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The new skill in AI is not prompting, it's context engineering

JohnMakin

> Building powerful and reliable AI Agents is becoming less about finding a magic prompt or model updates.

Ok, I can buy this

> It is about the engineering of context and providing the right information and tools, in the right format, at the right time.

when the "right" format and "right" time are essentially, and maybe even necessarily, undefined, then aren't you still reaching for a "magic" solution?

If the definition of "right" information is "information which results in a sufficiently accurate answer from a language model" then I fail to see how you are doing anything fundamentally differently than prompt engineering. Since these are non-deterministic machines, I fail to see any reliable heuristic that is fundamentally indistinguishable than "trying and seeing" with prompts.

mentalgear

It's magical thinking all the way down. Whether they call it now "prompt" or "context" engineering because it's the same tinkering to find something that "sticks" in non-deterministic space.

nonethewiser

>Whether they call it now "prompt" or "context" engineering because it's the same tinkering to find something that "sticks" in non-deterministic space.

I dont quite follow. Prompts and contexts are different things. Sure, you can get thing into contexts with prompts but that doesn't mean they are entirely the same.

You could have a long running conversation with a lot in the context. A given prompt may work poorly, whereas it would have worked quite well earlier. I don't think this difference is purely semantic.

For whatever it's worth I've never liked the term "prompt engineering." It is perhaps the quintessential example of overusing the word engineering.

felipeerias

If someone asked you about the usages of a particular element in a codebase, you would probably give a more accurate answer if you were able to use a code search tool rather than reading every source file from top to bottom.

For that kind of tasks (and there are many of those!), I don't see why you would expect something fundamentally different in the case of LLMs.

dinvlad

> when the "right" format and "right" time are essentially, and maybe even necessarily, undefined, then aren't you still reaching for a "magic" solution?

Exactly the problem with all "knowing how to use AI correctly" advice out there rn. Shamans with drums, at the end of the day :-)

andy99

It's called over-fitting, that's basically what prompt engineering is.

edwardbernays

The state of the art theoretical frameworks typically separates these into two distinct exploratory and discovery phases. The first phase, which is exploratory, is best conceptualized as utilizing an atmospheric dispersion device. An easily identifiable marker material, usually a variety of feces, is metaphorically introduced at high velocity. The discovery phase is then conceptualized as analyzing the dispersal patterns of the exploratory phase. These two phases are best summarized, respectively, as "Fuck Around" followed by "Find Out."

null

[deleted]

FridgeSeal

It’s just AI people moving the goalposts now that everyone has realised that “prompt engineering” isn’t a special skill.

coliveira

In other words, "if AI doesn't work for you the problem is not IA, it is the user", that's what AI companies want us to believe.

shermantanktop

That’s a good indicator of an ideology at work: no-true-Scotsman deployed at every turn.

j45

Everything is new to someone and the tends of reference will evolve.

csallen

This is like telling a soccer player that no change in practice or technique is fundamentally different than another, because ultimately people are non-deterministic machines.

simonw

I wrote a bit about this the other day: https://simonwillison.net/2025/Jun/27/context-engineering/

Drew Breunig has been doing some fantastic writing on this subject - coincidentally at the same time as the "context engineering" buzzword appeared but actually unrelated to that meme.

How Long Contexts Fail - https://www.dbreunig.com/2025/06/22/how-contexts-fail-and-ho... - talks about the various ways in which longer contexts can start causing problems (also known as "context rot")

How to Fix Your Context - https://www.dbreunig.com/2025/06/26/how-to-fix-your-context.... - gives names to a bunch of techniques for working around these problems including Tool Loadout, Context Quarantine, Context Pruning, Context Summarization, and Context Offloading.

the_mitsuhiko

Drew Breunig's posts are a must read on this. This is not only important for writing your own agents, it is also critical when using agentic coding right now. These limitations/behaviors will be with us for a while.

outofpaper

They might be good reads on the topic but Drew makes some significant etymological mistakes. For example loadout doesn't come from gaming but military terminology. It's essentially the same as kit or gear.

simonw

Drew isn't using that term in a military context, he's using it in a gaming context. He defines what he means very clearly:

> The term “loadout” is a gaming term that refers to the specific combination of abilities, weapons, and equipment you select before a level, match, or round.

