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This is such a lovely balanced thoughtful refreshingly hype-free post to read. 2025 really was the year when things shifted and many first-rate developers (often previously AI skeptics, as Mitchell was) found the tools had actually got good enough that they could incorporate AI agents into their workflows.

It's a shame that AI coding tools have become such a polarizing issue among developers. I understand the reasons, but I wish there had been a smoother path to this future. The early LLMs like GPT-3 could sort of code enough for it to look like there was a lot of potential, and so there was a lot of hype to drum up investment and a lot of promises made that weren't really viable with the tech as it was then. This created a large number of AI skeptics (of whom I was one, for a while) and a whole bunch of cynicism and suspicion and resistance amongst a large swathe of developers. But could it have been different? It seems a lot of transformative new tech is fated to evolve this way. Early aircraft were extremely unreliable and dangerous and not yet worthy of the promises being made about them, but eventually with enough evolution and lessons learned we got the Douglas DC-3, and then in the end the 747.

If you're a developer who still doesn't believe that AI tools are useful, I would recommend you go read Mitchell's post, and give Claude Code a trial run like he did. Try and forget about the annoying hype and the vibe-coding influencers and the noise and just treat it like any new tool you might put through its paces. There are many important conversations about AI to be had, it has plenty of downsides, but a proper discussion begins with close engagement with the tools.

This matches my experience, especially "don’t draw the owl" and the harness-engineering idea.

The failure mode I kept hitting wasn’t just "it makes mistakes", it was drift: it can stay locally plausible while slowly walking away from the real constraints of the repo. The output still sounds confident, so you don’t notice until you run into reality (tests, runtime behaviour, perf, ops, UX).

What ended up working for me was treating chat as where I shape the plan (tradeoffs, invariants, failure modes) and treating the agent as something that does narrow, reviewable diffs against that plan. The human job stays very boring: run it, verify it, and decide what’s actually acceptable. That separation is what made it click for me.

Once I got that loop stable, it stopped being a toy and started being a lever. I’ve shipped real features this way across a few projects (a git like tool for heavy media projects, a ticketing/payment flow with real users, a local-first genealogy tool, and a small CMS/publishing pipeline). The common thread is the same: small diffs, fast verification, and continuously tightening the harness so the agent can’t drift unnoticed.

This was a great post, one of the best I've seen on this topic at HN.

But why is the cost never discussed or disclosed in these conversations? I feel like I'm going crazy, there is so much written extolling the virtues of these tools but with no mention of what it costs to run them now. It will surely only get more expensive from here!

> Break down sessions into separate clear, actionable tasks. Don't try to "draw the owl" in one mega session.

This is the key one I think. At one extreme you can tell an agent "write a for loop that iterates over the variable `numbers` and computes the sum" and they'll do this successfully, but the scope is so small there's not much point in using an LLM. On the other extreme you can tell an agent "make me an app that's Facebook for dogs" and it'll make so many assumptions about the architecture, code and product that there's no chance it produces anything useful beyond a cool prototype to show mom and dad.

A lot of successful LLM adoption for code is finding this sweet spot. Overly specific instructions don't make you feel productive, and overly broad instructions you end up redoing too much of the work.

I still use the chatbot but like to do it outside-in. Provide what I need, and instruct it to not write any code except the api (signatures of classes, interfaces, hierarchy, essential methods etc). We keep iterating about this until it looks good - still no real code. Then I ask it to do a fresh review of the broad outline, any issues it foresees etc. Then I ask it to write some demonstrator test cases to see how ergonomic and testable the code is - we fine tune the apis but nothing is fleshed out yet. Once this is done, we are done with the most time consuming phase.

After that is basically just asking it to flesh out the layers starting from zero dependencies to arriving at the top of the castle. Even if we have any complexities within the pieces or the implementation is not exactly as per my liking, the issues are localised - I can dive in and handle it myself (most of the time, I don't need to).

I feel like this approach works very well for me having a mental model of how things are connected because the most of the time I spent was spent on that model.

For those wondering how that looks in practice, here's one of OP's past blog posts describing a coding session to implement a non-trivial feature: https://mitchellh.com/writing/non-trivial-vibing (covered on HN here: https://news.ycombinator.com/item?id=45549434)

> Always Have an Agent Running

I'm a huge believer in AI agent use and even I think this is wrong. It's like saying "always have something compiling" or "make sure your Internet is always downloading something".

