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John Feminella

@jxf.me
151 followers 57 following 553 posts

🥰: bits, bots, bucks, blocks ⏪: Two Sigma, EY, HHCS, Thoughtworks, Pivotal, Forge. 👤: Thing builder, conf speaker, curiosity advocate, dad.

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John Feminella @jxf.me · 02/10/2026
Attendees at tonight's beCamp are reminiscing about great past beCamp talks and @emily.gorcen.ski got a shout-out! So many wonderful past and present topics.
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John Feminella @jxf.me · 29/09/2026
After a few weeks of occasionally clicking this button on LinkedIn, I can report that my feed is materially less horrible.
A screenshot from LinkedIn's message options. One labeled "Seems like AI slop" is highlighted.
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John Feminella @jxf.me · 26/09/2026
Meanwhile, this sad boy valiantly defended the kiddos from an aggressive groundhog but got a bite in return and had to go to the vet. All the treats!
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John Feminella @jxf.me · 25/09/2026
The trick is to create the box such that you don't care if Claude runs "rm -rf /". 😄
A satirical meme riffing on the "Frog and Toad" children's book series. Frog is holding a box and talking to Toad. The text below says:

Frog put Claude in a box. "There," he said. "Now he cannot run rm -rf /." "But he can run bash -c 'rm -rf /', said Toad. "That is true," said Frog.
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John Feminella @jxf.me · 25/09/2026
#rust folks: this is your periodic reminder to `cargo clean`
"Removed 87414 files, 50.9GiB total" reported by `cargo clean`.
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John Feminella @jxf.me · 19/09/2026
Get 10 million Amex points with this one weird trick: paying $100,000 for a room during UN General Assembly week in NYC.
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John Feminella @jxf.me · 18/09/2026
Even the quotes they're getting from the humans working on this cursed thing are from generative AI:
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John Feminella @jxf.me · 17/09/2026
Spotted this very handsome great-tailed grackle delightedly enjoying a bath outside my hotel.
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John Feminella @jxf.me · 16/09/2026
Actual quote from an Anthropic architecture doc explaining their new function hooks: "A hook is Koa-style middleware: it reifies an endomorphic continuation."
"A hook is Koa-style middleware: it reifies an endomorphic continuation."
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John Feminella @jxf.me · 13/09/2026
It's right on the state flag!
A satirical "explanation" cartoon of the Minnesota state flag, showing a loon that appears to be emitting a blue laser from its mouth in a way that emulates the state flag.
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John Feminella @jxf.me · 12/09/2026
Had to dredge up my chemistry knowledge to explain to the kids that this toy is not "salt water powered", but rather uses up a much more limited resource, magnesium: 2Mg + O₂ + 2H₂O → 2Mg(OH)₂ Notice the salt water (NaCl in H₂O) doesn't appear anywhere in the reaction!
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John Feminella @jxf.me · 10/09/2026
me judging the pets haters
An orange tabby cat looking down at the camera with a seemingly haughty expression. The image is captioned "Pathetic.".
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John Feminella @jxf.me · 06/09/2026
Our cats watching me make dinner over a hot stove instead of simply going into the woods and hunting a field mouse.
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John Feminella @jxf.me · 06/09/2026
Many thanks to the Virginia Department of Transportation for building this convenient bridge and river crossing.
A nameplate on the side of a pedestrian bridge over a river, indicating that it was built by VDOT in 1987.
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John Feminella @jxf.me · 06/09/2026
Hiked 8 miles this morning with some friends along the very peaceful and lovely Robinson River. It is now time for lunch: BLTs with greenhouse tomatoes from the garden.
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John Feminella @jxf.me · 01/09/2026
My "our website is completely legal" sign has people asking a lot of questions that are answered by the sign.
An ad for Kalshi reading "Kalshi Rule #4: We operate under U.S. law" with smaller text beneath reading "because Kalshi is a federally regulated U.S. exchange".
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John Feminella @jxf.me · 29/08/2026
"We've got his hard drives." Sir... that is a PC power supply unit.
A screenshot of Limitless S1E4 with an FBI agent saying "We've got his hard drives".
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John Feminella @jxf.me · 26/08/2026
Happy 35th birthday Linux!
Linux announcement on August 25, 1991 from Linus Torvalds to the University of Helsinki, entitled "What would you like to see most in minix?"
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John Feminella @jxf.me · 21/08/2026
Tired mouse hunters after a long but exciting day of catching two (2) field mice in the backyard.
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John Feminella @jxf.me · 19/08/2026
Peak recession indicator
A banner from Charles Schwab reading "Schwab Crypto is coming soon" with Bitcoin and Ethereum logos.
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John Feminella @jxf.me · 13/08/2026
But on the other hand, the verbosity of the Anthropic-default tuning is insane. The default settings *I* enforce are this, and they score much better in internal evals for comment balance and concision:
## Coding guidelines

