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Twenty-five years and half a mile
The morning before my first day I went for a run through Chicago, and a couple of miles in I recognised the route.
Aug 11
•
Justin Johnson
3
Take the Cast Off
Anthropic deleted more than 80% of Claude Code's system prompt and lost nothing they could measure. I ran the same test on my own instructions. I now…
Aug 9
•
Justin Johnson
1
I moved my whole AI coding setup to a model that costs 40 cents. Nobody noticed the difference.
A two-year-old harness, ported in an afternoon, for under forty cents. Then the model that did it wrote this post.
Aug 4
•
Justin Johnson
1
July 2026
Somebody Is Finally Checking
A contest opened eleven days ago has produced more reproduction attempts than the field's own dedicated effort has managed in any year. Whether that…
Jul 26
•
Justin Johnson
1
Nobody Saves Money on the Model
A team just swapped in a model that costs twice as much per token, and their bill went down. Here is why that is not a paradox, and what it means for…
Jul 21
•
Justin Johnson
1
1
The Failure That Leaves No Corpse
Your management apparatus is built for known unknowns. AI collaborators mostly produce the other kind.
Jul 20
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Justin Johnson
1
Workflows, Seven Weeks In
I called the economics of fan-out the day it shipped. Running it as a daily default since taught me the caveat I buried in a footnote is the actual…
Jul 20
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Justin Johnson
1
It Spreads Sideways. Someone Still Has to Light It.
Anthropic's Claude Code lead published a five-rung adoption ladder this week. Microsoft published the measurement fifteen days earlier, and the two do…
Jul 17
•
Justin Johnson
1
The Loop Is Simpler Than It Sounds
A dumb little trick that keeps its progress on your hard drive, not the model's head, and the three questions that decide whether it pays off or burns…
Jul 15
•
Justin Johnson
2
1
Last 30 Days: The Loop
The 30-day sweep behind today's Run Data Run post: the moat thesis, the skeptics who got there first, the cost numbers nobody pitches, and the one stat…
Jul 15
•
Justin Johnson
1
Last 30 Days: The AI Scientists
Four autonomous discovery systems cleared peer review in four months. Every one of them was already a year old. Here is the full sweep, including the…
Jul 12
•
Justin Johnson
1
The Year Nature Caught Up
Robin found a new use for an old glaucoma drug and landed in Nature. The preprint was fourteen months old. Once you notice that lag, you notice it…
Jul 12
•
Justin Johnson
1
2
1
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