8 ms·

Scaling long-running autonomous coding

290 points by samwillis 9mo ago

jphoward 9mo ago
The browser it built, obviously the context window of the entire project is huge. They mention loads of parallel agents in the blog post, so I guess each agent is given a module to work on, and some tests? And then a 'manager' agent plugs this in without reading the code? Otherwise I can't see how, even with ChatGPT 5.2/Gemini 3, you could do this otherwise? In retrospect it seems an obvious approach and akin to how humans work in teams, but it's still interesting.
- simonw 9mo ago
  GPT-5.2-Codex has a 400,000 token window. Claude 4.5 Opus is half of that, 200,000 tokens. It turns out to matter a whole lot less than you would expect. Coding Agents are really good at using grep and writing out plans to files, which means they can operate successfully against way more code than fits in their context at a single time.
  - jaggederest 9mo ago
    The other issue with "a huge token window" is that if you fill it, it seems like relevance for any specific part of the window is diminished - which makes it hard to override default model behavior. Interestingly, recently it seems to me like codex is actually compressing early and often so that it stays in the smarter-feeling reasoning zone of the first 1/3rd of the window, which is a neat solution for this, albeit with the caveat of post-compression behavior differences cropping up more often.
- observationist 9mo ago
  Get a good "project manager" agents.md and it changes the whole approach of vibe coding. For a professional environment, with each person given a little domain, arranged in the usual hierarchy of your coding team, truly amazing things can get done. Presumably the security and validation of code still needs work, I haven't read anything that indicates those are solved yet, so people still need to read and understand the code, but we're at the "can do massive projects that work" stage. Division of labor and planning and hierarchy are all rapidly advancing, the orchestration and coordination capabilities are going to explode in '26.
  - azan_ 8mo ago
    Could you perhaps share such agents.md? Sounds interesting
  - heliumtera 8mo ago
    I tried this approach yesterday and I`m loving our daily standup with the agents. Looking forward to our retro and health-checks rituals
- galaxyLogic 9mo ago
  > so I guess each agent is given a module to work on, and some tests? Who created those agents and gives them the tasks to work on. Who created the tests? AI, or the humans?
- nl 9mo ago
  Generally they only load a bit of the project into the context at a time. Grep works really well for working out what.
simonw 9mo ago
"To test this system, we pointed it at an ambitious goal: building a web browser from scratch." I shared my LLM predictions last week, and one of them was that by 2029 "Someone will build a new browser using mainly AI-assisted coding and it won’t even be a surprise" https://simonwillison.net/2026/Jan/8/llm-predictions-for-2026/#3-years-someone-will-build-a-new-browser-using-mainly-ai-assisted-coding-and-it-won-t-even-be-a-surprise https://simonwillison.net/2026/Jan/8/llm-predictions-for-202... and https://www.youtube.com/watch?v=lVDhQMiAbR8&t=3913s https://www.youtube.com/watch?v=lVDhQMiAbR8&t=3913s This project from Cursor is the second attempt I've seen at this now! The other is this one: https://www.reddit.com/r/Anthropic/comments/1q4xfm0/over_christmas_break_i_wrote_a_fully_functional/ https://www.reddit.com/r/Anthropic/comments/1q4xfm0/over_chr...
- cheevly 9mo ago
  2029? I have no idea why you would think this is so far off. More like Q2 2026.
  - xmprt 9mo ago
    You're either overestimating the capabilities of current AI models or underestimating the complexity of building a web browser. There are tons of tiny edge cases and standards to comply with where implementing one standard will break 3 others if not done carefully. AI can't do that right now.
    - rvz 9mo ago
      It's most likely both. > There are tons of tiny edge cases and standards to comply with where implementing one standard will break 3 others if not done carefully. AI can't do that right now. Firstly the CI is completely broken on every commit, all tests have failed and its and looking closely at the code, it is exactly what you expect for unmaintainable slop. Having more lines of code is not a good measure of robust software, especially if it does not work.
    - torginus 8mo ago
      Even if AI will not achieve the ability to perform at this level on its own, it clearly is going to be an enormous force multiplier, allowing highly skilled devs to tackle huge projects more or less on their own.
sashank_1509 9mo ago
Can a browser expert please go through the code the agent wrote (skim it), and let us know how it is. Is it comparable to ladybird, or Servo, can it ever reach that capability soon?
- krackers 9mo ago
  I'm interested in this too. I was expecting just a chromium reskin, but it does seem to be at least something more than that. https://news.ycombinator.com/item?id=46625189 https://news.ycombinator.com/item?id=46625189 claims it uses Taffy for CSS layout but the docs also claim "Taffy for flex/grid, native for tables/block/inline"
- missingdays 8mo ago
  You can start by trying to compile the project (spoiler: you can't)
- polyglotfacto 8mo ago
  I've done this in the parallel post, see https://news.ycombinator.com/item?id=46705625 https://news.ycombinator.com/item?id=46705625 (and a couple of other replies in that thread) TLDR; the code is not a valid POC but throw-away level quality that could never support a functioning web engine. It's actually very clear hallucinated AI BS, which is what you get when you don't have a human expert in the loop. I actually like using AI, but only to save me the typing.
ZitchDog 9mo ago
I used similar techniques to build tjs [1] - the worlds fastest and most accurate json schema validator, with magical TypeScript types. I learned a lot about autonomous programming. I found a similar "planner/delegate" pattern to work really well, with the use of git subtrees to fan out work [2]. I think any large piece of software with well established standards and test suites will be able to be quickly rewritten and optimized by coding agents. [1] https://github.com/sberan/tjs https://github.com/sberan/tjs [2] /spawn-perf-agents claude command: https://github.com/sberan/tjs/blob/main/.claude/commands/spawn-perf-agents.md https://github.com/sberan/tjs/blob/main/.claude/commands/spa...
trjordan 9mo ago
This is going to sound sarcastic, but I mean this fully: why haven't they merged that PR. The implied future here is _unreal cool_. Swarms of coding agents that can build anything, with little oversight. Long-running projects that converge on high-quality, complex projects. But the examples feel thin. Web browsers, Excel, and Windows 7 exist, and they specifically exist in the LLM's training sets. The closest to real code is what they've done with Cursor's codebase .... but it's not merged yet. I don't want to say, call me when it's merged. But I'm not worried about agents ability to produce millions of lines of code. I'm worried about their ability to intersect with the humans in the real world, both as users of that code and developers who want to build on top of it.
- dist-epoch 9mo ago
  Pretty much everything exists in the training sets. All non-research software is just a mishmash of various standard modules and algorithms.
  - galaxyLogic 9mo ago
    Not everything, only code-bases of existing (open-source?) applications. But what would be the point of re-creating existing applications? It would be useful if you can produce a better version of those applications. But the point in this experiment was to produce something "from scratch" I think. Impressive yes, but is it useful? A more practically useful task would be for Mozilla Foundation and others to ask AI to fix all bugs in their application(s). And perhaps they are trying to do that, let's wait and see.
    - mkoubaa 9mo ago
      You have to be careful which codebase to try this on. I have a feeling if someone unleashed agents on the Linux kernel to fix bugs it'd lead to a ban on agents there
    - conradev 8mo ago
      Re-creating closed source applications as open source would have a clear benefit because people could use those applications in a bunch of new ways. (implied: same quality bar)
dist-epoch 9mo ago
So, who is going to compile the browser and post the binaries so we can check it out? (in a sandbox/VM obviously)
- missingdays 8mo ago
  It doesn't compile
mk599 9mo ago
Define "from scratch" in "building a web browser from scratch". This thing has over 100 crates as dependencies... To implement css layouting, it uses Taffy, a crate used by existing browser implementations...
- rvz 9mo ago
  When I see hundreds of crates being used in a project, I have to just scratch my head and ask: What the f___? If one vulnerability exists in those crates well, thats that.
- qingcharles 8mo ago
  And it's not necessarily a bad move to use all those dependencies, but you're right it makes the claim shady. I can create a web browser in under a minute in Copilot if I ask it to build a WinForms project that embeds the WebView2 "Edge" component and just adds an address bar and a back button.
ora-600 9mo ago
I would love to know the cost of building this browser. I think that multi-agent orchestration systems will probably be the theme for systems this year. I think the north-star metric for a multi-agent orchestrator system would be how much did it cost to get this done. how much better could we have done? should we have used a cheaper model for doing a trivial task and an expensive one to monitor it?
mccoyb 9mo ago
