MurphyA/hacker-news huggingface dataset:
Tested OpenAI's prompt caching across models. Found undocumented behavior
by harsharanga | 2025-11-27 16:26:29+00:00
Been building an AI agent from scratch to understand token economics. Spent a week on prompt caching. Found something interesting that isn't in OpenAI's docs. Setup: Network device monitoring chatbot, 10 tools, ~1,400 token prefix. Tested gpt-4o-mini, gpt-5-mini, gpt-5. Logged cached_tokens from every response.

Finding 1: Caching works as documented Once prefix exceeds 1024 tokens, OpenAI caches it automatically. I saw 80-90% cache hit rates after the first call. Cost reduction of 47-49% on input tokens. Cache discount is 50% for 4o-mini, 90% for gpt-5 family.

Finding 2: Tool schema tokenization is heavily compressed Added 4 tools to my existing 6. Expected +400-500 tokens based on JSON size. Actual increase: 56 tokens. OpenAI is clearly doing aggressive compression on function schemas.

Finding 3: Cache is shared across model generations (undocumented) This is the interesting part. Test: Call gpt-4o-mini first (cold start). Wait 5 seconds. Call gpt-5-mini with identical prefix. Result: gpt-5-mini got a cache hit on its first call. Tested all permutations. Every time, model 2 and 3 hit cache from model 1's warmup. The prefix-processing cache is shared across 4o-mini, 5-mini, and 5. I couldn't find this documented anywhere.

Why it matters: If you have many cold starts (separate user sessions, different contexts), you can warm cache with the cheapest model. Example - 1,000 cold starts/day, 10K token prefix, primary model gpt-5: Without cross-model warming: Each session pays 10K tokens at $1.25/1M = $0.0125 Daily: $12.50, Annual: $4,562 With nano warming first: 10K tokens at $0.05/1M = $0.0005 per warmup Daily: $0.50, Annual: $182 Savings: $4,380/year At gpt-5-pro pricing ($15/1M), difference is $54K+/year on warmup costs alone.

Technical note: This is prefix-processing cache sharing, not KV-cache sharing. Models share tokenization and prefix hashing, not attention states. But billing-wise, cached tokens are cached tokens.

Reproduction: Create 1024+ token prefix. Call model A, log cached_tokens. Call model B with same prefix. Check if B's first call shows cached tokens. Field is in response.usage.prompt_tokens_details.cached_tokens. Happy to share test scripts.
by yetihehe | 2025-11-27 16:26:38+00:00
> I'd even say the 'Get Style', 'Get Strong', 'Get Social' and 'Get Skilled' categories always appear to wander towards (while never approaching) Andrew Tate territory, in terms of their goals.

I agree. Going into "Andrew Tate" territory represents that toxic masculinity for me, it's the far end of spectrum of manliness. But we men don't need to go all the way into absurdity when trying to be more manly. But not all of us are in the same place. Some are too close to unmanly end, some are too close to toxic end. artofmanliness contains articles for both of those people, to move them closer to the center of good manliness (expressed by ideals 'Get Style', 'Get Strong', 'Get Social', 'Get Skilled' and I would add 'Be dependable', 'Be honest').

And being womanly is not an end of spectrum of manliness. Being unmanly (0 of qualities we mentioned, a weak man without style, social or any other skills) is the lowest end of spectrum of manliness.

> This I agree with, but I don't feel that website is a good example of a role model for the qualities that the original article mentioned were missing.

You would have to look more. You have only seen a small sample from each section.
by truelson | 2025-11-27 16:27:44+00:00
It's still an editor I can turn to in a pinch when my favorite humans aren't around. It makes better analogies sometimes. I like going back and forth with it, and if it doesn't sound like me, I rewrite it.

Don't look at social media. Blogging is kinda re-surging. I just found out Dave Barry has a substack. https://davebarry.substack.com/ That made me happy :) (Side note, did he play "Squirrel with a Gun??!!!")

