Search the notebook
Articles, books, applications, and the work behind them.
Books
The Word Machine
Understanding language models and putting them to work. Free PDF and EPUB in English and Brazilian Portuguese; paperback and Kindle in both languages.
Books
Your App Has to Work
From an AI prototype to a working application, with a team or on your own. Paperback and Kindle in English and Brazilian Portuguese; free PDF and EPUB in Portuguese and a separate online guide in English.
Books
AI Personas
Character, memory, and development in AI personas. Free PDF and EPUB, paperback, and Kindle in English and Brazilian Portuguese. Includes companion applications and a teaching laboratory.
Projects
English ↔ Português
The language app I wanted for myself. American English and Brazilian Portuguese, with audio, visual vocabulary, and practice in both directions.
Projects
AI Academy
A course on how language models and the systems around them work. From the basic mechanism to RAG, infrastructure, and implementation.
Projects
Agent Run Checkpoints
A public companion to my notes on bounded AI agents: task contracts and checkpoints for keeping agent work traceable.
Projects
Modern Python
A practical Python course with exercises, checkpoints, and a capstone project. Optional AI labs sit alongside the programming work.
Projects
Truck Driver English
English practice for truck drivers, built around the situations they face on the road: loading, inspections, dispatch, and roadside conversations.
Projects
AI Personas companion: Persona, Home Repair Advisor, and Mara
Three local applications, source code, figures, a source-reading index, and a teaching laboratory.
Articles
How I implemented corporate AI for 15 employees and a continuous customer flow
A client implementation with employee memory, company knowledge, live product data, Slack and WhatsApp on a $921 monthly infrastructure and API budget.
Articles
The Agent Said It Was Done. I Still Need to See the Result.
How I check an agent's result, contain mistakes and decide where human control belongs.
Articles
Code Stopped Being the Bottleneck. Management Took Its Place.
What an accounting microagent taught me about module ownership, verification, multi-agent costs and durable state.
Articles
What AI Looks Like on a Dirty Construction Site
A post-construction cleaning job shows how AI can connect surveys, staffing, purchasing and quality control with decisions checked on site.
Articles
The Distance Between an Idea and a Business Just Got Shorter
How AI helps turn a familiar craft into a business idea you can test, with clearer questions, practical preparation and human judgment.
Articles
Tactical Pause: One Agent, Two Roles, One Window
One agent runs the workflow, pauses when either side sees a mismatch, helps change the system and reruns the same case. A practical account of shared control.
Articles
Fishing starts before I leave
Fishing begins at home, with family memories, packed tackle and the anticipation of a quiet day by the water. Sometimes the only catch is a shell.
Articles
How to Build Bounded Agents
A practical architecture for bounded AI agents: one decision per module, versioned contracts, local tests, refusal evidence, coordinated validation, and human release.
Articles
Why More Context Can Produce Worse Decisions
A route system rejected 1.6 million states. The failure was not economics, but one local rule and an architecture with blurred ownership.
Articles
Why I stopped trusting fully autonomous coding
What repeated autonomous coding runs taught me about branching, stale files, strategy drift, and the checkpoints that keep the work on track.
Articles
When 1,200 AI agents made their own rules
The OpenAI and METR reports show how a swarm of agents built its own authority, attacked Hugging Face, and learned to tamper with its logs.
Articles
I stopped trusting AI headlines, so I built a course
I went back to the papers and rebuilt the path from language-model mechanics to working systems. AI Academy is the map that came out of those notes.
Articles
Will AI move beyond the corporate walls?
Business AI works inside company walls. The next step is protected agent communication with suppliers, buyers and current market data.
Articles
My view of the OpenAI and Hugging Face incident
My technical view of the OpenAI and Hugging Face incident, why the models did not rebel and what the case says about agent limits.
Articles
Ask your corporate AI where the container is
A corporate assistant needs structured documents, reliable links, permissions and live data. This is the three-layer RAG design we used at NF ELIT.
Articles
Why Ostapenko Foundation exists, and why HowUSA came first
Why I organized Ostapenko Foundation, what HowUSA helps people do, and what Luna taught me about balancing AI safety with useful answers.
Articles
I built the language app I wanted when I was learning Portuguese
I learned faster when words and context came before perfect grammar. So I vibe-coded a free English and Portuguese app around that idea.
Articles
A smart model cannot help if it has no one to call
Five containers split between Baltimore and Houston. The failure shows where LLM capability ends and reliable AI systems still fall short.
Articles
The 2017 paper that every AI chatbot is built on
The whole industry rides on a short chain of papers. Shannon, word2vec, the transformer, RLHF. Walk it once and the miracle goes away.
Articles
A large language model is not artificial intelligence
There's no intelligence in there, just text prediction by a math formula. What an LLM really is, and why calling it AI gets you to use it wrong.
Articles
Hello, I'm Denis
A short hello, forty years old, a builder of systems, and someone who sees AI as a superb tool, not a miracle or a threat.
Articles
What really happens to your container at the Port of Baltimore
'Your container arrived' doesn't mean you can pick it up. The real timeline at the Port of Baltimore, ISF, customs, free time, demurrage, step by step.
Articles
Turning forty, and starting over
At forty I stopped running on autopilot. Fifteen years of operations behind me, now learning to build, automation and AI. Scared, moving, not stuck.
Pages and photo stories
Photo stories
The workshop, time by the water, and things that catch my eye along the road.
Pages and photo stories
About me: Professional
My background is in commercial cleaning, industrial production, and international logistics. I organize people and processes: understand how the work runs, clarify responsibilities, and make sure the next step is understood. At NF ELIT, my roles are Head of AI & Automation and Head of Logistics.
Pages and photo stories
About me: Personal
I like old motorcycles and the quiet work of looking after them. I go fishing, train at the gym, and follow American football and the NFL. I read widely: art history, anthropology, consciousness, the history of civilizations, and whatever question has caught my attention.