Lauren Tan XAi Grokbot
1474 segments
Everyone, I am Lauren Lauren Tan. I
guess not many people know my last name.
Uh, I am Potato on Twitter. Uh, potato
with spelled with an E. Um, and I have
been at Cursor for about 5 months. Uh,
previously I was at Meta where I worked
on the React team. Uh, specifically
working on the React compiler, uh, which
was a whole lot of fun. Uh I'm still on
the on the core team and and uh
contributing to open source here and
there. Uh so that that's really nice
that they still let me do that. Uh and
before Meta, I was at Netflix uh where I
was uh both a tech lead and uh I
transitioned to be be an engineering
manager um for about two years. So I've
had a I've have had a lot of experience
going between engineering management and
being an individual contributor. Uh and
I think something I've noticed actually
which is quite interesting is that there
are so many parallels with you know
management skills and how to like manage
agents. Uh and that's actually a big
part about what I wanted to chat with
you and everybody else about today. Um
but yeah that's that's me. Uh I do have
some like very light slides but uh it's
not going to be uh just rambling. So let
me just share my screen
and hope that I don't leak anything. Uh
oh no I need to allow permissions.
>> No worries. Take your time. There's
always tech tech trouble. Uh give me one
second to rejoin.
>> Yeah, go for it.
I see many of you already know Lauren
from from the looks of the chat here.
Um, so yeah, it's exciting to to get a
chance to chat with her uh and and go
through some of her her recent work. As
you guys heard, you know, a lot of
recent experience from from Netflix to
to Meta and then now over at Cursor. Uh,
we're going to chat a little bit about
Grockbot as well. So, uh, that'll be
exciting. I don't know if you guys saw
that was a recent release. I think
literally maybe yesterday or the day
before uh from the cursor team which is
kind of like um let's call it like
agents for everyone. You can go check it
out if you want and learn a little bit
more about the product but um but yeah
we'll we'll explore that a little bit
today as well.
All righty. Welcome back.
And Lauren, you're just on mute there if
uh you want to hop off of mute if you're
chatting.
>> Yeah, sorry.
>> No worries.
>> It's 2026 and I still don't know how to
use Zoom. [laughter]
>> That's all good.
>> Uh okay, so I assume you can see my
screen.
>> Yes. Yeah, we're good. Um, so yeah,
today, yeah, I think I think the big
theme for me as I've been using agents
to write code, and I'm sure a lot of you
have had the same experience as well, is
how do you trust it? You know,
especially if you are an engineer that's
been writing code for a very long time,
you have a lot of opinions and lessons
that you've learned about doing good
engineering. And when you see agents
just, you know, winging it and, you
know, guessing, hallucinating,
uh, you know, confidently stating that
they found the smoking gun, uh, for the
hundth time, uh, but it's actually not
the real problem. You lose a lot of
trust. And when you lose when you don't
have much trust in your agents,
I feel like you you really can't get the
most out of them. And for me, the
parallel is like with management. Uh so
if I'm an a manager an engineering
manager of a team and I have a bunch of
you know I have a team of engineers uh
on my team and I don't trust them then
the mode of operation I'm going to be in
is going to be like micromanagement
right I'll have to spend a lot of time
looking over my reports shoulders and
checking that they're doing their work
well you know that they're not shipping
bugs to production
and so I drew this chart cuz uh it's not
it's not a very scientific chart but
like this is how I imagine myself and my
journey through using agents. So you
know like fast forward or back forward
uh or fast back uh fast backwards like a
year or so when you know nobody was or
not many people were using agents to
code. Uh I think you
uh you know get into this mode where you
are
in very heavily in the loop with one or
several like a handful of agents and you
find yourself just constantly fig uh you
know trying to understand what your
agents are doing uh and you're very very
in the loop. You're watching every
single output. you are sitting there
prompting um and you really can't
parallelize beyond that because you
don't again you don't have that trust
right you can't go to a 100 agents uh
like spawn 100 agents when you don't
even trust the output of one agent
so over the past 5 months I feel like
I've really been able to uh like ascend
this trust curve and now I'm at the
point where uh I actually have this
Sounds kind of scary to say this and it
it makes me sound like a slop artist,
but I I promise I'm not, but I actually
have my agents now um automerging PRs
for me. Uh which is like a wild thing to
say, but um like I woke up today and
there were like 20 PRs landed and I just
reviewed them on Maine like they were
already landed and they were good. Uh so
how did I get to that point is basically
what I wanted to talk about today.
Uh, and again like yeah, feel free to
jump in if you have questions, Colin.
Um, but uh, oh yeah, of course I got to
show this this chart. Uh, where uh,
no do not trust to someone requested to
control my computer. Uh, probably won't
do that. Uh but yeah, so this chart I
think I I'm sharing this chart not to
kind of like flex but to kind of show
like the journey like so you can see
like the curve like it sort of like
inversely matches the contributions I've
been able to land at cursor. So I joined
five months ago and five months ago like
I you know my first month I was like not
very productive because I was ob you
know I was learning the codebase didn't
know what the heck was going on and as I
got more confident in in my agents uh
I've really been able to kind of ramp up
my productivity. Uh and again like yeah
like last month I shipped a thousand PRs
which is ridiculous. Uh, and then this
month we're only on the 12th. I'm
already at like almost 800 PRs landed.
Uh, so the velocity is definitely high
and you you I'm sure a lot of you will
definitely be questioning like how how
much of this code is actually good. Um,
and I think yeah, like that's definitely
fair to question.
Um, but uh, yeah, I think I think if you
set up your agents well, you can
definitely get to a very similar level.
Um, and so I'm going to talk about how
we do that.