The most important work happens when an agent is not running, and if you spend most of your time looking for ways to run more agents you're going to streetlight-effect your way into solving the wrong problems https://en.wikipedia.org/wiki/Streetlight_effect

Much more pragmatic and less performative than other posts hitting frontpage. Good article.

AI chat for research is great and really helps me.

I just don't need the AI writing code for me, don't see the point. Once I know from the ai chat research what my solution is I can code it myself with the benefit I then understand more what I am doing.

And yes I've tried the latest models! Tried agent mode in copilot! Don't need it!

I've been thinking about this as three maturity levels.

Level 1 is what Mitchell describes — AGENTS.md, a static harness. Prevents known mistakes. But it rots. Nobody updates the checklist when the environment changes.

Level 2 is treating each agent failure as an inoculation. Agent duplicates a util function? Don't just fix it — write a rule file: "grep existing helpers before writing new ones." Agent tries to build a feature while the build is broken? Rule: "fix blockers first." After a few months you have 30+ of these. Each one is an antibody against a specific failure class. The harness becomes an immune system that compounds.

Level 3 is what I haven't seen discussed much: specs need to push, not just be read. If a requirement in auth-spec.md changes, every linked in-progress task should get flagged automatically. The spec shouldn't wait to be consulted.

The real bottleneck isn't agent capability — it's supervision cost. Every type of drift (requirements change, environments diverge, docs rot) inflates the cost of checking the agent's work.

Crush that cost and adoption follows.

I don't understand how Agents make you feel productive. Single/Multiple agents reading specs, specs often produced with agents itself and iterated over time with human in the loop, a lot of reviewing of giant gibberish specs. Never had a clear spec in my life. Then all the dancing for this apperantly new paradigm, of not reviewing code but verifying behaviour, and so many other things. All of this to me is a total UNproductive mess. I use Cursor autocomplete from day one till to this day, I was super productive before LLMs, I'm more productive now, I'm capable, I have experience, product is hard to maintain but customers are happy, management is happy. So I can't really relate anymore to many of the programmers out there, that's sad, I can count on my hands devs that I can talk to that have hard skills and know-how to share instead of astroturfing about AI Agents

I think the sweet spot is ai-assisted chat with manual review: readily available, not as costly

agents jump ahead to the point of the user and project being out of control and more expensive

I think a lot of us still hesitate to make that jump; or at least I am not sure of a cost-effective agent approach (I guess I could manually review their output, but I could see it going off track quickly)

I guess I'd like to see more of an exact breakdown of what prompts and tools and AI are used to get ideas on if I'd use that for myself more

It's amusing how everyone seems to be going through the same journey.

I do run multiple models at once now. On different parts of the code base.

I focus solely on the less boring tasks for myself and outsource all of the slam dunk and then review. Often use another model to validate the previous models work while doing so myself.

I do git reset still quite often but I find more ways to not get to that point by knowing the tools better and better.

Autocompleting our brains! What a crazy time.

How much does it cost per day to have all these agents running on your computer?

Is your company paying for it or you?

What is your process of the agent writes a piece of code, let's say a really complex recursive function, and you aren't confident you could have come up with the same solution? Do you still submit it?

> This blog post was fully written by hand, in my own words.

This reminded me of back when wysiwyg web editors started becoming a thing, and coders started adding those "Created in notepad" stickers to their webpages, to point out they were 'real' web developers. Fun times.

With so much noise in the AI world and constant model updates (just today GPT-5.3-Codex and Claude Opus 4.6 were announced), this was a really refreshing read. It’s easy to relate to his phased approach to finding real value in tooling and not just hype. There are solid insights and practical tips here. I’m increasingly convinced that the best way not to get overwhelmed is to set clear expectations for what you want to achieve with AI and tailor how you use it to work for you, rather than trying to chase every new headline. Very refreshing.

Very nice. As a consequence of this new way of working I'm using `git worktree` and diffview all the time.