In the military you don't select your abilities before entering a level.

DiggyJohnson

This seems like a rather unimportant type of mistake, especially because the definition is still accurate, it’s just the etymology isn’t complete.

coldtea

>Drew makes some significant etymological mistakes. For example loadout doesn't come from gaming but military terminology

Does he pretend to give the etymology and ultimately origin of the term, or just where he or other AI-discussions found it? Because if it's the latter, he is entitled to call it a "gaming" term, because that's what it is to him and those in the discussion. He didn't find it in some military manual or learned it at boot camp!

But I would mostly challenge this mistake, if we admit it as such, is "significant" in any way.

The origin of loadout is totally irrelevant to the point he makes and the subject he discusses. It's just a useful term he adopted, it's history is not really relevant.

ZYbCRq22HbJ2y7

> They might be good reads on the topic but Drew makes some significant etymological mistakes. For example loadout doesn't come from gaming but military terminology. It's essentially the same as kit or gear.

Doesn't seem that significant?

Not to say those blog posts say anything much anyway that any "prompt engineer" (someone who uses LLMs frequently) doesn't already know, but maybe it is useful to some at such an early stage of these things.

scubbo

It _is_ a gaming term - it is also a military term (from which the gaming term arose).

luckydata

this is textbook pointless pedantry. I'm just commenting to find it again in the future.

Daub

For visual art I feel that the existing approaches in context engineering are very much lacking. An Ai understands well enough such simple things as content (bird, dog, owl etc), color (blue green etc) and has a fair understanding of foreground/background. However, the really important stuff is not addressed.

For example: in form, things like negative shape and overlap. In color contrast things like Ratio contrast and dynamic range contrast. Or how manipulating neighboring regional contrast produces tone wrap. I could go on.

One reason for this state of affairs is that artists and designers lack the consistent terminology to describe what they are doing (though this does not stop them from operating at a high level). Indeed, many of the terms I have used here we (my colleagues and I) had to invent ourselves. I would love to work with an AI guru to address this developing problem.

skydhash

> artists and designers lack the consistent terminology to describe what they are doing

I don't think they do. It may not be completely consistent, but open any art book and you find the same thing being explained again and again. Just for drawing humans, you will find emphasis on the skeleton and muscle volume for forms and poses, planes (especially the head) for values and shadows, some abstract things like stability and line weight, and some more concrete things like foreshortening.

Several books and course have gone over those concepts. They are not difficult to explain, they are just difficult to master. That's because you have to apply judgement for every single line or brush stroke deciding which factors matter most and if you even want to do the stroke. Then there's the whole hand eye coordination.

So unless you can solve judgement (which styles derive from), there's not a lot of hope there.

ADDENDUM

And when you do a study of another's work, it's not copying the data, extracting colors, or comparing labels,... It's just studying judgement. You know the complete formula from which a more basic version is being used for the work, and you only want to know the parameters. Whereas machine training is mostly going for the wrong formula with completely different variables.

dosnem

Providing context makes sense to me, but do you have any examples of providing context and then getting the AI to produce something complex? I am quite a proponent of AI but even I find myself failing to produce significant results on complex problems, even when I have clone + memory bank, etc. it ends up being a time sink of trying to get the ai to do something only to have me eventually take over and do it myself.

simonw

Quite a few times, I've been able to give it enough context to write me an entire working piece of software in a single shot. I use that for plugins pretty often, eg this:

  llm -m openai/o3 \
    -f https://raw.githubusercontent.com/simonw/llm-hacker-news/refs/heads/main/llm_hacker_news.py \
    -f https://raw.githubusercontent.com/simonw/tools/refs/heads/main/github-issue-to-markdown.html \
    -s 'Write a new fragments plugin in Python that registers issue:org/repo/123 which fetches that issue
      number from the specified github repo and uses the same markdown logic as the HTML page to turn that into a fragment'
Which produced this: https://gist.github.com/simonw/249e16edffe6350f7265012bee9e3...

AnotherGoodName

I had a series of “Using Manim create an animation for formula X rearranging into formula Y with a graph of values of the function”

Beautiful one shot results and i now have really nice animations of some complex maths to help others understand. (I’ll put it up on youtube soon).