Uh so for me I think I'm curious like I
guess call in your experience as well
but uh for me I think the most important
skill that you should have in your
toolbox when you work with agents is
verification.
Uh and by verification I mean the
ability for an agent to actually run the
code uh or take CPU traces or heap
snapshots or uh you know open an iOS
simulator whatever you know however your
application is exposed to your users it
can do the same thing and uh run it for
real and actually test and verify it
don't work because that's the thing that
really closes the loop. Uh it doesn't
guarantee your agent writes good code uh
but it allows them to at least write
correct code uh which is a big a really
big step forward for being able to trust
your agents. Um
I will I can share one example that we
have uh within cursor. Uh
oops
where let me open this.
Let's make this uh make me full screen.
There you go.
Uh so for the for cursor's agent window
uh so this is actually an interesting
story but uh when I joined cursor 5
months ago uh they're actually uh well I
was supposed to join a different team I
was supposed to join like the cloud
agents team uh but then since I have a
lot of experience working on react and
agents window is a react application uh
I was
uh I was asked to basically help out
with uh the agent window work. Uh but um
there wasn't really a lot of like skills
to help me. So I just found myself like
okay uh agent window is going to launch
in like a week, right? we have a really
tight deadline and um there was uh you
know I was just sitting there like okay
I'm going to open up the performant the
the Chrome dev tools and just like take
a trace look at it myself and try to
make sense of this flame graph and keep
in mind I was just like in my first week
so I had no idea what I was looking at
no idea what you know I mean I had some
idea but you know the codebase was
completely fresh to me uh and I realized
like my agent had no idea either you
know like I would take a screenshot of
the tree. I would download trades. I
would send it to it and it be like,
"Yeah, it kind of looks like this, you
know, uh, and it would like confidently
state like it's this thing." And then
I'd try to fix that. And turns out
that's not the actual thing.
So, this was very very slow process. And
if you've ever done any like performance
work yourself or, you know, just even
development with an agent where you
don't have a verification skill, you are
the verifier, right? You you're the
bottleneck. you you you tell your agent
to do something and then it goes off and
write some code. Then you open up your
you know local dev build and then you
start to say oh you know doesn't work.
Then you got to copy paste screen uh you
know screenshots or console errors or
whatever. Uh and then your agent like
slowly kind of like uh you know works
with that and then tries to understand
it and um fix the thing but then you're
constantly just in the loop and and
being a bottleneck. So there's really no
way to parallelize. So the control glass
skills are like one of the first skills
I built uh for cursor. Uh and glass by
the way is the code name for agents
window that we use internally but it's
just cursor I guess. Um and so this
skill uh is I guess the the the code
itself is not super interesting. Your
agent can very easily make one for you.
uh where if if you're building an
Electron app or a web app or even iOS uh
applications uh you can teach your agent
how to use like the ChromeDev tools
protocol or through uh Apple has some
utilities as well for running the
simulator and taking traces and
controlling programmatic control as
well. Uh so that's really useful. Uh but
one thing I want to talk about is uh the
this thing
uh where is the read me? Uh so this
skill comes with this very unique
feature called or not feature uh unique
file called a feature map. And so the
story then is like I built this skill
and so now the agent was able to uh
actually run the agent window and take
traces and whatnot. Uh but it had no
idea what what the agents window was. So
um you know like someone would say like
oh the the left sidebar is like laggy or
something like that or you know the
right side the the PR tab is not working
and the agent would just be like kind of
flailing around. It would spend a lot of
time trying to like look up the code and
you know where is this feature? How do I
actually get to it on the UI which made
it basically completely useless. uh you
know like we would I would run this
skill locally and you know it would
spawn a dev build uh but then it' just
be churning like I just try to click
here it wouldn't know how to get to
things um and it was just an awful
experience uh so is putting arrows on my
screen um so uh yeah this this feature
map has been really useful uh because it
teaches the agent how to get to all of
the features that you have. Um, and in
PAC, the plugin that I I've made, uh, if
you search for PAC cursor on Google, you
you'll find it. Uh, but there is a
create verification skill in that plugin
where it actually helps you set up
something like this for yourself. Um,
including the feature map. So, it will
actually explore the code and build up
this initial feature map that tells your
agent how to get to all of the different
features that you have. Uh and this is
extremely powerful because now like you
have these user reports that come in uh
you you can actually map even like a
vague report or even a screenshot. So we
have this uh internally at cursor where
uh we have a slack channel with you know
lots of people giving us feedback on the
agents window and rockbot and whatnot.
Uh, and often times the report is very
bad like very low quality like someone
will just put very often we get like a
screenshot like and then someone just
says question mark question mark
question mark like what is this and you
know like without this your agent is
like I have no clue right but with a
feature map like this it has a lot more
context and understanding of how to
actually navigate how to get to all the
different features. Uh so like you know
example like I guess like the sidebar
like what is the sidebar uh you know
like all the different sub features that
are present in it um like from the user
point of view here's where how do I get
to it all the different keyboard
shortcuts
uh even like the the what do you call it
the DOM elements or yeah like the
attributes that you use for selecting
things through the CDP uh are all there.
So uh again yeah this is like really
really powerful uh for for agents
>> uh and pstack ships uh that create
verification skill but also a maintain
verification skill uh so you can keep
this up to date.
>> Cool. Yeah, I was just going to ask how
you created that. So do you mind sharing
a little bit more about um that that
process in the context of Pstack and
maybe just what Pstack is for the folks
who aren't familiar?
Yeah. So, P stack is pretty interesting
because uh well, first of all, the name
is kind of goofy. like the P the P and P
sack is like potato potato snack because
I um so uh uh there is a pretty uh
famous person Gary Tan who is the CEO of
Y Combinator and he's come up with this
plugin called Gstack uh Gary Stack and
uh funnily enough we share the last name
we have no relations uh but I thought it
would be funny to kind of you know poke
fun at Gary and make peace stack my
version of of of of [laughter] his
plugin. Uh but kind of tailor it to my
own set of p engineering practices.
