Anthropic Built a C Compiler
219 segments
Anthropic just released a marketing
video proving that Claude, their
flagship programming model, can produce
a C compiler from scratch, no human
intervention, and they can do it in
parallel. And it can compile Linux,
SQLite, Reddus, Lua,
and even Doom. Hey, what's with the
frame rate? This is going to be a weird
video because I'm going to say something
positive about Anthropic. And then I'm
also gonna call Anthropics one of the
most deceitful companies I have ever
seen. This little product demo that they
did, the language inside the video, it
is the most dishonest framing of what
they actually did versus what they're
saying they did. Anthropic and its
non-stop hyping of the AI models is
perhaps one of the most annoying
features of 2025 and it's coming into
2026 with a whole new level of rigor and
completeness. All right, so let's go
over what they did, what the actual cool
part, and actually why what they did was
complete hype nonsense. So don't worry,
it's not over. You don't have to pack it
up. Software engineering is in fact not
over quite yet. Now, that video that you
just got done seeing, there's so many
lies into it. So, we're going to just
try we're going to try our best to kind
of take apart the lie. So, first off,
the thing that they were actually
building was trying to see, can they get
Claude to run by itself long enough to
produce a functional piece of software.
Functional, of course, just means that
it can do what it says it does,
regardless of how good it does it. Long
as at the end of the day, you say do X,
it does X. you compile Linux, it should
produce Linux as an artifact. Also, put
a little star on that because that even
that not so true. All right, the article
kind of kicks off with to test it. Now,
it being this multi- aent harness to be
able to have Claude run autonomously for
multiple weeks. I task 16 agents with
writing a Rustbased C compiler from
scratch capable of compiling the Linux
kernel. Over nearly 2,000 cloud code
sessions and $20,000 worth of API cost.
The agent produced a 100,000 line
compiler that can build Linux 6.9 on x86
ARM and risk 5. Again, there's no
asterisk. So, what are these so-called
asterisks? Well, first off, I don't know
if you know this, but GCC, which is what
they're basing this off of, not only is
it open source, which means that they've
already trained on top of it. And we all
know if in case you didn't know that uh
these models, you can produce nearly
perfect identical copyright works back
out of them if you can convince them to
produce it. Like this one right here
showing that Claude 37 can produce 95.8%
of the first book of Harry Potter.
Almost a near verbatim reproduction. But
Anthropic in its in its wisdom when
starting from scratch, scratch meant 37
years of developed torture test suite
from GCC. Yes, you know this classic way
of doing software development. Usually
when I start a new project, I first get
handed 37 years of prior art in which
contains the perfect golden test suite
so that I can test my new project in
every conceivable way possible. And then
on top of it, I have the actual working
version of the thing I'm about to build
that I can also test my working version
against. And that's known as the online
Oracle. As we as we say in this software
biz. Also, when I say it can compile
Linux from scratch, I want you to
understand that it lacks a 16bit x86
compiler necessary to boot Linux out of
the real mode. That's because Opus was
unable to implement a 16-bit x86 code
generated needed to boot into 16-bit
real mode. While the compiler can output
the correct 16-bit x86 via the 66 and 67
op code prefixes, the resulting compiled
output is over 60KB, far exceeding the
32K code limit enforced by Linux. See,
it's honestly it's Linux's fault. Like,
they have this stupid 32bit maximum
number on. It's not my fault. I'm not
holding it wrong. It's Lionus. He's
holding it wrong. All right. So to say
that all in a quick sentence, they
started a project from scratch having
every single conceivable test and a way
to test it under all conditions. They
had an online version of it, GCC online,
to be able to call out to to validate
everything they've done. And lastly,
they couldn't actually make Linux boot
because they were unable to produce an
artifact small enough. So they built a
compiler completely from scratch in two
weeks and they just had to walk away.
