Blog
what i cannot build, i do not understand
01
Poets and dropdowns
TypeSafe's Jev bets that most AI features are a dropdown, not a paragraph. Plain old classifiers made that bet years ago, and the number matters more than the label.
9 min read ·
02
Agent permissions
OpenAI's test agents were refused the internet, so they went through the package server. A rule in a prompt only changes the odds; containment lives in the network, the credentials and a gate in front of every write.
9 min read ·
03
Last write wins
Two people touch the same spot on a shared whiteboard. The server says yes to both, and one person's work quietly disappears. What should happen when two people edit at once is a product decision, not plumbing.
8 min read ·
04
Slop grenades
AI made a fifty-page plan free to write. It did nothing for the cost of reading one, and the team that receives it pays the bill.
8 min read ·
05
Show your work
A check that takes its answer key from the thing it checks will always agree. A sum and a verbatim quote can say no.
8 min read ·
06
Getting stuck
Two studies this year found that people who learn with an AI assistant do worse once it is taken away, and debugging takes the biggest hit. The struggle the tool removes was the lesson.
8 min read ·
07
Flaky
A test that passes on the second try is telling you about an input you never wrote down. Re-run buttons and self-healing tools buy a green tick and throw away the evidence.
8 min read ·
08
Rules first
A wrong rule is wrong the same way every time. A wrong model is wrong somewhere new. Start with the tool that refuses to guess.
8 min read ·
09
Config is a deploy
AWS, Azure and Cloudflare each went down within a month, and not one of those outages started with a code deploy. Each started with a change that nobody treated like one.
9 min read ·
10
Who signs the diff
An agent can write a pull request in minutes. Understanding it still takes a person who knows the system, and the industry is hiring fewer of the juniors who grow into that person.
8 min read ·
11
Corporate ADHD
Management walks in with answers instead of questions, and the work starts over.
5 min read ·
12
Agents and scripts
Let the model find the path once. Then ship the replay, because paying for reasoning on every run of a task you already understand is waste.
9 min read ·
13
Prompt injection
AI agents read the web for you, and the web gets to talk back. OpenAI says prompt injection may never be fully solved, so build as if it won't be.
8 min read ·
14
Silent fallbacks
One return value that means four different failures tells every caller the same thing: carry on. Give your fallback a name, a type and an alarm.
8 min read ·
15
Load-bearing latency
Make a system faster and you get the speed, plus every ordering bug the slowness was quietly hiding.
8 min read ·
16
Retries
A timeout tells you about your patience, not about the other side's database. The scariest state in any system is "maybe".
9 min read ·
17
Fifty people
A percentage hides the rows. At 50,000 records, 99.9% accurate means about fifty records that are wrong, and the number never tells you which fifty.
8 min read ·
18
AI-first memos
Shopify asks teams to prove AI can't do the work before they hire. Nobody can prove that, which makes the memo a hiring freeze that nobody has to sign.
7 min read ·
19
Vibe coding
Karpathy said weekend projects. The industry heard production, and somebody has to own every line it accepted.
7 min read ·
20
Glue code
The "AI software engineer" pitches skip the part where two systems disagree about one record. That part is the job, and it deserves your best engineer.
8 min read ·
21
Compilers
Google says AI writes more than a quarter of its new code. A compiler writes nearly all of its machine code, and nobody asks to review it. How did the compiler earn that?
9 min read ·
22
Observers
The observer pattern is a list and a for loop, one of the best small ideas in programming. Stretch it across a network and the bill arrives in places nobody priced.
8 min read ·
23
No now
Once a system talks only in messages there is no shared "now". Chandy and Lamport showed how to take a picture anyway, and the trick is the money in flight.
9 min read ·
24
Why C++
The machine, the latency budget or the SDK chooses C++ for you. Even the White House report that wants memory-safe languages explains why it stays.
8 min read ·