Supposing agents and their organization improve, it seems like we’re approaching a point where the cost of a piece of software will be driven down to the cost of running the hardware, and the cost of the tokens required to replicate it. The tokens were “expensive” from the minds of humans …
- Daishiman 9mo ago
  It will be driven down to the cost of having a good project and product manager effectively understanding what the customer wants, which has been the main barrier to excellent software for a good long time.
  - galaxyLogic 9mo ago
    And not only understanding what the customer wants, but communicating that unambiguously to the AI. And note who is the "customer" here? Is it the end-users, or is it a client-company which contracts the project-manager for this task? But then the issue is still there, who in the client-company decides exactly what is needed and what the (potential) users want? I think this situation emphasizes the importance of (something like) Agile. To produce something useful can only happen via experimentation and getting feedback from actual users, and re-iterating relentlessly.
jphelan 9mo ago
This looks like extremely brittle code to my eyes. Look at https://github.com/wilsonzlin/fastrender/blob/main/crates/fastrender-renderer/src/lib.rs https://github.com/wilsonzlin/fastrender/blob/main/crates/fa... What is `FrameState::render_placeholder`? ``` pub fn render_placeholder(&self, frame_id: FrameId) -> Result<FrameBuffer, String> { let (width, height) = self.viewport_css; let len = (width as usize) .checked_mul(height as usize) .and_then(|px| px.checked_mul(4)) .ok_or_else(|| "viewport size overflow".to_string())?; if len > MAX_FRAME_BYTES { return Err(format!( "requested frame buffer too large: {width}x{height} => {len} bytes" )); } // Deterministic per-frame fill color to help catch cross-talk in tests/debugging. let id = frame_id.0; let url_hash = match self.navigation.as_ref() { Some(IframeNavigation::Url(url)) => Self::url_hash(url), Some(IframeNavigation::AboutBlank) => Self::url_hash("about:blank"), Some(IframeNavigation::Srcdoc { content_hash }) => { let folded = (*content_hash as u32) ^ ((*content_hash >> 32) as u32); Self::url_hash("about:srcdoc") ^ folded } None => 0, }; let r = (id as u8) ^ (url_hash as u8); let g = ((id >> 8) as u8) ^ ((url_hash >> 8) as u8); let b = ((id >> 16) as u8) ^ ((url_hash >> 16) as u8); let a = 0xFF; let mut rgba8 = vec![0u8; len]; for px in rgba8.chunks_exact_mut(4) { px[0] = r; px[1] = g; px[2] = b; px[3] = a; } Ok(FrameBuffer { width, height, rgba8, }) } } ``` What is it doing in these diffs? https://github.com/wilsonzlin/fastrender/commit/f4a0974594e3945a26c7335a67d16e62ef09d71f https://github.com/wilsonzlin/fastrender/commit/f4a0974594e3... I'd be really curious to see the amount of work/rework over time, and the token/time cost for each additional actual completed test case.
- blibble 9mo ago
  this is certainly an interesting way to pull out an attribute from a tag: https://github.com/wilsonzlin/fastrender/blob/main/crates/fastrender-renderer/src/lib.rs#L441 https://github.com/wilsonzlin/fastrender/blob/main/crates/fa...
- blamestross 9mo ago
  I suppose brittle code is fine if you have cursor to update and fix it. Ideal really, keeps you dependent.
embedding-shape 9mo ago
Did anyone manage to run the tests from the repository itself? The code seems filled with errors and warnings, as far as I can tell none of them because of the platform I'm on (Linux). I went and looked at the Action workflow history for some pages, and seems CI been failing for a while, PRs also all been failing CI but merged. How exactly was this verified to be something to be used as an successful example, or am I misunderstanding what point they are trying to make? They mention a screenshot, but they never actually mention if their goal was successfully met, do they? I'm not sure the approach of "completely autonomous coding" is the right way to go. I feel like maybe we'll be able to use it more effectively if we think of them as something to be used by a human to accomplish some thing instead, lean into letting the human drive the thing instead, because quality spirals so quickly out of control.
- snek_case 9mo ago
  I found the codebase very hard to navigate. Hundreds (over a thousand?) tiny files with less than 200 lines of code, in deeply nested subdirectories. I wanted to find where the JavaScript engine was, and where the DOM implementation was located, and I couldn't easily find it, even using the GitHub search feature. I'm not exactly sure what this browser implements and how. Even their README is kind of crappy. Ideally you want installation instructions right near the top, but it's broken into multiple files. The README link that says "running + architecture" (but the file is actually called browser_ui.md???) is hard to follow. There is no explicit list of dependencies, and again no explanation of how JavaScript execution works, or how rendering works, really. It's impressive that they got such a big project to be built by agents and to compile, but this codebase... Feels like AI slop, and you couldn't pay me to maintain it. You could try to get AI agents to maintain it, but my prediction is that past some scale, they would have a hard time figuring out their own mess. You would just be left with permanent bugs you can't easily fix.
  - bonesss 8mo ago
    So the chain of events here is: copy existing tutorials and public/available code, train the model to spit it out-ish when asked, a mature-ish specification is used, and now they jitter and jumble towards a facsimile of a junior copy paste outsourcing nightmare they can’t maintain (creating exciting liabilities for all parties involved). I can’t shake the feeling that simply being a shameless about copy-paste (ie copyright infringement), would let existing tools do much the same faster and more efficiently. Download Chromium, search-replace ‘Google’ with ‘ME!’, run Make… if I put that in a small app someone would explain that’s actually solvable as a bash one-liner. There’s a lot of utility in better search and natural language interactions. The siren call of feedback loops plays with our sense of time and might be clouding or sense of progress and utility.
micimize 9mo ago
> While it might seem like a simple screenshot, building a browser from scratch is extremely difficult. > Another experiment was doing an in-place migration of Solid to React in the Cursor codebase. It took over 3 weeks with +266K/-193K edits. As we've started to test the changes, we do believe it's possible to merge this change. In my view, this post does not go into sufficient detail or nuance to warrant any serious discussion, and the sparseness of info mostly implies failure, especially in the browser case. It _is_ impressive that the browser repo can do _anything at all_, but if there was anything more noteworthy than that, I feel they'd go into more detail than volume metrics like 30K commits, 1M LoC. For instance, the entire capability on display could be constrained to a handful of lines that delegate to other libs. And, it "is possible" to merge any change that avoids regressions, but the majority of our craft asks the question "Is it possible to merge _the next_ change? And the next, and the 100th?" If they merge the MR they're walking the walk. If they present more analysis of the browser it's worth the talk (not that useful a test if they didn't scrutinize it beyond "it renders") Until then, it's a mountain of inscrutable agent output that manages to compile, and that contains an execution pathway which can screenshot apple.com by some undiscovered mechanism.
- embedding-shape 9mo ago
  > it's a mountain of inscrutable agent output that manages to compile But is this actually true? They don't say that as far as I can tell, and it also doesn't compile for me nor their own CI it seems.
  - sashank_1509 9mo ago
    Oh it doesn’t compile? that’s very revealing
    - rvz 9mo ago
      Some people just believe anything said on X these days. No timeline from start to finish, just "trust me bro". If you can't reproduce or compile the experiment then it really doesn't work at all and nothing but a hype piece.
tired_and_awake 9mo ago
The moment all code is interacted with through agents I cease to care about code quality. The only thing that matters is the quality of the product, cost of maintenance etc. exactly the thing we measure software development orgs against. It could be handy to have these projects deployed to demonstrate their utility and efficacy? Looking at PRs of agents feels a wrong headed, like who cares if agents code is hard to read if agents are managing the code base?
- icedchai 9mo ago
  This is how we wound up with non-technical "engineering managers." Looks good to me.
  - tired_and_awake 9mo ago
    I think this misses the point, see the other comments. Fully scaled agentic coding replaces managers too :) cause for celebration all around
    - icedchai 9mo ago
      I don't believe that. If you go fully agentic and you don't understand the output, you become the manager. You're in no better position than the pointy-haired boss from Dilbert.
      - tired_and_awake 8mo ago
        Hey just wanted to thank you for the healthy back and forth! I respect your opinion and don't hold mine strongly. That said I'm eager for this space to mature and for us all to figure out the best way to interact with fault prone code generation tooling... Especially at scale where we all have the hardest time navigating complexity.
        icedchai 8mo ago
        Thanks. It's fun chatting about this stuff! I don't hold mine strongly, either, though I am dealing with lots of AI generated slop code from others. Interesting times ahead.
matthewfcarlson 9mo ago
It’s fascinating that many of the issues they faced I’ve seen in human software engineering teams. Things like integration creating bottlenecks or a lack of consistent top down direction leading to small risk adverse changes instead of bold redesigns. All things I’ve seen before.