Uh but I honestly actually never set out
to build PAC. Uh it just started with a
bunch of skills, right? Like I started
with that control glass skill and then I
started with another skill like called
how which I also noticed through like
observing agents. Um, so like you know
in the early days of me, you know,
trying to climb this ladder, I was like
super in the loop and I was basically
nitpicking my agents to an extreme
degree. I was like I would tell it um,
you know, this feature has stopped
working. Here's a bug report. Like why
isn't it working?
And very often the agent would just like
confidently state like, "Oh, it has to
be this, right? It has to be this
thing." And I noticed like when I looked
at the actual tool calls, I noticed it
wasn't actually reading the code that I
thought should be affected. And that
made me just extremely suspicious. And
at that point, I was like, I'm not going
to I can't trust any this agent anymore
cuz it's just it's just completely
hallucinating. And I think
I think it's very easy to just you know
like build up that distrust and not and
kind of feel helpless like you know you
don't know how to help your agents
succeed. But like again I think the the
the management analogy is super helpful
because like imagine if you were a
manager of an engineering team and you
had an engineer on your team who was a
really good coder. No business context
whatsoever. you know they they just you
just hired them and they they onboarded
you know like five seconds ago. Uh and
so how do you actually teach that person
to be effective? So how you do that is
through a skill. uh a skill being just
you know it's just markdown right but
you know it encodes a lot of information
instructions a lot of uh you can really
draw out a lot of intelligence from an
agent by well some people on Twitter
call it like you know pull the agent to
a different latent space which is kind
of like a fancy way of just saying like
since uh you LLMs are sort of like they
predict the next token uh when you give
it some high quality tokens uh to to
begin with then you know it it can kind
of pattern match on like a higher space
that's you know smarter
um so that's like a very interesting
model there but yeah I built Pstack very
very incrementally uh so uh started with
just really observing how agents you
know all the fail different failure
modes of of that agents were having and
every time I saw that I just okay I'm
just going to make that a skill right
like stop hallucinating actually go and
search up, look up the code, use a lot
of sub agents, uh, and yeah, stop
guessing.
>> Yeah, that makes sense. One, one kind of
followup question here, uh, both from
myself and from a bunch of people in the
chat. So,
>> I guess it's two two parts. So, one is
like how do you maintain these skills?
So, like the product changes over time.
Obviously, there's a lot of people who
are shipping against the codebase. So,
how do these skills get maintained? Uh
and then second to that is like how do
you know when your verification is is
good enough? Uh like and you know you
can trust that the ver verification
loops that you've built are going to I
guess you trust that the outputs uh when
they're done.
>> Uh yeah maybe I'll talk about um I think
there are some related maybe I'll start
with this one first. So like how do I
maintain these skills?
So, um, if you're not familiar with this
concept, an eval [clears throat] is
essentially like a way to, uh, well, I
the mental model I have is like it's
like a unit test for an agent. Um, and,
uh, you can actually make your own
evals. You don't need like a special
framework for them. You can build you
can you can build one depending on like,
you know, how scientific and how
rigorous you want to be. Uh, my screen
is red.
>> Yeah, there's a little button. Um,
sorry. Do
>> you mind like disabling the drawing or
something? I I can't see my screen.
>> Yeah, sorry. If you guys could not draw
on the screen, that'd be great. But, um,
there's a little button in the
>> troll.
>> Yeah, the little drop down.
>> How do I clear?
>> Yeah, you got it. Perfect.
>> Yeah. So, eval
test your skills basically. And actually
in Pstack we ship uh under potato mode
there's a playbook if you search for it
called eval playbook. Um and it's uh
uh it's like not it's actually pretty
pretty rigorous the way it's done. Uh
but um essentially what I do is I spawn
a lot of different sub agents. I have
like my main coordinator agent uh come
up with a rubric for uh what I want the
skill to do. Um, and then it spawns all
these sub aents and it's it creates
individual directories for them, uh,
which are cleverly named to not let the
sub agent know that it's being evaluated
because, uh, agents can actually tell
and when they do, they change their
behavior. Uh, but it does a bunch of
stuff like that to um essentially yeah
like test whether or not the skill I'm
making or changing is actually doing
what I think it does. Um, and one of the
really nice things about cursor is that
we are we we support so many different
models. So you can actually eval your
skill across all sorts of different
models um and you know get a sense of
how well it performs across that
different matrix. um especially for the
models that you use.
Uh so I do this a lot. Every time I I
modify a skill, I will run one of these
uh like the EBAL playbook uh and make
sure that you know it's actually leading
to a result I want. Uh but I will say
like
maintaining skills is actually pretty
hard. Uh it requires I think a lot of
taste and observation. So, you kind of
need to be very good at being a backseat
driver, you know what I mean? Like if
you do pair, if you ever done pair
programming, for example, uh, and you
watch a co-orker code and you just like
you, you could probably do this better,
you know, you could do, you know, like
why did you not do this, right? You you
ask a lot of questions to your coworker.
And it's kind of a similar thing here.
