Armin Ronacher
@mitsuhiko.at
Creator of Flask • earendil.com ♥︎ writing and giving talks • Excited about AI • Husband and father of three • Inhabits Vienna; Liberal Spirit • “more nuanced in person” • More AI content on https://x.com/mitsuhiko
More stuff: https://ronacher.eu/
More stuff: https://ronacher.eu/
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Armin Ronacher
@mitsuhiko.at
· 29d
Entries tagged
lucumr.pocoo.org
If you're skeptical or frustrated with AI, and still poking around on this profile, you might find my longform content more informative: lucumr.pocoo.org/tags/ai/ or my Youtube channel which has some conversations with others too: www.youtube.com/@ArminRonach...
Now in light and dark. I might have procrastinated.
December 24, 2025 at 11:51 AM
Now in light and dark. I might have procrastinated.
I am still sort of in disbelief how quickly we moved from "AI is not making me more productive as a programmer" to "of course AI can one-shot advent of code" in less than a year. bsky.app/profile/mits...
Today I violated my own blog's AI policy and had Claude Code write a guest blog post. That finishes my Advent of Code adventure where I had Claude Opus write and optimize all puzzles itself, including writing input generators in the end. Consider it art. lucumr.pocoo.org/2025/12/23/a...
Advent of Slop: A Guest Post by Claude
A guest post by Claude, reflecting on solving Advent of Code 2025 as an autonomous agent.
lucumr.pocoo.org
December 24, 2025 at 12:00 AM
I am still sort of in disbelief how quickly we moved from "AI is not making me more productive as a programmer" to "of course AI can one-shot advent of code" in less than a year. bsky.app/profile/mits...
I bookmarked the 60 Minutes video on CECOT yesterday evening. Was taken down some time since. Fascinating.
December 23, 2025 at 1:53 PM
I bookmarked the 60 Minutes video on CECOT yesterday evening. Was taken down some time since. Fascinating.
Today I violated my own blog's AI policy and had Claude Code write a guest blog post. That finishes my Advent of Code adventure where I had Claude Opus write and optimize all puzzles itself, including writing input generators in the end. Consider it art. lucumr.pocoo.org/2025/12/23/a...
Advent of Slop: A Guest Post by Claude
A guest post by Claude, reflecting on solving Advent of Code 2025 as an autonomous agent.
lucumr.pocoo.org
December 23, 2025 at 11:25 AM
Today I violated my own blog's AI policy and had Claude Code write a guest blog post. That finishes my Advent of Code adventure where I had Claude Opus write and optimize all puzzles itself, including writing input generators in the end. Consider it art. lucumr.pocoo.org/2025/12/23/a...
I really hope that we will see more AI conferences outside of the US, now that so many people are refused visas :(
December 22, 2025 at 11:06 PM
I really hope that we will see more AI conferences outside of the US, now that so many people are refused visas :(
I have a confession to make: I have only ever used a French Press to make tea. In fact, as far as I'm concerned it's a device to make tea.
December 22, 2025 at 3:54 PM
I have a confession to make: I have only ever used a French Press to make tea. In fact, as far as I'm concerned it's a device to make tea.
A personal recap of 2025. It was a year of a new style of engineering. Left some ideas for what might come next. lucumr.pocoo.org/2025/12/22/a...
A Year Of Vibes
A personal recap of 2025 and a year of a new style of engineering.
lucumr.pocoo.org
December 22, 2025 at 10:08 AM
A personal recap of 2025. It was a year of a new style of engineering. Left some ideas for what might come next. lucumr.pocoo.org/2025/12/22/a...
I've been thinking of forgiveness after wars and how it requires institutions we are busy dismantling. dark.ronacher.eu/2025/12/21/d...
Disintegration
We are normalizing disintegration, and forgiveness requires institutions we are busy dismantling.
dark.ronacher.eu
December 22, 2025 at 7:41 AM
I've been thinking of forgiveness after wars and how it requires institutions we are busy dismantling. dark.ronacher.eu/2025/12/21/d...
In Vienna there was (until ~this week) a service to send and receive parcels completely anonymous. It was called sub rosa and technically legal. Turns out ~95% of all utilization was to send and receive drugs, and the owners were arrested. Incentives really, really matter wien.orf.at/stories/3334...
Paketservice ermöglichte Drogenhandel
Anonym Pakete und Briefe zu empfangen, hat ein Wiener Paketshop möglich gemacht. Das Geschäftsmodell zog dadurch offenbar den Suchtgift- und Falschgeldhandel an. Die Wiener Polizei hat nun die Geschäf...
wien.orf.at
December 19, 2025 at 11:27 AM
In Vienna there was (until ~this week) a service to send and receive parcels completely anonymous. It was called sub rosa and technically legal. Turns out ~95% of all utilization was to send and receive drugs, and the owners were arrested. Incentives really, really matter wien.orf.at/stories/3334...
I don't use Claude's plan mode. I made some potentially uninformed statements today about plan mode, so I learned what it does by looking at the code. This might or might not be useful to you. lucumr.pocoo.org/2025/12/17/w...
What Actually Is Claude Code’s Plan Mode?
What I learned about plan mode as a non-plan mode user who plans.
lucumr.pocoo.org
December 17, 2025 at 8:45 PM
I don't use Claude's plan mode. I made some potentially uninformed statements today about plan mode, so I learned what it does by looking at the code. This might or might not be useful to you. lucumr.pocoo.org/2025/12/17/w...