For more on the "harness engineering", see what Armin Ronacher and Mario Zechner are doing with pi: https://lucumr.pocoo.org/2026/1/31/pi/ https://mariozechner.at/posts/2025-11-30-pi-coding-agent/

> I really don't care one way or the other if AI is here to stay3, I'm a software craftsman that just wants to build stuff for the love of the game.

I suspect having three comma on one's bank account helps being very relaxed about the outcome ;)

> I'm a software craftsman

This perspective is why I think this article is so refreshing.

Craftsmen approach tools differently. They don't expect tools to work for them out-of-the-box. They customize the tool to their liking and reexamine their workflow in light of the tool. Either that or they have such idiosyncratic workflows they have to build their own tools.

They know their tools are custom to _them_. It would be silly to impose that everyone else use their tools-- they build different things!

This seems like a pretty reasonable approach that charts a course between skepticism and "it's a miracle".

I wonder how much all this costs on a monthly basis?

Very much the same experience. But it does not talk much about the project setup and the influence of it on the session success. In the narrow scoped projects it works really well, especially when tests are easy to execute. I found that this approach melts down when facing enterprise software with large repositories and unconventional layouts. Then you need to do a bunch of context management upfront, and verbose instructions for evaluations. But we know what it needs is a refactor thats all.

And the post touches on a next type of a problem, how to plan far ahead of time to utilise agents when you are away. It is a difficult problem but IMO we’re going in a direction of having some sort of shared “templated plans”/workflows and budgeted/throttled task execution to achieve that. It is like you want to give a little world to explore so that it does not stop early, like a little game to play, then you come back in the morning and check how far it went.

It's so sad that we're the ones who have to tell the agent how to improve by extending agent.md or whatever. I constantly have to tell it what I don't like or what can be improved or need to request clarifications or alternative solutions.

This is what's so annoying about it. It's like a child that does the same errors again and again.

But couldn't it adjust itself with the goal of reducing the error bit by bit? Wouldn't this lead to the ultimate agent who can read your mind? That would be awesome.

I've been building systems like what the OP is using since gpt3 came out.

This is the honeymoon phase. You're learning the ins and outs of the specific model you're using and becoming more productive. It's magical. Nothing can stop you. Then you might not be improving as fast as you did at the start, but things are getting better every day. Or maybe every week. But it's heaps better than doing it by hand because you have so much mental capacity left.

Then a new release comes up. An arbitrary fraction of your hard earned intuition is not only useless but actively harmful to getting good results with the new models. Worse you will never know which part it is without unlearning everything you learned and starting over again.

I've had to learn the quirks of three generations of frontier families now. It's not worth the hassle. I've gone back to managing the context window in Emacs because I can't be bothered to learn how to deal with another model family that will be thrown out in six months. Copy and paste is the universal interface and being able to do surgery on the chat history is still better than whatever tooling is out there.

Unironically learning vim or Emacs and the standard Unix code tools is still the best thing you can do to level up your llm usage.

LLMs are not for me. My position is that the advantage we humans have over the rest of the natural world, is our minds. Our ability to think, create and express ideas is what separates us from the rest of the animal kingdom. Once we give that over to "thinking" machines, we weaken ourselves, both individually and as a species.

That said, I've given it a go. I used zed, which I think is a pretty great tool. I bought a pro subscription and used the built in agent with Claude Sonnet 4.x and Opus. I'm a Rails developer in my day job, and, like MitchellH and many others, found out fairly quickly that tasks for the LLM need to be quite specific and discrete. The agent is great a renames and minor refactors, but my preferred use of the agent was to get it to write RSpec tests once I'd written something like a controller or service object.

And generally, the LLM agent does a pretty great job of this.

But here's the rub: I found that I was losing the ability to write rspec.

I went to do it manually and found myself trying to remember API calls and approaches required to write some specs. The feeling of skill leaving me was quite sobering and marked my abandonment of LLMs and Zed, and my return to neovim, agent-free.

The thing is, this is a common experience generally. If you don't use it, you lose it. It applies to all things: fitness, language (natural or otherwise), skills of all kinds. Why should it not apply to thinking itself.

Now you may write me and my experience off as that of a lesser mind, and that you won't have such a problem. You've been doing it so long that it's "hard-wired in" by now. Perhaps.

