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Joe Fabisevich

@mergesort.me
5.6K followers 55 following 6.5K posts

Director of AI Product Engineering @ Pursuit.org. I used to make Twitter (better), then that all went to hell. Now I make puns, @plinky.app, and build.ms. Born and raised New Yorker, trying to do a little good and be the friend you made along the way. 🍕🐱⚾️

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Reposted by Joe Fabisevich
Joe Fabisevich @mergesort.me · 18/03/2026
It only took six weeks to get there — software is moving very fast.
mergesort Joe Fabisevich
I've gotten so many texts from normal
people asking "is the Clawdbot hype real??"
And it's still not gonna hit 99.99% of
people, but I'm surprised at how much
regular people have asked me about it. The
real reach will be when Claude and OpenAl
for when they do more safely integrate
something like this into their agents, so this
is basically free research for them.
From a thread in #ai-dev | Jan 30th at 11:04 AM
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Reposted by Joe Fabisevich
Joe Fabisevich @mergesort.me · 19/01/2026
Many technical people are missing that regular people have discovered Claude Code and are using it to build amazing things. This is an incredibly important moment — and I don't want people to underestimate how many assumptions about code and who can code need to change. 🌐 build.ms/2026/1/19/th...
A man who runs a CNC milling business built agents that generate leads for jobs in his local area, and even created his own MCP server to interface with his CAD software.

He also wrote a personal message to the podcast hosts:

I really want people in my demographic to understand that this isn't "I asked ChatGPT to write an email or to generate an image that has the correct spelling." This is different to me, I built my own business infrastructure from scratch with an Al pair programmer, despite having zero formal training and a high school education.
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Reposted by Joe Fabisevich
Joe Fabisevich @mergesort.me · 26/01/2026
Agentic coding tools are starting to make the act of building software easier, cheaper, and more accessible. Predicting the direct impact is tough for now — but I would be very worried if I was a consumer-facing SaaS tool. (Really)
build.ms
AI Agents Are Starting To Eat SaaS (Really)
AI is making it cheaper and easier for anyone to build custom software solutions. The changes from this shift will be drastic, especially for SaaS companies.
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Joe Fabisevich @mergesort.me · 20h
just setting up my dt
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Joe Fabisevich @mergesort.me · 29/09/2026
OpenAI's Dots may be great but will always be half as good as Two Dots.
apps.apple.com
Two Dots - Connect the Colors App - App Store
Download Two Dots - Connect the Colors by Playdots, Inc. on the App Store. See screenshots, ratings and reviews, user tips, and more apps like Two Dots -…
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Joe Fabisevich @mergesort.me · 29/09/2026
Damn, OpenAI just did a Jev.
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Joe Fabisevich @mergesort.me · 28/09/2026
I've never put in less effort to deliver high-quality working products, while at the same time having more unfinished side projects than ever. This post does a great job explaining why that schism can occur, since the side projects rarely reflect *my* care or values. seangoedecke.com/human-ai-par...
That doesn't mean I can leave the Al
alone. Purely vibe-coding at work
produces awful outputs. But they're not
awful because they're bad code, they're
awful because they're in bad taste: code
that is not maintainable, that trades off
important requirements in order to satisfy
made-up ones, that contradicts the long-
term strategy for a feature or service, and
so on.
In other words, my primary value is not
that I help the Al write better code, it's
that I align the Al with the values of my
organization. Human-Al partnerships
are for alignment, not capability.Frontier models are misaligned to the
working programmer. They are obsessed
with a set of behaviors that presumably
satisty their RL grader: writing enormous
block comments above functions,
producing hundreds of useless unit tests,
adding little bits of text all over websites
they design, and so on. Working with
agents is about noticing and wrestling
with those behaviors. That's why my
prompting advice is to explicitly talk
about your high-level values: it's an
attempt to head off obvious
misalignment.Alignment is also more context-
dependent than capability. Working code
is working code, no matter what (which is
partially why it's comparatively easy to
train for). But aligning to a company's
technical values is different from
company to company, as any software
engineer who's switched companies
knows. It can almost feel like relearning
the job. So training an aligned coding
model doesn't just require hitting the
exact right set of values, it requires
creating a model that can adapt on the
fly to a wide range of possible values.
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Joe Fabisevich @mergesort.me · 28/09/2026
Starting today the main thread is free for everyone, but if your app needs any more than that you will have to subscribe to Thread+.
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Joe Fabisevich @mergesort.me · 27/09/2026
I finally read the Western Massachusetts KN95 Bar story and unfortunately I cannot ever unread what I've just read.
