Building
Build your own Nuri card
One blank card carries passkeys, an SSH key, a bitcoin cosigner and a vault. Full build with real commands, plus a Tangem, YubiKey and Bitkey comparison.
Emin Mahrt · Journalist and publisher
Notes on Bitcoin, AI agents and building things.
I'm Emin Mahrt, publisher of proud magazine and a founder in Berlin and Zanzibar. This is where I write at length, and freely, about what I build and think. More about me.
Latest
All posts- Building
I built a Chrome extension to control my browser location
A small Chrome and Brave extension that overrides navigator.geolocation, why it alone did not fix a Spotify Family country mismatch, and what it cannot touch.
- Culture
How to make a music video with Claudia
A complete making-of: the open character Claudia, a song map, 16:9 scene plates, target-audio lip sync, the edit, the subtitles and every version I made, including the failures.
- Agents and AI
Who goes to jail when the agent does it?
My agent bought DHL postage for an eBay sale. Who is responsible when an agent acts, and why hard wallet limits are a better answer than blame after the fact.
- Agents and AI
An agent can pick up the phone
A real phone on the desk, two hundred tyre shops, and a wallet with a small budget. What it takes before an agent can do one boring job for money.
- Building
Learning to fly in Tanzania, plus my small PPL study app
I compared Tanzania's five beginner flight school options, checked the German conversion rules and built a free PPL(A) app with 90 original questions.
- Agents and AI
Let ChatGPT make a real phone call
A live demo: the free version of ChatGPT calls a tyre shop, asks for winter tyres, price and a slot, and reports back. How the call tool works, and how your agent can use it.
Nuri & Bitcoin
More Nuri & Bitcoin- Nuri
Just add any Nuri user
Referrals, guardians, inheritance, multisig and saving together all become one feature at Nuri. You add a username in the settings, and everything else follows from that.
- Nuri
The agent has no hands: Why Nuri wallet can win the machine economy
An AI agent can write code and book things, but it can't pay. Why we think Nuri and its MCP can give agents a way to pay in the real world.
- Nuri
Nuri Passkey Wallet, Bitcoin, IBAN and Visa Without an Account
How Nuri turns one passkey into a self-custodial wallet for people, businesses and AI agents, with no account in between.
Agents & AI
More Agents & AI- Agents and AI
My agent needs tools, not more subscriptions
Why I want agents to buy useful tools one job at a time, what Bitcoin has to do with it, and why building faster does not remove my responsibility.
- Agents and AI
What agent ready actually means
Four public scanners now grade whether AI agents can read your site. Here is what each one measures, which checks a static host can never pass, and the exact files and headers that move the score.
- Agents and AI
I asked my Mac how much AI I burned. It found 45 billion token events
I scanned every AI tool on my Mac for usage logs. About 45 billion token-events and roughly $9.3k at API rates, almost all of it from Codex.
Building
More Building- Building
Fazua Ride 50 speed unlock from a Mac, no box
How my agent and I raised the speed limit of a Fazua Ride 50 Evation from 25 to 55 and then 69.77 km/h over USB from a MacBook, with firmware 2.04 and an open source tool.
- Building
Badass Box 4 on a Fazua Ride 50, the yellow light
My Badass Box 4 on a Fazua Ride 50 kept blinking yellow. What the light means, where the magnet goes, what the black ring is for, and what Badass said.
- Building
Riverside 500E faster, bike tuning
A complete how-to for the Riverside 500E: the free magnet hack, the Badass Box, and a KT controller swap, with drawings, part links and test steps.
Science
More Science- Science
Can sound do what quantum particles do?
Sound bends, spreads and interferes like electrons in the double slit. So is sound quantum? Where the comparison works and where it breaks.
- Science
Cracked lips, neon urine, and two people who took the same pill
Same B vitamin pill, two people, opposite results. I slept better and my partner couldn't sleep at all. What the studies say and what we test next.
- Science
Could the shape of randomness help explain why matter won?
An idea to talk about with physicists. Maybe the Boltzmann peak is where a tiny matter advantage got big enough to win
Culture
More Culture- Culture
One who toils in the sun eats in the shade
A look back over a bare shoulder in leaf shade, read closely. Real E-M5 II EXIF, 1/320 s at ISO 100, a lens with no name, measured sun patches, 12 June history and one fix.
- Culture
A tree does not burn alone
A pine forest portrait read closely. Real Olympus E-M5 II EXIF, a likely Voigtländer 25mm f/0.95, low sun, 1/8000 s mechanical shutter, measured tones, and one fix with annotated crops.
- Culture
It is not taboo to go back and fetch what you forgot
A garden path portrait read closely. Real Olympus E-M5 II EXIF, a likely Voigtländer 25mm f/0.95, low warm sun, shallow focus, measured shadows and one fix, with annotated crops.
More
Archive- One man cannot launch a vessel
- Mountains never meet, but people do
- The sun cannot be covered with mud
- A thousand friends are few, one enemy is too many
- The eyes say as much as the mouth
- The player is lost, the onlooker sees clearly
- The darkest place is under the candlestick
- What you give away is yours, what you keep is lost
- If you wait, the sea road will have fair weather
- Bread is in the lion's mouth
- Whoever loves the rose bears its thorns
- Looking at flowers from horseback