You like you don't want to just be a
passive observer of your agent. You want
to be very in the driver seat in the
initial stages when you're building up
your own set of skills. uh you know
obviously you can use something like PAC
but if you're building your own set of
skills it's very I think you know
opening up the all the tool calls and
like reading the code and reading all
the uh the agent behavior and their
thinking blocks is a really great way to
see where they they fail right like what
what you know where are they being done
and then you can go and build a skill
for that and then with verification how
you trust it is it's I think it's also a
very similar iteration loop uh where you
know like I actually did the same
process for verifying the verification
skill where I actually get um so one
thing that's interesting about eval is
that you can sort of hill climb them
meaning that uh your eval can produce a
score right uh a score that you can get
your coordinator to produce uh but also
comp uh you can have a judge agent of a
different model to uh kind cross
reference and make sure that the first
model is not being biased, right? The
model that's judging all of the sub
aents that are running the thing. Uh but
you can also like hill climb. So meaning
that you can you can use like /loop in
cursor and you can say okay keep looping
on this eval right until everything is
10 out of 10 as an example. Uh and I did
the same the basically the same approach
with the control skill. And so I kind of
it was very it was very hands-off
actually. Uh so you know I uh I kind of
built I built that skill that way like
the CLI in that skill. Um and over time
it's gotten really good. Uh but yeah it
was definitely not super smooth at the
beginning. It required a lot of
iteration and I think there's an analogy
here for me which is um well I make this
analogy later in a different slide on my
drawing here. Uh but I think of it like
uh you know as a as a engineer now
you're sort of more like you uh like
maybe a manager or the analogy I like is
like you're like a a chef in a
restaurant. Uh you you're the head chef.
Uh you're not cooking all the food
yourself anymore. You have a team of
cooks, right? You have line cooks, you
have a sue chef, you have, you know, all
these different stations.
Um and it's your job to really design
the environment. you know, you you're in
charge of setting up the kitchen. You're
in charge of, you know, like giving
tasks to different people. So,
um yeah, it's a very interesting way of
working. Uh but yeah, that's that's how
I've basically built uh these
verification skills.
>> Yeah, just just one followup there on
like to go try to go one layer deeper.
So, are you let's say we wanted to build
um an eval or a skill for for something
and we wanted to kind of get better on
its own, which is is what I think you're
suggesting. Uh are you doing that in
like a work tree kind of isolated with
like the sub agents and and then the
reviewer agent and and all that? Is it
happening like in some type of cloud
hosted environment? Like what's the the
more the practical steps? If I wanted to
go do this uh and like set up a
verification system for something, what
would I what would I do or where would I
start?
Um I think that uh the best place to
start is local because you can observe
you can definitely observe what your
agents are doing. So, uh, if you're
building a verification skill for
yourself, uh, I would definitely start
local and just have your agent bring up
the application, whether it's like a CLI
or, uh, desktop app or whatever. And so,
you can actually observe, right? You can
see how the agent is interacting with
the the application. You can see it, you
know, how it calls like the different
APIs that that allow it to interact with
the uh the application.
Um but uh for me personally uh I have
basically been kind of all in mostly all
in on cloud agents because they're
extremely powerful. Uh and the really
powerful thing about cursor is the the
cloud agents actually where if you spend
a little bit of time setting up your
environment
these control skills these verification
skills pay a huge amount of dividends
because it's not just something that
makes you as a single engineer better.
It actually levels up your whole team uh
and even your whole company because uh
you can actually start thinking about
cloud agents. start thinking about
automations that automatically do things
like uh I I get I I kind of talk about
this a bit later, but I'll just kind of
get into it. Uh where where you know,
for example, like I talk a lot about
this agent we have called Benny, right?
who who uh you know takes all of the bug
reports that we get and it automatically
goes off in the cloud, opens up a cloud
uh it's you know its desktop. It runs
cursor in its own computer and it uses
the same control skills to interact with
the application and try to reproduce the
bug uh or the user report, right? And
this is so so powerful because at once I
can immediately I I get so much
information from this automatically like
here in this example you can see that uh
the Benny actually reproduced the bug uh
but it's already fixed on main. So it
actually confirms that we fixed this
problem already and all I need to do is
just release another build of of cursor.
Uh, so that's like huge information
there that I didn't have to go off and
sit with an agent, you know, and spend
an hour trying to figure like is this
fixed, is this not fixed. So you you you
gain back so much time. Uh, but you
know, everybody on my team benefits from
this. Everybody at the company benefits
from this. Uh, so definitely think that
uh, you know, keeping these uh, using
cloud agents is super powerful. Uh, but
yeah, it's like a journey. You have to
trust it first, right? before you you
get to this point. And that's it goes
back to what I was saying here where,
you know, it's very hard. It's almost
impossible. And I would definitely
encourage you not to try to jump from,
you know, like if you're still in this
zone, you don't want to jump to like I'm
going to spawn a hundred of thousand or
thousands of cloud agents right now
because you're just going to waste a lot
of tokens. Um, and it's going to be
extremely expensive.
>> Yeah. So just to kind of recap so far,
basically the if we wanted to go on the
journey that you've kind of gone on, it
would be to start with verification,
building some some skills and some some
ways of determining that the agents are
producing at least like correct code.
Whether like you said whether it's good
code or not is maybe a separate
question, but like it's it's technically
solving the problem by looking at you
know stack traces, looking at you know
the the actual behavior in the app and
so on. Um, and then once we trust it
locally, then we can start to think
about scaling into the cloud and running
more agents that are picking up signals,
I guess, on their own, right? So whether
that's like a bug report that comes in
or something, they can go and pick it up
and solve the problem and and give us
back a PR. And then maybe the last step
is like automerging the PRs, which uh is
where you're at, maybe not where
everyone is at.
>> Um, and then and reviewing them on main,
but um, is that is that about right?