- 2001zhaozhao 9mo ago
  At least the AI teams aren't politically competing against each other unlike human teams. (Or are they?)
nl 9mo ago
Remember when 3D printers meant the death of factories? Everyone would just print what they wanted at home. I'm very bullish on LLMs building software, but this doesn't mean the death of software products anymore than 3D printers meant the death of factories.
- ben_w 8mo ago
  Perhaps, but I don't think that's a good analogy, there's too many important differences to say (3d printing : all manufacturing) : (vibe coding : all software). The hype may be similar, if that's your point then I agree, but the weakness of 3D printing is the range of materials and the conditions needed to work with them (titanium is merely extremely difficult, but no sane government will let the general public buy tetrafluoroethylene as a feedstock), while the weakness of machine learning (even more broadly than LLMs) is the number of examples they require in order to learn stuff.
luhego 9mo ago
> We initially built an integrator role for quality control and conflict resolution, but found it created more bottlenecks than it solved Of course it creates bottlenecks, since code quality takes time and people don’t get it right on the first try when the changes are complex. I could also be faster if I pushed directly to prod! Don’t get me wrong. I use these tools, and I can see the productivity gains. But I also believe the only way to achieve the results they show is to sacrifice quality, because no software engineer can review the changes at the same speed the agent generates code. They may solve that problem, or maybe the industry will change so only output and LOC matter, but until then I will keep cursing the agent until I get the result I want.
WOTERMEON 9mo ago
Weird twist the hiring call at the end for a company that says > Our mission is to automate coding
mdswanson 9mo ago
Over the past year or so, I've built my own system of agents that behaves almost exactly like this. I can describe what I'd like built before I go to bed and have a fantastic foundation in place by the next day. For simpler projects, they'll be complete. Because of the reviews, the code continually improves until the agents are satisfied. I'm impressed every time.
- z_zetetic_z 8mo ago
  Any chance you would care to share more about this?
reactordev 9mo ago
The planner worker architecture works well for me. About 3 layers is the sweet spot. From prompt -> plan -> task division -> workers. Sometimes workers will task other workers and act as a planner if the task is more complex. It’s a good setup but it’s nothing like Claude Code.
logicallee 9mo ago
At the same time they were doing this, I also iterated on an AI-built web browser with around 2,000 lines of code. I was heavily in the loop for it, it didn't run autonomously. You can see the current version of the source code here: https://taonexus.com/publicfiles/jan2026/172toy-browser.py.txt https://taonexus.com/publicfiles/jan2026/172toy-browser.py.t... (turn the sound down, it's a bit loud if you interact with the built-in Tetris clone.) You can run it after installing the packages, "pip install requests pillow urllib3 numpy simpleaudio" I livestreamed the latest version here 2 weeks ago, it's a ten minute video: https://www.youtube.com/watch?v=4xdIMmrLMLo&t=45s https://www.youtube.com/watch?v=4xdIMmrLMLo&t=45s I'm posting from that web browser. As an easter egg, mine has a cool Tetris clone (called Pentrix) based on pieces with 5 segments, the button for this is at the upper-right. If you have any feature suggestions for what you want in a browser, please make them here: https://pollunit.com/polls/ahysed74t8gaktvqno100g https://pollunit.com/polls/ahysed74t8gaktvqno100g
tehsauce 9mo ago
I was excited to try it out so I downloaded the repo and ran the build. However there were 100+ compilation errors. So I checked the commit history on github and saw that for at least several pages back all recent commits had failed in the CI. It was not clear which commit I should pick to get the semi-working version advertised. I started looking in the Cargo.toml to at least get an idea how the project was constructed. I saw there that rather than being built from scratch as the post seemed to imply that almost every core component was simply pulled in from an open source library. quickjs engine, wgpu graphics, winit windowing & input, egui for ui, html parsing, the list goes on. On twitter their CEO explicitly stated that it uses a "custom js vm" which seemed particularly misleading / untrue to me. Integrating all of these existing components is still super impressive for these models to do autonomously, so I'm just at a loss how to feel when it does something impressive but they then feel the need to misrepresent so much. I guess I just have a lot less respect and trust for the cursor leadership, but maybe a little relief knowing that soon I may just generate my own custom cursor!
- whatever1 8mo ago
  You are doing it wrong. Take a screenshot and take it to your manager / investor and make a presentation “Imagine what is now possible for our business”. Get promoted / exit, move to other pastures and let them figure it out.
- eeL3bo1mohn7pee 8mo ago
  Of 63295 workflow runs, apparently only 1426 have been successful. It's hard to avoid the impression that this is an unverified pile of slop that may have actually never worked. The CI process certainly hasn't succeeded for the vast majority of commits. Baffling, really.
  - alfalfasprout 8mo ago
    You should see the code. It's true slop. The organization makes no sense.
- handfuloflight 8mo ago
navinsylvester 9mo ago
all these focus on long running agents without focussing on core restructure is baffling. the immediate need is to break down complex tasks into smaller ones and single shot them with some amount of parallelism. imo - we need an opinionated system but with human in the middle and then think about dreamy next steps. we need to focus on groundedness first instead of worrying about agent conjuring something from thin air. the decision to leap frog into automated long running agents is quite baffling. boys are trying to single shot a browser when a moderate complex task can derail a repo. there’s no good amount of info which might be deliberate but from what i can pick, their value add was “distributed computing and organisational design” but that too they simplified. i agree that simplicity is always the first option but flat filesystem structure without standards will not work. period.
- vivekv 8mo ago
  I would agree with this. There are definite challenges in grounded specifications today and the tendency for an LLM to go in tangents that is still a struggle that we all deal with every day.
measurablefunc 9mo ago
All of these things have readily available analogues on the web which means they are more than likely just laundering open source code & claiming victory.
- rzmmm 8mo ago
  There are many open-source toy browser implementations available, so this seems quite likely.
- random_mutex 8mo ago
  It doesn't compile so no victory
  - measurablefunc 8mo ago
    Just the usual corporate marketing & hype.
foota 8mo ago
I've always liked the idea of intelligence in the autonomous ships of the Revelation Space universe. Little agents reporting to progressively more intelligent and higher level ones.
- satvikpendem 8mo ago
  That's essentially all life from the sub-cellular level on up
foota 8mo ago
Slightly off topic, but they want to move from solid to react? Isn't that the reverse of the newest trend? Would be interesting to know more.
- random_mutex 8mo ago
  Most likely LLMs are better at writing react
gaigalas 8mo ago
There's a clear conflict between SKILLS, tools and multi-tasking. I think "intra-context" tooling is already dead. It's too narrow. It's all "extra-context" now: how one instruments for multiple agents, at multiple times, handling things. Personally, I think the best tool in this realm will come from open source, and be agnostic (many agents from many places interacting), in order to leverage differences between subtle provider qualities (speed, price and so on). Building a browser is an interesting and expensive experiment. How much did it cost?
dinkm 8mo ago
“Arthur looked up. ‘Ford,’ he said, ‘there’s an infinite number of monkeys outside who want to talk to us about this script for Hamlet they’ve worked out.”
torginus 8mo ago
I'm kinda surprised how negative and skeptical anyone is here. It kinda blows my mind that this is possible, to build a browser engine that approximates a somewhat working website renderer. Even if we take the most pessimistic interpretation of events ( heavy human steering, relies on existing libraries, sloppy code quality at places, not all versions compile etc)
- ben_w 8mo ago
  I'm not too surprised, the way I read a lot of (not all!*) the negative comments is ~"I'm imagining having to work with this code, I'd hate it". Even though I'm fairly impressed with the work LLMs do, this has also been my experience of them… albeit with a vibe-coding** sample size of 1, done over a few days with some spare credit. The positive views are mostly from people who point out that what matters in the end is what the code does, not what it looks like, e.g. users don't see the code, nor do they care about the code, and that even for businesses who do care, LLMs may be the ones who have to pay down any technical debt that builds up. * Anyone in a field where mistakes are expensive. In one project, I asked the LLM to code-review itself and it found security vulnerabilities in its own solutions. It's probably still got more I don't know about. ** In the original sense of just letting the LLM do whatever it wanted in response to the prompt, never reading or code reviewing the result myself until the end.