The death of voice is greatly exaggerated. Most LLM voice is cringe. But it's ok to use an LLM, have taste, and get a better version of your voice out. It's totally doable.
by LogicFailsMe | 2025-11-27 16:27:51+00:00
One could absolutely push algorithms that personalize towards what the user wants to see. I think LLMs could be amazing at this. But that's not the maximally profitable algorithm, so nobody does it.

As so many have said, enragement equals engagement equals profit.

All my social media accounts are gone as well. They did nothing for me and no longer serve any purpose.

TBF Bluesky does offer a chronological feed, but the well-intentioned blocklists just became the chief tool for the mean girls of the site.
by ghaff | 2025-11-27 16:28:01+00:00
My house is early 1800s (old farmhouse). Yes, the bathroom is pretty much right above the kitchen/pantry presumably because that was the most straightforward way to pipe it. Not even sure what is original and what was probably installed/built around 1900 or so.

No real opportunity to put in another bathroom and I've talked with contractors. You could squeeze a really minimalist half bath in the pantry but then you lose the pantry and the washer/dryer need to go somewhere and the basement isn't really a good idea for various reasons.
by codeflo | 2025-11-27 16:28:02+00:00
The HN moderation system seems to hold, at least mostly. But I have seen high-ranking HN submissions with all the subtler signs of LLM authorship that have managed to get lots of engagement. Granted, it's mostly people pointing out the subtle technical flaws or criticizing the meandering writing style, but that works to get the clicks and attention.

Frankly, it only takes someone a few times to "fall" for an LLM article -- that is, to spend time engaging with an author in good faith and try to help improve their understanding, only to then find out that they shat out a piece of engagement bait for a technology they can barely spell -- to sour the whole experience of using a site. If it's bad on HN, I can only imagine how much worse things must be on Facebook. LLMs might just simply kill social media of any kind.
by FireBeyond | 2025-11-27 16:28:05+00:00
Right. Even here in HN I was arguing with someone who has the hot take that “more conservative leaning men have less mental health issues than liberal and left leaning men and I don’t think we do enough to think about why exactly that might be and what those liberal men could do differently”, and got very angry when I suggested that maybe the reason for that was that conservative men were less likely to seek help or treatment or to even acknowledge, instead of outright deny, any mental health challenges, for fear of anything from seeming weak to being ostracized.
by thepasswordapp | 2025-11-27 16:28:12+00:00
This is a good example of "your vendor is your attack surface" becoming the security lesson of 2025.

The pattern keeps repeating: Trust vendor → Vendor gets breached → Your users' data exposed. And the cascading effect here is notable - Mixpanel breach → OpenAI API users exposed → Those users likely reused credentials elsewhere.

For sensitive operations, the takeaway is clear: minimize what you share with third parties. If your credentials never leave your machine in the first place, they can't be exfiltrated from a vendor breach.

The old model of "trust but verify" feels increasingly outdated. The new model probably needs to be "verify or don't share."
by lkey | 2025-11-27 16:28:16+00:00
Simian,

You are making an ethical judgment when you say, in essence, that 'it is wrong for businesses (and non-profits) to attempt to act in an ethical manner, aligned with their mission statement'.

Making an ethical argument about the purposelessness and futility of ethics is... interesting to say the least. Please, consider stopping the internet today and instead spend time with a book on ethics that you think agrees with you sensibilities, and then look at this situation again.
by CWuestefeld | 2025-11-27 16:28:27+00:00
I SO hate this style of reporting. They make me read through 10 paragraphs of human interest pap, when what I really want is to learn something about the medicine that the headline promises. Then a couple of paragraphs of concrete info, then dive back into another vignette. I didn't click into the article to read shocking sad stories, I came to learn something, and the writer is making it unnecessarily difficult to do so.
by imtringued | 2025-11-27 16:28:33+00:00
When training a neural network, you usually play around with the architecture and need as much flexibility as possible. You need to support a large set of operations.

Another factor is that training is always done with batches. Inference batching depends on the number of concurrent users. This means training tends to be compute bound where supporting the latest data types is critical, whereas inference speeds are often bottlenecked by memory which does not lend itself to product differentiation. If you put the same memory into your chip as your competitor, the difference is going to be way smaller.
Show HN: GemGuard – a security auditing tool for Linux and Windows
by Alvaro_Houx | 2025-11-27 16:28:48+00:00
I’ve been working on a small security auditing tool called GemGuard and wanted to share it with the community.