>> Yeah, exactly. I think yeah, that's why
I drew this this uh this this curve,
right? because that this this basically
describes my journey of you know when I
started barely could use a couple agents
and I was just observing every single
thing. I think there's really no
shortcut for going from here to there
because this is really about your
personal level of trust in agents,
right? Um obviously, you know, as a as
engineer, you don't want to just slop
code into production. So, how do you
actually build up that trust? Takes um a
lot of uh I guess taste and judgment. Um
but, uh you know, like I think plugins
like Pstack definitely kind of help you
uh get up to speed much quicker. Uh, and
so I guess it's like if you trust me and
you trust Pstack, then in by extension
you can maybe trust your agents. But if
you don't trust me and I I definitely
would not encourage people to blindly
trust me. Uh, uh, you know, if you build
up your own set of skills that you can
obviously, you know, take a look at PAC
and kind of fork it, make it your own,
improve the skills. Definitely encourage
that. Uh but for me it's really all
about it just keeps coming back to
trust. You know every one of us here in
this chat have a different standard for
engineering. Uh and there are different
things that are important for us in our
codebase. And uh when you are able to
encode all of that into skills and you
can verify that your agent is actually
doing them that allows you to really
kind of ascend this curve and um uh you
know start automating things. Uh there's
another piece I wanted to talk about. Um
if there's more
>> Yeah, go for it. I'll I'll pick up more
questions as I go. But
>> yeah, I think there's a third part to
this which I haven't talked about yet,
which is kind of an interesting one
which is like refactoring and rewriting
like one of the uh I guess most
controversial one of the most
controversial topics in the industry I
think is like should you rewrite your
app or not? Um because I think engineers
are very prone to this where especially
when you join a company you come in and
you see like the code base and you're
like oh man this is like who wrote
this code you know it's terrible I want
to rewrite the whole thing there is a
very common inclination and I think a
lot of you know before agents um and I
guess arguably even now people will
definitely discourage you from re
rewriting stuff but I'm actually here to
make a case for why you might want to
consider
Um because
I think it really depends. Uh you know
uh brownfield applications I think are
actually in a pretty good spot
especially if they're set up well
already. Uh and like recently I've been
talking to some people but uh you know I
I was just observing I I just noticed
this parallel which is that a lot of big
tech company problems are now
everybody's problems. Um, and the big
tech company problem, you know, like
when I was working at Meta, like we had
this giant monora repo, we had like, I
don't know, tens of thousands of
engineers just, you know, like banging
on their keyboards and and shipping code
and
a lot of really great engineers at Meta.
Uh, but, uh, I'll say like, you know,
you'll be surprised that the code
quality is actually not that good.
[laughter] Um, and so I often joke that
like, you know, before AI sloth, we had
human sloth. Um and so uh you know I
think a lot of big tech infra like uh
like what Meta has or Google you know
you know really big tech companies are
actually designed for that where you
you're sort of like you're catering to
the the you know like uh this sounds so
bad to say but like the the least
capable engineer on your team right you
build you build frameworks you build
conventions you build guard rails you
know you restrict credentials so that
you know your intern doesn't wipe your
production database
Um
there's uh you know if you have that
level of infra already I think your
agents can actually already do a very
solid job right because they have the
the guard rails are already in place for
agents to not cause havoc or not cause
too much havoc uh in your codebase um
and you can always add more you know
guard rails. Uh but I think like green
field applications especially are you
know like the brand new applications are
like the biggest risk in my opinion. Uh
and also the greatest opportunity
because you know if you vibe code a
project uh a prototype um like we did
for Grockbot you know Grockbot was spun
up very very very quickly. Um and if you
if you haven't heard of of Grockbot it's
like a a new application we just
launched yesterday. Uh it's it's really
cool. uh lets you orchestrate your
create like individual agents that have
their own identity and you can kind of
orchestrate them. It's super cool.
Definitely check it out. Um but yeah,
that was it's like a very it was a very
green field application like most
prototypes are so like vibe coded very
quickly. Humans were not reading the
code at all. And uh I had this tweet
recently uh where I said something about
organic architecture. Um
maybe I'll find it. Uh but the idea is
that
uh when you have a completely vibe coded
application, you essentially have no
guard rails whatsoever. So uh your
agents
when you give them a task, they will
just solve it in whatever method is the
most convenient. And over time you get
into this uh situation where you have a
codebase that is spiraling out of
control because you don't understand it.
Uh your agents understand it I guess in
a way but like they've built something
that is you know optimized for short for
shortcuts. Uh and uh you know it will
you will suffer you'll have a lot of of
issues with that application.
Uh so I think starting your codebase
with uh like very strong constraints is
very much needed uh because like when
you have a codebase that you can trust,
right? when you have guardrails that
actually help you uh uh help your agents
write good code, you can get into the
you know like into this part of the
curve where I I where like I I said you
know I woke up today and I had like 20
PRs merged u by my agents and that's
because I invested a lot a lot of time
uh over 600 PRs I I I calculated
yesterday uh when I refactored all of
Grockbot to this new architecture that
I've been
Um,
and yeah, I've gotten to a point where I
I don't really look I really don't look
at the code anymore. And um, I say that
not just, you know, to sell you tokens,
but because I, you know, it it it took a
lot of work to get to that point. I
spent a lot of tokens to get the
codebase to this point where I no longer
have to look at it. Uh but I'm very
excited because you know of the
potential where you know it's not just
this doesn't just benefit me it benefits
everyone contributing to Grockbot and it
also empowers you know designers and
product managers and you know pe uh even
GTM people to add features to Grockbot
and I don't have to worry you know I
don't have to to wake up at night in in
the middle of the night and worry like
oh someone's just merged a perf
regression right I have a ton of
constraints and CI is like it's actually
very annoying to write code in in graph
web but like agents absorb all of that
annoyance.