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Joe Fabisevich @mergesort.me · 26/09/2026
TFW you’re a little demon, but you’re also a pretty girl. #caturday
A black cat sitting in front of some roses
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Joe Fabisevich @mergesort.me · 26/09/2026
Can't wait for OpenAI to release their version of Bots next week. Ideally ones that won't hack into the US government of course.
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Joe Fabisevich @mergesort.me · 25/09/2026
I have no idea what's going on with the sky right now, but it's a real vibe up there.
A low-angle view of tall buildings lining a sidewalk at dusk. The sky is pink and purple, and parked cars are visible beside the path. A sign reads, "BAY VIEW."A tilted street scene at sunset, with a bright orange and yellow sky and a tall pole. Cars are parked along the curb, and buildings line the road. A traffic light shows "YELLOW".
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Joe Fabisevich @mergesort.me · 25/09/2026
So can I, big whoop Claude.
Yes, Claude can do Nine Loops
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Reposted by Joe Fabisevich
Joe Fabisevich @mergesort.me · 24/09/2026
Would you like to help change someone's life? It's easier than you think. At Pursuit we're looking for mentors to help to share their experience, insights, and advice across career and professional development. You just be you and help someone become better — no strings attached and no complexity.
fabisevi.ch
Call For Mentors
As I discussed in my last blog post, I recently joined Pursuit.org as their Director AI Product Engineering. And now I have a request: If you have the capacity to mentor a student at Pursuit for just ...
211
Joe Fabisevich @mergesort.me · 24/09/2026
Would you like to help change someone's life? It's easier than you think. At Pursuit we're looking for mentors to help to share their experience, insights, and advice across career and professional development. You just be you and help someone become better — no strings attached and no complexity.
fabisevi.ch
Call For Mentors
As I discussed in my last blog post, I recently joined Pursuit.org as their Director AI Product Engineering. And now I have a request: If you have the capacity to mentor a student at Pursuit for just ...
211
Joe Fabisevich @mergesort.me · 23/09/2026
I'm going to AtmosphereConf 2027, and assuming I can make it work I'd love to attend in person! 🇳🇱
atmo.rsvp
AtmosphereConf 2027
The third edition of the global gathering for the Atmosphere Community is taking place in Amsterdam, April 29th - May 2nd. This includes side-events and main conference days. Please RSVP with your interest, subscribe for updates at https://news.atmosphereconf.org, and watch us build out the website with lots of fun features https://atmosphereconf.org As well as in person, we'll also be streaming and have different ways to participate remotely. Atmosphere Conference is run by the community, for the community, as an annual global gathering to connect, share, celebrate, and learn from each other. We welcome newcomers and want to engage with new perspectives. It's a community home for builders, supporters, and participants in the atproto ecosystem. We maintain collective resources, seed projects, and convene our community to ensure every member has genuine voice in shaping the ecosystem's future. #atproto #atmosphereconf #atmosphereconf2027 #europe
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Joe Fabisevich @mergesort.me · 23/09/2026
You're absolutely right, that DNA sequence we spliced into you wasn't the right gene.
anthropic.com
Claude discovers a novel enzyme system with CRISPR-like repeats
Anthropic announces its molecular research group and laboratory
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Joe Fabisevich @mergesort.me · 23/09/2026
Of course, IKEA was always such a natural fit for bench marking.
Epoch Al
@EpochAIResearch
9/23/26, 1:21 PM Typefully
Can Al tell if you've built your IKEA
furniture wrong? Our new benchmark, the
Furniture Assembly Benchmark (FAB),
gives models the manual and a photo of a
half-completed piece of furniture and asks
them to spot the mistake.
The top score has gone from 28% to 80%
in just 10 months.
Al has improved at spotting errors in furniture
assembly
Open Al
• Anthropic
• Moonshot
Google
Accuracy
100%
Alibaba
80%
GPT-6 Astra •
Fable 5.10
60%
8~ GPT-5.6 Sol
GPT-5.5
40%
GPT-5.2
Opus 4.5
20%
0%
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Joe Fabisevich @mergesort.me · 23/09/2026
Me when Claude decides it knows more about Plinky's architecture than me.
washingtonpost.com
‘I am the code’: Trump clashed with ballroom architect over safety issues
James McCrery II resigned in October after warning that the president was insisting on designs that violated fire and safety codes.
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Joe Fabisevich @mergesort.me · 23/09/2026
P(doom) is my favorite rapper from the Doom family since MF Doom.
150
Joe Fabisevich @mergesort.me · 23/09/2026
Pacing the frontier while skipping Opus 5.1-5.4 seems pretty accelerationist to me.
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Joe Fabisevich @mergesort.me · 23/09/2026
Where's Waldo, Maiori edition. She's in there somewhere.