I don't know the manim library at all so saved me about a week of work learning and implementing

old_man_cato

First, you pay a human artist to draw a pelican on a bicycle.

Then, you provide that as "context".

Next, you prompt the model.

Voila!

_carbyau_

How to draw an owl.

1. Draw some circles.

2. Prompt an AI to draw the rest of the fucking owl.

crsv

And then the AI doesn’t handle the front end caching properly for the 100th time in a row so you edit the owl and nothing changes after you press save.

NomDePlum

And if you want 2 owls?

d0gsg0w00f

This hits too close to home.

jknoepfler

Oh, and don't forget to retain the artist to correct the ever-increasingly weird and expensive mistakes made by the context when you need to draw newer, fancier pelicans. Maybe we can just train product to draw?

storus

Those issues are considered artifacts of the current crop of LLMs in academic circles; there is already research allowing LLMs to use millions of different tools at the same time, and stable long contexts, likely reducing the amount of agents to one for most use cases outside interfacing different providers.

Anyone basing their future agentic systems on current LLMs would likely face LangChain fate - built for GPT-3, made obsolete by GPT-3.5.

simonw

Can you link to the research on millions of different terms and stable long contexts? I haven't come across that yet.

storus

You can look at AnyTool, 2024 (16,000 tools) and start looking at newer research from there.

https://arxiv.org/abs/2402.04253

For long contexts start with activation beacons and RoPE scaling.

ZYbCRq22HbJ2y7

How would "a million different tool calls at the same time" work? For instance, MCP is HTTP based, even at low latency in incredibly parallel environments that would take forever.

Art9681

It wouldn't. There is a difference between theory and practicality. Just because we could, doesnt mean we should, especially when costs per token are considered. Capability and scale are often at odds.

Jarwain

MCPs aren't the only way to embed tool calls into an LLM

dinvlad

> already research allowing LLMs to use millions of different tools

Hmm first time hearing about this, could you share any examples please?

Foreignborn

yes, but those aren’t released and even then you’ll always need glue code.

you just need to knowingly resource what glue code is needed, and build it in a way it can scale with whatever new limits that upgraded models give you.

i can’t imagine a world where people aren’t building products that try to overcome the limitations of SOTA models

storus

My point is that newer models will have those baked in, so instead of supporting ~30 tools before falling apart they will reliably support 10,000 tools defined in their context. That alone would dramatically change the need for more than one agent in most cases as the architectural split into multiple agents is often driven by the inability to reliably run many tools within a single agent. Now you can hack around it today by turning tools on/off depending on the agent's state but at some point in the future you might afford not to bother and just dump all your tools to a long stable context, maybe cache it for performance, and that will be it.

TZubiri

Rediscovering encapsulation

JoeOfTexas

So who will develop the first Logic Core that automates the context engineer.

igravious

The first rule of automation: that which can be automated will be automated.

Observation: this isn't anything that can't be automated /

risyachka

“A month-long skill” after which it won’t be a thing anymore, like so many other.

simonw

Most of the LLM prompting skills I figured out ~three years ago are still useful to me today. Even the ones that I've dropped are useful because I know that things that used to be helpful aren't helpful any more, which helps me build an intuition for how the models have improved over time.

dbreunig

While researching the above posts Simon linked, I was struck by how many of these techniques came from the pre-ChatGPT era. NLP researchers have been dealing with this for awhile.

refulgentis

I agree with you, but would echo OP's concern, in a way that makes me feel like a party pooper, but, is open about what I see us all expressing squeamish-ness about.

It is somewhat bothersome to have another buzz phrase. I don't why we are doing this, other than there was a Xeet from the Shopify CEO, QT'd approvingly by Karpathy, then its written up at length, and tied to another set of blog posts.

To wit, it went from "buzzphrase" to "skill that'll probably be useful in 3 years still" over the course of this thread.

Has it even been a week since the original tweet?

There doesn't seem to be a strong foundation here, but due to the reach potential of the names involved, and their insistence on this being a thing while also indicating they're sheepish it is a thing, it will now be a thing.