Um but yeah I'm happy to talk about what
exactly that is. Um
>> yeah I think one question um
>> before we get into the this part here is
just around that element of like what
your your your CI looks like or maybe
some of the constraints and then also
like the average PR size. I saw a
question about that earlier just to give
people you know kind of a a glance. So
it doesn't have to be like
mathematically average, but just uh you
know like what generally the size of the
a PR is. Um if it's only a couple lines
of code or you know um yeah
>> um
I think it depends uh
I'm trying to do this in a way where I'm
not going to like
>> you. Yeah, you don't have to share the
actual number like an actual average. I
think this this is fine
>> benchmark
>> but like we have so okay this is not
that interesting but uh well fun fact is
that virtualization in grockbot and in
uh cursor is actually powered by uh
pretext uh which is a sort of new
library that someone's built um that's
really interesting you should you should
check it out but that's not really that
important uh I think the average PR size
I actually don't know. I pro I don't
know if I want to click on these. Uh I
probably can, but I would say like they
can range anywhere from a few hundred
lines or 50 lines to like a thousand
depending on what the thing is doing. Uh
so like here I'm actually like deleting
a bunch of files. So I expect that it's
just like mostly deletion. Uh but yeah,
it kind of varies.
>> There's no like Yeah,
>> there's no like hard cap or hard limit.
Are there all like 50 line P?
>> There's no hard cap. Yeah, there's
definitely no hard cap, but I I do
encourage my agents to split up their
work into multiple PRs. Uh I do that
mostly because uh I like I like the idea
of the I guess maybe this is much harder
to do now as in the world of agents and
you have like so many commits, but I
like the idea that you know the git
history is a very rich source of
context. Uh, and I like the I like each
PR to sort of atomically describe what
that small piece of thing is doing,
which also makes it easier for me to
revert changes and like figure out, you
know, oh, I shipped a bug and it's just
it's here, right? It's not in this
40,000 line PR where who knows what
landed in there.
Uh, but yeah, I don't have a hard cap on
PR size.
>> Cool. And then um yeah, also quick
question on like CI. So again, you don't
have to go into like uh the screen share
of like your CI does, but just generally
would you describe what the CI kind of
looks like uh or how strict it is?
>> Uh yeah, so
uh well specifically for Grockbot. So
Dune is the is the sort of cheeky code
code name for the architecture that
we've built for Grockbot. Um the CI
looks pretty annoying because there's
checks for everything. So like literally
I have um uh well if you've written any
React for example you know you know that
one of the biggest foot guns in React is
use effect. Uh so in
uh Dune and in graphbot we've banned use
effect. So Dune is just you can the the
mental model of what Dune is uh you can
kind of think of it as like Nex.js JS
for uh electron apps and it's designed
for agents to write uh and it's like
custom for you know our agent powered
applications. Um so the CI checks are
very like specific to that like you know
don't use use effect it's it's it's
banned like CI will fail uh and yell at
you. We have like some of the more
interesting ones that people might raise
eyebrows is like I actually ban code
comments as well. Uh which is very
interesting. Uh but I've noticed that
99% of the time agents just write code
comments that kind of describe some
historical thing that is actually
totally irrelevant to the code. Um like
it will often say like you know oh
Lauren said you should never do this and
it's now in in a code comment. I'm like
what? like why what that was I didn't
say that as like a durable you know
global rule I just meant like your this
PR sucks and you should change that part
but agents don't really understand us
that well surprisingly uh and or they
kind of assume too much and they kind of
do things in like very stupid ways so
like yeah we just ban everything
everything you can imagine like the
agents are bad at we ban uh so one
example that we actually suffer for a
lot in the agents window is we have uh
you know you if you've used the agents
window you've definitely seen
performance issues and you know we're
constantly trying to fix them. Uh but
it's like a it's a never- ending
struggle because there's so many pull
requests that get merged every any one
of them could just regress performance
or stability or reliability. Uh you know
the agents window doesn't have this
architecture yet. I plan to do bring
this learning back there and kind of
refactor everything there. Uh but uh it
just regresses super often uh because uh
there's just one example is like we have
very poor um isolation between
processes. So like on you know on on
Electron you have a renderer thread that
renders your UI but you also have like a
main thread that you can run other code
that you know doesn't need to block the
renderer.
Um, but we do a poor job of separating
those things. And so oftentimes you just
accidentally have code that gets pulled
into running on the renderer thread and
then all of a sudden you're competing
with the the renderer that you know that
has a very if you want like 60 fps you
have to every frame that gets drawn has
to be done in 16 milliseconds. So very
very small you know deadline per frame
uh if you want you know a very smooth
product. Uh and when you start building
bringing in accidentally bringing in you
know things that are like very
computationally heavy or they have a lot
of IO uh then you just get into like a
lot of jank right your your FPS really
drops you start uh you know losing
frames you get long tasks that take more
than 16 milliseconds and you just get
this really choppy experience.
So all of those patterns that we've
learned basically building electron apps
we've encoded into this framework and it
becomes like a hard failure. So I
literally in in grabbot we literally
have a directory called electron main
electron renderer and we have uh import
uh CI guess where we actually check the
dependency graph to make sure you're not
accidentally importing code from one
directory to another. Uh so that's
enforced by CI um as well as bug bots uh
which is our which cursors um like code
review tool that runs on CI uh you know
in our agents MD it's everywhere like so
I I I um I have this thing here where I
I talk about like um you know like there
are multiple layers I think for building
a good codebase. Uh obviously the
codebase is one where uh if you have an
architecture like this where it's
extremely strict uh you know the the the
way to build features is very
conventional that's like the strongest
strongest level of enforcement because
agents just love to copy existing
patterns. So uh one example of this in
rockbot is like we have this these
concepts called like a feature and we
have entry points and transcript cards
like oh you know the cards that you see
in the chat these are all like like
nouns I guess in in the framework and so
there's a very conventional way of
creating them and so like a feature is
all in in a single directory as an
example and so all of the code that
contributes to that feature lives in one
directory so it's all collocated in one
place. Makes it super easy. You know,
agents don't have to like uh grap around
and try to figure out like where all the
things are. It just looks at the feature
and like, oh, okay, I'm working on the
onboarding feature in Grockbot. Uh I'm
just going to work in this directory.