  - satvikpendem 8mo ago
    The problem I've had with vibe coding is akin the adage of the first 90% of the code taking 90% of the time, and the last 10% taking the other 90% of the time. The LLM can get you to 90% initially but it hits a wall unless you the user know what it's doing and outputting, but that is very difficult when you're vibe coding by its very definition, meaning that you're not looking at the code at all. And then you have to read thousands of lines of code which you don't understand that it's entirely easier to stop and hand code a new version yourself, which is precisely what I've done with some of my projects.
    - alfalfasprout 8mo ago
laszlojamf 8mo ago
They mention billions of tokens, but I'm left wondering how much this experiment actually cost them...
torginus 8mo ago
Personally what I don't like about this now that I think about it, is that they didn't scale up gradually, let's say there there's a ladder of complexity in software, starting at a simple React CRUD app, going on to something more complex, such as a Paint clone, to something even more complex, like a file manager etc, ending up at one of the most complex pieces of software ever made, a web browser. I'd want to see some system, that 100%s the first task, saturation, does a great job on the next, then does a valiant effort on the third, then finally makes something promising but as yet unusable on the last. This way we could see that scaling up difficulty results in a gradual decline in quality, and could have a decent measurement of where we are at and where we are going.
throwaway63467 8mo ago
I‘m running opus 4.5 which is arguably their best model and while it’s really good for a lot of work it always introduces subtle errors or inconsistencies when left unsupervised as prompts are never good enough to remove all ambiguity for complex asks, so I can’t imagine what it will do to a code base when left alone with it for days or weeks.
sidgarimella 8mo ago
Very cool. Seems long running AI Agents are the new monuments.
physicsguy 8mo ago
I have been trying Claude Code a lot this week. Two projects: * A small statically generated Hugo website but with some clever linking/taxonomy stuff. This was a fairly self-contained project that is now 'finished' but wouldn't hvae taken me more than a few days to code up from scratch. * A scientific simulation package, to try and do a clean refresh of an existing one which i can point at for implementation details but which has some technical problems I would like to reduce/remove. Claude code absolutely smashed the first one - no issues at all. With the second, no matter what I tried, it just made lots of mistakes, even when I just told it to copy the problematic parts and transpose them into the new structure. It basically got to a point where it wasn't correct and it didn't seem to be able to get out of a bit of a 'doom loop' and required manual intervention, no matter how much prompting and hints I gave it.
- underdeserver 8mo ago
  On Twitter people are saying GPT-5.2 is better. That's also what Cursor used in their testing. Maybe try it?
  - physicsguy 8mo ago
    I have Web access for ChatGPT through work, but not API access annoyingly.
    - xpil 8mo ago
      Codex plugin (VSCode) allows consuming your "web" (ie non-api) subscription for coding/agentic tasks.
- Bishonen88 8mo ago
  Similar experience here. Did sign up for Claude Code myself this week, too, given the $10/month promo. I have experience with AI by using AWS Kiro at work and directly prompting Claude Opus for convos. After just 2 days and ~5-6 vibe coding sessions in total I got a working Life-OS-App created for my needs. - Clone of Todoist with the features that I actually use/want. Projects, Tags, due dates, quick adding with a todoist like text-aware input (e.g. !p1, Today etc.) - A fantastical like calendar. Again, 80% of the features I used from Fantastical - A Habit Tracker - A Goal Tracker (Quarterly / Yearly) - A dashboard page showing todays summary with single click edit/complete marking - User authentication and sharing of various features (e.g. tasks) - Docker deployment which will eventually run on my NAS I'm going to add a few more things and cancel quite a few subscriptions. It one-shots all tasks within minutes. It's wild. I can code but didn't bother looking at the code myself, because ... why. Even though do not earn US Tech money, am tempted to buy the max subscription for a month or two although the price is still hard to swallow. Claude and vibe coding is wild. If I can clone todoist within a few vibe coding sessions and then implement any additional/new feature I want within minutes instead proposing, praying and then waiting for months, why would I pay $$$...
ramon156 8mo ago
> A long-running agent made video rendering 25x faster with an efficient Rust version. Which is not an optimization. This is coming from a Rust dev; Rewriting it in Rust is not the optimization. Also, I do not believe they actually reviewed the SolidJS->React PR. This PR is incredibly unrealistic and should've been done with either stacker PRs or incremental non-breaking changes. None of this feels organic, can we stop pretending it is? To continue the pessimistic tone, none of the writing went in-depth. I did not gain any knowledge, just a marketing post.
Havoc 8mo ago
> long running I really dislike this as a measure. A LLM on CPU is also long running cause it’s slow. I get what it’s meant to convey but time is such a terrible measure of anything if tk/s isn’t static
danieloj 8mo ago
I'm not sure "building a web browser" is such a great test for an LLM. It helps confirm that they can handle large codebases. But the actual logic in the browser engine will be based very heavily on Chromium/Firefox etc.
kilroy123 8mo ago
My test for whether we've created an AGI like AI? Build a Linux kernel from scratch that can actually run a full OS on your computer. But, if I'm being fair, a full working browser from scratch is just as good.
george_atom 8mo ago
Reviewing all this code is the issue.
jamesnorden 8mo ago
Is the code not even compiling a feature or...
tgtweak 8mo ago
Is it too much to expect companies to share some of this in the open vs just the results?
Snuggly73 8mo ago
The only thing that I got to actually run on WSL2 was the "Excel" (couldnt get anything actually to compile on Mac or Windows). It a broken mess that probably implements 0.00001% of Excel. And its 1.2m locs. With codebases developed in this way - either they need to figure out how agents are going to maintain them (in which case SWE as we know is dead - it will only be limited to those that can spend trillions of tokens, or they are going to remain weird demos.
- timabdulla 8mo ago
  I'd be curious to see screenshots or a video! I only have a Mac at my disposal, unfortunately.
Snuggly73 8mo ago
And there is the thing about the cost. The blog post says that they've spent trillions (plural!) of tokens on that experiment. Looking at OAI API pricing, 5.2 Codex is $14 per 1 million output tokens. Which makes cool $14m for 1 trillion tokens (multiplied by whatever the plural is). For something that "kind of works". Its a nice ad for OAI and Anysphere, but maybe next time - just donate the money to a browser team?
deleted 8mo ago
[deleted]
darioush 8mo ago
I find it interesting that this line of adventure quickly lead to locking problems.
thesurlydev 8mo ago
Pretty cool and related to another path of work I'm following from Steve Yegge: https://medium.com/@steve-yegge/welcome-to-gas-town-4f25ee16dd04 https://medium.com/@steve-yegge/welcome-to-gas-town-4f25ee16...
cawksuwcka 8mo ago
would really appreciate some elaboration as they gloss over the most important part in my kind. why can’t one agent just do it. that’s what ai seems to be - an amalgamation of all our knowledge. why split it back up into separate tentacles. i think focus should be on letting it envelop the problem like a fog and swallow it whole, instead of molesting it independently at touch points and reporting back to … the brain? it’s pretty ridiculous actually. just mimicking ourselves yet again.
- cawksuwcka 8mo ago
  perhaps ai is a human based solution thus it’s limitations? further, it’s a human problem so we can only solve it in a human way? can we not escape our damned humanity?
isusmelj 8mo ago
I think we are just very close to the peak of a typical Gartner hype cycle around LLMs. They are useful but overhyped. There will be more posts about fuckups that happen because people run things on autopilot and cannot keep up with reviewing AI generated code. Do not get me wrong. I use AI all day to speed things up. But I believe that there is only a small group, maybe 5 percent or less, that actually knows how to use AI properly (I'd count myself not yet in that 5%), which I see as potentially dangerous. The other issue I see is inexperienced software engineers writing software. Although I see this as a great value add and productivity boost for prototyping, I am afraid of the “I do not know much about coding but can also make PRs to our codebase” mentality. For those of you that run things on autopilot, how do you keep code quality under control? And how do you handle refactoring? I am really curious, because one option now is also to just YOLO your LLMs to write code based on the maturity of the product. You can refactor an app or parts of it pretty fast again with LLMs. While tech debt accumulates faster, we also have the opportunity to rebuild faster.
nashadelic 8mo ago
I'm very curious about how much of it is re-using (remixing?) an existing browser implementation it has seen in the while or its trained on. Even in that case, 99% of all code isn't doing anything novel so this copying would still have significant practical use.
deleted 8mo ago
[deleted]