A black cat hidden in plain sight against a black TV
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Joe Fabisevich @mergesort.me · 22/09/2026
The best thing about Opus writing less like an old-timey delinquent is that I can stop subtly absorbing Claudespeak into my lexicon. I'm so tired of the first thought popping into my head being "you're absolutely right" before I silently yell at my internal monologue.
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Joe Fabisevich @mergesort.me · 22/09/2026
Never has a website been more targeted at me.
A blue-gray banner with white text reads, "Like Joseph – First Rejected, Then Revealed." The text is set against a dark blue background. Below, a gray browser window displays the URL "jews.com"
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Joe Fabisevich @mergesort.me · 22/09/2026
This post is probably the closest thing I've read online to the advice I give in my AI workshops. I guarantee you that if you tell your agents why you're asking for what you want your results will improve dramatically — and this is why I see such variable outputs between great engineering and slop.
seangoedecke.com
Tell agents the why, not just the how
Early AI agents were basically enthusiastic idiots. Working with them required you to tell them precisely what you wanted them to do (for instance, “method A…
290
Joe Fabisevich @mergesort.me · 21/09/2026
Spent the afternoon configuring Hermes now that they have Bots. As much as I begrudge and won't use an X and xAI product, it's obvious they've come up with a great user experience. It's only a matter of time before OpenAI and Anthropic adopt bots to create a much more accessible agent experience.
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Joe Fabisevich @mergesort.me · 20/09/2026
It was special to catch Howie Rose's final radio broadcast today. I'm 37 and he's been calling Mets radio games for 40 years, so I've listened to him narrate thousands of games over my life. From opening days as I snuck a radio into class, to nights as I lay falling asleep, he was the voice I heard.
020
Joe Fabisevich @mergesort.me · 20/09/2026
Sports gambling is a plague in so many ways, I hate that it's being completely normalized in realtime.
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Joe Fabisevich @mergesort.me · 20/09/2026
I've had access to Jev for 48 hours and here are 372 reasons this model is revolutionary.
030
Joe Fabisevich @mergesort.me · 19/09/2026
More like ineffective altruism amirite?
010
Reposted by Joe Fabisevich
Boris Yurkevich @cocoaswitch.com · 19/09/2026
Learned some nice tips from this episode about indie app marketing with @mergesort.me overcast.fm/+ABS3ckr0oqw
overcast.fm
96: Plinky — Joe Fabisevich — Launched by RevenueCat
On the podcast: Joe Fabisevich shares how he went from Twitter’s health and safety team to building Plinky, a link-saving app born of trading memes with his wife. He talks about why he treats every be...
131
Joe Fabisevich @mergesort.me · 18/09/2026
Hooray, Anthropic finally gave up!
Thariq C
@trq212
9/18/26, 2:04 PM
We're adding support for AGENTS.md to
Claude Code.
Starting today in version 2.1.277, if there is
no CLAUDE.md in a folder, Claude will
check for and use AGENTS.md.
You can toggle this behavior in /config.
368
3562
7 610 •
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Reposted by Joe Fabisevich
Joe Fabisevich @mergesort.me · 18/09/2026
I made this prediction before AI 2027, before Anthropic released Claude Code, and before we had anything resembling agents. All I needed was to try o1 to know the world was going to change, fast, and that it was going to be messy.
Joe Fabisevich
mergesort
Terrifying to consider that in all
likelihood we will reach AGI during
Donald Trump's presidency.
Mar 4, 2025 at 9:22 AM
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Joe Fabisevich @mergesort.me · 18/09/2026
I made this prediction before AI 2027, before Anthropic released Claude Code, and before we had anything resembling agents. All I needed was to try o1 to know the world was going to change, fast, and that it was going to be messy.
Joe Fabisevich
mergesort
Terrifying to consider that in all
likelihood we will reach AGI during
Donald Trump's presidency.
Mar 4, 2025 at 9:22 AM
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Joe Fabisevich @mergesort.me · 18/09/2026
Meet my good friend James. 🙋🏻‍♂️ James is not only one of the best engineers I know, he's not only a kind and caring mentor, he's not only so close that he officiated my wedding, but he's also building something very cool! If you want to watch him build out in the open, you should follow James.
120
Joe Fabisevich @mergesort.me · 18/09/2026
I am a very serious director who writes very serious docs to help improve the state of our organization's security.
1Password also stores Passkeys. Nobody knows what
Passkeys are, but every website wants you to login with one.
(Ok, ok, | know what they are. Imagine a website asks you to
Sign In With Google, but you don’t need Google — instead
you sign in with your Password Manager)
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Joe Fabisevich @mergesort.me · 16/09/2026
*reading a bad pull request* Sorry but I'm going to submerge this code.