And for 80% of the work, it's mostly
just very encapsulated there. But, uh
like it's like very it's like designed
again for you know like the dumbest
agent like you don't have to think,
right? the the the one of the key
principles I have for this framework is
like the shortest the shortest path is
the best path.
So uh because that plays exactly to how
agents love to write code is like they
like to take shortcuts really you know
they they'll find the quickest way to
solve the problem. So why not make that
the best way to solve the problem? Uh so
I I I probably won't get into all the
specific details. Um and uh the the this
framework is really more of a collection
of ideas and principles rather than
something that will open source. Uh you
can you can you know screenshot this I
guess if you want and uh tell your agent
to uh do some build build something like
this for you too.
Um yeah, but it's really all about the
layers uh you know like the the codebase
is one part with features uh and
directories and you know import or
blocking import dependencies uh that
shouldn't be imported. Uh but and and it
all enforces that and static analysis.
So like uh there's CI checks, we have a
lot of lints for bad patterns that we
observe. uh compiler diagnostics
uh there's also rules and bugbot which
are um I think like three four five are
more soft right these two actually make
make CI red right so that you know
there's a hard constraint where the
agent can't just write crappy code
for rules and skills and buggbot your
agents can still forget right you can
still or it may not always consistently
apply them. So, I like to layer them,
but I don't I don't like to rely on them
as the only source of enforcement
because it's very very soft, right? And
if you if you only have rules and bug
ball and skills and a style guide for
your code, you will it's only a matter
of time before your code base looks like
complete trash. I'm sorry to say that,
but uh I definitely recommend yeah like
you know investing in you know things
that can be hard and forced, right?
Okay. And this is why you know maybe uh
the choice of text stack that you use is
also very important. Um like I think for
example Rust is sort of making you know
it's like getting super popular again.
Uh because the compiler is so strict
right the compiler enforces so many
different things. you know, there's a
borrow checker that you have to appease
and if as long as you make sure your
agents don't write unsafe code blocks,
uh you can more or less feel somewhat
confident that if the code compiles, it
probably works and it's good. Uh but you
see it gives you that level of trust and
confidence that you as a human engineer
no longer need to go and check it
yourself. you know, you you rely on code
and static analysis to actually make
that uh a lot smoother. Um, and I I
guess the worst part, the worst place to
be in is if you are stuck in code review
land where you actually enforce all of
the constraints, the invariance in your
codebase by literally the human person
saying, you know, reading the code and
like, okay, you should not do this,
right?
Every time you have to do that, you
should consider that as a code smell
like a anti- pattern and you should say,
"Okay, instead of me commenting on the
PR, how do I turn this into a hard
rule?" Right? How do I turn this into a
lint rule? How do I turn this into a CI
failure? Or how do I even categorically
eliminate this problem uh entirely? Uh I
I can talk about another migration I've
done, but I'll probably pause here.
>> Sure.
>> Yeah. I feel like that's that's where I
am to be honest is is what you're
describing right now which is that like
I don't have all of these rules. So I
have some things to go do after this
session in terms of being able to scale
my agents. I'm I'm definitely on like
the uh you know maybe a couple of
parallel ones locally stage like two to
three locally and I'm sure most people
here are on the same. So uh yeah I know
we only have a couple minutes left.
Lauren, was there anything else that you
wanted to to highlight? I obviously
there's lots of questions so I can grab
more but I want to give you a few
minutes if there's anything else you
want to talk about.
>> Well, I think I've been yapping for
quite a lot so maybe let's just do
questions.
>> Okay, cool. Uh, one question that had uh
a couple of uh came up a couple times
was just around like token usage.
>> So the the question is like is is what
you're describing a realistic thing for
people who are on you know uh a normal
set of token usage. They don't have you
know basically unlimited tokens uh to
work with.
I think that's a really good point. I
mean, like obviously, you know, I work
at a AI lab where we have unlimited
tokens. So, uh I definitely cannot
say that, you know, this is something
everyone should do in the exact same way
that I did it. I think it's possible to
get to this point without, you know,
breaking the bank.
But you know if you're like an
engineering leader or you know you're
you you have a startup that you lead um
I think to me it's a question of ROI um
and it's like uh yes you spend a lot of
money on tokens in the upfront stage you
know like refactoring a code base is
going to take a lot of tokens uh adding
all these things uh is going to take a
bunch of tokens but if we're heading to
a world where agents are writing all the
code and you know You want to be very
lean, right? You don't want to have to
hire, you don't want to be, you don't
want to become like meta, right? Like I
mean like in terms of you don't want to
become a 10,000 person engineering or
because I mean that's a cool problem to
have, but also you you have so much
overhead. There's like planning, you
know, like you it's it's a personally I
I wouldn't uh it it's not super fun. But
um I think you want to stay very nimble,
right? And you want to you want to be
like agents are all about allowing you
to do things that you couldn't do
before. That's really to me like the
value of agents, you know, it's not just
storing tokens on every single little
thing, but um to me like the thing I
couldn't do before is like enforce this
level of constraints in a codebase by
myself, right? Like I'm just a single
person, you know? Uh it would have taken
me years to build this framework uh and
do all the refactoring and
test everything myself and verify you
know like run imagine if there it was
just me right know in in pre- agent era
just like running you know by it would
take me so long right and my salary is
pretty high right like so you know the
the question I think an engineering
leader might have is just then you know
like what is there's a trade-off of do
Do you hire someone to do this or do you
spend the tokens to set up a codebase so
that even the the most naive, right, the
dumbest agents can do a good job? And
when you actually get to this point,
like even agents that are not, you know,
fable size do an excellent job of
writing code. And this pays a lot of
dividends as well for me personally
where I've empowered not just myself but
again like PMs, designers, engineers who
are not familiar with Grockbot to just
contribute in a way that is sustainable.
