Hacker News: johnfn

New comment by johnfn in "Claude: System Prompts"

johnfn — Sun, 16 Aug 2026 20:34:02 +0000

It’s really fascinating to me how when the community dislikes certain content people always jump to conspiratorial justifications rather than the much more mundane “this content is not very good”. The first article is poor and all the comments on it say exactly that. The second one actually did fairly well for what is a fairly middle-of-the-road Ask HN. There’s no shadowy cabal removing anti-AI content from the front page.

New comment by johnfn in "How Claude's text watermarking works"

johnfn — Fri, 14 Aug 2026 20:35:56 +0000

I'm not sure how that changes the question -- just add `has_watermark(text) < 0.5`.

New comment by johnfn in "How Claude's text watermarking works"

johnfn — Fri, 14 Aug 2026 20:34:59 +0000

Sure, but I imagined it'd be something like Anthropic handing over this API only to trusted third-parties, not everyone in the world.

New comment by johnfn in "How Claude's text watermarking works"

johnfn — Fri, 14 Aug 2026 20:12:36 +0000

> We will soon be offering a watermark detection API. We’re in the process of working out the details of its implementation.

Dumb question - doesn't this defeat the purpose of a watermark? i.e., anyone who wants to avoid detection can simply run `while (has_watermark(text)) text = slightly_rewrite_with_non_anthropic_llm(text)` until it's gone? I feel I am missing the intent of the watermark if it is so easily defeated.

New comment by johnfn in "Understanding is the new bottleneck"

johnfn — Fri, 14 Aug 2026 01:12:31 +0000

I remember when I raised this point like a year or two ago -- in response to someone saying that coding AI made all their work trivial I said something like "if you have multiple agents the work changes and becomes more managerial - don't you think that managers contribute value" and I got a bunch of downvotes and all the responses were like "no manager has ever contributed value." Ahh, good times.

New comment by johnfn in "Accelerating GPT-5.6 Sol Ultrafast"

johnfn — Thu, 13 Aug 2026 20:55:33 +0000

This does look pretty incredible, but don't forget that incredible token thoroughput can only necessarily solve certain bottlenecks. If your e2e tests take an hour, they'll still take an hour after Ultracode. If the agent runs a 10 minute typecheck after a change, that will still take 10 minutes. grep over a massive codebase is still just as slow, etc. I say this not to take away from this accomplishment but just to ensure everyone here keeps a clear head about what it means - 14x faster tokens does not mean it completes every task 14x faster.

I suspect Humanity's Last Exam is without tool-calls, making it kind of the perfect benchmark to highlight how fast Ultrafast is, but not really the same as the everyday work you or I do.

New comment by johnfn in "Show HN: Isopolis – Isometric pixel map of SF"

johnfn — Sat, 08 Aug 2026 01:50:29 +0000

I think “soulless” crosses a line into unkind. Just say you don’t like AI generated text.

New comment by johnfn in "Taste Is All That's Left"

johnfn — Fri, 07 Aug 2026 18:07:50 +0000

> the one-word lines

The funny thing is that there are no "one-word lines". This more or less cements the fact that it must be AI in my mind.

New comment by johnfn in "Show HN: Isopolis – Isometric pixel map of SF"

johnfn — Mon, 03 Aug 2026 15:00:51 +0000

Ouch, this seems unnecessarily harsh for a side project made for fun. This might be acceptable if this was a low effort single prompt to an AI but it’s pretty clear from the write up that that is far from the case.

FWIW I thought this was really cool.

New comment by johnfn in "Just brute force your embeddings"

johnfn — Fri, 31 Jul 2026 22:10:51 +0000

384 is a tad small. How does it perform on 1k/2k/4k..?

New comment by johnfn in "Investigating three real-world incidents in our cybersecurity evaluations"

johnfn — Fri, 31 Jul 2026 00:51:54 +0000

AWS never "humblebrags" about an outage. No blog post looks as good as an extra 9.

New comment by johnfn in "Investigating three real-world incidents in our cybersecurity evaluations"

johnfn — Fri, 31 Jul 2026 00:16:53 +0000

Companies post deeply embarrassing eng blogs all the time. See: every post about downtime or a security incident ever.

New comment by johnfn in "Superlogical"

johnfn — Wed, 29 Jul 2026 18:56:28 +0000

> If their AI finished it, where's the release?

`bun upgrade --canary`. You can use it today.

Keeping a large release, like a total rewrite, on canary for a while to iron out bugs is a very reasonable software engineering practice.

New comment by johnfn in "Jacobian Conjecture for Baby"

johnfn — Mon, 27 Jul 2026 04:44:11 +0000

This is really good - miles ahead of almost all other math writing I have read. One particular thing I really liked was the explanation of the determinant. When I was in college I spent a very long time trying to get some intuitive explanation for a determinant of a matrix and the best I could get is that you just multiplied and subtracted some numbers and poof there you go. I KNEW there had to be some more comprehensible explanation and it drove me crazy that people just parroted textbooks without any real understanding.

This reminds me of that silly video everyone was shown in middle school about inverting a sphere :-)

I am very curious how it was written (will there be a write up to the write up?!). It feels likely AI assisted, but this seems to me to be the best possible use of AI -- crunching out a bunch of visualizations of complex ideas so that they are easy to understand just by looking. The writing also feels a little AI written but definitely feels very human-assisted.

New comment by johnfn in "It's not empowering to hand off the details"

johnfn — Mon, 27 Jul 2026 00:38:11 +0000

But surely at some point you need to stop, right? Most web developers are perfectly capable without understanding the intricacies of the file system or OS, even though the browser sits on top them. Most engineers don’t know assembly, or transistors or electrical engineering. Steve Jobs didn’t know every line of Objective-C that went into OSX. I don’t think Michelangelo collected all his paint materials by hand when painting the Sistine Chapel. In some sense I don’t understand a lot of the panic around AI when the entire career progression of what it means to be a software engineer has simply been to deal with ever-increasing levels of abstraction.

New comment by johnfn in "I wouldn't say Pangram is broken, but I would say that it's brittle"

johnfn — Sun, 26 Jul 2026 20:44:35 +0000

The response says "I also believe we can do better". How is that in any way "you're holding it wrong"?

New comment by johnfn in "[dead]"

johnfn — Sun, 26 Jul 2026 18:20:41 +0000

To be blunt the degree to which I take these projects seriously is basically the same as how extensive their eval suite is. A single guided refactor is better than nothing, but one success could just be a fluke. I want to see hundreds, if not thousands, of evals to convince me you’re a project worth looking into.

The AI generated text is also not doing you any favors.

New comment by johnfn in "I wouldn't say Pangram is broken, but I would say that it's brittle"

johnfn — Sun, 26 Jul 2026 15:44:27 +0000

Pangram said a bunch of reasonable things and responded very coherently to the point and you skipped over it and misinterpreted this one section.

New comment by johnfn in "I wouldn't say Pangram is broken, but I would say that it's brittle"

johnfn — Sun, 26 Jul 2026 15:30:33 +0000

This issue is, like, exactly what the response from Pangram is talking about.

New comment by johnfn in "ARC-AGI Leaderboard"

johnfn — Sat, 25 Jul 2026 16:18:34 +0000

How do you propose they check for something like this? They can't exactly ctrl-f the model weights for "Arc-AGI".