It's in our nature to take the path of least resistance, to seek ease and convenience at every turn. We've certainly given away our privacy and anonymity so that we can pay for things with our phones and send email for "free".

LLMs are the ultimate convenience. A peer or slave mind that we can use to do our thinking and our work for us. Some believe that the LLM represents a local maxima, that the approach can't get much better. I dunno, but as AI improves, we will hand over more and more thinking and work to it. To do otherwise would be to go against our very nature and every other choice we've made so far.

But it's not for me. I'm no MitchellH, and I'm probably better off performing the mundane activities of my work, as well as the creative ones, so as to preserve my hard-won knowledge and skills.

YMMV

I'll leave off with the quote that resonates the most with me as I contemplate AI:-

"I say your civilization, because as soon as we started thinking for you, it really became our civilization, which is, of course, what this is all about." -- Agent Smith "The Matrix"

> At a bare minimum, the agent must have the ability to: read files, execute programs, and make HTTP requests.

That's one very short step removed from Simon Willison's lethal trifecta.

I'm kind of on the same journey, a bit less far along. One thing I have observed is that I am constantly running out of tokens in claude. I guess this is not an issue for a wealthy person like Mitchell but it does significantly hamper my ability to experiment.

OT but, the style. The journey. What is it? What does this remind me of?

Flowers for Algernon.

Or at least the first half. I don't wanna see what it looks like when AI capabilities start going in reverse.

But I want to know.

Just wanted to say that was a nice and very grounded write up; and as a result very informative. Thank you. More stuff like this is a breath of fresh air in a landscape that has veered into hyperbole territory both in the for and against ai sides

I recently also reflected on the evolution of my use of ai in programming. Same evolution, other path. If anyone is interested: https://www.asfaload.com/blog/ai_use/

> Immediately cease trying to perform meaningful work via a chatbot.

That depends on your budget. To work within my pro plan's codex limits, I attach the codebase as a single file to various chat windows (GPT 5.2 Thinking - Heavy) and ask it to find bugs/plan a feature/etc. Then I copy the dense tasklist from chat to codex for implementation. This reduces the tokens that codex burns.

Also don't sleep on GPT 5.2 Pro. That model is a beast for planning.

What a lovely read. Thank you for sharing your experience.

The human-agent relationship described in the article made me wonder: are natural, or experienced, managers having more success with AI as subordinates than people without managerial skill? Are AI agents enormously different than arbitrary contractors half a world away where the only communication is daily text exchanges?

not quite as technically rich as i came to expect from previous posts from op, but very insightful regardless.

not ashamed to say that i am between steps 2 and 3 in my personal workflow.

>Adopting a tool feels like work, and I do not want to put in the effort

all the different approaches floating online feel ephemeral to me. this, just like for different tools for the op, seem like a chore to adopt. i like the fomo mongering from the community does not help here, but in the end it is a matter of personal discovery to stick with what works for you.

I respect Hashimoto for his contributions in the field, but to be honest, I am fed up with posts talking about using AI in ways that are impossible for most people due to high costs. I want to see more posts on cost-effective techniques, rather than just another guy showing off how he turned a creative 'burning-time' hobby into a 'burning-money' one.

Good article! I especially liked the approach to replicate manual commits with the agent. I did not do that when learning but I suspect I'd have been much better off if I had.

So does everyone just run with giving full permissions on Claude code these days? It seems like I’m constantly coming back to CC to validate that it’s not running some bash that’s going to nuke my system. I would love to be able to fully step away but it feels like I can’t.

I'd be interested to know what agents you're using. You mentioned Claude and GPT in passing, but don't actually talk about which you're using or for which tasks.

> Context switching is very expensive. In order to remain efficient, I found that it was my job as a human to be in control of when I interrupt the agent, not the other way around. Don't let the agent notify you.

This I have found to be important too.

This is yet one more indication to me that the winds have shifted with regards to the utility of the “agent” paradigm of coding with an LLM. With all the talk around Opus 4.5 I decided to finally make the jump there myself and haven’t yet been disappointed (though admittedly I’m starting it on some pretty straightforward stuff).