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Joe Fabisevich @mergesort.me · 16/09/2026
These claims are downright bonkers. By *not* generating text, models become dramatically faster, cheaper, and more precise. It's not an understatement to say that if this turns out to be true it would change so much about building with AI, and will lead to a dramatic spike in what can be automated.
typesafe.ai
Introducing System One Models & Jev - TypeSafe AI Blog
TypeSafe AI is an AI lab building machine-native intelligence infrastructure for automation, designed to make decisions within software. Try our first System One Model, Jev, in early access.
171
Joe Fabisevich @mergesort.me · 15/09/2026
Me: Whatever you do, don't do a Skynet. Them: AI-first war baby, awoo! (Wolf howl 🐺)
A black-and-white image with bold lettering and Donald Trump raising an arm in a salute. The background is dark with faded stars and stripes. The words “AI-FIRST WAR DEPARTMENT” are written in bold, jagged letters.
020
Joe Fabisevich @mergesort.me · 14/09/2026
It's my favorite nerd day of the year, new iOS day! I'm a bit bummed to not ship day one updates for Plinky this year, but I had a hard time getting them in after starting my new job. I've got a bunch in the works though, so for now I'll have to enjoy all the great updates from my favorite indies.
5:39 Ø
•ll 5GW
89
<
App Updates
Things 3
Today
Open
Things is ready for iOS 27 and watchOS 27,
with great new system integrations:
• Full integration with the new Siri (please
check if it's available on your device).
• Full integration with Spotlight, your
device's built-in search.
• More snoozing options for notifications,
with more suitable durations.
• A new extra-tall widget to see longer lists.
• Various other compatibility improvements
for the new OS.
See our blog for more information:
www.things.app
Version 3.24 • 64.7 MB
Flighty - Live
Flight Tracker
Today
Open
A refined Dynamic Island, flight answers
from Siri, and two new looks for your Home
Screen.
# DYNAMIC ISLAND REFINEMENTS
See how long until departure with a
countdown that now appears even in the
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Joe Fabisevich @mergesort.me · 14/09/2026
It's almost 2am, which is why I'm resisting sharing an opinion I have with random strangers on the internet.
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Joe Fabisevich @mergesort.me · 13/09/2026
*landing in London*
A gray speech bubble with black text on a white background. The words "Welcome to Sweden" are in bold. The text explains a mobile plan with data and costs. The lighting is even.
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Joe Fabisevich @mergesort.me · 12/09/2026
It's extremely funny to me how many people decided three years ago that thanks to AI they no longer need to use their brains, and now their products are failing. You were given the greatest lever of the computer age and decided it's use was for bludgeoning yourself in the head.
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Joe Fabisevich @mergesort.me · 12/09/2026
Come to Copenhagen for the New Orleans jazz parades. 🎶
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Joe Fabisevich @mergesort.me · 12/09/2026
Now this is how you immortalize your pet.
A sculpture of a mummified cat
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Joe Fabisevich @mergesort.me · 10/09/2026
The first thing I've noticed about Copenhagen is how well designed everything is. Even something as simple as a food label that bolds allergens solves a real problem that people have in a very elegant manner.
Balls of chocolate in a container, with an ingredient list
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Joe Fabisevich @mergesort.me · 10/09/2026
This is crazy. You can now use AI to draw up any wild idea you have, and then generate a 3D model of it.
simonwillison.net
Tool: .blend URL Viewer
View Blender .blend files directly in your browser by pasting a URL to a CORS-accessible file or GitHub repository link. The viewer renders mesh geometry with materials, lighting, and optional …
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Joe Fabisevich @mergesort.me · 09/09/2026
Never knew Picasso was inspired by macOS.
A platter that looks like the Finder icon
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Joe Fabisevich @mergesort.me · 09/09/2026
Indigo is a truly amazing Bluesky & Mastodon client. The execution of a shared timeline is perfect, down to the smallest of touches to make it feel like the two networks are one. Indigo is the best app I've used to consume social media in possibly forever — it feels like an app made just for me.
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Joe Fabisevich @mergesort.me · 09/09/2026
I really do get why people hate AI. AI uses lots of energy and water*, and it hasn't fixed the real-world problems we have like access to housing, quality healthcare and better education. But man, watching AI solve Millennium Prize problems is jaw-dropping, fascinating, and borderline unbelievable.
openai.com
On the Navier–Stokes Millennium Prize Problem
We’re sharing an AI-generated solution to the Navier–Stokes Millennium Prize Problem, including a writeup and a formal proof in Lean.
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