What it feels like to work with Mythos (oneusefulthing.org)

128 points by swolpers 4 hours ago

eithed 2 hours ago

What I find fascinating that there is so little substance in this article about the quality of produced code and the medium. Is the code documented and tested? Is it understandable and extendable? Is it secure? What language, framework, database was used? Author mentions judgement and taste - well, is the code tasteful? Will the model rearchitecture the entire thing if I ask it to add new functionality, spending another 9.5h in tokens? I assume that the research part is domain knowledge = how different types of travel translate to time making it presentable; how did the author verify this?

These questions are even not about AI: if I were to give money to a human agency and were given something they tell me works, I would ask the same questions. If I did not know how to evaluate, I would hire people that do. With LLMs the verification part is what bothers me the most.

cgearhart an hour ago

I’m starting to realize that LLMs are really good at building low-stakes projects. Your questions mostly presume that the stakes are higher. The software will last a long time; the requirements will evolve; we can’t tolerate mistakes; etc.

The trick to getting good at using LLMs for software is to learn how to make _all_ projects low-stakes.

qaq an hour ago

You don't need LLM for that. You make _all_ projects low-stakes by working on green field project using (insert buzzword soup of the day) and leaving for a new green field opportunity (that requires experience with buzzword soup of the day) before the project ships.

acedTrex an hour ago

> The trick to getting good at using LLMs for software is to learn how to make _all_ projects low-stakes.

this doesn't really work in the real world. There are many things that actually matter, engineering is fundamentally about handling them.

an0malous 30 minutes ago

These posts are never written by software engineers, it’s always some tech exec, retired engineer, or VC. This author is apparently a professor at the Wharton School of Management? None of these people have to ship or maintain real products, they’re just making side projects.

The only decent software engineering perspective I’ve seen has been from Mitchell Hashimoto.

jimbokun 15 minutes ago

Well that’s kind of the point.

They can just summon bespoke software out of the ether that only handles the use cases of themselves and a few of their collaborators.

Making “side projects” was mot possible for non-developers before powerful LLMs. Now it is.

hypfer 2 hours ago

Being the first to release an article gives you great SEO or whatever. Doing the things you've mentioned takes time.

jstummbillig 2 hours ago

Less fascinating when you consider that this is a non-coders perspective.

eithed an hour ago

Fair enough, but enterpreunership should, I guess, ask questions if given Next Big Thing has substance behind it or is it just snake oil.

munk-a an hour ago

nomel an hour ago

So, the perspective of the one that gains the most, that will value this the most, and that will pay the most? ;)

unholiness 33 minutes ago

Yeah, this made it basically clickbait for me, in terms of time I wasted with the wrong expectation.

The lack of downvotes on posts on HN has always felt like more of a bug than a feature to me.

coldtea 40 minutes ago

>What I find fascinating that there is so little substance in this article about the quality of produced code and the medium.

I clicked one of his examples intrigued "a snake game where the snake is self-aware and crazy things happen;". Played for 1-2 minutes, and it's the classic 1980s snake game. Am I missing something? What is "self-aware" about it? Some funny messages at the bottom of the screen? And what are the "crazy things"?

vunderba 6 minutes ago

I had the exact same thought. To me, it feels like they just took the fairly common “sentient video game character” trope and bolted it onto a very conventional snake game.

I will say, the act of eating creates a "bulge distortion" that flows down the length of the snake is a nice touch though.

jimbokun 17 minutes ago

Does it matter to the people requesting the software if it acts in the way they expect?

grafporno an hour ago

It's an ad.

adamtaylor_13 2 hours ago

I'm becoming more convinced these are questions of the Before Times. Yes, yes—heresy, I know.

Yet, I can't deny the reality that I observe working with LLMs every day. If this truly is a step-function (as some are sgguesting), then I have absolutely zero concern for the quality of the code.

JumpCrisscross 2 hours ago

Anecdote: I fed Fable some models I’ve been hand verifying (basically, I sketch out a scenario for Opus to model, it builds it, I ask it to show me the math, I correct it, we iterate like this, then I double check its code to make sure the math matches the model logic). Fable found almost every error I found, and then had some interesting suggestions for additional variables.