So I think yeah it's definitely like a
trade-off for sure. You know like
nothing is like free for sure. Uh and
tokens are pretty expensive. Uh but oh
actually uh I I I don't know how many of
you have seen this but we actually
announced Grock 4.6 today so very
exciting finally out um so yeah graph
4.6 would be like a great it was very
very smart uh it's really good on the on
the benchmarks uh and it's the same the
tokens uh well uh I hopefully I'm not
saying this incorrectly but uh I believe
the cost per token is the same as 4.5 so
you're actually getting more
intelligence for the same cost uh I
think this is an area that cursor tries
to cursor and spaceex AI try to really
optimize for like that heredto frontier
here of you know cost versus
intelligence. Uh you know we don't
necessarily want to build the biggest
model ever because that is extremely
expensive to run. It's really about like
how do you find that sweet spot right?
You don't you don't need a giant model
but it's just super smart right and it's
not very expensive for inference.
Uh but um yeah, I think to kind of round
it up, um I think it's like a it's it's
there's a if you do your own analysis, I
feel like it's pretty positive. It it'll
be pretty positive that the ROI you get
from investing in stuff like this, uh
just empowers not just yourself, but
your whole team to be so much more
productive, right? Like imagine if you
have an army of engineers like me who
are shipping so much improvements and
and bug fixes uh you know every day
right like that is pretty exciting.
>> Cool. Uh one last question before we
wrap up. This one is for the people in
product on the on the call.
>> So let's say we do have an army of
engineers who are shipping like Lauren.
I'm just curious like how is the product
team or other functions of your company
keeping up given that like if you're
shipping so quickly have are they using
AI more to do their jobs? Like as much
as you can speak to that obviously you
don't have like you're not in that role
but just curious about how that works.
>> Um I think this is where Grothbot has
been actually exceedingly powerful. uh
where so before graphbot like you know
uh obviously cursor only had cursor like
we only had agents window we had a CLI
we had an IDE and these are really like
power user tools right like de they're
designed for developers so it's very
very developerentric you can do
knowledge work in them but it like the
UI is not really optimized for that so
we actually didn't really have uh well I
think like a lot of people like you know
GTM product like they might have used
cursor uh to do their work but it
definitely wasn't like a delightful
experience for them. Um I think now with
Grogbot
uh it's become Grogbot is basically like
the kusher moment for people who are not
in tech in my opinion like it's like
it's like a very very accessible way to
use agents in a very comfortable very
familiar interface. It looks like
iMessage. Um, and it's very fun to, you
know, you can give your agent a fun
name. Uh, you can have you can kind of
do orchestration with in a very like
natural way where you can sort of, you
know, each agent's like a person and now
you got a team of agents like working on
you have one one agent per account that
you manage as an example. Or if you're a
PM, you have, you know, you can have an
agent that summarizes all the work that
Lauren did last night and then now you
know what I did, right? So I think our
PMs are leveraging that a lot and
they're shipping code too. Uh so you
know like often times they will just say
oh here's a bug I fixed it can you look
at it and then I'll go review it and
actually it's just perfect. I'm like
okay stamp. Uh so uh that I think that
shows that you know the the Dune
architecture is holding up right the all
the the really strict constraints allow
people who are not experts in
engineering to contribute at a high
level. Uh so I'm I feel like I'm already
seeing that pay off a lot where uh you
know designers and PMs are just able to
to to ship features directly. Um and
that just makes the Grockbot team super
fast, right? Where we can ship so
quickly. Um and we have a lot planned.
So I'm very excited uh to you know uh to
to ship more ship more stuff.
>> Yeah, that's awesome. Uh well, we are at
time. So, uh I guess Lauren, if if folks
want to support you, maybe go try out
Crockbot, try out uh 46 and uh you know,
get provide some feedback. But yeah,
this was awesome. Really appreciate you
taking the time. Uh thanks everyone for
all the messages in the chat. Lots of
good questions. I know we didn't get
through everything, but as I kind of
said at the top, way more questions than
than we could get through, but uh yeah,
really really thanks thanks for for
joining. Thanks everyone for joining and
uh hopefully you enjoyed the session.
>> Yep.
>> All right.
>> Yeah, I see it. Thank thanks for having
me. And uh if you have any more
questions yet, just DM me on Twitter.
I'll I'll open them up. I guess I'll let
the let the
>> You're going to get a lot of DMs.
>> Yeah, I'll open the updates. So yeah, DM
me. Maybe I'll do like a Twitter space
at some point. That's all for more
questions. But
>> really appreciate everyone for showing
up uh you know, taking an hour out of
your day.
>> Yeah. All right. Thanks all. I'll see
you the next one.
>> Okay. Thanks everyone. And bye.
Ask follow-up questions or revisit key timestamps.
Lauren Tan shares her journey and strategies for effectively using AI agents in software development at Cursor. She emphasizes that building trust in agents through 'verification skills'—such as running code, taking traces, and using feature maps—is crucial to moving from a manual, micromanaging loop to an automated, high-velocity workflow. Lauren also discusses the importance of architectural constraints and rigorous CI practices to prevent 'sloth' and errors, allowing even non-experts to contribute safely to projects like Grockbot.
Videos recently processed by our community