290 points by samwillis 9mo ago

The browser it built, obviously the context window of the entire project is huge. They mention loads of parallel agents in the blog post, so I guess each agent is given a module to work on, and some tests? And then a 'manager' agent plugs this in without reading the code? Otherwise I can't see how, even with ChatGPT 5.2/Gemini 3, you could do this otherwise? In retrospect it seems an obvious approach and akin to how humans work in teams, but it's still interesting.

simonw 9mo ago
GPT-5.2-Codex has a 400,000 token window. Claude 4.5 Opus is half of that, 200,000 tokens. It turns out to matter a whole lot less than you would expect. Coding Agents are really good at using grep and writing out plans to files, which means they can operate successfully against way more code than fits in their context at a single time.
- jaggederest 9mo ago
  The other issue with "a huge token window" is that if you fill it, it seems like relevance for any specific part of the window is diminished - which makes it hard to override default model behavior. Interestingly, recently it seems to me like codex is actually compressing early and often so that it stays in the smarter-feeling reasoning zone of the first 1/3rd of the window, which is a neat solution for this, albeit with the caveat of post-compression behavior differences cropping up more often.
observationist 9mo ago
Get a good "project manager" agents.md and it changes the whole approach of vibe coding. For a professional environment, with each person given a little domain, arranged in the usual hierarchy of your coding team, truly amazing things can get done. Presumably the security and validation of code still needs work, I haven't read anything that indicates those are solved yet, so people still need to read and understand the code, but we're at the "can do massive projects that work" stage. Division of labor and planning and hierarchy are all rapidly advancing, the orchestration and coordination capabilities are going to explode in '26.
- azan_ 8mo ago
  Could you perhaps share such agents.md? Sounds interesting
- heliumtera 8mo ago
  I tried this approach yesterday and I`m loving our daily standup with the agents. Looking forward to our retro and health-checks rituals
galaxyLogic 9mo ago
> so I guess each agent is given a module to work on, and some tests? Who created those agents and gives them the tasks to work on. Who created the tests? AI, or the humans?
nl 9mo ago
Generally they only load a bit of the project into the context at a time. Grep works really well for working out what.

simonw 9mo ago

"To test this system, we pointed it at an ambitious goal: building a web browser from scratch." I shared my LLM predictions last week, and one of them was that by 2029 "Someone will build a new browser using mainly AI-assisted coding and it won’t even be a surprise" https://simonwillison.net/2026/Jan/8/llm-predictions-for-2026/#3-years-someone-will-build-a-new-browser-using-mainly-ai-assisted-coding-and-it-won-t-even-be-a-surprise https://simonwillison.net/2026/Jan/8/llm-predictions-for-202... and https://www.youtube.com/watch?v=lVDhQMiAbR8&t=3913s https://www.youtube.com/watch?v=lVDhQMiAbR8&t=3913s This project from Cursor is the second attempt I've seen at this now! The other is this one: https://www.reddit.com/r/Anthropic/comments/1q4xfm0/over_christmas_break_i_wrote_a_fully_functional/ https://www.reddit.com/r/Anthropic/comments/1q4xfm0/over_chr...

cheevly 9mo ago
2029? I have no idea why you would think this is so far off. More like Q2 2026.
- xmprt 9mo ago
  You're either overestimating the capabilities of current AI models or underestimating the complexity of building a web browser. There are tons of tiny edge cases and standards to comply with where implementing one standard will break 3 others if not done carefully. AI can't do that right now.
  - rvz 9mo ago
    It's most likely both. > There are tons of tiny edge cases and standards to comply with where implementing one standard will break 3 others if not done carefully. AI can't do that right now. Firstly the CI is completely broken on every commit, all tests have failed and its and looking closely at the code, it is exactly what you expect for unmaintainable slop. Having more lines of code is not a good measure of robust software, especially if it does not work.
  - torginus 8mo ago
    Even if AI will not achieve the ability to perform at this level on its own, it clearly is going to be an enormous force multiplier, allowing highly skilled devs to tackle huge projects more or less on their own.

sashank_1509 9mo ago

Can a browser expert please go through the code the agent wrote (skim it), and let us know how it is. Is it comparable to ladybird, or Servo, can it ever reach that capability soon?

krackers 9mo ago
I'm interested in this too. I was expecting just a chromium reskin, but it does seem to be at least something more than that. https://news.ycombinator.com/item?id=46625189 https://news.ycombinator.com/item?id=46625189 claims it uses Taffy for CSS layout but the docs also claim "Taffy for flex/grid, native for tables/block/inline"
missingdays 8mo ago
You can start by trying to compile the project (spoiler: you can't)
polyglotfacto 8mo ago
I've done this in the parallel post, see https://news.ycombinator.com/item?id=46705625 https://news.ycombinator.com/item?id=46705625 (and a couple of other replies in that thread) TLDR; the code is not a valid POC but throw-away level quality that could never support a functioning web engine. It's actually very clear hallucinated AI BS, which is what you get when you don't have a human expert in the loop. I actually like using AI, but only to save me the typing.

ZitchDog 9mo ago

I used similar techniques to build tjs [1] - the worlds fastest and most accurate json schema validator, with magical TypeScript types. I learned a lot about autonomous programming. I found a similar "planner/delegate" pattern to work really well, with the use of git subtrees to fan out work [2]. I think any large piece of software with well established standards and test suites will be able to be quickly rewritten and optimized by coding agents. [1] https://github.com/sberan/tjs https://github.com/sberan/tjs [2] /spawn-perf-agents claude command: https://github.com/sberan/tjs/blob/main/.claude/commands/spawn-perf-agents.md https://github.com/sberan/tjs/blob/main/.claude/commands/spa...

trjordan 9mo ago

This is going to sound sarcastic, but I mean this fully: why haven't they merged that PR. The implied future here is _unreal cool_. Swarms of coding agents that can build anything, with little oversight. Long-running projects that converge on high-quality, complex projects. But the examples feel thin. Web browsers, Excel, and Windows 7 exist, and they specifically exist in the LLM's training sets. The closest to real code is what they've done with Cursor's codebase .... but it's not merged yet. I don't want to say, call me when it's merged. But I'm not worried about agents ability to produce millions of lines of code. I'm worried about their ability to intersect with the humans in the real world, both as users of that code and developers who want to build on top of it.

dist-epoch 9mo ago
Pretty much everything exists in the training sets. All non-research software is just a mishmash of various standard modules and algorithms.
- galaxyLogic 9mo ago
  Not everything, only code-bases of existing (open-source?) applications. But what would be the point of re-creating existing applications? It would be useful if you can produce a better version of those applications. But the point in this experiment was to produce something "from scratch" I think. Impressive yes, but is it useful? A more practically useful task would be for Mozilla Foundation and others to ask AI to fix all bugs in their application(s). And perhaps they are trying to do that, let's wait and see.
  - mkoubaa 9mo ago
    You have to be careful which codebase to try this on. I have a feeling if someone unleashed agents on the Linux kernel to fix bugs it'd lead to a ban on agents there
  - conradev 8mo ago
    Re-creating closed source applications as open source would have a clear benefit because people could use those applications in a bunch of new ways. (implied: same quality bar)

dist-epoch 9mo ago

So, who is going to compile the browser and post the binaries so we can check it out? (in a sandbox/VM obviously)

missingdays 8mo ago
It doesn't compile

mk599 9mo ago

Define "from scratch" in "building a web browser from scratch". This thing has over 100 crates as dependencies... To implement css layouting, it uses Taffy, a crate used by existing browser implementations...

rvz 9mo ago
When I see hundreds of crates being used in a project, I have to just scratch my head and ask: What the f___? If one vulnerability exists in those crates well, thats that.
qingcharles 8mo ago
And it's not necessarily a bad move to use all those dependencies, but you're right it makes the claim shady. I can create a web browser in under a minute in Copilot if I ask it to build a WinForms project that embeds the WebView2 "Edge" component and just adds an address bar and a back button.

ora-600 9mo ago

I would love to know the cost of building this browser. I think that multi-agent orchestration systems will probably be the theme for systems this year. I think the north-star metric for a multi-agent orchestrator system would be how much did it cost to get this done. how much better could we have done? should we have used a cheaper model for doing a trivial task and an expensive one to monitor it?

