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Author Founder / CEO
Marcin Ostrowski

Marcin Ostrowski

Kept hiring the same people at every company he built, then stopped pretending that was a coincidence and made it a company. fryga is the band he always wanted: small, handpicked, no bench. Too many ideas on a normal day, the anchor when something's on fire. Answers for the result, not the scope of the task. Writes about AI-assisted coding at rubyonai.com. Mentors at 42 Warsaw.

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Articles by Marcin · 6
Marcin Ostrowski · Apr 17, 2026

You need an AI brain.

Your agent is only as good as the context it can reach. How I turned markdown files in a git repository into one brain my agents and I both read and write — across clients, initiatives, decisions, and research.

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Marcin Ostrowski · Mar 20, 2026

My Harness: How I stopped babysitting AI and went kitesurfing.

I built a system that builds the system. 4 hours from idea to production. Here's my full AI coding workflow for Rails.

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Marcin Ostrowski · Feb 11, 2026

Your AI has no memory. Your Rails codebase does.

AI wakes up every session like Leonard in Memento — no memory, trusting only the tattoos. Your conventions are those tattoos. Here are the Rails rules I'd ink first: business logic in models, boring controllers, views that contain the mess.

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Marcin Ostrowski · Feb 3, 2026

How do you know the software is working?

You don’t know software works because you read it. You know it works because automated checks, strict constraints, and structured review make it hard for it to fail silently.

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Marcin Ostrowski · Jan 27, 2026

The single most important thing that made me believe AI coding could work

AI coding didn’t start working when prompts improved, but when rules became enforceable. Loading and applying coding conventions upfront fundamentally changed how reliable AI-generated code was.

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Marcin Ostrowski · Nov 12, 2025

How I learned to brainstorm effectively with AI: A structured approach using Claude

Brainstorm effectively with AI using a structured approach. Learn how with Claude you can turn unstructured chat into a focused, collaborative process for designing ideas, products, and code

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fryga.io
fryga — a product engineering consultancy in Kraków, Poland. We build with companies in Spain, Norway, the US, and beyond.
Marcin writes about Rails and AI at rubyonai.com
Rails conventions in the open at github.com/marostr/superpowers-rails
We're four people — maybe five: careers
[email protected]
RubyPL sp. z o. o.; ul. Będzińska 5 /8, 31-403 Kraków, Poland; KRS: 0001044822; NIP: 6762646011; REGON: 52575800600000