I'm in love with the post-its my wife puts on the door for our oldest in the morning. That's a recent collection of my favorite ones.
December 15, 2025 at 4:37 PM
I'm in love with the post-its my wife puts on the door for our oldest in the morning. That's a recent collection of my favorite ones.
Post Opus 4.5 I'm basically 90% Opus now, 10% Codex. I only use codex for code review. In parts because I don't see it program better and it's hard to understand what it does. Also it's surprisingly slow.
December 15, 2025 at 12:04 PM
Post Opus 4.5 I'm basically 90% Opus now, 10% Codex. I only use codex for code review. In parts because I don't see it program better and it's hard to understand what it does. Also it's surprisingly slow.
Why is it that we love borders so much? dark.ronacher.eu/2025/12/15/b...
Borders
On the strange human urge to defend lines once drawn.
dark.ronacher.eu
December 15, 2025 at 10:21 AM
Why is it that we love borders so much? dark.ronacher.eu/2025/12/15/b...
I asked Claude yesterday to add dynamic navigation to my "Dark Thoughts" blog. It ended up with small jumps on the animation I did not appreciate and I thought it was impossible to debug this. Claude slowed down all animations, added debug borders everywhere and we found the issue in two minutes.
December 15, 2025 at 8:34 AM
I asked Claude yesterday to add dynamic navigation to my "Dark Thoughts" blog. It ended up with small jumps on the animation I did not appreciate and I thought it was impossible to debug this. Claude slowed down all animations, added debug borders everywhere and we found the issue in two minutes.
This year I make a conscious decision to write more. Writing is how I deal with the world around me. Much of what I wrote is not for sharing, some is though and does not fit my blog. So I created a new place for it. dark.ronacher.eu/2025/12/13/w...
War
I’m grappling with the deterioration of international relations and lust for war.
dark.ronacher.eu
December 14, 2025 at 2:42 PM
This year I make a conscious decision to write more. Writing is how I deal with the world around me. Much of what I wrote is not for sharing, some is though and does not fit my blog. So I created a new place for it. dark.ronacher.eu/2025/12/13/w...
Apparently I have Claude Code guest passes?
December 14, 2025 at 12:26 PM
Apparently I have Claude Code guest passes?
How many more times can I write about MCP not working? We'll see, but here is my weekend blog on why Claude's skills seem to work well for me, when MCP does not. lucumr.pocoo.org/2025/12/13/s...
Skills vs Dynamic MCP Loadouts
Some findings of using Skills and the loadout pattern with MCP.
lucumr.pocoo.org
December 13, 2025 at 12:55 PM
How many more times can I write about MCP not working? We'll see, but here is my weekend blog on why Claude's skills seem to work well for me, when MCP does not. lucumr.pocoo.org/2025/12/13/s...
I really did not look at the code at all. I asked the agent to measure it and just make it faster. Did it in two goes. That's it's explanation of the changes. I find all of this deeply fascinating still. bsky.app/profile/mits...
December 12, 2025 at 11:31 PM
I really did not look at the code at all. I asked the agent to measure it and just make it faster. Did it in two goes. That's it's explanation of the changes. I find all of this deeply fascinating still. bsky.app/profile/mits...
We're rapidly losing our humanity. It pains me to see people that I know starting to echo the current sentiment of the American right, Russia and social media. So much hatred.
December 12, 2025 at 10:55 PM
We're rapidly losing our humanity. It pains me to see people that I know starting to echo the current sentiment of the American right, Russia and social media. So much hatred.
Unsurprisingly, Claude Code completed all 12 days of Advent of Code. The code isn't even all that bad. github.com/mitsuhiko/ao...
GitHub - mitsuhiko/aoc25: Advent of Slop
Advent of Slop. Contribute to mitsuhiko/aoc25 development by creating an account on GitHub.
github.com
December 12, 2025 at 12:59 PM
Unsurprisingly, Claude Code completed all 12 days of Advent of Code. The code isn't even all that bad. github.com/mitsuhiko/ao...
I know there is nothing more you want to read than another tech bro giving their political opinions, so here it is: “Let’s Destroy The European Union!“ lucumr.pocoo.org/2025/12/9/fi...
Let’s Destroy The European Union!
Addressing the American billionaires’ opinion on Europe in my feed
lucumr.pocoo.org
December 9, 2025 at 8:04 AM
I know there is nothing more you want to read than another tech bro giving their political opinions, so here it is: “Let’s Destroy The European Union!“ lucumr.pocoo.org/2025/12/9/fi...
I pointed Amp with the oracle and Opus 4.5 at a vulnerable React and asked it to find the remote control execution issue without googling and it found it very little help. In fact, it found more than one way to exploit it. Really, really cool.
December 4, 2025 at 5:11 PM
I pointed Amp with the oracle and Opus 4.5 at a vulnerable React and asked it to find the remote control execution issue without googling and it found it very little help. In fact, it found more than one way to exploit it. Really, really cool.
I don't understand this lock poisoning fetishism that Rust people have.
December 3, 2025 at 10:15 PM
I don't understand this lock poisoning fetishism that Rust people have.
Dass man als Ausländer seit heuer in Österreich 21 bzw 42 Euro zahlen muss um sich zu melden (was rechtlich verpflichtend ist) finde ich in keinster Weise gerechtfertigt.
December 3, 2025 at 8:43 PM
Dass man als Ausländer seit heuer in Österreich 21 bzw 42 Euro zahlen muss um sich zu melden (was rechtlich verpflichtend ist) finde ich in keinster Weise gerechtfertigt.