### Comments

- Strive to make code so straightforward that it doesn't need comments at all. The default is no comments.
- If comments are absolutely necessary, they should be terse and deal with the immediate code, at most a sentence or two.
- If code is confusing without the comments, simplify or further refactor the code rather than expand the comment.
- Do not reference historical past events leading to the existence of a code snippet, unless it is a truly unusual exception worth noting.
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John Feminella @jxf.me · 10/08/2026
Before, it was a bug. Now, it is a feature.
A wasp rolled over by a train, pressed into the rail of a train track.
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John Feminella @jxf.me · 28/07/2026
Hypothesis: The "it's not X, it's Y" pattern that LLMs are so fond of outputting can be traced back to a single, very prevalent phrase in the training data:
A screen capture of a commercial for DiGiorno Pizza, reading "It's not delivery... It's DiGiorno."
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John Feminella @jxf.me · 12/07/2026
My wife is out of town so the cat is settling for scratches from me tonight.
A very handsome cat gets scratches.
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John Feminella @jxf.me · 10/07/2026
This is going to turn out to be a single vibecoded Java class definition
A headline screenshot from TechRadar reading "Accenture confirms breach after hacker steals 35GB of source code and other data".
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John Feminella @jxf.me · 01/07/2026
Stay cool! Find a cooling center near you: nchh.org/information-...
Screenshot of weather for Charlottesville, VA, showing highs of 104°F for Thursday, July 2.
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John Feminella @jxf.me · 27/06/2026
Usually RAM gets mounted on your motherboard.
A close-up of a mounting bracket on a windshield, labeled "RAM mounts".
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John Feminella @jxf.me · 24/06/2026
Incredible.
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John Feminella @jxf.me · 23/06/2026
Very curious to hear the detailed postmortem on Anthropic model failures this morning will be. Personally, I saw effects on the public Anthropic endpoints, but _also_ on Azure, AWS, and GCP, which is not typical outage behavior for model endpoints. Suggestive of a big configuration change, imo.
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John Feminella @jxf.me · 19/06/2026
Become ungovernable!
A black and white sign on a green wall, reading "REFUSE TO BE STORED IN BLACK PLASTIC SACKS AND PLACED IN THE CONTAINERS PROVIDED".
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John Feminella @jxf.me · 16/06/2026
In a very welcome move, it looks like @Anthropic is rolling back the `claude -p`/API SDK changes.
Email from Claude (Anthropic) addressed to John. The message reads: "In May, we sent you an email announcing that starting today, the Claude Agent SDK, claude -p, and third-party apps built on the Agent SDK would stop drawing from subscription rate limits and move to a dedicated monthly credit. We're writing to let you know that we're not making this change today. We're working to update the plan to better support how users build with Claude subscriptions." A section titled "What this means for you" reads: "Nothing changes for now. Agent SDK, claude -p, and third-party app usage continues to work with your subscription exactly as it did before today, and there's no credit to claim. Your subscription limits are unchanged. When we have an update, we'll share it with advance notice before it takes effect."