It also burned through my usage quota like a late-90s Hummer.

matheusmoreira 18 minutes ago

> It also burned through my usage quota like a late-90s Hummer.

Yeah. I have a Max 5x subscription and Fable burned through 16% of my weekly quota in a 40 minute code review session. It didn't even finish the review, it switched back to Opus 4.8 in the critical memory safety parts where I actually needed Fable.

I feel like I'm going to get priced out of these models soon. I should probably try to get the most out of Fable until June 22nd.

cyanydeez 2 hours ago

now for the best question: whats your ROI here?

Ferret7446 an hour ago

Humans are very expensive, so the equation almost always falls against them.

It's not just salary, but also safety/labor regulation, legal risk, vacations, sick time, personal conflicts, HR, benefits.

Even when automation is more expensive on paper, it's generally still cheaper

warkdarrior an hour ago

Qhemlomo an hour ago

It just got released, it shouldn't matter.

We know this model will be cheaper and faster with time.

And we have not even reached the timespan/timeframe were we have ASIC style models.

OpenAI has to do something which will beat Fable otherwise Anthropic won. China currently overtakes cars, pv, batteries and very soon silicon chip making, it has all the incentive to also take over AI.

camillomiller an hour ago

PunchyHamster 2 hours ago

It will be great when the price of compute/memory drops to normal level!

cyanydeez 14 minutes ago

ecocentrik 2 hours ago

Reading the first few paragraphs of what he calls "the most sophisticated academic social science paper I have yet seen from an AI" does not impress as much as I hoped.

"Posterior beliefs about market demand are purely referencedependent: holding dollars raised constant, they track only performance relative to the founder’s self-chosen goal—jumping half a standard deviation at the threshold, responding steeply for the first ten points past it, and flattening thereafter"

Humans generally don't verbalize data this way. The summary document is also very fluffy.

olafmol 2 hours ago

This little line from the article scares me: "but a software engineer would iron out the remaining potential bugs that I could not find quickly"

Every sw dev knows this is a very dangerous, and unrealistic, assumption.

selfawareMammal 2 hours ago

What are people working on that they see such a substantial difference between Mythos and Opus? I'd say I'm working with advanced stuff and more than often Deepseek is even more than enough. Why is everybody a genius in here?

jenniferhooley an hour ago

Just depends what you are working on. If you are trying to make a video game that's at a level of a decent indie game (think Hades/Baazar/etc), making UI elements/VFX/complex shaders/etc that are organic/interactive/animated that don't feel like a little dogshit vibeslop web-game, then none of the models are even close to good enough to get it done easily. Huge percentage of problems in top 3% games is really hard for any of the models to do with simple prompting.

Personally I don't really care, because I like coding and learning myself and DeepSeek Flash is all I really care about. But it's really easy to have a ton of benchmarks where the top models can't get anywhere close - and I like to test them on these problems to see how good they are getting.

Fable 5 is def a little better than 4.8 btw.

ianm218 2 hours ago

I’ve been working on implementing some common web infra type projects in Rust lately. Basically trying to use a lot of the great primatives in Rust like rustls (modern openSSL) and Tokio (async) to build memory safe or close, nginx drop in replacements.

A small portion of this effort is having a high quality Lua in Rust repo. I’m using mythos to fix some of the performance issues with my Lua interpreter that gpt 5.5/ opus 4.8 had stone walled on.

Not sure if Mythos will be able to crack this but it has been running for a couple hours now with some promising results.

Performance charts linked here if your curious https://github.com/ianm199/lua-rs

mervz 2 hours ago

We see the same thing when new laptops are announced and every employee all of a sudden needs to upgrade, despite the fact that 90% of people would be able to make do with a Macbook Neo.

Our_Benefactors 33 minutes ago

> despite the fact that 90% of people would be able to make do with a Macbook Neo.

Myth. Total myth! I recently had to beg for more RAM after continually hitting swap space which causes tools like dictation to stop working, failure to load certain websites without rebooting, and so on. Devs do in fact need powerful machines and the ~$500-1000 an employer saves upfront in machine costs is dwarfed by productivity losses.

