Hacker News: Kostarrr

New comment by Kostarrr in "YAML document from hell (2023)"

Kostarrr — Tue, 23 Sep 2025 12:04:39 +0000

So... what are the good alternatives to yaml?

For quite some time I thought toml, but the way you can spread e.g. lists all over the document can also cause some headaches.

Dhall is exactly my kind of type fest but you can hit a hard brick wall because the type system is not as strong as you think.

New comment by Kostarrr in "Developing with GitHub Copilot Agent Mode and MCP"

Kostarrr — Fri, 04 Jul 2025 11:35:12 +0000

If they didn't change it, Playwright uses the aria (accessibility) representation for their MCP agent. It strongly depends on the web page whether or not that yields good results.

We at Octomind use a mix of augmented screenshots and page representation to guide the agent. If Playwright MCP doesnt work on you page, give our MCP a try. We have a free tier.

New comment by Kostarrr in "The story of Max, a real programmer"

Kostarrr — Thu, 03 Jul 2025 12:48:15 +0000

Ok now I want to know. Does Max php code have security issues? Because especially in early straightforward PHP, those were all over the place. I vaguely remember PHP3 just injected query variables into your variables? But as $_GET is mentioned, this is probably at least not the case...

New comment by Kostarrr in "Yes-rs: A fast, memory-safe rewrite of the classic Unix yes command"

Kostarrr — Tue, 27 May 2025 06:14:47 +0000

This is rust, not Java.

New comment by Kostarrr in "Resistance to Rust abstractions for DMA mapping"

Kostarrr — Tue, 04 Feb 2025 06:06:33 +0000

Zug does not attempt to solve memory safety. It aims to be a better C

New comment by Kostarrr in "Show HN: Stagehand – an open source browser automation framework powered by AI"

Kostarrr — Mon, 13 Jan 2025 08:24:04 +0000

Sorry didnt see this earlier. If you're interested reach out to me (Kosta Welke) on linkedin. Or write me an email, you can find me on Octominds About page.

New comment by Kostarrr in "Show HN: Stagehand – an open source browser automation framework powered by AI"

Kostarrr — Thu, 09 Jan 2025 09:31:11 +0000

Hi! Kosta from Octomind here.

We built basically this: Let an LLM agent take a look at your web page and generate the playwright code to test it. Running the test is just running the deterministic playwright code.

Of course, the actual hard work is _maintaining_ end-to-end tests so our agent can do that for you as well.

Feel free to check us out, we have a no-hassle free tier.

New comment by Kostarrr in "A visual proof that a^2 – b^2 = (a + b)(a – b)"

Kostarrr — Mon, 16 Dec 2024 09:11:31 +0000

Super cool, thank you!

New comment by Kostarrr in "AWS and Azure Are at Least 4x–10x More Expensive Than Hetzner"

Kostarrr — Mon, 21 Oct 2024 11:20:21 +0000

Also note: traffic costs. On Hetzner, it's almost impossible to pay for traffic. Even their tiniest machine has 20 TB outgoing traffic (and unlimited incoming). If you used it up (you most probably wont), that's another 1,792 USD of costs saved by your tiny 4$/month VM compared to AWS. (At least if I was able to use the AWS cost calculator correctly).

They will have object storage soon, but dont hold your breath for one-click kubernetes etc. So the fancier you infrastructure, the more you your startup would need to invest in time and money to use Hetzner and thus make it "not worth it".

New comment by Kostarrr in "Project Servo (2010) [pdf]"

Kostarrr — Tue, 24 Sep 2024 08:35:38 +0000

If you look at rust now, I think it's a great example of keeping the _spirit_ but allowing to question just about any specific decision.

Funny that the "why not go" still stands, minus the "no generics" part.

New comment by Kostarrr in "Master Hexagonal Architecture in Rust"

Kostarrr — Tue, 17 Sep 2024 05:41:35 +0000

Well here's the take from the Author itself: https://alistair.cockburn.us/hexagonal-architecture/

New comment by Kostarrr in "Master Hexagonal Architecture in Rust"

Kostarrr — Tue, 17 Sep 2024 05:40:29 +0000

Cool article on how to abstract things in Rust. I must admit, I usually write the "bad rust application".

Total nitpick: For `CreateAuthorError::Duplicate`, I would return a 409 Conflict, not a 422 Unprocessable Entity. When I see a 422 I think utf-8 encoding error or maybe some bad json, not a duplicate key in a database.

New comment by Kostarrr in "Deploying Rust in existing firmware codebases"

Kostarrr — Fri, 06 Sep 2024 07:17:35 +0000

It was blank for me as well until I reloaded with dev tools open and cache disabled. Figured it was a caching issue but maybe something more weird?

New comment by Kostarrr in "Deploying Rust in existing firmware codebases"

Kostarrr — Thu, 05 Sep 2024 18:47:40 +0000

It's really cool that google is investing so heavily in rust. However, the blog post is more of a "starting point" than a "lessons learned" (which I hoped for).

New comment by Kostarrr in "State of S3 – Your Laptop is no Laptop anymore – a personal Rant"

Kostarrr — Wed, 04 Sep 2024 07:52:34 +0000

Apple does this during sleep when connected to power, so maybe Microsoft thought it needs that as well?

New comment by Kostarrr in "Why we no longer use LangChain for building our AI agents"

Kostarrr — Fri, 21 Jun 2024 07:16:47 +0000

Disclamer: I work for Octomind.

I think the reading is more "It's hard to find a good abstraction in a field that has not settled yet on what a good abstraction is. In that case, you might want to avoid frameworks as things shift around too much."

New comment by Kostarrr in "Rust's concurrency model vs. Go's concurrency model"

Kostarrr — Thu, 20 Jun 2024 17:56:18 +0000

If one goroutine uses 2 KiB stack, then 10,000 goroutines use 20,000 KiB, right? Not 20,000 MiB.

New comment by Kostarrr in "Why Perl?"

Kostarrr — Fri, 21 Apr 2023 11:14:46 +0000

Friends dont let friends write perl. Source: The legendary "Perl Jam" talk from the chaos communication congress.

* https://www.youtube.com/watch?v=noQcWra6sbU * https://www.youtube.com/watch?v=RPvORV2Amic

Also I find the "ubiquity" argument very side loped. What I could agree with is "small/self-contained install" (e.g. small single executable available for many platforms). But not sure how well perl fares there.

New comment by Kostarrr in "Crimes with Go Generics"

Kostarrr — Mon, 25 Apr 2022 08:09:35 +0000

My bad. I was not aware on incredibly limited go generics are. I tried to make it work despite all restrictions but gave up here https://go.dev/play/p/XVTuJ--ZLgS

New comment by Kostarrr in "Crimes with Go Generics"

Kostarrr — Mon, 25 Apr 2022 06:44:13 +0000

I don’t think the Option presented here is sufficient (it is indeed a “crime”) as you cannot express Some(nil).

But you could probably achieve that using go's not-well-known sum types, e.g. like this

https://github.com/FSMaxB/type-safe-builder-experiment/blob/...