @alexn.org · 17/08/2026
In fairness, when you bump up reasoning to max/xhigh, you get overengineered shit straight out of the Clean Code manual.
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Alexandru Nedelcu @alexn.org · 17/08/2026
My experience is limited, but IME, Claude Opus 5 is unusable due to its proclivity to generate slop the user hasn't asked for. I used it a little and hated it.
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Alexandru Nedelcu @alexn.org · 17/08/2026
The web is filled w/ connoisseurs of the fine differences b/w various LLM models. Story goes that many can't tell good code from bad. Well, I often can't tell the difference (e.g., DSv4 vs Sol vs Terra vs Luna) b/c too often they yield the same shit.
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Alexandru Nedelcu @alexn.org · 11/08/2026
Wow, TIL, thanks 🥰 serranofp.com/poke-fun/wel...
serranofp.com
Welcome
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Alexandru Nedelcu @alexn.org · 11/08/2026
Does anyone have experience with this #Kotlin library for building agents? Thoughts? I need Kotlin as it'd like to build an Android app. github.com/JetBrains/...
github.com
GitHub - JetBrains/koog: Koog is a JVM (Java and Kotlin) framework for building predictable, fault-tolerant and enterprise-ready AI agents across all platforms – from backend services to Android and iOS, JVM, and even in-browser environments. Koog is based on our AI products expertise and provides proven solutions for complex LLM and AI problems
Koog is a JVM (Java and Kotlin) framework for building predictable, fault-tolerant and enterprise-ready AI agents across all platforms – from backend services to Android and iOS, JVM, and even in-b...
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