Giving your engineering employees new machines in a 2-year cycle that are between the middle and high end is one of the cheapest ROI decisions that a tech org can make.

mohsen1 2 hours ago

I had a few of the benchmarks left alone and was working on tech debt knowing that a new model is going to be released soon. For my project (tsz.dev) Opus 4.8 was running in circles without producing results for a while for those tasks

gopalv 4 hours ago

> It worked for nine and a half hours.

> Again, it wasn’t perfect. As an expert, I was able to spot some errors and omissions (some as a result of the design I had asked for) that I had the AI correct

That's the bit that stuck out to me - that's longer than I would expect to work on a problem in a day or even expect to go back & fix the output of something that has a core reward loop of hours.

My customers are currently clamoring to push down my agent response times from 85 seconds down to below the 20s mark.

At the same time, it is very dissonant to see the industry heading towards hour+ long workflows with an agent.

matneyx 4 hours ago

In Claude's defense (and I cannot believe I'm defending it), I know no single dev who could create what it did (Concord), from a 19-page design document, in 9.5 working hours.

We're gonna go back to the days where our bosses ask why we're just sitting around, but instead of saying "compiling," we'll just say, "waiting for Claude."

giancarlostoro 2 hours ago

This. I get told things like "you can't build all that on your own?" I've had Claude poop out full feature web apps in under 30 minutes, to a spec. Was it perfect? No, but sometimes even in a simple setup phase you can burn 15 minutes to some obscure setup step that's failing. I cannot just code nonstop at 900WPM or whatever ridiculous speed, and poop out an entire full feature web app, with maybe a few bugs here or there. If you can, come show me, I'll gladly have you race against my Claude prompting capabilities.

Will Claude's code be perfect in one shot? Probably not, will it get you 80 to 90% of the way there with your chosen design patterns in under a few hours? Absolutely.

neogodless 4 hours ago

For the rare uninitiated:

https://xkcd.com/303/

petesergeant 2 hours ago

Sadly I didn't get very many answers to my Ask HN, "What are you doing during inference?": https://news.ycombinator.com/item?id=47944917

ModernMech 2 hours ago

giancarlostoro 2 hours ago

> At the same time, it is very dissonant to see the industry heading towards hour+ long workflows with an agent.

At this point, pay me significantly more, and I'll do it.

warkdarrior an hour ago

> pay me significantly more

Ha ha, that's how you negotiate yourself out of a job!

PeterStuer 4 hours ago

My Opus 4.8 regularly works for 10+minutes on a single non-trivial coding request.

ASalazarMX 3 hours ago

Your Opus 4.8? Is it now usual to refer to LLMs like that?

w4yai 2 hours ago

wongarsu 2 hours ago

giancarlostoro 2 hours ago

hedgehog 3 hours ago

Work duration is also not that valuable of a measure, you're usually better off defining the process yourself in code and having that delegate chunks of work to the models. The only real issue there is that it's harder to take advantage of the providers' subscription discounts, but on the other hand it's easier to do your own model routing, and there's no way I've seen for the normal chatbots to maintain coherence on streams of work measured in days and weeks.

cyanydeez 2 hours ago

I think we hit the sigmoid back when the QWEN models were released. By properly structuring my project, I can point it at any extension I want and get it going for 30 minutes to extend whatever. It can't effectively do 'god mode' on all the code, but being a mindful observer and code "professional" I don't need more than what a 128GB VRAM needs.

I'm amazed we're so far into SOTA bloat that the chinese will kill once they start etching silicon with these models.

pu_pe 35 minutes ago

The isochrone maps are quite beautiful [1], and go beyond the scope and refinement of some earlier human attempts I could find [2][3][4].

