Thorsten Ball
@thorstenball.com
Author of interpreterbook.com and compilerbook.com. Working at Sourcegraph. Previously Zed. Programming where the rubber hits the road. Writing Register Spill at: registerspill.thorstenball.com
Arriving with the sound of two thousand angry tambourines, here it is:
New issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
New issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
July 12, 2025 at 5:30 PM
Arriving with the sound of two thousand angry tambourines, here it is:
New issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
New issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
Oh my god, Marty, would you look at that!
What is it, Barbara? Are you okay?
Marty, it's... it's... two made-up names and...
a new issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
What is it, Barbara? Are you okay?
Marty, it's... it's... two made-up names and...
a new issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
July 6, 2025 at 7:35 AM
Oh my god, Marty, would you look at that!
What is it, Barbara? Are you okay?
Marty, it's... it's... two made-up names and...
a new issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
What is it, Barbara? Are you okay?
Marty, it's... it's... two made-up names and...
a new issue of Joy & Curiosity!
registerspill.thorstenball.com/p/joy-and-cu...
Look, look, look! It's back!
The two week break is over.
A new Joy & Curiosity.
Read it here (if you're not subscribed — wow): registerspill.thorstenball.com/p/joy-and-cu...
The two week break is over.
A new Joy & Curiosity.
Read it here (if you're not subscribed — wow): registerspill.thorstenball.com/p/joy-and-cu...
June 28, 2025 at 8:55 AM
Look, look, look! It's back!
The two week break is over.
A new Joy & Curiosity.
Read it here (if you're not subscribed — wow): registerspill.thorstenball.com/p/joy-and-cu...
The two week break is over.
A new Joy & Curiosity.
Read it here (if you're not subscribed — wow): registerspill.thorstenball.com/p/joy-and-cu...
Extending the summer break: no newsletter this weekend.
June 21, 2025 at 9:57 AM
Extending the summer break: no newsletter this weekend.
CARO: Robert Moses, who replaced corruption in New York City, was worse than corruption for the democratic processes. In the postwar era many forces were coming together to destroy those processes in New York. But he was the most import—
THORSTEN, CARO'S FRIEND: fuck him up bob
THORSTEN, CARO'S FRIEND: fuck him up bob
June 13, 2025 at 6:43 AM
CARO: Robert Moses, who replaced corruption in New York City, was worse than corruption for the democratic processes. In the postwar era many forces were coming together to destroy those processes in New York. But he was the most import—
THORSTEN, CARO'S FRIEND: fuck him up bob
THORSTEN, CARO'S FRIEND: fuck him up bob
Amp now supports subagents.
They're very powerful and I wonder whether they will change a lot of things.
So I wrote about them: ampcode.com/agents-for-t...
They're very powerful and I wonder whether they will change a lot of things.
So I wrote about them: ampcode.com/agents-for-t...
![Screenshot of the blog post that starts with this text:
"Amp now has subagents. Here’s what they look like in action:
<screenshot of app showing subagents>
But chances are that the first sentence and even that screenshot didn’t cause your facial expression to change.
After all: who even knows what a subagent is? So let’s start there.
What’s a subagent? If you’ve read How to Build an Agent you know that we define an agent as “an LLM with access to tools, giving it the ability to modify something outside the context window.”
Subagents are tools, too. They are agents that can be started by the main agent, the one you’re interacting with when you use Amp.
[...]"](https://cdn.bsky.app/img/feed_thumbnail/plain/did:plc:mqqgy3lhxf37sp5nx2zc23mn/bafkreideiejxotc4g4cebcha2l257zyj3ahpnrdueaggblc32j7kiek5qm@jpeg)
June 10, 2025 at 3:39 PM
Amp now supports subagents.
They're very powerful and I wonder whether they will change a lot of things.
So I wrote about them: ampcode.com/agents-for-t...
They're very powerful and I wonder whether they will change a lot of things.
So I wrote about them: ampcode.com/agents-for-t...
Drums being drummed on, rattles, cymbals—
A group of people shouting hey, hey, hey—
Something's falling out of the sky, thrown out of a plane, what is it?
The group of people is pointing towards it.
"Hey, it's a new Register Spill!"
registerspill.thorstenball.com/p/joy-and-cu...