Smacks of a self-aware version of Jared Friedman's tweet re: watching the invention of "Founder Mode" was like a startup version of the Potsdam Conference. (which sorted out Earth post-WWII. and he was not kidding. I could not even remember the phrase for the life of me. Lasted maybe 3 months?)

orbital-decay

Many people figured it out two-three years ago when AI-assisted coding basically wasn't a thing, and it's still relevant and will stay relevant. These are fundamental principles, all big models work similarly, not just transformers and not just LLMs.

However, many fundamental phenomena are missing from the "context engineering" scope, so neither context engineering nor prompt engineering are useful terms.

tptacek

If you're not writing your own agents, you can skip this skill.

anilgulecha

Are you sure? Looking forward - AI is going to be so pervasively used, that understanding what information is to be input will be a general skill. What we've been calling "prompt engineering" - the better ones were actually doing context engineering.

coldtea

What exactly month-long AI skills of 2023 AI are obsolete now?

Surely not prompt engineering itself, for example.

bgwalter

These discussions increasingly remind me of gamers discussing various strategies in WoW or similar. Purportedly working strategies found by trial and error and discussed in a language that is only intelligible to the in-group (because no one else is interested).

We are entering a new era of gamification of programming, where the power users force their imaginary strategies on innocent people by selling them to the equally clueless and gaming-addicted management.

dysoco

> Purportedly working strategies found by trial and error and discussed in a language that is only intelligible to the in-group

This really does sound like Computer Science since it's very beginnings.

The only difference is that now it's a much more popular field, and not restricted to a few nerds sharing tips over e-mail or bbs.

coderatlarge

i tend to share your view. but then your comment describes a lot of previous cycles of enterprise software selling. it’s just that this time is reaching a little uncomfortably into the builder’s /developer’s traditional areas of influence/control/workflow. how devs feel now is probably how others (ex csr, qa, sre) felt in the past when their managers pushed whatever tooling/practice was becoming popular or sine qua non in previous “waves”.

sarchertech

This has been happening to developers for years.

25 years ago it was object oriented programming.

coliveira

The difference is that with OO there was at least hope that a well trained programmer could make it work. Nowadays, any person who understands how AI knows that's near impossible.

coderatlarge

or agile and scrums.

Madmallard

There's quite a lot science that goes into WoW strategizing at this point.

People are using their thinking caps and modelling data.

mrits

Tuning the JVM, compiler optimizations, design patterns, agile methodologies, seo , are just a few things that come to mind

benreesman

The new skill is programming, same as the old skill. To the extent these things are comprehensible, you understand them by writing programs: programs that train them, programs that run inferenve, programs that analyze their behavior. You get the most out of LLMs by knowing how they work in detail.

I had one view of what these things were and how they work, and a bunch of outcomes attached to that. And then I spent a bunch of time training language models in various ways and doing other related upstream and downstream work, and I had a different set of beliefs and outcomes attached to it. The second set of outcomes is much preferable.

I know people really want there to be some different answer, but it remains the case that mastering a programming tool involves implemtenting such, to one degree or another. I've only done medium sophistication ML programming, and my understand is therefore kinda medium, but like compilers, even doing a medium one is the difference between getting good results from a high complexity one and guessing.

Go train an LLM! How do you think Karpathy figured it out? The answer is on his blog!

pyman

Saying the best way to understand LLMs is by building one is like saying the best way to understand compilers is by writing one. Technically true, but most people aren't interested in going that deep.

benreesman

I don't know, I've heard that meme too but it doesn't track with the number of cool compiler projects on GitHub or that frontpage HN, and while the LLM thing is a lot newer, you see a ton of useful/interesting stuff at the "an individual could do this on their weekends and it would mean they fundamentally know how all the pieces fit together" type stuff.

There will always be a crowd that wants the "master XYZ in 72 hours with this ONE NEAT TRICK" course, and there will always be a..., uh, group of people serving that market need.

But most people? Especially in a place like HN? I think most people know that getting buff involves going to the gym, especially in a place like this. I have a pretty high opinion of the typical person. We're all tempted by the "most people are stupid" meme, but that's because bad interactions are memorable, not because most people are stupid or lazy or whatever. Most people are very smart if they apply themselves, and most people will work very hard if the reward for doing so is reasonably clear.

https://www.youtube.com/shorts/IQmOGlbdn8g

munificent

All of these blog posts to me read like nerds speedrunning "how to be a tech lead for a non-disastrous internship".