mccoyb 9mo ago

Supposing agents and their organization improve, it seems like we’re approaching a point where the cost of a piece of software will be driven down to the cost of running the hardware, and the cost of the tokens required to replicate it. The tokens were “expensive” from the minds of humans …

Daishiman 9mo ago
It will be driven down to the cost of having a good project and product manager effectively understanding what the customer wants, which has been the main barrier to excellent software for a good long time.
- galaxyLogic 9mo ago
  And not only understanding what the customer wants, but communicating that unambiguously to the AI. And note who is the "customer" here? Is it the end-users, or is it a client-company which contracts the project-manager for this task? But then the issue is still there, who in the client-company decides exactly what is needed and what the (potential) users want? I think this situation emphasizes the importance of (something like) Agile. To produce something useful can only happen via experimentation and getting feedback from actual users, and re-iterating relentlessly.

jphelan 9mo ago

This looks like extremely brittle code to my eyes. Look at https://github.com/wilsonzlin/fastrender/blob/main/crates/fastrender-renderer/src/lib.rs https://github.com/wilsonzlin/fastrender/blob/main/crates/fa... What is `FrameState::render_placeholder`? ``` pub fn render_placeholder(&self, frame_id: FrameId) -> Result<FrameBuffer, String> { let (width, height) = self.viewport_css; let len = (width as usize) .checked_mul(height as usize) .and_then(|px| px.checked_mul(4)) .ok_or_else(|| "viewport size overflow".to_string())?; if len > MAX_FRAME_BYTES { return Err(format!( "requested frame buffer too large: {width}x{height} => {len} bytes" )); } // Deterministic per-frame fill color to help catch cross-talk in tests/debugging. let id = frame_id.0; let url_hash = match self.navigation.as_ref() { Some(IframeNavigation::Url(url)) => Self::url_hash(url), Some(IframeNavigation::AboutBlank) => Self::url_hash("about:blank"), Some(IframeNavigation::Srcdoc { content_hash }) => { let folded = (*content_hash as u32) ^ ((*content_hash >> 32) as u32); Self::url_hash("about:srcdoc") ^ folded } None => 0, }; let r = (id as u8) ^ (url_hash as u8); let g = ((id >> 8) as u8) ^ ((url_hash >> 8) as u8); let b = ((id >> 16) as u8) ^ ((url_hash >> 16) as u8); let a = 0xFF; let mut rgba8 = vec![0u8; len]; for px in rgba8.chunks_exact_mut(4) { px[0] = r; px[1] = g; px[2] = b; px[3] = a; } Ok(FrameBuffer { width, height, rgba8, }) } } ``` What is it doing in these diffs? https://github.com/wilsonzlin/fastrender/commit/f4a0974594e3945a26c7335a67d16e62ef09d71f https://github.com/wilsonzlin/fastrender/commit/f4a0974594e3... I'd be really curious to see the amount of work/rework over time, and the token/time cost for each additional actual completed test case.

blibble 9mo ago
this is certainly an interesting way to pull out an attribute from a tag: https://github.com/wilsonzlin/fastrender/blob/main/crates/fastrender-renderer/src/lib.rs#L441 https://github.com/wilsonzlin/fastrender/blob/main/crates/fa...
blamestross 9mo ago
I suppose brittle code is fine if you have cursor to update and fix it. Ideal really, keeps you dependent.

embedding-shape 9mo ago

Did anyone manage to run the tests from the repository itself? The code seems filled with errors and warnings, as far as I can tell none of them because of the platform I'm on (Linux). I went and looked at the Action workflow history for some pages, and seems CI been failing for a while, PRs also all been failing CI but merged. How exactly was this verified to be something to be used as an successful example, or am I misunderstanding what point they are trying to make? They mention a screenshot, but they never actually mention if their goal was successfully met, do they? I'm not sure the approach of "completely autonomous coding" is the right way to go. I feel like maybe we'll be able to use it more effectively if we think of them as something to be used by a human to accomplish some thing instead, lean into letting the human drive the thing instead, because quality spirals so quickly out of control.

snek_case 9mo ago
I found the codebase very hard to navigate. Hundreds (over a thousand?) tiny files with less than 200 lines of code, in deeply nested subdirectories. I wanted to find where the JavaScript engine was, and where the DOM implementation was located, and I couldn't easily find it, even using the GitHub search feature. I'm not exactly sure what this browser implements and how. Even their README is kind of crappy. Ideally you want installation instructions right near the top, but it's broken into multiple files. The README link that says "running + architecture" (but the file is actually called browser_ui.md???) is hard to follow. There is no explicit list of dependencies, and again no explanation of how JavaScript execution works, or how rendering works, really. It's impressive that they got such a big project to be built by agents and to compile, but this codebase... Feels like AI slop, and you couldn't pay me to maintain it. You could try to get AI agents to maintain it, but my prediction is that past some scale, they would have a hard time figuring out their own mess. You would just be left with permanent bugs you can't easily fix.
- bonesss 8mo ago
  So the chain of events here is: copy existing tutorials and public/available code, train the model to spit it out-ish when asked, a mature-ish specification is used, and now they jitter and jumble towards a facsimile of a junior copy paste outsourcing nightmare they can’t maintain (creating exciting liabilities for all parties involved). I can’t shake the feeling that simply being a shameless about copy-paste (ie copyright infringement), would let existing tools do much the same faster and more efficiently. Download Chromium, search-replace ‘Google’ with ‘ME!’, run Make… if I put that in a small app someone would explain that’s actually solvable as a bash one-liner. There’s a lot of utility in better search and natural language interactions. The siren call of feedback loops plays with our sense of time and might be clouding or sense of progress and utility.

micimize 9mo ago

> While it might seem like a simple screenshot, building a browser from scratch is extremely difficult. > Another experiment was doing an in-place migration of Solid to React in the Cursor codebase. It took over 3 weeks with +266K/-193K edits. As we've started to test the changes, we do believe it's possible to merge this change. In my view, this post does not go into sufficient detail or nuance to warrant any serious discussion, and the sparseness of info mostly implies failure, especially in the browser case. It _is_ impressive that the browser repo can do _anything at all_, but if there was anything more noteworthy than that, I feel they'd go into more detail than volume metrics like 30K commits, 1M LoC. For instance, the entire capability on display could be constrained to a handful of lines that delegate to other libs. And, it "is possible" to merge any change that avoids regressions, but the majority of our craft asks the question "Is it possible to merge _the next_ change? And the next, and the 100th?" If they merge the MR they're walking the walk. If they present more analysis of the browser it's worth the talk (not that useful a test if they didn't scrutinize it beyond "it renders") Until then, it's a mountain of inscrutable agent output that manages to compile, and that contains an execution pathway which can screenshot apple.com by some undiscovered mechanism.

embedding-shape 9mo ago
> it's a mountain of inscrutable agent output that manages to compile But is this actually true? They don't say that as far as I can tell, and it also doesn't compile for me nor their own CI it seems.
- sashank_1509 9mo ago
  Oh it doesn’t compile? that’s very revealing
  - rvz 9mo ago
    Some people just believe anything said on X these days. No timeline from start to finish, just "trust me bro". If you can't reproduce or compile the experiment then it really doesn't work at all and nothing but a hype piece.

tired_and_awake 9mo ago

The moment all code is interacted with through agents I cease to care about code quality. The only thing that matters is the quality of the product, cost of maintenance etc. exactly the thing we measure software development orgs against. It could be handy to have these projects deployed to demonstrate their utility and efficacy? Looking at PRs of agents feels a wrong headed, like who cares if agents code is hard to read if agents are managing the code base?

icedchai 9mo ago
This is how we wound up with non-technical "engineering managers." Looks good to me.
- tired_and_awake 9mo ago
  I think this misses the point, see the other comments. Fully scaled agentic coding replaces managers too :) cause for celebration all around
  - icedchai 9mo ago
    I don't believe that. If you go fully agentic and you don't understand the output, you become the manager. You're in no better position than the pointy-haired boss from Dilbert.
    - tired_and_awake 8mo ago
      Hey just wanted to thank you for the healthy back and forth! I respect your opinion and don't hold mine strongly. That said I'm eager for this space to mature and for us all to figure out the best way to interact with fault prone code generation tooling... Especially at scale where we all have the hardest time navigating complexity.
      - icedchai 8mo ago
        Thanks. It's fun chatting about this stuff! I don't hold mine strongly, either, though I am dealing with lots of AI generated slop code from others. Interesting times ahead.

matthewfcarlson 9mo ago

It’s fascinating that many of the issues they faced I’ve seen in human software engineering teams. Things like integration creating bottlenecks or a lack of consistent top down direction leading to small risk adverse changes instead of bold redesigns. All things I’ve seen before.