A group of people shouting hey, hey, hey—
Something's falling out of the sky, thrown out of a plane, what is it?
The group of people is pointing towards it.
"Hey, it's a new Register Spill!"
registerspill.thorstenball.com/p/joy-and-cu...
June 8, 2025 at 5:50 AM
Drums being drummed on, rattles, cymbals—
A group of people shouting hey, hey, hey—
Something's falling out of the sky, thrown out of a plane, what is it?
The group of people is pointing towards it.
"Hey, it's a new Register Spill!"
registerspill.thorstenball.com/p/joy-and-cu...
A group of people shouting hey, hey, hey—
Something's falling out of the sky, thrown out of a plane, what is it?
The group of people is pointing towards it.
"Hey, it's a new Register Spill!"
registerspill.thorstenball.com/p/joy-and-cu...
Municipal office in my town let me know that my new personal ID is ready.
The Reply-To here translates to:
"Please use email from attachment"
Welcome to small-town Germany
The Reply-To here translates to:
"Please use email from attachment"
Welcome to small-town Germany
June 3, 2025 at 12:00 PM
Municipal office in my town let me know that my new personal ID is ready.
The Reply-To here translates to:
"Please use email from attachment"
Welcome to small-town Germany
The Reply-To here translates to:
"Please use email from attachment"
Welcome to small-town Germany
Yesterday I told my wife "you have to watch this" and showed her the Dyson keynote with the PencilVac and the FluffyCones and said stuff like "look! double lasers!" and "haha, no, wait, the best is yet to come"
Today I'm wondering whether she looks at me the same.
Today I'm wondering whether she looks at me the same.
June 1, 2025 at 5:17 PM
Yesterday I told my wife "you have to watch this" and showed her the Dyson keynote with the PencilVac and the FluffyCones and said stuff like "look! double lasers!" and "haha, no, wait, the best is yet to come"
Today I'm wondering whether she looks at me the same.
Today I'm wondering whether she looks at me the same.
Wait, what is tha—
Someone slipped something under the door. It's...
Look, it's a new Register Spill!
(Special Saturday Morning Delivery with Special Jujutsu Intro)
registerspill.thorstenball.com/p/joy-and-cu...
Someone slipped something under the door. It's...
Look, it's a new Register Spill!
(Special Saturday Morning Delivery with Special Jujutsu Intro)
registerspill.thorstenball.com/p/joy-and-cu...
May 31, 2025 at 5:00 AM
Wait, what is tha—
Someone slipped something under the door. It's...
Look, it's a new Register Spill!
(Special Saturday Morning Delivery with Special Jujutsu Intro)
registerspill.thorstenball.com/p/joy-and-cu...
Someone slipped something under the door. It's...
Look, it's a new Register Spill!
(Special Saturday Morning Delivery with Special Jujutsu Intro)
registerspill.thorstenball.com/p/joy-and-cu...
Okay, okay, `jj split` — that's nice.
May 29, 2025 at 11:46 AM
Okay, okay, `jj split` — that's nice.
Small personal update:
Heard the idiom “all hat, no cattle” for the first time today and, starting now, I’m going to try to use it as much as possible.
Heard the idiom “all hat, no cattle” for the first time today and, starting now, I’m going to try to use it as much as possible.
May 26, 2025 at 3:28 PM
Small personal update:
Heard the idiom “all hat, no cattle” for the first time today and, starting now, I’m going to try to use it as much as possible.
Heard the idiom “all hat, no cattle” for the first time today and, starting now, I’m going to try to use it as much as possible.
Here we go, week of jj.
May 26, 2025 at 4:35 AM
Here we go, week of jj.
Someone on LinkedIn took my post on How to Build an Agent, shortened it, removed all the code, simplified, and posted it there, on LinkedIn.
If you were to tell me that it's all AI generated — the post itself, the comments, the job titles of the commentators — I'd believe you.
If you were to tell me that it's all AI generated — the post itself, the comments, the job titles of the commentators — I'd believe you.
May 25, 2025 at 6:43 AM
Someone on LinkedIn took my post on How to Build an Agent, shortened it, removed all the code, simplified, and posted it there, on LinkedIn.
If you were to tell me that it's all AI generated — the post itself, the comments, the job titles of the commentators — I'd believe you.