[1] https://isochronic-passage-chart.netlify.app/

[2] https://mapitout.welcome-to-nl.nl/

[3] https://commutetimemap.com/

[4] https://andrewding.ca/flightisochrones/

thepasch 2 hours ago

What it feels like to work with Fable:

> Switched to Opus 4.8: Fable 5 has safety measures that flag messages on most cybersecurity or biology topics. They may flag safe, normal content as well. These measures let us bring you Mythos-level capability in other areas sooner, and we're working to refine them. Send feedback or learn more.

theturtletalks 2 hours ago

This is what he built:

https://isochronic-passage-chart.netlify.app/

Doesn’t work too well on mobile but looks interesting

skipants 2 hours ago

It looks interesting but, like a lot of AI, looks correct but is not. Most of northwestern Canada says you can get there by road. If you look at Google Maps, there's no roads there for quite awhile. I see one highway between Inuvik and Tuktoyaktuk but that's about it.

neom an hour ago

Reminds me of a fun story. Some 20 years ago when I moved from Fort Frances to Toronto for college, my high school best friend was also going to college in Toronto, and his dad offered to drive us together in his truck with all our stuff in the back. We were saying our goodbyes and my buddies dad said to my dad "We'll get there a lot faster, I found a shortcut!" My dad, confused says "shortcut? there is no shortcut, just highway 1..." and his dad insists he found an alternative route, much shorter by kms and we'll fly up there 6 hours faster! Get into the truck and he pulls out 5 pages of printed mapquest... I assure you, having done it, Sault Ste. Marie to Sudbury via Elliot Lake on logging roads, may look interesting, but not correct, added a good 8 hours to the trip.

jampa 2 hours ago

It is hallucinating many flights in my region, some that never existed (so it is not an outdated data problem).

I also see some logic flaws. It overlooks the option of going to a major hub to access faster aircraft, rather than hopping on local hubs.

Also, immigration and customs are cleared at the first airport you arrive at in the country, not at the last one.

In some countries, you need to clear immigration even while going to a third country, so 1 hour is not enough to do it.

mohsen1 2 hours ago

I have been using it for less than an hour so take this with a grain of salt of being excited for the new tech.

In a project like mine (https://github.com/tsz-org/tsz) I am constantly frustrated that models were not doing enough research and were not taking into account other situations. Again and again models would produce code that would fix one thing and break 2 other tests that were "unrelated".

With Fable it seems like tasks are taking much longer (I have not seen a pull request from Fable sessions yet) but reading the transcription of those sessions I can see how it is doing the right thing by not leaving any stone unturned.

As the article says, it's hard to communicate this "feeling" about models because it is very project specific but I thought I share

anematode an hour ago

Does this not indicate that the project might not be structured in an appropriate way that allows incrementally adding features?

layer8 an hour ago

In general, sooner or later you need to restructure one thing or another when requirements are changing. Good code lets you reason about a refactoring, and experience tells you when it is necessary or appropriate. Coding agents aren’t very good at the latter.

mohsen1 an hour ago

the setup is solid. there are thousands of tests and CI won't let things to merge if tests are failing.

But overall, this is pretty normal for compilers to have this sort of "unexpected" tests failing due to some work in an area. It happened to me when I was coding everything manually back in the day too

wxw an hour ago

I am… underwhelmed by the artifacts in the post.

I don’t see why working longer is a pro. The results don’t seem much better than you’d get from putting Opus in a long loop.

warkdarrior an hour ago

> The results don’t seem much better than you’d get from putting Opus in a long loop.

Care to share the results you got from Opus working on the same prompt? It should be easy to compare quality.

mjamesaustin an hour ago

The snake game is legit very fun. Once I got the ability to pick up the apples and plant apple trees, I was sold.

neaden 2 hours ago

Man, that poem it made is terrible. Like just incredibly bad. Sure it's neat that software can make an incredibly bad poem but there is enough bad poetry in the world that we don't need it.

Kiro 3 minutes ago

How good can a rhyming poem about a haircut where every word starts with S be?

layer8 an hour ago

I wonder what Vogons would think of it.

recursivedoubts 3 hours ago

would it be possible for mythos to make the space bar scroll the pages on your website properly?

mulr00ney 2 hours ago

Seems to be hijacked the video of some game they generated. :(

albedoa 38 minutes ago

If you delete the video from the DOM, then click back into the content area, it reattaches the video lol.

steve1977 an hour ago

> it is indicative of AI solving a hard problem involving research, math, visual development, taste, judgement, complex coding, and more.

Is it a hard problem or is it just labor intensive?

warkdarrior an hour ago

Depends on the skill of the person working on it.

vb-8448 an hour ago

Nice, but I'm really curious about how many tokens have been used.