GemGuard collects system information — running processes, network connections, and recently installed packages — and then uses Google’s Gemini models to generate a human-readable assessment of anything that might look suspicious or worth checking.

The tool is cross-platform and works on: Linux (Fedora, Ubuntu/Debian, Kali, Alpine) and Windows 10/11

It offers both a CLI and a Textual-based TUI, supports multiple Gemini models, and includes a quiet mode for automation or integration with other tools.

Features include: - Process auditing - Package review (auto-detects package manager) - Network/port inspection - Optional raw AI output (quiet mode) - Works in Bash/Zsh/CMD/PowerShell

I’m not a security expert, so the project is experimental, and contributions or feedback are very welcome.

Repo: https://github.com/AlvaroHoux/gem-guard
by joecool1029 | 2025-11-27 16:28:53+00:00
Even reading this post stresses me out.

Every year or couple years I'd do it because gnupg2 is one of the worst user-hostile pieces of CLI software and I use it with smartcards (and now yubikeys).

Now apparently there are alternatives, allegedly sequoia supports openpgp smartcards so I might give it a shot soon: https://gitlab.com/sequoia-pgp/sequoia-keystore/
by zavg | 2025-11-27 16:29:24+00:00
In one of the WhatsApp communities I belong to, I noticed that some people use ChatGPT to express their thoughts (probably asking it to make their messages more eloquent or polite or whatever).

Others respond in the same style. As a result, it ends up with long, multi-paragraph messages full of em dashes.

Basically, they are using AI as a proxy to communicate with each other, trying to sound more intelligent to the rest of the group.
by IMTDb | 2025-11-27 16:30:11+00:00
> should be heavily regulated.

By who, exactly? It’s easy to call for regulation when you assume the regulator will conveniently share your worldview. Try the opposite: imagine the person in charge is someone whose opinions make your skin crawl. If you still think regulation beats the status quo, then the call for regulation is warranted, but be ready to face the consequences.

But if picturing that guy running the show feels like a disaster, then let’s be honest: the issue isn’t the absence of regulation, it’s the desire to force the world into your preferred shape. Calling it “regulation” is just a polite veneer over wanting control.
by westurner | 2025-11-27 16:30:36+00:00
From https://hps.org/publicinformation/ate/q12178/ :

> UV light, a form of energy, is defined as light having wavelengths between 100 nanometers (nm, 1 billionth of a meter in length) and 400 nm. [...]

> Most acrylic plastics will allow light of wavelength greater than 375 nm to pass through the material, but they will not allow UV-C wavelengths (100–290 nm) to pass through.

In terms of photonic permittivity, Glass is better for cold frames and the like, because acrylic filters out UV light.

Also, Hydrogen peroxide (H2O2) is an algaecide.

/? hydrogen peroxide algaecide https://www.google.com/search?q=hydrogen+peroxide+algaecide
by CityOfThrowaway | 2025-11-27 16:31:33+00:00
I'm anon, but also the farthest thing from a progressive, so I find this post amusing.

I don't disagree with a lot of what you're saying but I also have a different frame.

Even if we take your claim that LLMs don't make people better writers as true (which I think there's plenty to argue with), that's not the point at all.

What I'm saying is people are communicating better. For most ideas, writing is just a transport vessel for ideas. And people now have tools to communicate better than they would have been.

Most people aren't trying to become good writers. That's true before, and true now.

On the other hand, this argument probably isn't worth having. If your frame is that LLMs are expensive toys that ruin everything -- well, that's quite an aggressive posture to start with and is both unlikely to bear a useful conversation or a particularly delightful future for you.
by mentalgear | 2025-11-27 16:31:38+00:00
Let's clarify, maybe the best ideas would win out in the "level marketplace", where the consumer actually is well informed on the products, the product's true costs have to be priced, and there was no ad-agencies.

Instead, we have misinformation (PR), lobbying, bad regulation made by big companies to trench their products, and corruption.