2001zhaozhao 9mo ago
At least the AI teams aren't politically competing against each other unlike human teams. (Or are they?)

nl 9mo ago

Remember when 3D printers meant the death of factories? Everyone would just print what they wanted at home. I'm very bullish on LLMs building software, but this doesn't mean the death of software products anymore than 3D printers meant the death of factories.

ben_w 8mo ago
Perhaps, but I don't think that's a good analogy, there's too many important differences to say (3d printing : all manufacturing) : (vibe coding : all software). The hype may be similar, if that's your point then I agree, but the weakness of 3D printing is the range of materials and the conditions needed to work with them (titanium is merely extremely difficult, but no sane government will let the general public buy tetrafluoroethylene as a feedstock), while the weakness of machine learning (even more broadly than LLMs) is the number of examples they require in order to learn stuff.

luhego 9mo ago

> We initially built an integrator role for quality control and conflict resolution, but found it created more bottlenecks than it solved Of course it creates bottlenecks, since code quality takes time and people don’t get it right on the first try when the changes are complex. I could also be faster if I pushed directly to prod! Don’t get me wrong. I use these tools, and I can see the productivity gains. But I also believe the only way to achieve the results they show is to sacrifice quality, because no software engineer can review the changes at the same speed the agent generates code. They may solve that problem, or maybe the industry will change so only output and LOC matter, but until then I will keep cursing the agent until I get the result I want.

WOTERMEON 9mo ago

Weird twist the hiring call at the end for a company that says > Our mission is to automate coding

mdswanson 9mo ago

Over the past year or so, I've built my own system of agents that behaves almost exactly like this. I can describe what I'd like built before I go to bed and have a fantastic foundation in place by the next day. For simpler projects, they'll be complete. Because of the reviews, the code continually improves until the agents are satisfied. I'm impressed every time.

z_zetetic_z 8mo ago
Any chance you would care to share more about this?

reactordev 9mo ago

The planner worker architecture works well for me. About 3 layers is the sweet spot. From prompt -> plan -> task division -> workers. Sometimes workers will task other workers and act as a planner if the task is more complex. It’s a good setup but it’s nothing like Claude Code.

logicallee 9mo ago

At the same time they were doing this, I also iterated on an AI-built web browser with around 2,000 lines of code. I was heavily in the loop for it, it didn't run autonomously. You can see the current version of the source code here: https://taonexus.com/publicfiles/jan2026/172toy-browser.py.txt https://taonexus.com/publicfiles/jan2026/172toy-browser.py.t... (turn the sound down, it's a bit loud if you interact with the built-in Tetris clone.) You can run it after installing the packages, "pip install requests pillow urllib3 numpy simpleaudio" I livestreamed the latest version here 2 weeks ago, it's a ten minute video: https://www.youtube.com/watch?v=4xdIMmrLMLo&t=45s https://www.youtube.com/watch?v=4xdIMmrLMLo&t=45s I'm posting from that web browser. As an easter egg, mine has a cool Tetris clone (called Pentrix) based on pieces with 5 segments, the button for this is at the upper-right. If you have any feature suggestions for what you want in a browser, please make them here: https://pollunit.com/polls/ahysed74t8gaktvqno100g https://pollunit.com/polls/ahysed74t8gaktvqno100g

tehsauce 9mo ago

I was excited to try it out so I downloaded the repo and ran the build. However there were 100+ compilation errors. So I checked the commit history on github and saw that for at least several pages back all recent commits had failed in the CI. It was not clear which commit I should pick to get the semi-working version advertised. I started looking in the Cargo.toml to at least get an idea how the project was constructed. I saw there that rather than being built from scratch as the post seemed to imply that almost every core component was simply pulled in from an open source library. quickjs engine, wgpu graphics, winit windowing & input, egui for ui, html parsing, the list goes on. On twitter their CEO explicitly stated that it uses a "custom js vm" which seemed particularly misleading / untrue to me. Integrating all of these existing components is still super impressive for these models to do autonomously, so I'm just at a loss how to feel when it does something impressive but they then feel the need to misrepresent so much. I guess I just have a lot less respect and trust for the cursor leadership, but maybe a little relief knowing that soon I may just generate my own custom cursor!

whatever1 8mo ago
You are doing it wrong. Take a screenshot and take it to your manager / investor and make a presentation “Imagine what is now possible for our business”. Get promoted / exit, move to other pastures and let them figure it out.
eeL3bo1mohn7pee 8mo ago
Of 63295 workflow runs, apparently only 1426 have been successful. It's hard to avoid the impression that this is an unverified pile of slop that may have actually never worked. The CI process certainly hasn't succeeded for the vast majority of commits. Baffling, really.
- alfalfasprout 8mo ago
  You should see the code. It's true slop. The organization makes no sense.
handfuloflight 8mo ago

navinsylvester 9mo ago

all these focus on long running agents without focussing on core restructure is baffling. the immediate need is to break down complex tasks into smaller ones and single shot them with some amount of parallelism. imo - we need an opinionated system but with human in the middle and then think about dreamy next steps. we need to focus on groundedness first instead of worrying about agent conjuring something from thin air. the decision to leap frog into automated long running agents is quite baffling. boys are trying to single shot a browser when a moderate complex task can derail a repo. there’s no good amount of info which might be deliberate but from what i can pick, their value add was “distributed computing and organisational design” but that too they simplified. i agree that simplicity is always the first option but flat filesystem structure without standards will not work. period.

vivekv 8mo ago
I would agree with this. There are definite challenges in grounded specifications today and the tendency for an LLM to go in tangents that is still a struggle that we all deal with every day.

measurablefunc 9mo ago

All of these things have readily available analogues on the web which means they are more than likely just laundering open source code & claiming victory.

rzmmm 8mo ago
There are many open-source toy browser implementations available, so this seems quite likely.
random_mutex 8mo ago
It doesn't compile so no victory
- measurablefunc 8mo ago
  Just the usual corporate marketing & hype.

foota 8mo ago

I've always liked the idea of intelligence in the autonomous ships of the Revelation Space universe. Little agents reporting to progressively more intelligent and higher level ones.

satvikpendem 8mo ago
That's essentially all life from the sub-cellular level on up

foota 8mo ago

Slightly off topic, but they want to move from solid to react? Isn't that the reverse of the newest trend? Would be interesting to know more.

random_mutex 8mo ago
Most likely LLMs are better at writing react

gaigalas 8mo ago

There's a clear conflict between SKILLS, tools and multi-tasking. I think "intra-context" tooling is already dead. It's too narrow. It's all "extra-context" now: how one instruments for multiple agents, at multiple times, handling things. Personally, I think the best tool in this realm will come from open source, and be agnostic (many agents from many places interacting), in order to leverage differences between subtle provider qualities (speed, price and so on). Building a browser is an interesting and expensive experiment. How much did it cost?

dinkm 8mo ago

“Arthur looked up. ‘Ford,’ he said, ‘there’s an infinite number of monkeys outside who want to talk to us about this script for Hamlet they’ve worked out.”

torginus 8mo ago

I'm kinda surprised how negative and skeptical anyone is here. It kinda blows my mind that this is possible, to build a browser engine that approximates a somewhat working website renderer. Even if we take the most pessimistic interpretation of events ( heavy human steering, relies on existing libraries, sloppy code quality at places, not all versions compile etc)

ben_w 8mo ago
I'm not too surprised, the way I read a lot of (not all!*) the negative comments is ~"I'm imagining having to work with this code, I'd hate it". Even though I'm fairly impressed with the work LLMs do, this has also been my experience of them… albeit with a vibe-coding** sample size of 1, done over a few days with some spare credit. The positive views are mostly from people who point out that what matters in the end is what the code does, not what it looks like, e.g. users don't see the code, nor do they care about the code, and that even for businesses who do care, LLMs may be the ones who have to pay down any technical debt that builds up. * Anyone in a field where mistakes are expensive. In one project, I asked the LLM to code-review itself and it found security vulnerabilities in its own solutions. It's probably still got more I don't know about. ** In the original sense of just letting the LLM do whatever it wanted in response to the prompt, never reading or code reviewing the result myself until the end.
- satvikpendem 8mo ago
  The problem I've had with vibe coding is akin the adage of the first 90% of the code taking 90% of the time, and the last 10% taking the other 90% of the time. The LLM can get you to 90% initially but it hits a wall unless you the user know what it's doing and outputting, but that is very difficult when you're vibe coding by its very definition, meaning that you're not looking at the code at all. And then you have to read thousands of lines of code which you don't understand that it's entirely easier to stop and hand code a new version yourself, which is precisely what I've done with some of my projects.
  - alfalfasprout 8mo ago

laszlojamf 8mo ago

They mention billions of tokens, but I'm left wondering how much this experiment actually cost them...