> I'm not [yet?] running multiple agents, and currently don't really want to

This is the main reason to use AI agents, though: multitasking. If I'm working on some Terraform changes and I fire off an agent loop, I know it's going to take a while for it to produce something working. In the meantime I'm waiting for it to come back and pretend it's finished (really I'll have to fix it), so I start another agent on something else. I flip back and forth between the finished runs as they notify me. At the end of the day I have 5 things finished rather than two.

The "agent" doesn't have to be anything special either. Anything you can run in a VM or container (vscode w/copilot chat, any cli tool, etc) so you can enable YOLO mode.

AI is getting to the game-changing point. We need more hand-written reflections on how individuals are managing to get productivity gains for real (not a vibe coded app) software engineering.

> having an agent running at all times

This gave me a physical flinch. Perhaps this is unfounded, but all this makes me think of is this becoming the norm, millions of people doing this, and us cooking our planet out much faster than predicted.

Do you have any ideas on how to harness AI to only change specific parts of a system or workpiece? Like "I consider this part 80/100 done and only make 'meaningful' or 'new contributions' here" ...?

> If an agent isn't running, I ask myself "is there something an agent could be doing for me right now?"

Solution-looking-for-a-problem mentality is a curse.

I find it interesting that this thread is full of pragmatic posts that seem to honestly reflect the real limits of current Gen-Ai.

Versus other threads (here on HN, and especially on places like LinkedIn) where it's "I set up a pipeline and some agents and now I type two sentences and amazing technology comes out in 5 minutes that would have taken 3 devs 6 months to do".

For those of working on large proprietary, in fringe languages as well, what can we do? Upload all the source code to the cloud model? I am really wary of giving it a million lines of code it’s never seen.

Refreshing to read a balanced opinion, from a person who has significant experience and grounding in the real world.

If the author is here, please could you also confirm you’ve never been paid by any AI company, marketing representative, community programme, in any shape or form?

Thanks for sharing your experiences :)

You mentioned "harness engineering". How do you approach building "actual programmed tools" (like screenshot scripts) specifically for an LLM's consumption rather than a human's? Are there specific output formats or constraints you’ve found most effective?

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Now that the Nasdaq crashes, people switch from the stick to the carrot:

"Please let us sit down and have a reasonable conversation! I was a skeptic, too, but if all skeptics did what I did, they would come to Jesus as well! Oh, and pay the monthly Anthropic tithe!"

I know I'm in the minority here, but I've been finding AI to be increasingly useless.

I'd already abandoned it for generating code, for all the reasons everyone knows, that don't need to be rehashed.

I was still in the camp of "It's a better google" and can save me time with research.

The issue it, at this point in my career (30+ years) the questions I have are a bit more nuanced and complex. They aren't things like "how do I make a form with React".

I'm working on developing a very high performance peer server that will need to scale up to hundreds of thousands to a million concurrent web socket connections to work as a signaling server for WebRTC connection negotiation.

I wanted to start as simple as possible, so peerjs is attractive. I asked the AI if peerjs peer-server would work with NodeJS's cluster server. It enthusiastically told me it would work just fine and was, in fact, designed for that.

I took a look at the source code, and it looked to me like that was dead wrong. The AI kept arguing with me before finally admitting it was completely wrong. A total waste of time.

Same results asking it how to remove Sophos from a Mac.

Same with legal questions about HOA laws, it just totally hallucinates things thay don't exist.

My wife and I used to use it to try to settle disagreements (i.e a better google) but amusingly we've both reached a place where we distrust anything it says so much, we're back to sending each other web articles :-)

I'm still pretty excited about the potential use of AI in elementary education, maybe through high school in some cases, but for my personal use, I've been reaching for it less and less.

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This are all valid points and a hype-free pragmatic take, I've been wondering about the same things even when I'm still in the skeptics side. I think there are other things that should be added since Mitchell's reality won't apply to everyone:

- What about non opensource work that's not on Github?

- Costs! I would think "an agent always running" would add up quickly

- In open source work, how does it amplify others. Are you seeing AI Slop as PRs? Can you tell the difference?

There are so many stories about how people use agentic AI but they rarely post how much they spend. Before I can even consider it, I need to know how it will cost me per month. I'm currently using one pro subscription and it's already quite expensive for me. What are people doing, burning hundreds of dollars per month? Do they also evaluate how much value they get out of it?