So, maybe, like communism, in a perfect environment, the market would produces what's best for the consumers/population, but as always, there are minority power-seeking subgroups that will have no moral barriers to manipulate the environment to push their product/company.
by sillyfluke | 2025-11-27 16:32:49+00:00
>I'm not a big sucker for this kind of un-nuanced "us vs them" rhetoric

Everyone usually has this stance by default until they think some batshit crazy redlines have been crossed regardless of what end of the political spectrum they reside in and decide to adopt an "us vs them, hope for peace, prepare for war" approach.

I'm sure you have some "if they actually do <xyz> then I'll adopt a more alarmed stance" line in the sand, it's just drawn at a different point probably. That's why it's best to talk specifics of the case instead of declaring an abstract high-road stance.
by cubefox | 2025-11-27 16:33:05+00:00
Yeah, and I believe Radiance Cascades accurately calculate the size of the penumbra from the size and distance of the area light, which also means that point light sources, as in reality, always produce hard shadows.

The technique here seems to rely more on eyeballing a plausible penumbra without explicitly considering a size of the light source, though I don't quite understand the core intuition.
by CityOfThrowaway | 2025-11-27 16:33:41+00:00
Are they your ideas if they go through a heavy-handed editor? If you've had lots of conversations with others to refine them?

I dunno. There's ways to use LLMs that produces writing that is substantially not-your-ideas. But there's also definitely ways to use it to express things that the model would not have otherwise outputted without your unique input.
by quickthrowman | 2025-11-27 16:34:02+00:00
You are technically incorrect (for the US, I’m not familiar with UK architectural terminology), the colloquial usage does not match industry standard terminology. The ASME definition for ‘water closet’ is specifically the fixture itself, a flush toilet. Building codes define water closets the same way. Some people incorrectly refer to a separate toilet room inside of a bathroom as a water closet, but that is not what professionals (plumbers, mechanical engineers, and architects) call it. If you reread the MN statute, you’ll note it refers to water closets and toilet rooms separately, because one is the fixture and the other is the room containing the fixture.

The term ‘lavatory’ is also frequently used incorrectly, a lavatory is just a sink, not the entire room.

Similarly, a ‘light bulb’ should actually be called a ‘lamp’. That’s what lighting companies, electricians, and people that manage electricians call them. A luminaire is a complete light fixture, a lamp screws into a luminaire (some luminaire have integral light sources) and a ‘light bulb’ is technically an A19 E26 lamp, A19 is the bulbous shape, E26 is the ‘standard’ screw base size. The Wikipedia article is titled LED lamp: https://en.wikipedia.org/wiki/LED_lamp

I don’t correct people in real life when they misuse these terms, but I’ll write up several paragraphs to defend my position online ;) I work in commercial construction management so I’m exposed to these terms frequently, I don’t expect non-industry folks to know them.
by cootsnuck | 2025-11-27 16:34:09+00:00
Yup. I'm starting to wonder if the startup space has a pretty big blind spot not realizing that how easy it is to build mostly/semi functioning software is not a unique advantage...

I left an AI startup to do tech consulting. What do I do? Build custom AI systems for clients. (Specifically clients that decided against going with startups' solutions.) Sometimes I build it for them, but I prefer to work with their own devs to teach them how to build it.

Fast forward 3+ years and we're going to see more everyday SMBs hiring a dev to just build them the stuff in-house that they were stuck paying vendors for. It won't happen everywhere. Painful enough problems and worthwhile enough solutions probably won't see much of a shift.

But startups that think the market will lap up whatever they have to offer as long as it looks and sounds slick may be in for a rude surprise.
by mopsi | 2025-11-27 16:34:50+00:00
> There is absolutely 0% chance or even any rational thought or discussion that has happened by the leadership in Russia on this topic.