torginus 8mo ago

Personally what I don't like about this now that I think about it, is that they didn't scale up gradually, let's say there there's a ladder of complexity in software, starting at a simple React CRUD app, going on to something more complex, such as a Paint clone, to something even more complex, like a file manager etc, ending up at one of the most complex pieces of software ever made, a web browser. I'd want to see some system, that 100%s the first task, saturation, does a great job on the next, then does a valiant effort on the third, then finally makes something promising but as yet unusable on the last. This way we could see that scaling up difficulty results in a gradual decline in quality, and could have a decent measurement of where we are at and where we are going.

throwaway63467 8mo ago

I‘m running opus 4.5 which is arguably their best model and while it’s really good for a lot of work it always introduces subtle errors or inconsistencies when left unsupervised as prompts are never good enough to remove all ambiguity for complex asks, so I can’t imagine what it will do to a code base when left alone with it for days or weeks.

sidgarimella 8mo ago

Very cool. Seems long running AI Agents are the new monuments.

physicsguy 8mo ago

I have been trying Claude Code a lot this week. Two projects: * A small statically generated Hugo website but with some clever linking/taxonomy stuff. This was a fairly self-contained project that is now 'finished' but wouldn't hvae taken me more than a few days to code up from scratch. * A scientific simulation package, to try and do a clean refresh of an existing one which i can point at for implementation details but which has some technical problems I would like to reduce/remove. Claude code absolutely smashed the first one - no issues at all. With the second, no matter what I tried, it just made lots of mistakes, even when I just told it to copy the problematic parts and transpose them into the new structure. It basically got to a point where it wasn't correct and it didn't seem to be able to get out of a bit of a 'doom loop' and required manual intervention, no matter how much prompting and hints I gave it.

underdeserver 8mo ago
On Twitter people are saying GPT-5.2 is better. That's also what Cursor used in their testing. Maybe try it?
- physicsguy 8mo ago
  I have Web access for ChatGPT through work, but not API access annoyingly.
  - xpil 8mo ago
    Codex plugin (VSCode) allows consuming your "web" (ie non-api) subscription for coding/agentic tasks.
Bishonen88 8mo ago
Similar experience here. Did sign up for Claude Code myself this week, too, given the $10/month promo. I have experience with AI by using AWS Kiro at work and directly prompting Claude Opus for convos. After just 2 days and ~5-6 vibe coding sessions in total I got a working Life-OS-App created for my needs. - Clone of Todoist with the features that I actually use/want. Projects, Tags, due dates, quick adding with a todoist like text-aware input (e.g. !p1, Today etc.) - A fantastical like calendar. Again, 80% of the features I used from Fantastical - A Habit Tracker - A Goal Tracker (Quarterly / Yearly) - A dashboard page showing todays summary with single click edit/complete marking - User authentication and sharing of various features (e.g. tasks) - Docker deployment which will eventually run on my NAS I'm going to add a few more things and cancel quite a few subscriptions. It one-shots all tasks within minutes. It's wild. I can code but didn't bother looking at the code myself, because ... why. Even though do not earn US Tech money, am tempted to buy the max subscription for a month or two although the price is still hard to swallow. Claude and vibe coding is wild. If I can clone todoist within a few vibe coding sessions and then implement any additional/new feature I want within minutes instead proposing, praying and then waiting for months, why would I pay $$$...

ramon156 8mo ago

> A long-running agent made video rendering 25x faster with an efficient Rust version. Which is not an optimization. This is coming from a Rust dev; Rewriting it in Rust is not the optimization. Also, I do not believe they actually reviewed the SolidJS->React PR. This PR is incredibly unrealistic and should've been done with either stacker PRs or incremental non-breaking changes. None of this feels organic, can we stop pretending it is? To continue the pessimistic tone, none of the writing went in-depth. I did not gain any knowledge, just a marketing post.

Havoc 8mo ago

> long running I really dislike this as a measure. A LLM on CPU is also long running cause it’s slow. I get what it’s meant to convey but time is such a terrible measure of anything if tk/s isn’t static

danieloj 8mo ago

I'm not sure "building a web browser" is such a great test for an LLM. It helps confirm that they can handle large codebases. But the actual logic in the browser engine will be based very heavily on Chromium/Firefox etc.

kilroy123 8mo ago

My test for whether we've created an AGI like AI? Build a Linux kernel from scratch that can actually run a full OS on your computer. But, if I'm being fair, a full working browser from scratch is just as good.

george_atom 8mo ago

Reviewing all this code is the issue.

jamesnorden 8mo ago

Is the code not even compiling a feature or...

tgtweak 8mo ago

Is it too much to expect companies to share some of this in the open vs just the results?

Snuggly73 8mo ago

The only thing that I got to actually run on WSL2 was the "Excel" (couldnt get anything actually to compile on Mac or Windows). It a broken mess that probably implements 0.00001% of Excel. And its 1.2m locs. With codebases developed in this way - either they need to figure out how agents are going to maintain them (in which case SWE as we know is dead - it will only be limited to those that can spend trillions of tokens, or they are going to remain weird demos.

timabdulla 8mo ago
I'd be curious to see screenshots or a video! I only have a Mac at my disposal, unfortunately.

Snuggly73 8mo ago

And there is the thing about the cost. The blog post says that they've spent trillions (plural!) of tokens on that experiment. Looking at OAI API pricing, 5.2 Codex is $14 per 1 million output tokens. Which makes cool $14m for 1 trillion tokens (multiplied by whatever the plural is). For something that "kind of works". Its a nice ad for OAI and Anysphere, but maybe next time - just donate the money to a browser team?

deleted 8mo ago

[deleted]

darioush 8mo ago

I find it interesting that this line of adventure quickly lead to locking problems.

thesurlydev 8mo ago

Pretty cool and related to another path of work I'm following from Steve Yegge: https://medium.com/@steve-yegge/welcome-to-gas-town-4f25ee16dd04 https://medium.com/@steve-yegge/welcome-to-gas-town-4f25ee16...

cawksuwcka 8mo ago

would really appreciate some elaboration as they gloss over the most important part in my kind. why can’t one agent just do it. that’s what ai seems to be - an amalgamation of all our knowledge. why split it back up into separate tentacles. i think focus should be on letting it envelop the problem like a fog and swallow it whole, instead of molesting it independently at touch points and reporting back to … the brain? it’s pretty ridiculous actually. just mimicking ourselves yet again.

cawksuwcka 8mo ago
perhaps ai is a human based solution thus it’s limitations? further, it’s a human problem so we can only solve it in a human way? can we not escape our damned humanity?

isusmelj 8mo ago

I think we are just very close to the peak of a typical Gartner hype cycle around LLMs. They are useful but overhyped. There will be more posts about fuckups that happen because people run things on autopilot and cannot keep up with reviewing AI generated code. Do not get me wrong. I use AI all day to speed things up. But I believe that there is only a small group, maybe 5 percent or less, that actually knows how to use AI properly (I'd count myself not yet in that 5%), which I see as potentially dangerous. The other issue I see is inexperienced software engineers writing software. Although I see this as a great value add and productivity boost for prototyping, I am afraid of the “I do not know much about coding but can also make PRs to our codebase” mentality. For those of you that run things on autopilot, how do you keep code quality under control? And how do you handle refactoring? I am really curious, because one option now is also to just YOLO your LLMs to write code based on the maturity of the product. You can refactor an app or parts of it pretty fast again with LLMs. While tech debt accumulates faster, we also have the opportunity to rebuild faster.

nashadelic 8mo ago

I'm very curious about how much of it is re-using (remixing?) an existing browser implementation it has seen in the while or its trained on. Even in that case, 99% of all code isn't doing anything novel so this copying would still have significant practical use.

deleted 8mo ago

[deleted]