Okay. They also couldn't walk away
during those two weeks because sometimes
it did things and it would crash itself
and we had to restart it and make sure
things were working. Now, that's what I
call from scratch. And this is exactly
what I mean by dishonesty. Like look at
that. You saw the video in the
beginning. It's like yeah dude we said
hey Claude you'll build this from
scratch. Walked away two weeks later.
Linux was working. SQL light was
working. Reddus was working. And yeah,
we even played Doom, loser. This is not
from scratch. There's no from scratch,
no human intervention that don't just
just say what you did. Like, okay, so
the real takeaway, which everybody
should have, which is what is triggering
me and making me so angry again at
Anthropic, is that the real cool thing
is that they figured out how to get 16
agents to mostly run by themselves for
two weeks straight and actually produce
something given the correct guidelines
at the end of the day. Hey, that's
pretty cool. It's a pretty large
project. It shows that models are in
fact improving and can handle kind of
context up to this size and able to kind
of work together given the right
orchestration. Like that's a neat
takeaway, but that's not what they said.
And that of course is driving me nuts.
Which of course led to hilarious issues
on GitHub. Like the very first issue,
hello world does not compile cuz it
turns out the example program that they
put in their readme does not compile.
Sorry, that doesn't compile. You didn't
provide the linker, bro. You idiot.
Okay, CCC is not like GCC. It only is
the compiler. It's not an assembler or
linker. Okay, you think you just get
those for free, buddy? Which, by the
way, there's like 300 and some comments
on here of just people arguing back and
forth. Oh my gosh, it is just a actual
It's a claw slot mess in there. Okay,
and of course, I'm not the only person
saying this. There are some other people
saying, "Hey, this is kind of
ridiculous. This is a little out of like
out of pocket here calling this from
scratch and no human intervention. So,
at the end of the day, this could have
been an article about how we got Claude
to run for multiple weeks and produce
something with very little to almost
none uh human interaction and being able
to fulfill a spec. But instead, it
became a spectacle about how Anthropic
yet again is completely dishonest. This
is just another example of the AI hype
cycle. They're just here to try to raise
money and to take every piece of novel
work possible and sell it back to you.
Now, this is a future I'm personally
excited about. Am I right? Let's go. Oh
my gosh. The name is anthropic. If you
were just like a little bit more honest
about what you're doing, honestly, I
think a lot of people would be much more
excited about it and probably cheer you
on from the sideline. I think you have a
lot of potential. Your models are pretty
good. There's a lot of cool stuff about
AI. We don't have to be AI haters, but
sometimes you just say the stupidest
crap ever and just do the stupidest
stuff and make everybody hate you. How
about you just don't do that anymore?
Hey, you know what? I will give you my
service for free the next time you
decide to release another marketing
video. Just let me watch it and read
your article right I'll do it for free
for you. Okay, Daario. Okay. And maybe
we could frame this with a crazy radical
idea. Honesty. I know. It's a whole new
novel concept. A gen. Hey, is that HTTP?
Get that out of here. That's not how we
order coffee. We order coffee via SSH
terminal.shop. Yeah. You want a real
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>> Well, maybe the coffee is not for you.
Terminal [singing]
coffee [music]
in hand.
Living the dream.
Ask follow-up questions or revisit key timestamps.
The video discusses Anthropic's recent marketing video showcasing their AI model, Claude, generating a C compiler from scratch that can compile various software including Linux and SQLite. The speaker, however, criticizes Anthropic's presentation as deceptive, arguing that the process was not truly "from scratch" nor entirely autonomous. Key criticisms include the use of GCC's existing 37-year-old test suite and the presence of a working GCC version as an "online oracle." Furthermore, the generated compiler was unable to produce a 16-bit x86 code of sufficient size to boot Linux. The speaker highlights that the genuinely impressive aspect was Claude's ability to run autonomously with 16 agents for two weeks, producing a functional, albeit imperfect, piece of software, but this was downplayed in favor of the "from scratch" narrative. The video concludes by urging Anthropic to be more honest in their marketing to foster greater excitement and trust in AI development.
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