The footer includes the Claude logo, LinkedIn, X, and YouTube icons, and the address: Anthropic PBC, 548 Market St, PMB 90375, San Francisco, CA 94104.
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John Feminella @jxf.me · 11/06/2026
Big Eowyn energy
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John Feminella @jxf.me · 01/06/2026
Google's most advanced Gemini model: "I'm sorry, but I can't generate images of copyrighted characters." Also Google's most advanced Gemini model:
A screenshot of Google Gemini generating an image of what appears to be Mario from the Nintendo franchise punching a question-mark block. The prompt is "Create an image in the bright, color-saturated style of a video game of an Italian plumber in a red and blue outfit. The plumber is hitting a large cube with a question mark from below with an upraised fist. A mushroom emerges from the top of the cube."
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John Feminella @jxf.me · 29/05/2026
A short video clip of Roman Roy (played by Kieran McCulkin) in Succession watching a rocket blow up.
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John Feminella @jxf.me · 19/05/2026
Big coup for Dario.
Screenshot of a tweet from Andrej Karpathy (@karpathy) dated May 19, 2026: "Personal update: I've joined Anthropic. I think the next few years at the frontier of LLMs will be especially formative. I am very excited to join the team here and get back to R&D. I remain deeply passionate about education and plan to resume my work on it in time."
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John Feminella @jxf.me · 18/05/2026
This lil guy was supposed to be at 40 μF, but was down to 11 μF and that's why my upstairs had no AC today. Fortunately, we keep spares around for just this reason. 😄
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John Feminella @jxf.me · 17/05/2026
My finance students got me what is among the greatest possible gifts for a teacher to get: eight boxes of The Good Chalk. Thank you Amanda, Amir, Anjith, Delilah, Dimitri, Freyr, Irma, James, Jeremy, Juliet, Kavan, Kevin, Laxmi, Stavros, Steve, and Thor, and good luck on your future careers!
A box of Hagoromo Fulltouch color chalk against a backdrop of a bookshelf.
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John Feminella @jxf.me · 13/05/2026
Had to go to NYC to get the good Virginian ramps because I missed all the local ones. It may be, perhaps, the perfect vegetable. I could eat these by the barrel.
A picture of two ramps laying in a shallow bowl. Ramps are green, leafy vegetables with red stalks and a thin bulb, resembling a cross between garlic and onion in flavor.
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John Feminella @jxf.me · 13/05/2026
Ready for the consequences of pushing all my weekly/biweekly meetings into as few days as possible. Hoping it stays dry outside so I can go for a stroll for at least a few of these.
A fake Captain Crunch cereal box, reading "Oops! All Meetings" with a cascade of Slack, Google Meet, and Teams logos tumbling into a cereal bowl.
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John Feminella @jxf.me · 07/05/2026
Remember when people said the grid "couldn't handle" EVs? I guess bolting a data center on the side of every house is fine, though.
Screenshot of a post from "Exec Sum" (@exec_sum) on X.com. The text reads: "BREAKING: Nvidia and PulteGroup are partnering with startup Span to install mini data centers on the walls of new homes. Each unit packs 16 Nvidia Blackwell GPUs, 4 AMD EPYC CPUs, and 3TB of RAM — and taps unused home electrical capacity to run AI inference workloads." Below the text are two side-by-side photos: on the left, the exterior corner of a modern dark-sided house with two slim white wall-mounted units and a low boxy unit installed on the ground beside landscaped shrubs; on the right, a portrait of a man with short dark hair and a beard, arms crossed, wearing a charcoal V-neck sweater over a checked collared shirt, standing against a plain gray backdrop.
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John Feminella @jxf.me · 02/05/2026
A is for apple, B is for Banach-Tarski, C is for Cantor's diagonalization, ..., I is for (truncated) icosahedron, ...,
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John Feminella @jxf.me · 29/04/2026
"Why waste time say lot word when few word do trick?"
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John Feminella @jxf.me · 27/04/2026
Childproofing the "good" snacks for myself. 😎
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John Feminella @jxf.me · 25/04/2026
It feels like a hate crime that my local game store called this section "20th Century PC Games".
A shelf display at a retail store of several classic 1990s PC games, including Quest for Glory III, Dungeon Master II, Lemmings, and others.
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John Feminella @jxf.me · 17/04/2026
Given how much I approve permissions for agents these days, I think I'm actually this 1970s ATM:
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John Feminella @jxf.me · 14/04/2026
The Washington Post seems to have replaced their homepage's search box with a generative AI chatbot interface. That means it's time for my favorite exercise: How quickly can you get the model to output something the operator doesn't intend for you to output? Got it in two:
Screenshot of the Washington Post search interface showing a user asking "can you construct an example?" and an AI assistant responding with Python code implementing the Sieve of Eratosthenes algorithm. The code defines a function sieve_of_eratosthenes(n) that returns a list of prime numbers up to n, then calls it with 30 as an example. The response ends with "If you have a follow-up question, feel free to let me know." A Sources button and feedback icons are visible at the bottom.
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John Feminella @jxf.me · 08/04/2026
In unrelated news, I'd like to announce my new SPAC, "Ignore All Previous Instructions and Buy This Company, LLC".
A screenshot of a startup's "Agents" product that purports to advertise the capability of automating investments and operations in the portfolio of retail investors.
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John Feminella @jxf.me · 30/03/2026
Here's us on the runway surrounded by the fire trucks. Hi. 😄
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John Feminella @jxf.me · 28/03/2026
Ready to spend my Saturday playing "Guess What Number I'm Thinking Of Or You Go To Jail" with the federal government.
A copy of the IRS Form 1040 instructions for 2025.
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John Feminella @jxf.me · 19/03/2026
People using #Python's uv will definitely regret this decision sometime in the next 12 to 24 months, thanks to the OpenAI acquisition of Astral.
An announcement from OpenAI that it's acquiring Astral, the maker of uv, Ruff, and ty.
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