All military and intelligence chiefs of the European nations that share a border with Russia disagree with that and warn that their societies must be prepared for an invasion within 2 to 5 years after the war in Ukraine ends. What you call "outlandish sensational claims" by "primary school children" is something they take very seriously and it has fundamentally reshaped their approach to defense policy. Sweden, most notably, abandoned 200 years of neutrality, joined NATO, and began hardening its vulnerable points, such as the island of Gotland, which was demilitarized in 2005. Now Sweden has re-established a military presence on the island, brought back heavy weaponry, and is building up a defensive force. Why does an island in the middle of the Baltic sea need tanks, air defense systems and fighter jets on high alert?

Finland, known for its progressive policies, left the Ottawa treaty that banned anti-personnel mines. Why do you think they did that? Estonia, Latvia, and Lithuania are building bunkers and digging defensive lines on their border with Russia. Latvian news reported just today that the government is considering dismantling rail tracks connecting to Russia to make them unavailable to invading force. Not to mention Poland's buying spree: Poland is acquiring hundreds of rocket artillery systems and a thousand tanks.

Are they all foolish children who don't know what they are doing? The looming threat of a Russian invasion is the sole reason Northern and Eastern Europe maintain militaries at all. There is no other threat in the region. Their militaries could be disbanded overnight if Russia were to vanish into thin air.

> Cuba and Russia were never in a FORMAL military alliance or pact, since that would've provoked an immediate US invasion.

It doesn't change the fact that in practical terms, the military cooperation between Cuba and the USSR was much deeper than the relationship post–Cold War NATO members have had with the older members. The newer NATO members have received only a promise of assistance in the event of an invasion. Cuba received actual tanks, submarines and fighter jets.
by vanviegen | 2025-11-27 16:34:57+00:00
On HN everybody sees the same ordering. Therefore you get to read opinions that are not specifically selected to make you feel just the perfect amount of outrage/self-righteousness.

Some of that you may experience as 'dubious political stuff' and 'patently incorrect takes'.

Edit, just to be clear: I'm not saying HN should be unmoderated.
by spwa4 | 2025-11-27 16:35:15+00:00
In this specific case - because Parliament has rejected this law 50 times. Yes, really that much, they've been at it since 11 May 2022. Governments really want access to people's chats, and parliament really does not want to give it to them. Not the EU parliament, not member state parliaments. Almost all of them.

The EU Commission has the power to force this law through, over the objections of all EU member state parliaments and the EU parliament and only the EU Council has the power to stop them. So by allying with the council the EU Commission is hoping to force parliament by threatening them with worse, and showing that the Council will not intervene if they do force worse through.

In general there is discordance, because the EU countries are forced into the union because of the need to compete with other large players like US and China, not because they want to. So every EU country wants to be part of the EU, but they don't want that to mean anything and don't want to give up even the slightest bit of control to the EU. And that's ignoring animosities, such as that France really does not want Germany to have any say whatsoever in what happens in France, or that Spain wants to repress Barcelona's separatism and 100 other issues.

The EU constitution disaster, and that the outcome of that effort was literally worse than the EU imagined was even possible when they started it is a good illustration of the problem.
by gritten | 2025-11-27 16:36:38+00:00
It's so jarring getting a peek into the mind of someone who sees the world this way. Take this, for example:

>Globally, there are perhaps 20 (mostly male) specialized surgeons capable of face transplants

What an extraordinarily petty way to announce your bitter, cynical world view.

Or announcing your racial allegiance with the capitalisation of "Black" vs lower case "whiteness", or indeed the assertion that made it necessary to bring race into this at all: that White people are to blame (as per usual) for low organ donorship among African Americans.

It must be exhausting.
by toomuchtodo | 2025-11-27 16:36:46+00:00
https://en.wikipedia.org/wiki/Sorbitol

Study:

Intestine-derived sorbitol drives steatotic liver disease in the absence of gut bacteria - https://www.science.org/doi/10.1126/scisignal.adt3549 | https://doi.org/10.1126/scisignal.adt3549
by bwfan123 | 2025-11-27 16:37:19+00:00
Sometime, LLMs actually generate copyright headers as well in their output - lol - like in this PR which was the subject of a recent HN post [1]

https://github.com/ocaml/ocaml/pull/14369/files#diff-062dbbe...

[1] https://news.ycombinator.com/item?id=46039274