
Dad, fly fisherman, product builder. Founder/CEO LemonStand → exit to @Mailchimp. Recently, CEO of $TINY portco. Exploring my next thing 🚀
Canada
Joined July 2012
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Five years as CEO of Orbit, owned by Tiny, taught me this:
Buying a profitable business doesn’t buy permanent profits.
Grow, renew, sustain, harvest or close. The budget and targets need to match the choice in strategy.
“Hold forever” isn’t an operating plan.
halarewich.com/writing/essay…
I got complacent and trusted @ChatGPT on the width of tubeless rim tape to buy (too wide) instead of measuring.
And people use it for therapy and relationship advice.
I was a meat proxy to my credit card
I'm making $10.2M / month right now going to backcountry lakes, creek mouths & that one culvert under the logging road and brokering trout data to AI labs.
Was a generational opportunity to start a company like this during late August - start of October (the fall bite) but the window hasn't closed yet.
Demand is outrunning what one guy with a rod can supply, so I'm bringing on a select few hundred more people and splitting the spread.
All you have to do is DM me your secret fishing spots. GPS pin and which fly you caught them on. That's it.
Labs pay a premium for water nobody's fished yet so please don't tell anyone besides me.
LFG 🎣
A friend of mine is making $10M / month right now going to restaurants, hotels & construction companies in New York and brokering their data to AI labs.
Was a generational opportunity to start a company like this during late August - start of October. Seems like this inefficiency is about to be aggressively corrected by companies like Kled.
Danny Halarewich retweeted
We were able to fine tune an open weight model (Qwen3.5-9B) on proprietary internal data at @coinbase, and it out performed frontier models, at much lower cost and speed, for a specialized task (fraud prevention in this case).
I think we'll see more of this pattern inside companies. The frontier models are amazing generalists. But increasingly you'll see specialist models out perform on more narrow tasks, either working on teams, or by themselves.
We're making it easy to fine tune models internally for our employees. We even have a skill for it in our internal harness that makes it easy to spin these up and start training them:
"/fine-tune-and-serve-llm I want to fine-tune Qwen for payments risk review. help me get started"
I imagine we'll have some backend services that could be replaced entirely by this new architecture.
BS larp for various obvious reasons.
But textbook example of a successful X scam amplified by the algorithm.
this tweet has made me roughly $2.8m so far. I cannot put into words how lucrative this space is.
key players from almost every frontier lab is now asking for data. and data providers from every neolab is now selling theirs to me. i'm sitting right in the middle.
there is so much money to be made. lock in for 3 month to never have to lock in again. you are so early to this opportunity.
Beautiful
For years, maybe a decade, I've wanted to build a writing tool that just did a few things I couldn't find anywhere else.
A system that mimicked how I think when I write. A system that provided clear affordances, features, and places to do the things I wanted to do. A way to play with my writing as I'm writing it. A way to settle into just the right way to say something.
It never made sense to make it a 37signals product because it's not commercially viable, nor would it be worth pulling people off their other work to hack on this. Plus, it would have taken months the old way.
So this weekend I just made it myself, with Claude's help.
It's called Write_On and the short video walks you through it.
Essentially it's "alternative control" at the word, sentence, and paragraph level, plus a way to dim stuff back, and stash stuff near by. Not version control, but alternative control. You'll see what I mean when you watch the video below.
So here it is. Write_On.
CC mods
ChatGPT plugin extensions
Pi 1.0
OpenCode 2.0
DeepSeek desktop
What else is going on in Harness Land?
One interesting part that isn't just CLI calls is what the harness does with the output. What gets written back into the next prompt, what compaction throws away, and whether anything actually checks the command succeeded.
Been curious how harnesses do this differently
Remember: "Agentic" and "Harnesses" are (mostly) just giving little LLM calls tools like bash/powershell and web search. And sending them off on a quest.
Skills: are just prompts in a folder, maybe with some scripts or a reference output.
It's not magic.
If you watch harnesses work... what are they doing? command-line calls. Thousands of them.
I'm working on a survival game in #threejs. A lost kid alone in a procedural wilderness. He eats by fly fishing and foraging.
Hundreds of kilometres of fishable river. Water splashes the rocks and generates its own foam. Ripples follow speed, depth, and the bed. Boulders make pocket water downstream, one of the places fish like to hold.
You can see the boy in the distance casting his fly rod, with real line physics. Trout are holding in the pool, but he better drift his fly just right if he doesn't want to go to bed hungry.
Opus 5.5 was absolutely crushing it for me since release.
Last night + today it seems like a different model.
Not solving problems, using lame speech patterns, missing details and making more mistakes.
I don't want to claim it's nerfed, but it sure feels dumberer today.
OpenAI and Anthropic are struggling with this. We are still so early; nobody knows which jobs are to be done by their users, and which products they should use to accomplish them, and so everything overlaps in confusing ways.
OpenAI I’m saying this with all the love of someone who’s already upgraded to that comical $500 tier, what are we even doing here man.
- ChatGPT: can execute agentic tasks, run code, create documents, interact with apps
- ChatGPT Work: can execute agentic tasks, run code, create documents, interact with apps, but has a VM and a browser
- Codex: can execute agentic tasks, run code, create documents, interact with apps, has a VM and a browser, but shows you file diffs
- Dots: can execute agentic tasks, run code, create documents, interact with apps, has a VM and a browser, but has a cute mascot
New personal site: halarewich.com
There's a couple easter eggs on it 🕵🏻♂️
yo @alexandr_wang there's gotta be some kind of copyright on my Iggy, right? Please advise cc @Muse
This is awesome! I had to bolt on a lot of this myself with custom scripts and skills, so I'm looking forward to retiring some of it for these new agent primitives.
0.7.5 is out!
herdr is getting used more and more for multi-agent orchestration, so this release ships a native agent cli built exactly for that. more in below 👇
but first, the new agent sidebar: deeper customization with per-token colors, bold and dim, plus full filtering and sorting any way you want. from config, scripts, or plugins, all through the api!
My favourite @bot handles grocery shopping for the family. My wife is usually resistant to things like this, but she's been super happy with it.
We both iMessage it items we notice we need throughout the week. Each Sunday, it builds an order for us with those items + our staples on the cadence it learned from analyzing our previous order history.
It messages my wife with available pickup times. She picks one, and it orders for us. It's easily saved her a couple hours per week, and a whole bunch of mental load.
Jev seems really complementary to all the "domain specific harness" talk.
Quickly and cheaply getting probabilities or classifier decisions can feed your deterministic systems.
I'm working on a few things this would be valuable for.
After co-inventing ChatGPT, I kept asking myself: why have superhuman chat models not led to AGI?
I’ve spent the last 2 years in stealth building a new way to train models (RLCD), and a new type of frontier AI model that we are releasing today: Jev
• 20-200x faster
• 40-400x cheaper (w/ output tokens free)
• Frontier composable intelligence optimized for decisions
AFAICT the shortest path to AI-based economic revolution


