> babysitting my kind of stupid and yet mysteriously productive robot friend

LOL, been there, done that. It is much less frustrating and demoralizing than babysitting your kind of stupid colleague though. (Thankfully, I don't have any of those anymore. But at previous big companies? Oh man, if only their commits were ONLY as bad as a bad AI commit.)

How much electricity (and associated materials like water) must this use?

It makes me profoundly sad to think of the huge number of AI agents running endlessly to produce vibe-coded slop. The environmental impact must be massive.

How could the author write all of that and not talk about actual time savings versus the prior method?

I mean, what is the point of change if not to improve? I don't mean "I felt I was more efficient." Feelings aren't measurements. Numbers!

> a period of inefficiency

I think this is something people ignore, and is significant. The only way to get good at coding with LLMs is actually trying to do it. Even if it's inefficient or slower at first. It's just another skill to develop [0].

And it's not really about using all the plugins and features available. In fact, many plugins and features are counter-productive. Just learn how to prompt and steer the LLM better.

[0]: https://ricardoanderegg.com/posts/getting-better-coding-llms...

For the AI skeptics reading this, there is an overwhelming probability that Mitchell is a better developer than you. If he gets value out of these tools you should think about why you can't.

The Death of the "Stare": Why AI’s "Confident Stupidity" is a Threat to Human Genius

OPINION | THE REALITY CHECK In the gleaming offices of Silicon Valley and the boardrooms of the Fortune 500, a new religion has taken hold. Its deity is the Large Language Model, and its disciples—the AI Evangelists—speak in a dialect of "disruption," "optimization," and "seamless integration." But outside the vacuum of the digital world, a dangerous friction is building between AI’s statistical hallucinations and the unyielding laws of physics.

The danger of Artificial Intelligence isn't that it will become our overlord; the danger is that it is fundamentally, confidently, and authoritatively stupid.

The Paradox of the Wind-Powered Car The divide between AI hype and reality is best illustrated by a recent technical "solution" suggested by a popular AI model: an electric vehicle equipped with wind generators on the front to recharge the battery while driving. To the AI, this was a brilliant synergy. It even claimed the added weight and wind resistance amounted to "zero."

To any human who has ever held a wrench or understood the First Law of Thermodynamics, this is a joke—a perpetual motion fallacy that ignores the reality of drag and energy loss. But to the AI, it was just a series of words that sounded "correct" based on patterns. The machine doesn't know what wind is; it only knows how to predict the next syllable.

The Erosion of the "Human Spark" The true threat lies in what we are sacrificing to adopt this "shortcut" culture. There is a specific human process—call it The Stare. It is that thirty-minute window where a person looks at a broken machine, a flawed blueprint, or a complex problem and simply observes.

In that half-hour, the human brain runs millions of mental simulations. It feels the tension of the metal, the heat of the circuit, and the logic of the physical universe. It is a "Black Box" of consciousness that develops solutions from absolutely nothing—no forums, no books, and no Google.

However, the new generation of AI-dependent thinkers views this "Stare" as an inefficiency. By outsourcing our thinking to models that cannot feel the consequences of being wrong, we are witnessing a form of evolutionary regression. We are trading hard-earned competence for a "Yes-Man" in a box.

The Gaslighting of the Realist Perhaps most chilling is the social cost. Those who still rely on their intuition and physical experience are increasingly being marginalized. In a world where the screen is king, the person pointing out that "the Emperor has no clothes" is labeled as erratic, uneducated, or naive.

When a master craftsman or a practical thinker challenges an AI’s "hallucination," they aren't met with logic; they are met with a robotic refusal to acknowledge reality. The "AI Evangelists" have begun to walk, talk, and act like the models they worship—confidently wrong, devoid of nuance, and completely detached from the ground beneath their feet.

The High Cost of Being "Authoritatively Wrong" We are building a world on a foundation of digital sand. If we continue to trust AI to design our structures and manage our logic, we will eventually hit a wall that no "prompt" can fix.

The human brain runs on 20 watts and can solve a problem by looking at it. The AI runs on megawatts and can’t understand why a wind-powered car won't run forever. If we lose the ability to tell the difference, we aren't just losing our jobs—we're losing our grip on reality itself.