There is only one hint: 475k tokens in the screenshot when OP asked the model to fix some behaviour, but it would be fascinating to know the total tokens amount.

mawadev 2 hours ago

Isn't it weird that we started to gauge the quality of a model by checking the vibe of the vibe coding?

Aperocky 2 hours ago

> This is a map that shows the distance you can travel in a given length of time, and the first one was created in 1881 showing travel times from London.

The first item on the article, the first thing it showed, was wrong though.

It is 100% faster to go from London to New York in 1881 than Volgagrad. Or any of the Russian hinterland colored green or Turkey or Egypt.

patcon 2 hours ago

> faster to go from London to New York in 1881 than Volgagrad

the map is for 2026, yeah?

asdK120 4 hours ago

Mollick runs the Generative AI Lab at Wharton, with all the corporate sponsors.

He is a professor but sadly also an AI shill. He should switch to advertising washing power.

MostlyStable 4 hours ago

So...no engagement with the substance? Not even to explain why it is that this is not a useful description or test of capabilities? Ok.

dthread3 4 hours ago

I would like to see it do something useful, like converting pytorch to golang.

Philpax 10 minutes ago

cadamsdotcom 3 hours ago

lijok 3 hours ago

fdsdfsdfzxczxc 4 hours ago

whyenot 4 hours ago

Instead of attacking the author, please respond to the content of the article. That is the HN way, and it leads to more substantive and interesting discussions.

CuriouslyC 2 hours ago

Ethan is a booster but I wouldn't call him a shill. He cites data and mostly in a fair way, though you could argue the sources he chooses to focus on are biased.

zuzululu 2 hours ago

> First, how good is Fable? In experiment after experiment I conducted, it outperformed basically every other public model I have used by a considerable margin.

What makes me excited is that GPT 5.6 (its actually GPT 6) is going to be crazy

PaulHoule an hour ago

My wife likes to say "feelings aren't facts"

382hi 4 hours ago

I think Qwen 3.7-Plus is better at reasoning than Mythos, and I've used both for quite a while.

giancarlostoro 2 hours ago

Would love to see samples of the kinds of prompts you use with both. I sometimes wonder if the specific wording is the secret sauce, I have very few issues with Opus / Claude, but when I try premier GPT models, I get weird output from what I've grown to expect with Claude.

LogicFailsMe an hour ago

I'm using Fable this afternoon and it's definitely a step up from Opus 4.8, finding and fixing things Opus 4.8 was blind to even perceiving. The next 13 days are going to be fun IMO. And Opus 4.8 was less annoying than Opus 4.7 FWIW.

Edit: A couple hours in and I just got my first gaslighting attempt from the model. Good times!

root_axis 4 hours ago

I just can't stand this type of fawning language.

catigula an hour ago

>Ethan Mollick

Just an FYI this guy is an AI hype-beast. Some of his tweets are truly out there.

dogmayor an hour ago

Huge fanboy for sure

zb3 2 hours ago

Was the condition of being granted early access to this castrated model writing a post praising it?

younglunaman an hour ago

>What it feels like to work with Mythos >Looks Inside >So I did this with fable...

What?

warkdarrior an hour ago

Fable is Mythos with extra guardrails, so the analysis holds.

ThejaCH 2 hours ago

What it feels like to work with Mythos? Feels like am poor

the_doctah 4 hours ago

More Mythos Marketing.

boringg 2 hours ago

The mythos of Mythos is marketing.

honeycrispy 2 hours ago

Reading it, I can't help but feel he's being paid to write this. Or maybe he hopes to be paid. The language he uses makes him sound like he's fawning over the lost days of his childhood. Pardon me for being skeptical, but a trillion dollar company running a net-loss is hoping to IPO, and needs to sway public opinion by any means necessary. I would imagine that no dirty marketing scheme is off of the table, even from the self-proclaimed "good guys".

et-al 4 hours ago

[flagged]

astrange 4 hours ago

It is not a sponsored article and he writes one of these every time a new model releases. Why would a professor at Wharton need to write sponsored Substack articles.

0x1ceb00da 4 hours ago

"I don't care who the IRS sends I am not paying taxes!"