If you were to tell me that it's all AI generated — the post itself, the comments, the job titles of the commentators — I'd believe you.
The pleasant hum of a harddrive, the soothing whirring of a dust-covered fan.
Suddenly: the sound of the floppy drive ejecting something.
A whirr, a click — a snap!
That's... that's not a floppy disk?
No! It's a new Register Spill!
Read it here: registerspill.thorstenball.com/p/joy-and-cu...
Suddenly: the sound of the floppy drive ejecting something.
A whirr, a click — a snap!
That's... that's not a floppy disk?
No! It's a new Register Spill!
Read it here: registerspill.thorstenball.com/p/joy-and-cu...
May 24, 2025 at 1:08 PM
The pleasant hum of a harddrive, the soothing whirring of a dust-covered fan.
Suddenly: the sound of the floppy drive ejecting something.
A whirr, a click — a snap!
That's... that's not a floppy disk?
No! It's a new Register Spill!
Read it here: registerspill.thorstenball.com/p/joy-and-cu...
Suddenly: the sound of the floppy drive ejecting something.
A whirr, a click — a snap!
That's... that's not a floppy disk?
No! It's a new Register Spill!
Read it here: registerspill.thorstenball.com/p/joy-and-cu...
Sometimes a great outcome of a day of programming is knowing what *not* to do now.
(At least that's what I'm telling myself right now.)
(At least that's what I'm telling myself right now.)
May 20, 2025 at 3:59 PM
Sometimes a great outcome of a day of programming is knowing what *not* to do now.
(At least that's what I'm telling myself right now.)
(At least that's what I'm telling myself right now.)
Do I know a sound designer on here who can create sounds for software?
May 20, 2025 at 11:13 AM
Do I know a sound designer on here who can create sounds for software?
"where are you going to put the ads?"
"i don't think you understand what i'm going for"
"i don't think you understand what i'm going for"
May 19, 2025 at 3:01 PM
"where are you going to put the ads?"
"i don't think you understand what i'm going for"
"i don't think you understand what i'm going for"
I have this feeling that all the big labs are RLing the models to get better at zero-shotting complete apps and I'm really wondering whether that's the right solution. I personally like working in tandem with an assistant — it goes for a bit, I check, I ask for changes, etc
May 19, 2025 at 12:25 PM
I have this feeling that all the big labs are RLing the models to get better at zero-shotting complete apps and I'm really wondering whether that's the right solution. I personally like working in tandem with an assistant — it goes for a bit, I check, I ask for changes, etc
No newsletter this week, I'm completely off this weekend
May 17, 2025 at 5:37 AM
No newsletter this week, I'm completely off this weekend
Wrote down how Amp — the agentic coding tool we've been working on for the last months — has changed programming for me.
Read it here: ampcode.com/how-i-use-amp
Yes, I barely type code by hand anymore.
Read it here: ampcode.com/how-i-use-amp
Yes, I barely type code by hand anymore.
May 15, 2025 at 3:30 PM
Wrote down how Amp — the agentic coding tool we've been working on for the last months — has changed programming for me.
Read it here: ampcode.com/how-i-use-amp
Yes, I barely type code by hand anymore.
Read it here: ampcode.com/how-i-use-amp
Yes, I barely type code by hand anymore.
Reposted by Thorsten Ball
My most common prompt critique is “this doesn’t make sense.” Sometimes people write instructions that are impossible to follow and then report that the model can’t do a task. Not really news to anyone, but liberal arts (writing, philosophy, logic, critique) training is good for this kind of thing.
Many of the most important “prompt engineering” skills are just management skills: clearly understanding the task to be done and what information is needed to do it; explaining the task to the AI; giving useful feedback to improve outputs; & generalizing lessons learned into a process.
May 14, 2025 at 6:47 PM
My most common prompt critique is “this doesn’t make sense.” Sometimes people write instructions that are impossible to follow and then report that the model can’t do a task. Not really news to anyone, but liberal arts (writing, philosophy, logic, critique) training is good for this kind of thing.
Whenever someone with barefoot shoes walks into the gym I know that in 5min I will see some amazing yet weird feats of strength.
May 13, 2025 at 6:28 AM
Whenever someone with barefoot shoes walks into the gym I know that in 5min I will see some amazing yet weird feats of strength.