Yes, if you have an over-eager but inexperienced entity that wants nothing more to please you by writing as much code as possible, as the entity's lead, you have to architect a good space where they have all the information they need but can't get easily distracted by nonessential stuff.

tptacek

Just to keep some clarity here, this is mostly about writing agents. In agent design, LLM calls are just primitives, a little like how a block cipher transform is just a primitive and not a cryptosystem. Agent designers (like cryptography engineers) carefully manage the inputs and outputs to their primitives, which are then composed and filtered.

baxtr

>Conclusion

Building powerful and reliable AI Agents is becoming less about finding a magic prompt or model updates. It is about the engineering of context and providing the right information and tools, in the right format, at the right time. It’s a cross-functional challenge that involves understanding your business use case, defining your outputs, and structuring all the necessary information so that an LLM can “accomplish the task."

That’s actually also true for humans: the more context (aka right info at the right time) you provide the better for solving tasks.

root_axis

I am not a fan of this banal trend of superficially comparing aspects of machine learning to humans. It doesn't provide any insight and is hardly ever accurate.

furyofantares

I've seen a lot of cases where, if you look at the context you're giving the model and imagine giving it to a human (just not yourself or your coworker, someone who doesn't already know what you're trying to achieve - think mechanical turk), the human would be unlikely to give the output you want.

Context is often incomplete, unclear, contradictory, or just contains too much distracting information. Those are all things that will cause an LLM to fail that can be fixed by thinking about how an unrelated human would do the job.

EricMausler

Alternatively, I've gotten exactly what I wanted from an LLM by giving it information that would not be enough for a human to work with, knowing that the llm is just going to fill in the gaps anyway.

It's easy to forget that the conversation itself is what the LLM is helping to create. Humans will ignore or depriotitize extra information. They also need the extra information to get an idea of what you're looking for in a loose sense. The LLM is much more easily influenced by any extra wording you include, and loose guiding is likely to become strict guiding

stefan_

Theres all these philosophers popping up everywhere. This is also another one of these topics that featured in peoples favorite scifi hyperfixation so all discussions inevitably get ruined with scifi fanfic (see also: room temperature superconductivity).

ModernMech

I agree, however I do appreciate comparisons to other human-made systems. For example, "providing the right information and tools, in the right format, at the right time" sounds a lot like a bureaucracy, particularly because "right" is decided for you, it's left undefined, and may change at any time with no warning or recourse.

layer8

The difference is that humans can actively seek to acquire the necessary context by themselves. They don't have to passively sit there and wait for someone else to do the tedious work of feeding them all necessary context upfront. And we value humans who are able to proactively do that seeking by themselves, until they are satisfied that they can do a good job.

simonw

> The difference is that humans can actively seek to acquire the necessary context by themselves

These days, so can LLM systems. The tool calling pattern got really good in the last six months, and one of the most common uses of that is to let LLMs search for information they need to add to their context.

o3 and o4-mini and Claude 4 all do this with web search in their user-facing apps and it's extremely effective.

The same patterns is increasingly showing up in coding agents, giving them the ability to search for relevant files or even pull in official document documentation for libraries.

mentalgear

Basically, finding the right buttons to push within the constraints of the environment. Not so much different from what (SW) engineering is, only non-deterministic in the outcomes.

QuercusMax

Yeah... I'm always asking my UX and product folks for mocks, requirements, acceptance criteria, sample inputs and outputs, why we care about this feature, etc.

Until we can scan your brain and figure out what you really want, it's going to be necessary to actually describe what you want built, and not just rely on vibes.

lupire

Not "more" context. "Better" context.

(X-Y problem, for example.)

zaptheimpaler

I feel like this is incredibly obvious to anyone who's ever used an LLM or has any concept of how they work. It was equally obvious before this that the "skill" of prompt-engineering was a bunch of hacks that would quickly cease to matter. Basically they have the raw intelligence, you now have to give them the ability to get input and the ability to take actions as output and there's a lot of plumbing to make that happen.

ozim

Finding a magic prompt was never “prompt engineering” it was always “context engineering” - lots of “AI wannabe gurus” sold it as such but they never knew any better.

RAG wasn’t invented this year.

Proper tooling that wraps esoteric knowledge like using embeddings, vector dba or graph dba becomes more mainstream. Big players improve their tooling so more stuff is available.

crystal_revenge

Definitely mirrors my experience. One heuristic I've often used when providing context to model is "is this enough information for a human to solve this task?". Building some text2SQL products in the past it was very interesting to see how often when the model failed, a real data analyst would reply something like "oh yea, that's an older table we don't use any more, the correct table is...". This means the model was likely making a mistake that a real human analyst would have without the proper context.

One thing that is missing from this list is: evaluations!

I'm shocked how often I still see large AI projects being run without any regard to evals. Evals are more important for AI projects than test suites are for traditional engineering ones. You don't even need a big eval set, just one that covers your problem surface reasonably well. However without it you're basically just "guessing" rather than iterating on your problem, and you're not even guessing in a way where each guess is an improvement on the last.

edit: To clarify, I ask myself this question. It's frequently the case that we expect LLMs to solve problems without the necessary information for a human to solve them.

adiabatichottub

A classic law of computer programming:

"Make it possible for programmers to write in English and you will find that programmers cannot write in English."

It's meant to be a bit tongue-in-cheek, but there is a certain truth to it. Most human languages fail at being precise in their expression and interpretation. If you can exactly define what you want in English, you probably could have saved yourself the time and written it in a machine-interpretable language.

kevin_thibedeau

Asking yes no questions will get you a lie 50% of the time.

adriand

I have pretty good success with asking the model this question before it starts working as well. I’ll tell it to ask questions about anything it’s unsure of and to ask for examples of code patterns that are in use in the application already that it can use as a template.

hobs

The thing is, all the people cosplaying as data scientists don't want evaluations, and that's why you saw so little in fake C level projects, because telling people the emperor has no clothes doesn't pay.

For those actually using the products to make money well, hey - all of those have evaluations.

shermantanktop

I know this proliferation of excited wannabes is just another mark of a hype cycle, and there’s real value this time. But I find myself unreasonably annoyed by people getting high on their own supply and shouting into a megaphone.

mountainriver

You can give most of the modern LLMs pretty darn good context and they will still fail. Our company has been deep down this path for over 2 years. The context crowd seems oddly in denial about this

arkmm

What are some examples where you've provided the LLM enough context that it ought to figure out the problem but it's still failing?

tupac_speedrap

I mean at some point it is probably easier to do the work without AI and at least then you would actually learn something useful instead of spending hours crafting context to actually get something useful out of an AI.

dinvlad

I feel like ppl just keep inventing concepts for the same old things, which come down to dancing with the drums around the fire and screaming shamanic incantations :-)

viccis

When I first used these kinds of methods, I described it along those lines to my friend. I told him I felt like I was summoning a demon and that I had to be careful to do the right incantations with the right words and hope that it followed my commands. I was being a little disparaging with the comment because the engineer in me that wants reliability, repeatability, and rock solid testability struggles with something that's so much less under my control.

God bless the people who give large scale demos of apps built on this stuff. It brings me back to the days of doing vulnerability research and exploitation demos, in which no matter how much you harden your exploits, it's easy for something to go wrong and wind up sputtering and sweating in front of an audience.

CharlieDigital

I was at a startup that started using OpenAI APIs pretty early (almost 2 years ago now?).

"Back in the day", we had to be very sparing with context to get great results so we really focused on how to build great context. Indexing and retrieval were pretty much our core focus.

Now, even with the larger windows, I find this still to be true.

The moat for most companies is actually their data, data indexing, and data retrieval[0]. Companies that 1) have the data and 2) know how to use that data are going to win.

My analogy is this:

    > The LLM is just an oven; a fantastical oven.  But for it to produce a good product still depends on picking good ingredients, in the right ratio, and preparing them with care.  You hit the bake button, then you still need to finish it off with presentation and decoration.
[0] https://chrlschn.dev/blog/2024/11/on-bakers-ovens-and-ai-sta...